#include "spl_sema.h"
#include "spl_type.h"

void spl_scope_init(spl_scope_t *scope) {
    vec_init(scope->scopes);
    vec_push(scope->scopes, (spl_scope_node_t){0});
    scope->current_scope = 0;
    scope->root_scope = 0;
}

void spl_scope_drop(spl_scope_t *scope) {
    for (usize i = 0; i < vec_size(scope->scopes); ++i) {
        map_free(vec_at(scope->scopes, i).symbols);
    }
    vec_free(scope->scopes);
    scope->current_scope = 0;
    scope->root_scope = 0;
}

spl_scope_id_t spl_scope_alloc(spl_scope_t *scope) {
    spl_scope_node_t n = {0};
    n.parent = scope->current_scope;
    map_init(n.symbols, MAP_HASH_STR, MAP_CMP_STR);
    vec_push(scope->scopes, n);
    return vec_size(scope->scopes) - 1;
}

bool spl_scope_insert(spl_scope_t *scope, spl_scope_id_t id, spl_symbol_t symbol) {
    if (!id || id >= vec_size(scope->scopes)) {
        LOG_FATAL("sema scope insert error");
        return false;
    }
    spl_scope_node_t *node = &vec_at(scope->scopes, id);
    spl_symbol_t old = {0};
    if (map_get(node->symbols, symbol.name, &old)) {
        SPL_ERROR(&(spl_dbg_node_t){0}, "duplicate symbol `%s`", symbol.name);
        return false;
    }
    map_put(node->symbols, symbol.name, symbol);
    return true;
}

bool spl_scope_find(spl_scope_t *scope, const char *name, spl_symbol_t *out) {
    if (!scope || !name || !out)
        return false;
    for (spl_scope_id_t id = scope->current_scope; id != 0; id = vec_at(scope->scopes, id).parent) {
        spl_scope_node_t *s = &vec_at(scope->scopes, id);
        if (map_get(s->symbols, name, out)) {
            return true;
        }
    }
    return false;
}

static inline void sema_push_scope(spl_sema_t *sema) {
    spl_scope_id_t new_scope = spl_scope_alloc(sema->scope);
    sema->store_scope = sema->scope->current_scope;
    sema->scope->current_scope = new_scope;
}

static inline void sema_pop_scope(spl_sema_t *sema) {
    sema->scope->current_scope = sema->store_scope;
}

static spl_lang_type_id_t sema_for_elem_type(spl_sema_t *sema, spl_lang_type_id_t lang_tid) {
    spl_lang_type_node_t *n = spl_lang_type_node(sema->type, lang_tid);
    if (!n)
        return 0;
    switch (n->kind) {
    case SPL_LANG_TYPE_ARRAY:
    case SPL_LANG_TYPE_SLICE:
    case SPL_LANG_TYPE_RANGE:
    case SPL_LANG_TYPE_PTR:
        return n->extra.elem;
    default:
        return 0;
    }
}

static void sema_collect(spl_sema_t *sema, spl_ast_node_ref_t ref) {
    spl_ast_node_t *n = spl_ast_node(sema->ast, ref);
    if (!n)
        return;

    switch (n->kind) {
    case SPL_AST_CONTAINER_MEMBERS: {
        /* root_scope 只在第一次创建，后续 module 复用 */
        if (sema->scope->root_scope == 0) {
            spl_scope_id_t root = spl_scope_alloc(sema->scope);
            sema->scope->root_scope = root;
        }

        /* 进入 root_scope，再为当前 module 开一个子 scope */
        sema->scope->current_scope = sema->scope->root_scope;
        spl_scope_id_t mod_scope = spl_scope_alloc(sema->scope);
        sema->scope->current_scope = mod_scope;

        spl_symbol_t file_sym = {.name = "$file", .kind = SPL_SYMBOL_KIND_TYPE};
        file_sym.node = spl_def_alloc(sema->type, SPL_DEF_AGG, "$file", n->dbg, ref);
        n->resolved_def_id = file_sym.node;
        spl_scope_insert(sema->scope, mod_scope, file_sym);

        for (usize i = 0; i < vec_size(n->container_members.declarations); ++i) {
            sema_collect(sema, vec_at(n->container_members.declarations, i));
        }

        /* 故意不恢复 current_scope
           保持 mod_scope 交给随后的 sema_parse 使用。
           恢复由 spl_sema_run_module 统一负责 */
        break;
    }
    case SPL_AST_TYPE_DECL: {
        spl_symbol_t sym = {.name = n->type_decl.name, .kind = SPL_SYMBOL_KIND_TYPE};
        spl_ast_node_t *te = spl_ast_node(sema->ast, n->type_decl.type_expr);
        if (!te) {
            SPL_ERROR(&n->dbg, "type declaration `%s` missing type expression", n->type_decl.name);
            sema->error_count++;
            return;
        }

        if (te->kind == SPL_AST_TYPE_AGGREGATE) {
            sym.node = spl_def_alloc(sema->type, SPL_DEF_AGG, sym.name, te->dbg, ref);
            n->resolved_def_id = sym.node;
            spl_scope_insert(sema->scope, sema->scope->current_scope, sym);

            spl_scope_id_t old_scope = sema->scope->current_scope;
            spl_scope_id_t inner_scope = spl_scope_alloc(sema->scope);
            sema->scope->current_scope = inner_scope;

            for (usize i = 0; i < vec_size(te->type_aggregate.members); ++i) {
                sema_collect(sema, vec_at(te->type_aggregate.members, i));
            }
            sema->scope->current_scope = old_scope;
        } else {
            sym.node = spl_def_alloc(sema->type, SPL_DEF_SCALAR, sym.name, te->dbg, ref);
            n->resolved_def_id = sym.node;
            spl_scope_insert(sema->scope, sema->scope->current_scope, sym);
        }
        break;
    }
    case SPL_AST_FN_DECL: {
        spl_symbol_t sym = {.name = n->fn_decl.name, .kind = SPL_SYMBOL_KIND_FN};
        sym.node = spl_def_alloc(sema->type, SPL_DEF_FN, sym.name, n->dbg, ref);
        n->resolved_def_id = sym.node;
        spl_scope_insert(sema->scope, sema->scope->current_scope, sym);
        break;
    }
    case SPL_AST_VAR_DECL:
    case SPL_AST_CONST_DECL: {
        spl_ast_node_t *pat = spl_ast_node(sema->ast, n->var_const_decl.pattern);
        if (pat && pat->kind == SPL_AST_PATTERN_IDENT) {
            const char *name = pat->pattern_ident.name;
            spl_symbol_t sym = {.name = name, .kind = SPL_SYMBOL_KIND_VAR};
            sym.node = spl_def_alloc(sema->type, SPL_DEF_VAR, name, n->dbg, ref);
            n->resolved_def_id = sym.node;
            spl_scope_insert(sema->scope, sema->scope->current_scope, sym);
        } else {
            SPL_ERROR(&n->dbg, "unsupported variable pattern (only simple identifier)");
            sema->error_count++;
        }
        break;
    }
    case SPL_AST_TOP_LEVEL_BLOCK:
        if (n->top_level_block.block) {
            sema_collect(sema, n->top_level_block.block);
        }
        break;
    default:
        break;
    }
}

