#ifndef __AST_H__
#define __AST_H__

#include "../../frontend.h"
#include "../../lexer/lexer.h"
#include "../../../../libcore/vector.h"
#include "../type.h"

typedef enum {
    NT_INIT,
    NT_ROOT, // global scope in root node
    NT_ADD, // (expr) + (expr)
    NT_SUB, // (expr) - (expr)
    NT_MUL, // (expr) * (expr)
    NT_DIV, // (expr) / (expr)
    NT_MOD, // (expr) % (expr)
    NT_AND, // (expr) & (expr)
    NT_OR,  // (expr) | (expr)
    NT_XOR, // (expr) ^ (expr)
    NT_L_SH, // (expr) << (expr)
    NT_R_SH, // (expr) >> (expr)
    NT_EQ, // (expr) == (expr)
    NT_NEQ, // (expr) != (expr)
    NT_LE, // (expr) <= (expr)
    NT_GE, // (expr) >= (expr)
    NT_LT, // (expr) < (expr)
    NT_GT, // (expr) > (expr)
    NT_AND_AND, // (expr) && (expr)
    NT_OR_OR, // (expr) || (expr)
    NT_NOT, // ! (expr)
    NT_BIT_NOT, // ~ (expr)
    NT_COND, // (expr) ? (expr) : (expr)
    NT_COMMA,     // expr, expr 逗号运算符
    NT_ASSIGN, // (expr) = (expr)

    NT_ADDRESS,   // &expr (取地址)
    NT_DEREF,     // *expr (解引用)
    NT_INDEX,     // arr[index] (数组访问)
    NT_MEMBER,    // struct.member
    NT_PTR_MEMBER,// ptr->member

    NT_CAST,      // (type)expr 强制类型转换
    NT_SIZEOF,    // sizeof(type|expr)
// NT_ALIGNOF,   // _Alignof(type) (C11)

    NT_STMT_EMPTY,      // ;
    NT_STMT_IF,         // if (cond) { ... } [else {...}]
    NT_STMT_WHILE,      // while (cond) { ... }
    NT_STMT_DOWHILE,    // do {...} while (cond)
    NT_STMT_FOR,        // for (init; cond; iter) {...}
    NT_STMT_SWITCH,     // switch (expr) { case ... }
    NT_STMT_BREAK,      // break;
    NT_STMT_CONTINUE,   // continue;
    NT_STMT_GOTO,       // goto label;
    NT_STMT_CASE,       // case const_expr:
    NT_STMT_DEFAULT,    // default:
    NT_STMT_LABEL,      // label:
    NT_STMT_BLOCK,      // { ... }
    NT_STMT_RETURN,     // return expr;
    NT_STMT_EXPR,       // expr;

    NT_BLOCK,
    // NT_TYPE_BASE,  // 基础类型节点
    // NT_TYPE_PTR,   // 指针类型
    // NT_TYPE_ARRAY, // 数组类型
    // NT_TYPE_FUNC,  // 函数类型
    // NT_TYPE_QUAL,   // 限定符节点

    NT_DECL_VAR,            // type name; or type name = expr;
    NT_DECL_FUNC,           // type func_name(param_list);
    NT_FUNC,        // type func_name(param_list) {...}
    NT_PARAM,     // 函数形参
    NT_ARG_LIST,  // 实参列表（需要与NT_CALL配合）
    
    NT_TERM_CALL, // func (expr)
    NT_TERM_VAL,
    NT_TERM_IDENT,
    NT_TERM_TYPE,
} ast_type_t;

typedef struct ASTNode {
    ast_type_t type;

    union {
        void *children[6];
        struct {
            vector_header(children, struct ASTNode*);
        } root;
        struct {
            vector_header(children, struct ASTNode*);
        } block;
        struct {
            struct ASTNode* decl_node;
            tok_t tok;
        } syms;
        struct {
            vector_header(params, struct ASTNode*);
        } params;
        struct {
            struct ASTNode* name;
            struct ASTNode* params;
            struct ASTNode* func_decl;
        } call;
        struct {
            struct ASTNode *type;
            struct ASTNode *name;
            struct ASTNode *expr_stmt; // optional
            void* data;
        } decl_val;
        struct {
            struct ASTNode *ret;
            struct ASTNode *name;
            struct ASTNode *params; // array of params
            struct ASTNode *def;
        } decl_func;
        struct {
            struct ASTNode *decl;
            struct ASTNode *body; // optional
            void* data;
        } func;
        struct {
            struct ASTNode *left;
            struct ASTNode *right;
            struct ASTNode *optional; // optional
        } expr;
        struct {
            struct ASTNode *cond;
            struct ASTNode *if_stmt; 
            struct ASTNode *else_stmt; // optional
        } if_stmt;
        struct {
            struct ASTNode *cond;
            struct ASTNode *body;
        } switch_stmt;
        struct {
            struct ASTNode *cond;
            struct ASTNode *body;
        } while_stmt;
        struct {
            struct ASTNode *body;
            struct ASTNode *cond;
        } do_while_stmt;
        struct {
            struct ASTNode *init;
            struct ASTNode *cond; // optional
            struct ASTNode *iter; // optional
            struct ASTNode *body;
        } for_stmt;
        struct {
            struct ASTNode *expr_stmt; // optional
        } return_stmt;
        struct {
            struct ASTNode *label;
        } goto_stmt;
        struct {
            struct ASTNode *label;
        } label_stmt;
        struct {
            struct ASTNode *block;
        } block_stmt;
        struct {
            struct ASTNode *expr_stmt;
        } expr_stmt;
    };
} ast_node_t;

struct ASTNode* new_ast_node(void);
void init_ast_node(struct ASTNode* node);
void pnt_ast(struct ASTNode* node, int depth);

typedef struct parser parser_t;
typedef struct ASTNode* (*parse_func_t) (parser_t*);

void parse_prog(parser_t* parser);
ast_node_t* parse_decl(parser_t* parser);
ast_node_t* parse_block(parser_t* parser);
ast_node_t* parse_stmt(parser_t* parser);
ast_node_t* parse_expr(parser_t* parser);

ast_node_t* parse_type(parser_t* parser);

ast_node_t* new_ast_ident_node(tok_t* tok);
ast_node_t* expect_pop_ident(tok_buf_t* tokbuf);

int peek_decl(tok_buf_t* tokbuf);

#endif