static spl_lang_type_id_t sema_parse(spl_sema_t *sema, spl_ast_node_ref_t ref) {
    if (ref == 0)
        return 0;
    spl_ast_node_t *n = spl_ast_node(sema->ast, ref);
    if (!n)
        return 0;

    switch (n->kind) {
    case SPL_AST_CONTAINER_MEMBERS:
        for (usize i = 0; i < vec_size(n->container_members.declarations); ++i) {
            sema_parse(sema, vec_at(n->container_members.declarations, i));
        }
        return 0;

    case SPL_AST_FN_DECL: {
        if (n->resolved_def_id == 0) {
            Panic("fn `%s` not collected", n->fn_decl.name);
        }

        spl_lang_type_id_vec_t param_types;
        vec_init(param_types);
        for (usize i = 0; i < vec_size(n->fn_decl.params); ++i) {
            spl_ast_node_t *pd = spl_ast_node(sema->ast, vec_at(n->fn_decl.params, i));
            if (pd && pd->kind == SPL_AST_PARAM_DECL && pd->param_decl.type_expr) {
                vec_push(param_types, sema_parse(sema, pd->param_decl.type_expr));
            } else {
                vec_push(param_types, spl_lang_make_varargs(sema->type));
            }
        }
        spl_lang_type_id_t ret_tid = sema_parse(sema, n->fn_decl.ret_type);
        if (ret_tid == 0) {
            ret_tid = spl_lang_make_unit(sema->type);
        }
        spl_lang_type_id_t fn_tid = spl_lang_make_fn(
            sema->type, ret_tid, vec_unsafe_get_data(param_types), vec_size(param_types));
        Assert(fn_tid != 0);
        vec_free(param_types);
        spl_def_resolve(sema->type, n->resolved_def_id, fn_tid);

        if (n->fn_decl.body) {
            sema_push_scope(sema);
            for (usize i = 0; i < vec_size(n->fn_decl.params); ++i) {
                spl_ast_node_t *pd = spl_ast_node(sema->ast, vec_at(n->fn_decl.params, i));
                if (pd && pd->kind == SPL_AST_PARAM_DECL) {
                    spl_symbol_t psym = {.name = pd->param_decl.name, .kind = SPL_SYMBOL_KIND_VAR};
                    psym.node = spl_def_alloc(sema->type, SPL_DEF_VAR, psym.name, pd->dbg,
                                              vec_at(n->fn_decl.params, i));
                    spl_lang_type_id_t p_tid = sema_parse(sema, pd->param_decl.type_expr);
                    spl_def_resolve(sema->type, psym.node, p_tid);
                    pd->resolved_def_id = psym.node;
                    spl_scope_insert(sema->scope, sema->scope->current_scope, psym);
                }
            }
            spl_lang_type_id_t old_ret = sema->current_fn_ret_tid;
            sema->current_fn_ret_tid = ret_tid;
            sema_parse(sema, n->fn_decl.body);
            sema->current_fn_ret_tid = old_ret;
            sema_pop_scope(sema);
        }
        return fn_tid;
    }

    case SPL_AST_TYPE_DECL: {
        if (!n->type_decl.type_expr)
            break;
        spl_ast_node_t *te = spl_ast_node(sema->ast, n->type_decl.type_expr);
        if (!te)
            break;

        if (te->kind == SPL_AST_TYPE_AGGREGATE) {
            spl_type_member_vec_t members;
            vec_init(members);
            for (usize i = 0; i < vec_size(te->type_aggregate.members); ++i) {
                spl_ast_node_t *mn = spl_ast_node(sema->ast, vec_at(te->type_aggregate.members, i));
                if (mn && mn->kind == SPL_AST_MEMBER_DECL) {
                    spl_lang_type_id_t mtid = sema_parse(sema, mn->member_decl.type_expr);
                    spl_type_member_t m = {.name = mn->member_decl.name,
                                           .type_id = spl_lang_type_get_ir_type(sema->type, mtid),
                                           .ast_node_ref = vec_at(te->type_aggregate.members, i)};
                    vec_push(members, m);
                }
            }

            spl_type_node_kind_t tk;
            if (strcmp(te->type_aggregate.kind_name, "struct") == 0)
                tk = SPL_TYPE_STRUCT;
            else if (strcmp(te->type_aggregate.kind_name, "union") == 0)
                tk = SPL_TYPE_UNION;
            else if (strcmp(te->type_aggregate.kind_name, "enum") == 0)
                tk = SPL_TYPE_ENUM;
            else
                tk = SPL_TYPE_STRUCT;

            spl_type_layout_t layout = {.mode = SPL_TYPE_LAYOUT_AUTO};
            spl_type_id_t agg_ir = spl_type_builder_agg(
                sema->type, tk, &members, spl_type_builder_int(sema->type, 32, 1), layout);
            vec_free(members);

            // 创建语言级节点
            spl_lang_type_node_t lang_node = {0};
            switch (tk) {
            case SPL_TYPE_STRUCT:
                lang_node.kind = SPL_LANG_TYPE_STRUCT;
                break;
            case SPL_TYPE_UNION:
                lang_node.kind = SPL_LANG_TYPE_UNION;
                break;
            case SPL_TYPE_ENUM:
                lang_node.kind = SPL_LANG_TYPE_ENUM;
                break;
            case SPL_TYPE_SHAPE:
                lang_node.kind = SPL_LANG_TYPE_SHAPE;
                break;
            default:
                break;
            }
            lang_node.ir_type_id = agg_ir;
            vec_push(sema->type->lang_table, lang_node);
            spl_lang_type_id_t agg_lang = vec_size(sema->type->lang_table) - 1;
            spl_def_resolve(sema->type, n->resolved_def_id, agg_lang);
            n->resolved_type_id = agg_lang; // 存储 lang_id

            // 处理聚合内部的函数声明
            for (usize i = 0; i < vec_size(te->type_aggregate.members); ++i) {
                spl_ast_node_t *mn = spl_ast_node(sema->ast, vec_at(te->type_aggregate.members, i));
                if (mn && mn->kind == SPL_AST_FN_DECL) {
                    sema_parse(sema, vec_at(te->type_aggregate.members, i));
                }
            }
        } else {
            spl_lang_type_id_t tid = sema_parse(sema, n->type_decl.type_expr);
            spl_def_resolve(sema->type, n->resolved_def_id, tid);
            n->resolved_type_id = tid; // 存储 lang_id
        }
        break;
    }

    case SPL_AST_VAR_DECL:
    case SPL_AST_CONST_DECL: {
        spl_ast_node_t *pat = spl_ast_node(sema->ast, n->var_const_decl.pattern);
        if (!pat || pat->kind != SPL_AST_PATTERN_IDENT) {
            SPL_ERROR(&n->dbg, "unsupported variable pattern");
            sema->error_count++;
            return 0;
        }
        const char *name = pat->pattern_ident.name;

        if (n->resolved_def_id == 0) {
            spl_symbol_t sym = {.name = name, .kind = SPL_SYMBOL_KIND_VAR};
            sym.node = spl_def_alloc(sema->type, SPL_DEF_VAR, name, n->dbg, ref);
            n->resolved_def_id = sym.node;
            spl_scope_insert(sema->scope, sema->scope->current_scope, sym);
        }

        spl_lang_type_id_t decl_tid;
        if (n->var_const_decl.type) {
            decl_tid = sema_parse(sema, n->var_const_decl.type);
        } else {
            decl_tid = spl_lang_make_infer(sema->type);
        }
        if (n->var_const_decl.init_expr == 0) {
            SPL_ERROR(&n->dbg, "variable `%s` must be initialized", name);
            sema->error_count++;
            return 0;
        }

        spl_ast_node_t *init_node = spl_ast_node(sema->ast, n->var_const_decl.init_expr);
        spl_lang_type_id_t init_tid = sema_parse(sema, n->var_const_decl.init_expr);
        spl_lang_type_id_t coerce_result = spl_lang_type_coerce_to(sema->type, decl_tid, init_tid);
        if (coerce_result == 0) {
            SPL_ERROR(&n->dbg, "cannot coerce initializer to declared type");
            sema->error_count++;
            return 0;
        }
        init_node->resolved_type_id = coerce_result;
        decl_tid = coerce_result;

        spl_def_resolve(sema->type, n->resolved_def_id, decl_tid);
        n->resolved_type_id = decl_tid;
        return decl_tid;
    }

    case SPL_AST_MEMBER_DECL: {
        if (n->member_decl.type_expr) {
            return sema_parse(sema, n->member_decl.type_expr);
        }
        return 0;
    }

    case SPL_AST_PARAM_DECL: {
        if (n->param_decl.type_expr) {
            return sema_parse(sema, n->param_decl.type_expr);
        }
        return 0;
    }

    case SPL_AST_EXPR_INT_LIT: {
        spl_lang_type_id_t ct = spl_lang_make_int(sema->type, 0, 1);
        n->resolved_type_id = ct;
        return ct;
    }
    case SPL_AST_EXPR_FLOAT_LIT: {
        spl_lang_type_id_t ct = spl_lang_make_float(sema->type, 0);
        n->resolved_type_id = ct;
        return ct;
    }
    case SPL_AST_EXPR_CHAR_LIT: {
        spl_lang_type_id_t u8 = spl_lang_make_int(sema->type, 8, 0);
        n->resolved_type_id = u8;
        return u8;
    }
    case SPL_AST_EXPR_STRING_LIT: {
        spl_lang_type_id_t u8 = spl_lang_make_int(sema->type, 8, 0);
        spl_lang_type_id_t slice = spl_lang_make_slice(sema->type, u8);
        n->resolved_type_id = slice;
        return slice;
    }
    case SPL_AST_EXPR_BOOL_LIT: {
        spl_lang_type_id_t bt = spl_lang_make_bool(sema->type);
        n->resolved_type_id = bt;
        return bt;
    }
    case SPL_AST_EXPR_NULL_LIT: {
        spl_lang_type_id_t never = spl_lang_make_never(sema->type);
        spl_lang_type_id_t ptr = spl_lang_make_ptr(sema->type, never);
        n->resolved_type_id = ptr;
        return ptr;
    }
    case SPL_AST_EXPR_UNDEFINED_LIT: {
        spl_lang_type_id_t t = spl_lang_make_never(sema->type);
        n->resolved_type_id = t;
        return t;
    }
    case SPL_AST_EXPR_IDENT: {
        const char *name = n->ident.name;
        spl_symbol_t sym;
        if (!spl_scope_find(sema->scope, name, &sym)) {
            SPL_ERROR(&n->dbg, "undefined identifier `%s`", name);
            sema->error_count++;
            return 0;
        }
        if (sym.node == 0) {
            SPL_ERROR(&n->dbg, "identifier `%s` has no definition", name);
            sema->error_count++;
            return 0;
        }
        n->resolved_def_id = sym.node;
        spl_def_node_t *def = spl_def_node(sema->type, sym.node);
        if (!def) {
            SPL_ERROR(&n->dbg, "definition for `%s` not found", name);
            sema->error_count++;
            return 0;
        }
        n->resolved_type_id = def->lang_id;
        return def->lang_id;
    }

    case SPL_AST_EXPR_UNARY: {
        spl_lang_type_id_t operand_tid = sema_parse(sema, n->unary.operand);
        if (operand_tid == 0)
            return 0;
        spl_lang_type_node_t *tn = spl_lang_type_node(sema->type, operand_tid);
        if (!tn)
            return 0;

        switch (n->unary.op) {
        case SPL_UNARY_OP_MINUS:
            if (tn->kind != SPL_LANG_TYPE_INT && tn->kind != SPL_LANG_TYPE_FLOAT) {
                SPL_ERROR(&n->dbg, "unary minus requires numeric operand");
                sema->error_count++;
                return 0;
            }
            n->resolved_type_id = operand_tid;
            return operand_tid;
        case SPL_UNARY_OP_NOT:
            if (tn->kind != SPL_LANG_TYPE_BOOL) {
                SPL_ERROR(&n->dbg, "logical not requires bool operand");
                sema->error_count++;
                return 0;
            }
            {
                spl_lang_type_id_t bt = spl_lang_make_bool(sema->type);
                n->resolved_type_id = bt;
                return bt;
            }
        case SPL_UNARY_OP_BIT_NOT:
            if (tn->kind != SPL_LANG_TYPE_INT) {
                SPL_ERROR(&n->dbg, "bitwise not requires integer operand");
                sema->error_count++;
                return 0;
            }
            n->resolved_type_id = operand_tid;
            return operand_tid;
        case SPL_UNARY_OP_ADDRESS: {
            spl_lang_type_id_t ptr_tid = spl_lang_make_ptr(sema->type, operand_tid);
            n->resolved_type_id = ptr_tid;
            return ptr_tid;
        }
        default:
            UNREACHABLE();
        }
        break;
    }

    case SPL_AST_EXPR_BINARY: {
        spl_lang_type_id_t lt = sema_parse(sema, n->binary.left);
        spl_lang_type_id_t rt = sema_parse(sema, n->binary.right);
        spl_binary_op_t op = n->binary.op;

        switch (op) {
        case SPL_OP_ASSIGN: {
            spl_ast_node_t *rhs = spl_ast_node(sema->ast, n->binary.right);
            spl_lang_type_id_t r = spl_lang_type_coerce_to(sema->type, lt, rt);
            if (r == 0) {
                SPL_ERROR(&n->dbg, "assignment type mismatch");
                sema->error_count++;
                return 0;
            }
            rhs->resolved_type_id = r;
            n->resolved_type_id = lt;
            return lt;
        }

        case SPL_OP_ASSIGN_ADD:
        case SPL_OP_ASSIGN_SUB:
        case SPL_OP_ASSIGN_MUL:
        case SPL_OP_ASSIGN_DIV:
        case SPL_OP_ASSIGN_MOD:
        case SPL_OP_ASSIGN_AND:
        case SPL_OP_ASSIGN_OR:
        case SPL_OP_ASSIGN_XOR:
        case SPL_OP_ASSIGN_LSHIFT:
        case SPL_OP_ASSIGN_RSHIFT: {
            spl_lang_type_id_t balanced = spl_lang_type_balance(sema->type, lt, rt);
            if (balanced == 0 || balanced != lt) {
                SPL_ERROR(&n->dbg, "compound assignment type mismatch");
                sema->error_count++;
                return 0;
            }
            spl_ast_node_t *rhs = spl_ast_node(sema->ast, n->binary.right);
            spl_lang_type_id_t r = spl_lang_type_coerce_to(sema->type, lt, rt);
            if (r == 0) {
                SPL_ERROR(&n->dbg, "compound assignment right type mismatch");
                sema->error_count++;
                return 0;
            }
            rhs->resolved_type_id = r;
            n->resolved_type_id = lt;
            return lt;
        }

        case SPL_OP_BOOL_OR:
        case SPL_OP_BOOL_AND: {
            spl_lang_type_node_t *ln = spl_lang_type_node(sema->type, lt);
            spl_lang_type_node_t *rn = spl_lang_type_node(sema->type, rt);
            if (!ln || ln->kind != SPL_LANG_TYPE_BOOL || !rn || rn->kind != SPL_LANG_TYPE_BOOL) {
                SPL_ERROR(&n->dbg, "logical operands must be bool");
                sema->error_count++;
                return 0;
            }
            spl_lang_type_id_t bt = spl_lang_make_bool(sema->type);
            n->resolved_type_id = bt;
            return bt;
        }

        case SPL_OP_BIT_OR:
        case SPL_OP_BIT_XOR:
        case SPL_OP_BIT_AND: {
            spl_lang_type_id_t bal = spl_lang_type_balance(sema->type, lt, rt);
            spl_lang_type_node_t *bn = spl_lang_type_node(sema->type, bal);
            if (!bn || bn->kind != SPL_LANG_TYPE_INT) {
                SPL_ERROR(&n->dbg, "bitwise operands must be integers");
                sema->error_count++;
                return 0;
            }
            /* 两边都 coerce 到 bal */
            if (lt != bal) {
                spl_ast_node_t *ln = spl_ast_node(sema->ast, n->binary.left);
                ln->resolved_type_id = spl_lang_type_coerce_to(sema->type, bal, lt);
            }
            if (rt != bal) {
                spl_ast_node_t *rn = spl_ast_node(sema->ast, n->binary.right);
                rn->resolved_type_id = spl_lang_type_coerce_to(sema->type, bal, rt);
            }
            n->resolved_type_id = bal;
            return bal;
        }

        case SPL_OP_CMP_EQ:
        case SPL_OP_CMP_NE:
        case SPL_OP_CMP_LE:
        case SPL_OP_CMP_GE:
        case SPL_OP_CMP_LT:
        case SPL_OP_CMP_GT: {
            spl_lang_type_node_t *ln = spl_lang_type_node(sema->type, lt);
            spl_lang_type_node_t *rn = spl_lang_type_node(sema->type, rt);
            bool numeric =
                (ln && (ln->kind == SPL_LANG_TYPE_INT || ln->kind == SPL_LANG_TYPE_FLOAT)) &&
                (rn && (rn->kind == SPL_LANG_TYPE_INT || rn->kind == SPL_LANG_TYPE_FLOAT));
            if (!numeric && spl_lang_type_balance(sema->type, lt, rt) == 0) {
                SPL_ERROR(&n->dbg, "comparison operands type mismatch");
                sema->error_count++;
                return 0;
            }
            spl_lang_type_id_t bt = spl_lang_make_bool(sema->type);
            n->resolved_type_id = bt;
            return bt;
        }

        case SPL_OP_LSHIFT:
        case SPL_OP_RSHIFT: {
            spl_lang_type_node_t *ln = spl_lang_type_node(sema->type, lt);
            spl_lang_type_node_t *rn = spl_lang_type_node(sema->type, rt);
            if (!ln || ln->kind != SPL_LANG_TYPE_INT || !rn || rn->kind != SPL_LANG_TYPE_INT) {
                SPL_ERROR(&n->dbg, "shift operands must be integers");
                sema->error_count++;
                return 0;
            }
            n->resolved_type_id = lt;
            return lt;
        }

        case SPL_OP_ADD:
        case SPL_OP_SUB:
        case SPL_OP_MUL:
        case SPL_OP_DIV:
        case SPL_OP_MOD: {
            spl_lang_type_id_t bal = spl_lang_type_balance(sema->type, lt, rt);
            spl_lang_type_node_t *bn = spl_lang_type_node(sema->type, bal);
            if (!bn || (bn->kind != SPL_LANG_TYPE_INT && bn->kind != SPL_LANG_TYPE_FLOAT)) {
                SPL_ERROR(&n->dbg, "arithmetic operands type mismatch");
                sema->error_count++;
                return 0;
            }
            if (lt != bal) {
                spl_ast_node_t *ln = spl_ast_node(sema->ast, n->binary.left);
                ln->resolved_type_id = spl_lang_type_coerce_to(sema->type, bal, lt);
            }
            if (rt != bal) {
                spl_ast_node_t *rn = spl_ast_node(sema->ast, n->binary.right);
                rn->resolved_type_id = spl_lang_type_coerce_to(sema->type, bal, rt);
            }
            n->resolved_type_id = bal;
            return bal;
        }

        case SPL_OP_RANGE: {
            spl_lang_type_id_t i64 = spl_lang_make_int(sema->type, 64, 1);
            spl_lang_type_id_t range = spl_lang_make_range(sema->type, i64);
            n->resolved_type_id = range;
            return range;
        }

        default:
            break;
        }
        break;
    }

    case SPL_AST_EXPR_CALL: {
        spl_lang_type_id_t callee_tid = sema_parse(sema, n->call.callee);
        spl_lang_type_node_t *fn = spl_lang_type_node(sema->type, callee_tid);
        if (!fn || fn->kind != SPL_LANG_TYPE_FN) {
            SPL_ERROR(&n->dbg, "callee is not a function");
            sema->error_count++;
            return 0;
        }

        // 检查函数是否可变参数：最后一个参数是否为 VARARGS
        bool has_varargs = false;
        usize fixed_param_count = vec_size(fn->extra.fn.params);
        if (fixed_param_count > 0) {
            spl_lang_type_id_t last_param = vec_at(fn->extra.fn.params, fixed_param_count - 1);
            spl_lang_type_node_t *last_node = spl_lang_type_node(sema->type, last_param);
            if (last_node && last_node->kind == SPL_LANG_TYPE_VARARGS) {
                has_varargs = true;
                fixed_param_count--; // 排除 VARARGS 参数
            }
        }

        if (has_varargs) {
            if (vec_size(n->call.args) < fixed_param_count) {
                SPL_ERROR(&n->dbg, "too few arguments (expected at least %zu)", fixed_param_count);
                sema->error_count++;
            } else {
                for (usize i = 0; i < fixed_param_count; ++i) {
                    spl_ast_node_ref_t arg_ref = vec_at(n->call.args, i);
                    spl_ast_node_t *arg_node = spl_ast_node(sema->ast, arg_ref);
                    spl_lang_type_id_t arg_tid = sema_parse(sema, arg_ref);
                    spl_lang_type_id_t param_tid = vec_at(fn->extra.fn.params, i);
                    spl_lang_type_id_t r = spl_lang_type_coerce_to(sema->type, param_tid, arg_tid);
                    if (r == 0) {
                        SPL_ERROR(&n->dbg, "argument %zu type mismatch", i + 1);
                        sema->error_count++;
                    } else {
                        arg_node->resolved_type_id = r;
                    }
                }
            }
        } else {
            if (vec_size(n->call.args) != vec_size(fn->extra.fn.params)) {
                SPL_ERROR(&n->dbg, "argument count mismatch (expected %zu, got %zu)",
                          vec_size(fn->extra.fn.params), vec_size(n->call.args));
                sema->error_count++;
            } else {
                for (usize i = 0; i < vec_size(n->call.args); ++i) {
                    spl_ast_node_ref_t arg_ref = vec_at(n->call.args, i);
                    spl_ast_node_t *arg_node = spl_ast_node(sema->ast, arg_ref);
                    spl_lang_type_id_t arg_tid = sema_parse(sema, arg_ref);
                    spl_lang_type_id_t param_tid = vec_at(fn->extra.fn.params, i);
                    spl_lang_type_id_t r = spl_lang_type_coerce_to(sema->type, param_tid, arg_tid);
                    if (r == 0) {
                        SPL_ERROR(&n->dbg, "argument %zu type mismatch", i + 1);
                        sema->error_count++;
                    } else {
                        arg_node->resolved_type_id = r;
                    }
                }
            }
        }

        spl_lang_type_id_t ret_tid = fn->extra.fn.ret;
        n->resolved_type_id = ret_tid;
        return ret_tid;
    }

    case SPL_AST_EXPR_FIELD: {
        spl_lang_type_id_t obj_tid = sema_parse(sema, n->field.obj);
        spl_lang_type_node_t *obj_node = spl_lang_type_node(sema->type, obj_tid);
        if (!obj_node)
            return 0;

        // 内建字段：数组/切片的 len
        if ((obj_node->kind == SPL_LANG_TYPE_ARRAY || obj_node->kind == SPL_LANG_TYPE_SLICE) &&
            strcmp(n->field.field, "len") == 0) {
            spl_lang_type_id_t usize_tid = spl_lang_make_int(sema->type, sizeof(void *) * 8, 0);
            n->resolved_type_id = usize_tid;
            return usize_tid;
        }

        // 自动解引用
        spl_lang_type_id_t agg_lang = obj_tid;
        if (obj_node->kind == SPL_LANG_TYPE_PTR) {
            agg_lang = obj_node->extra.elem;
        }
        spl_lang_type_node_t *agg_node = spl_lang_type_node(sema->type, agg_lang);
        if (!agg_node ||
            (agg_node->kind != SPL_LANG_TYPE_STRUCT && agg_node->kind != SPL_LANG_TYPE_UNION)) {
            SPL_ERROR(&n->dbg, "field access on non-aggregate type");
            sema->error_count++;
            return 0;
        }
        spl_type_id_t agg_ir = spl_lang_type_get_ir_type(sema->type, agg_lang);
        const spl_type_member_t *member = spl_type_agg_member(sema->type, agg_ir, n->field.field);
        if (!member) {
            SPL_ERROR(&n->dbg, "no field `%s`", n->field.field);
            sema->error_count++;
            return 0;
        }

        // 将底层字段类型映射回语言级类型
        spl_lang_type_id_t field_lang = 0;
        for (usize i = 1; i < vec_size(sema->type->lang_table); ++i) {
            spl_lang_type_node_t *ln = &vec_at(sema->type->lang_table, i);
            if (ln->ir_type_id == member->type_id) {
                field_lang = i;
                break;
            }
        }
        if (!field_lang) {
            SPL_ERROR(&n->dbg, "cannot resolve field type for `%s`", n->field.field);
            sema->error_count++;
            return 0;
        }
        n->resolved_type_id = field_lang;
        return field_lang;
    }

    case SPL_AST_EXPR_INDEX: {
        spl_lang_type_id_t obj_tid = sema_parse(sema, n->index.obj);
        spl_lang_type_id_t idx_tid = sema_parse(sema, n->index.index);
        spl_lang_type_node_t *obj_node = spl_lang_type_node(sema->type, obj_tid);
        if (!obj_node)
            return 0;

        spl_lang_type_id_t elem_lang = 0;
        switch (obj_node->kind) {
        case SPL_LANG_TYPE_ARRAY:
        case SPL_LANG_TYPE_SLICE:
        case SPL_LANG_TYPE_RANGE:
        case SPL_LANG_TYPE_PTR:
            elem_lang = obj_node->extra.elem;
            break;
        case SPL_LANG_TYPE_TUPLE:
            if (vec_size(obj_node->extra.elems) > 0)
                elem_lang = vec_at(obj_node->extra.elems, 0);
            else {
                SPL_ERROR(&n->dbg, "empty tuple");
                sema->error_count++;
                return 0;
            }
            break;
        default:
            SPL_ERROR(&n->dbg, "index base must be array, pointer, slice, or tuple");
            sema->error_count++;
            return 0;
        }
        (void)idx_tid;
        n->resolved_type_id = elem_lang;
        return elem_lang;
    }

    case SPL_AST_EXPR_SLICE: {
        spl_lang_type_id_t obj_tid = sema_parse(sema, n->slice.obj);
        if (n->slice.begin)
            sema_parse(sema, n->slice.begin);
        if (n->slice.end)
            sema_parse(sema, n->slice.end);

        spl_lang_type_node_t *obj_node = spl_lang_type_node(sema->type, obj_tid);
        if (!obj_node)
            return 0;

        spl_lang_type_id_t elem_lang = 0;
        if (obj_node->kind == SPL_LANG_TYPE_ARRAY || obj_node->kind == SPL_LANG_TYPE_PTR ||
            obj_node->kind == SPL_LANG_TYPE_SLICE) {
            elem_lang = obj_node->extra.elem;
        } else {
            SPL_ERROR(&n->dbg, "slice base must be array, pointer, or slice");
            sema->error_count++;
            return 0;
        }

        spl_lang_type_id_t slice_tid = spl_lang_make_slice(sema->type, elem_lang);
        n->resolved_type_id = slice_tid;
        return slice_tid;
    }

    case SPL_AST_EXPR_CAST: {
        spl_lang_type_id_t src_tid = sema_parse(sema, n->cast.expr);
        spl_lang_type_id_t dst_tid = sema_parse(sema, n->cast.type);
        spl_lang_type_node_t *src_node = spl_lang_type_node(sema->type, src_tid);
        if (!src_node)
            return 0;
        if (src_node->kind != SPL_LANG_TYPE_INT && src_node->kind != SPL_LANG_TYPE_FLOAT &&
            src_node->kind != SPL_LANG_TYPE_BOOL) {
            SPL_ERROR(&n->dbg, "invalid cast from non-primitive type");
            sema->error_count++;
            return 0;
        }
        n->resolved_type_id = dst_tid;
        return dst_tid;
    }

    case SPL_AST_EXPR_TUPLE: {
        spl_lang_type_id_vec_t elems;
        vec_init(elems);
        for (usize i = 0; i < vec_size(n->tuple.elems); ++i) {
            vec_push(elems, sema_parse(sema, vec_at(n->tuple.elems, i)));
        }
        spl_lang_type_id_t tuple =
            spl_lang_make_tuple(sema->type, vec_unsafe_get_data(elems), vec_size(elems));
        vec_free(elems);
        n->resolved_type_id = tuple;
        return tuple;
    }

    case SPL_AST_EXPR_ARRAY_LIT: {
        /* elem_type 可空：匿名 .[...] 时从元素推导 */
        spl_lang_type_id_t elem_tid = 0;
        if (n->array_literal.elem_type) {
            elem_tid = sema_parse(sema, n->array_literal.elem_type);
        }

        for (usize i = 0; i < vec_size(n->array_literal.elems); ++i) {
            spl_ast_node_ref_t elem_ref = vec_at(n->array_literal.elems, i);
            spl_ast_node_t *elem_node = spl_ast_node(sema->ast, elem_ref);
            spl_lang_type_id_t et = sema_parse(sema, elem_ref);
            if (elem_tid == 0) {
                elem_tid = et;
            } else {
                spl_lang_type_id_t r = spl_lang_type_coerce_to(sema->type, elem_tid, et);
                if (r == 0) {
                    SPL_ERROR(&n->dbg, "array element type mismatch");
                    sema->error_count++;
                } else {
                    elem_node->resolved_type_id = r;
                }
            }
        }

        if (elem_tid == 0) {
            SPL_ERROR(&n->dbg, "cannot infer array element type "
                               "(empty literal without element type annotation)");
            sema->error_count++;
            return 0;
        }

        usize len;
        if (n->array_literal.is_underscore_len) {
            len = vec_size(n->array_literal.elems);
        } else if (n->array_literal.has_len) {
            len = (usize)n->array_literal.len;
            if (len != vec_size(n->array_literal.elems)) {
                SPL_ERROR(&n->dbg, "array literal length mismatch: declared %zu, got %zu", len,
                          vec_size(n->array_literal.elems));
                sema->error_count++;
            }
        } else {
            len = vec_size(n->array_literal.elems);
        }

        spl_lang_type_id_t arr_tid = spl_lang_make_array(sema->type, elem_tid, len);
        n->resolved_type_id = arr_tid;
        return arr_tid;
    }
    case SPL_AST_EXPR_AGGREGATE_LIT: {
        const char *type_name = n->aggregate_literal.name;

        /* 匿名 .{...}：需要类型上下文。
           SEMA 当前为自底向上，尚无"预期类型"传播机制；
           待上层注解散布到 init_expr 之前时启用。
           结构上已统一，只需在这里读取 n->resolved_type_id 即可。 */
        if (!type_name) {
            SPL_ERROR(&n->dbg, "anonymous aggregate literal requires expected type context "
                               "(not yet supported)");
            sema->error_count++;
            return 0;
        }

        spl_symbol_t sym;
        if (!spl_scope_find(sema->scope, type_name, &sym)) {
            SPL_ERROR(&n->dbg, "unknown type `%s`", type_name);
            sema->error_count++;
            return 0;
        }
        spl_def_node_t *def = spl_def_node(sema->type, sym.node);
        if (!def || !def->lang_id) {
            SPL_ERROR(&n->dbg, "type `%s` not resolved", type_name);
            sema->error_count++;
            return 0;
        }
        spl_lang_type_id_t agg_lang = def->lang_id;
        spl_lang_type_node_t *agg_node = spl_lang_type_node(sema->type, agg_lang);
        if (!agg_node ||
            (agg_node->kind != SPL_LANG_TYPE_STRUCT && agg_node->kind != SPL_LANG_TYPE_UNION)) {
            SPL_ERROR(&n->dbg, "`%s` is not a struct/union", type_name);
            sema->error_count++;
            return 0;
        }

        spl_type_id_t agg_ir = spl_lang_type_get_ir_type(sema->type, agg_lang);
        spl_type_node_t *agg_ir_node = spl_type_node(sema->type, agg_ir);
        if (!agg_ir_node) {
            SPL_ERROR(&n->dbg, "aggregate IR type `%s` not found", type_name);
            sema->error_count++;
            return 0;
        }
        usize total_fields = vec_size(agg_ir_node->agg_type.variants);

        /* 记录每个字段是否被初始化，最后检查缺省 */
        bool *seen = calloc(total_fields, sizeof(bool));
        if (!seen) {
            SPL_ERROR(&n->dbg, "out of memory");
            sema->error_count++;
            return 0;
        }

        for (usize i = 0; i < vec_size(n->aggregate_literal.fields); ++i) {
            spl_ast_node_t *item = spl_ast_node(sema->ast, vec_at(n->aggregate_literal.fields, i));
            if (!item || item->kind != SPL_AST_STRUCT_INIT_ITEM)
                continue;

            const char *fname = item->struct_init_item.name;
            usize field_idx = 0;
            if (!spl_type_agg_member_idx(sema->type, agg_ir, fname, &field_idx)) {
                SPL_ERROR(&item->dbg, "no field `%s` in `%s`", fname, type_name);
                sema->error_count++;
                continue;
            }
            if (seen[field_idx]) {
                SPL_ERROR(&item->dbg, "duplicate field `%s` in `%s`", fname, type_name);
                sema->error_count++;
                continue;
            }
            seen[field_idx] = true;

            const spl_type_member_t *member = &vec_at(agg_ir_node->agg_type.variants, field_idx);

            /* 通过字段的 ir 类型反查 lang 类型 */
            spl_lang_type_id_t expected_lang = 0;
            for (usize j = 1; j < vec_size(sema->type->lang_table); ++j) {
                spl_lang_type_node_t *ln = &vec_at(sema->type->lang_table, j);
                if (ln->ir_type_id == member->type_id) {
                    expected_lang = j;
                    break;
                }
            }
            if (!expected_lang) {
                SPL_ERROR(&item->dbg, "cannot resolve lang type for field `%s`", fname);
                sema->error_count++;
                continue;
            }

            if (!item->struct_init_item.expr) {
                SPL_ERROR(&item->dbg, "field `%s` requires an initializer", fname);
                sema->error_count++;
                continue;
            }

            spl_ast_node_t *fv = spl_ast_node(sema->ast, item->struct_init_item.expr);
            spl_lang_type_id_t field_lang = sema_parse(sema, item->struct_init_item.expr);
            spl_lang_type_id_t r = spl_lang_type_coerce_to(sema->type, expected_lang, field_lang);
            if (r == 0) {
                SPL_ERROR(&item->dbg, "field `%s` type mismatch", fname);
                sema->error_count++;
            } else {
                fv->resolved_type_id = r;
            }
        }

        /* 检查缺省字段 */
        for (usize i = 0; i < total_fields; ++i) {
            if (!seen[i]) {
                const spl_type_member_t *m = &vec_at(agg_ir_node->agg_type.variants, i);
                SPL_ERROR(&n->dbg, "missing field `%s` in `%s`", m->name, type_name);
                sema->error_count++;
            }
        }
        free(seen);

        n->resolved_type_id = agg_lang;
        return agg_lang;
    }

    case SPL_AST_EXPR_COMPTIME_CALL:
        return 0;

    case SPL_AST_EXPR_BLOCK: {
        for (usize i = 0; i < vec_size(n->block.stmts); ++i) {
            sema_parse(sema, vec_at(n->block.stmts, i));
        }
        if (n->block.tail_expr) {
            return sema_parse(sema, n->block.tail_expr);
        }
        return 0;
    }

    case SPL_AST_EXPR_IF: {
        spl_lang_type_id_t cond_tid = sema_parse(sema, n->if_expr.cond);
        spl_lang_type_id_t bool_tid = spl_lang_make_bool(sema->type);
        if (spl_lang_type_coerce_to(sema->type, bool_tid, cond_tid) == 0) {
            SPL_ERROR(&n->dbg, "if condition must be bool");
            sema->error_count++;
        }

        spl_lang_type_id_t then_t =
            n->if_expr.then_block ? sema_parse(sema, n->if_expr.then_block) : 0;
        spl_lang_type_id_t else_t =
            n->if_expr.else_branch ? sema_parse(sema, n->if_expr.else_branch) : 0;

        spl_lang_type_id_t result_t = 0;
        if (then_t && else_t) {
            result_t = spl_lang_type_balance(sema->type, then_t, else_t);
            if (result_t == 0) {
                SPL_ERROR(&n->dbg, "if branches type mismatch");
                sema->error_count++;
            } else {
                if (then_t != result_t) {
                    spl_ast_node_t *tn = spl_ast_node(sema->ast, n->if_expr.then_block);
                    spl_lang_type_id_t r = spl_lang_type_coerce_to(sema->type, result_t, then_t);
                    if (r)
                        tn->resolved_type_id = r;
                }
                if (else_t != result_t) {
                    spl_ast_node_t *en = spl_ast_node(sema->ast, n->if_expr.else_branch);
                    spl_lang_type_id_t r = spl_lang_type_coerce_to(sema->type, result_t, else_t);
                    if (r)
                        en->resolved_type_id = r;
                }
            }
        } else {
            result_t = then_t ? then_t : else_t;
        }

        n->resolved_type_id = result_t;
        return result_t;
    }

    case SPL_AST_EXPR_IFVAR: {
        sema_parse(sema, n->ifvar_expr.var_decl);
        sema_parse(sema, n->ifvar_expr.then_block);
        if (n->ifvar_expr.else_branch) {
            sema_parse(sema, n->ifvar_expr.else_branch);
        }
        return 0;
    }

    case SPL_AST_EXPR_WHILE: {
        spl_lang_type_id_t cond_tid = sema_parse(sema, n->while_expr.cond);
        spl_lang_type_id_t bool_tid = spl_lang_make_bool(sema->type);
        if (spl_lang_type_coerce_to(sema->type, bool_tid, cond_tid) == 0) {
            SPL_ERROR(&n->dbg, "while condition must be bool");
            sema->error_count++;
        }
        sema_parse(sema, n->while_expr.body);
        if (n->while_expr.else_branch) {
            sema_parse(sema, n->while_expr.else_branch);
        }
        return 0;
    }

    case SPL_AST_EXPR_LOOP: {
        sema_parse(sema, n->loop_expr.body);
        return 0;
    }

    case SPL_AST_EXPR_FOR: {
        sema_push_scope(sema);
        for (usize i = 0; i < vec_size(n->for_expr.iter_exprs); ++i) {
            spl_lang_type_id_t container_tid = sema_parse(sema, vec_at(n->for_expr.iter_exprs, i));
            spl_lang_type_id_t elem_tid = sema_for_elem_type(sema, container_tid);
            if (i < vec_size(n->for_expr.idents)) {
                spl_ast_node_t *id_node = spl_ast_node(sema->ast, vec_at(n->for_expr.idents, i));
                if (id_node && id_node->kind == SPL_AST_EXPR_IDENT) {
                    const char *var_name = id_node->ident.name;
                    if (strcmp(var_name, "_") != 0) {
                        spl_symbol_t sym = {.name = var_name, .kind = SPL_SYMBOL_KIND_VAR};
                        sym.node = spl_def_alloc(sema->type, SPL_DEF_VAR, var_name, id_node->dbg,
                                                 vec_at(n->for_expr.idents, i));
                        spl_def_resolve(sema->type, sym.node, elem_tid);
                        spl_scope_insert(sema->scope, sema->scope->current_scope, sym);
                        id_node->resolved_def_id = sym.node;
                    }
                }
            }
        }
        sema_parse(sema, n->for_expr.body);
        if (n->for_expr.else_branch) {
            sema_parse(sema, n->for_expr.else_branch);
        }
        sema_pop_scope(sema);
        return 0;
    }

    case SPL_AST_EXPR_MATCH: {
        sema_parse(sema, n->match_expr.matched_expr);
        for (usize i = 0; i < vec_size(n->match_expr.arms); ++i) {
            spl_ast_node_t *arm = spl_ast_node(sema->ast, vec_at(n->match_expr.arms, i));
            if (arm && arm->kind == SPL_AST_MATCH_ARM) {
                sema_parse(sema, arm->match_arm.pattern);
                sema_parse(sema, arm->match_arm.body);
            }
        }
        return 0;
    }

    case SPL_AST_EXPR_FN_TYPE: {
        spl_lang_type_id_vec_t params;
        vec_init(params);
        for (usize i = 0; i < vec_size(n->fn_type.params); ++i) {
            vec_push(params, sema_parse(sema, vec_at(n->fn_type.params, i)));
        }
        spl_lang_type_id_t ret_tid = sema_parse(sema, n->fn_type.ret_type);
        spl_lang_type_id_t fn_tid =
            spl_lang_make_fn(sema->type, ret_tid, vec_unsafe_get_data(params), vec_size(params));
        vec_free(params);
        n->resolved_type_id = fn_tid;
        return fn_tid;
    }

    case SPL_AST_TYPE_PATH: {
        const char *name = n->type_path.name;

        spl_lang_type_id_t builtin = spl_type_lookup_builtin(sema->type, name);
        if (builtin != 0) {
            n->resolved_type_id = builtin;
            return builtin;
        }

        spl_symbol_t sym;
        if (!spl_scope_find(sema->scope, name, &sym)) {
            SPL_ERROR(&n->dbg, "type `%s` not found", name);
            sema->error_count++;
            return 0;
        }
        spl_def_node_t *def = spl_def_node(sema->type, sym.node);
        if (!def || !def->lang_id)
            return 0;
        n->resolved_type_id = def->lang_id;
        return def->lang_id;
    }

    case SPL_AST_TYPE_POINTER: {
        spl_lang_type_id_t pointee_tid = sema_parse(sema, n->type_pointer.pointee);
        spl_lang_type_id_t ptr_tid = spl_lang_make_ptr(sema->type, pointee_tid);
        n->resolved_type_id = ptr_tid;
        return ptr_tid;
    }

    case SPL_AST_TYPE_ARRAY: {
        spl_lang_type_id_t elem_tid = sema_parse(sema, n->type_array.elem_type);
        usize len = n->type_array.has_len ? (usize)n->type_array.len : 0;
        spl_lang_type_id_t arr_tid = spl_lang_make_array(sema->type, elem_tid, len);
        n->resolved_type_id = arr_tid;
        return arr_tid;
    }

    case SPL_AST_TYPE_SLICE: {
        spl_lang_type_id_t elem_tid = sema_parse(sema, n->type_slice.elem_type);
        spl_lang_type_id_t slice_tid = spl_lang_make_slice(sema->type, elem_tid);
        n->resolved_type_id = slice_tid;
        return slice_tid;
    }

    case SPL_AST_TYPE_FN: {
        spl_lang_type_id_vec_t params;
        vec_init(params);
        for (usize i = 0; i < vec_size(n->type_fn.params); ++i) {
            vec_push(params, sema_parse(sema, vec_at(n->type_fn.params, i)));
        }
        spl_lang_type_id_t ret_tid = sema_parse(sema, n->type_fn.ret_type);
        spl_lang_type_id_t fn_tid =
            spl_lang_make_fn(sema->type, ret_tid, vec_unsafe_get_data(params), vec_size(params));
        vec_free(params);
        n->resolved_type_id = fn_tid;
        return fn_tid;
    }

    case SPL_AST_TYPE_PAREN: {
        usize count = vec_size(n->type_paren.types);
        if (count == 0) {
            spl_lang_type_id_t unit = spl_lang_make_unit(sema->type);
            n->resolved_type_id = unit;
            return unit;
        }
        if (count == 1) {
            return sema_parse(sema, vec_at(n->type_paren.types, 0));
        }

        spl_lang_type_id_vec_t elems;
        vec_init(elems);
        for (usize i = 0; i < count; ++i) {
            vec_push(elems, sema_parse(sema, vec_at(n->type_paren.types, i)));
        }
        spl_lang_type_id_t tuple =
            spl_lang_make_tuple(sema->type, vec_unsafe_get_data(elems), vec_size(elems));
        vec_free(elems);
        n->resolved_type_id = tuple;
        return tuple;
    }

    case SPL_AST_TYPE_AGGREGATE: {
        return 0;
    }

    case SPL_AST_TYPE_COMPTIME_CALL:
        return 0;

    case SPL_AST_STATEMENT_RET: {
        if (n->statement_ret.expr) {
            spl_ast_node_t *en = spl_ast_node(sema->ast, n->statement_ret.expr);
            spl_lang_type_id_t ret_tid = sema_parse(sema, n->statement_ret.expr);
            if (sema->current_fn_ret_tid != 0) {
                spl_lang_type_id_t r =
                    spl_lang_type_coerce_to(sema->type, sema->current_fn_ret_tid, ret_tid);
                if (r == 0) {
                    SPL_ERROR(&n->dbg, "return type mismatch");
                    sema->error_count++;
                } else {
                    en->resolved_type_id = r;
                }
            }
        }
        return 0;
    }
    case SPL_AST_STATEMENT_BREAK:
    case SPL_AST_STATEMENT_CONTINUE:
        return 0;

    case SPL_AST_STATEMENT_DEFER:
        if (n->statement_defer.body) {
            sema_parse(sema, n->statement_defer.body);
        }
        return 0;

    case SPL_AST_STATEMENT_COMPTIME:
        if (n->statement_comptime.body) {
            sema_parse(sema, n->statement_comptime.body);
        }
        return 0;

    case SPL_AST_STATEMENT_DECL:
        if (n->statement_decl.decl) {
            sema_parse(sema, n->statement_decl.decl);
        }
        return 0;

    case SPL_AST_STATEMENT_EXPR:
        if (n->statement_expr.expr) {
            sema_parse(sema, n->statement_expr.expr);
        }
        return 0;

    default:
        return 0;
    }
    return 0;
}

void spl_sema_init(spl_sema_t *sema, spl_ast_t *ast, spl_type_t *type, spl_scope_t *scope) {
    sema->ast = ast;
    sema->type = type;
    sema->scope = scope;
    sema->error_count = 0;
    sema->current_fn_ret_tid = 0;
    sema->root = (spl_symbol_t){0};
    sema->store_scope = 0;
}

void spl_sema_drop(spl_sema_t *sema) { (void)sema; }

void spl_sema_run_module(spl_sema_t *sema, spl_ast_node_ref_t module_ref) {
    if (!sema->ast || !module_ref)
        return;
    spl_ast_node_t *mod = spl_ast_node(sema->ast, module_ref);
    if (!mod || mod->kind != SPL_AST_CONTAINER_MEMBERS)
        return;

    spl_scope_id_t saved = sema->scope->current_scope;

    sema_collect(sema, module_ref);
    /* 此时 current_scope == 该 module 的 mod_scope */
    sema_parse(sema, module_ref);

    sema->scope->current_scope = saved;
}

void spl_sema_run(spl_sema_t *sema) {
    if (!sema->ast || !sema->ast->root)
        return;

    spl_ast_node_t *root = spl_ast_node(sema->ast, sema->ast->root);
    if (!root || root->kind != SPL_AST_ROOT)
        return;

    spl_sema_run_module(sema, root->root.members);
}

void spl_sema_dump(spl_sema_t *sema) {
    printf("Scopes:\n");
    for (usize i = 1; i < vec_size(sema->scope->scopes); ++i) {
        spl_scope_node_t *scope = &vec_at(sema->scope->scopes, i);
        printf("scope[%zu] parent=%zu\n", i, scope->parent);
        map_for(scope->symbols, j) {
            spl_symbol_t *symbol = &unsafe_map_at(scope->symbols, j).val;
            printf("  %s -> def`%s`#%zu\n", unsafe_map_at(scope->symbols, j).key, symbol->name,
                   symbol->node);
        }
    }
    printf("LangTypeTable:\n");
    for (usize i = 1; i < vec_size(sema->type->lang_table); ++i) {
        printf("  lang_id#%zu ", i);
        spl_lang_type_dump(sema->type, i);
        printf("\n");
    }
    printf("TypeTable:\n");
    for (usize i = 1; i < vec_size(sema->type->type_table); ++i) {
        printf("  type_id#%zu ", i);
        spl_type_pure_dump(sema->type, i);
        printf("\n");
    }
    printf("DefTable:\n");
    for (usize i = 1; i < vec_size(sema->type->def_table); ++i) {
        printf("  def#%zu ", i);
        spl_type_def_dump(sema->type, i);
        printf("\n");
    }
}