#define COMMON_CFLAGS "-Wall", "-Wextra", "-D_CRT_SECURE_NO_WARNINGS"
#define SPL_CFLAGS COMMON_CFLAGS, "-O0", "-g"
#define SPL_OPTIMIZATION_FLAG COMMON_CFLAGS, "-O2"
#define nob_cc_flags(cmd) nob_cmd_append(cmd, SPL_CFLAGS)
#undef UNICODE
#define NOB_IMPLEMENTATION
#include "nob.h"
#undef NOB_IMPLEMENTATION
#include "nob_popen.h"
#ifdef _WIN32
#include <consoleapi2.h>
#endif
#define BUILD_FOLDER "build/"

// Content of the .cflags stamp file; must match SPL_CFLAGS above.
#define CFLAGS_STR "-Wall -Wextra -O0 -g"
// Stamp file whose mtime is refreshed whenever the flags change so that all
// object files get rebuilt.
static const char *CFLAGS_STAMP = BUILD_FOLDER ".cflags";

/* clang-format off */
#define VM_SRCS "stage0/spl_mcode.c", "stage0/spl_syscall.c", "stage0/spl_vm.c",
static const char *spl_cli_srcs[] = {"stage0/spl_cli.c", VM_SRCS};
static const char *vm_test_srcs[] = {"stage0/test_spl_vm.c", VM_SRCS};
static const char *splc0_srcs[] = {
    "stage1/splc0.c",
    "stage1/spl_diag.c",
    "stage1/spl_tok.c",
    "stage1/spl_lexer.c",
    "stage1/spl_ast.c",
    "stage1/spl_parser.c",
    "stage1/spl_dumptree.c",
    "stage1/spl_type.c",
    "stage1/spl_fold.c",
    "stage1/spl_lang_type.c",
    "stage1/spl_attr.c",
    "stage1/spl_scope.c",
    "stage1/spl_sema.c",
    "stage1/spl_intrin.c",
    "stage1/spl_ir.c",
    "stage1/spl_ast2ir.c",
    "stage1/spl_layout.c",
    "stage1/spl_ir2vm.c",
    "stage1/ir_opt.c",
    "stage1/vm_opt.c",
    "stage0/spl_mcode.c",
};

static const char* splc1_deps[] = {
    "stage2/sys/exit.spl",
    "stage2/sys/file.spl",
    "stage2/sys/mem.spl",
    "stage2/sys/spl_rt.h",
    "stage2/sys/spl_vm_embed.h",
    "stage2/sys/time.spl",
    "stage2/sys/vm.spl",
    "stage2/utils/algorithm.spl",
    "stage2/utils/arena.spl",
    "stage2/utils/ascii.spl",
    "stage2/utils/byte_buffer.spl",
    "stage2/utils/byte_view.spl",
    "stage2/utils/error.spl",
    "stage2/utils/fmt.spl",
    "stage2/utils/hash.spl",
    "stage2/utils/io.spl",
    "stage2/utils/json.spl",
    "stage2/utils/log.spl",
    "stage2/utils/lsp_frame.spl",
    "stage2/utils/map.spl",
    "stage2/utils/memory.spl",
    "stage2/utils/mp.spl",
    "stage2/utils/path.spl",
    "stage2/utils/profile.spl",
    "stage2/utils/set.spl",
    "stage2/utils/source.spl",
    "stage2/utils/str.spl",
    "stage2/utils/utf8.spl",
    "stage2/utils/value.spl",
    "stage2/utils/vec.spl",
    "stage2/ast.spl",
    "stage2/ast2ir.spl",
    "stage2/attr.spl",
    "stage2/def.spl",
    "stage2/diag.spl",
    "stage2/eval.spl",
    "stage2/intrin.spl",
    "stage2/ir.spl",
    "stage2/ir2c.spl",
    "stage2/ir2vm.spl",
    "stage2/ir_builder.spl",
    "stage2/lang_type.spl",
    "stage2/layout.spl",
    "stage2/lexer.spl",
    "stage2/mcode.spl",
    "stage2/parser.spl",
    "stage2/scope.spl",
    "stage2/sema.spl",
    "stage2/splc1.spl",
    "stage2/token.spl",
    "stage2/type_table.spl",
};

static const char* splc2_deps[] = {

};

/* clang-format on */

static const char *obj_path(const char *src) {
    // "stage0/spl_vm.c" -> "build/stage0_spl_vm.o"
    size_t prefix_len = strlen(BUILD_FOLDER);
    char *out = (char *)nob_temp_alloc(prefix_len + strlen(src) + 2 + 1);
    char *w = out;
    memcpy(w, BUILD_FOLDER, prefix_len);
    w += prefix_len;
    for (const char *p = src; *p && *p != '.'; ++p) {
        *w++ = (*p == '/' || *p == '\\') ? '_' : *p;
    }
    memcpy(w, ".o", 3);
    return out;
}

// Windows 上 clang/gcc 会输出 build/foo.exe；这里统一带上后缀，
// 否则 nob_needs_rebuild 找不到输出会每次重新链接。
static const char *exe_path(const char *name) {
#ifdef _WIN32
    return nob_temp_sprintf(BUILD_FOLDER "%s.exe", name);
#else
    return nob_temp_sprintf(BUILD_FOLDER "%s", name);
#endif
}

static const char *sir_path(const char *name) {
    return nob_temp_sprintf(BUILD_FOLDER "%s.sir", name);
}

static const char *c_path(const char *name) { return nob_temp_sprintf(BUILD_FOLDER "%s.c", name); }

static bool sync_cflags_stamp(void) {
    Nob_String_View cflags = nob_sv_from_cstr(CFLAGS_STR);
    Nob_String_Builder old = {0};
    bool changed = true;
    if (nob_file_exists(CFLAGS_STAMP) && nob_read_entire_file(CFLAGS_STAMP, &old)) {
        changed = !nob_sv_eq(nob_sb_to_sv(old), cflags);
    }
    nob_sb_free(old);

    if (changed) {
        if (!nob_write_entire_file(CFLAGS_STAMP, cflags.data, cflags.count)) {
            return false;
        }
    }
    return true;
}

static bool prepare_build(void) {
    if (!nob_mkdir_if_not_exists(BUILD_FOLDER))
        return false;
    if (!sync_cflags_stamp())
        return false;
    return true;
}

typedef struct build {
    const char *name;
    enum {
        BUILD_EXE,
        BUILD_EXE_WITH_OPTIMIZATION,
        BUILD_SIR,
        BUILD_NATIVE,
    } kind;
    union {
        struct {
            const char **srcs;
            size_t srcs_count;
            const char **headers;
            size_t headers_count;
        } exe;
        struct {
            const char *src;
            const char *compiler;
            const char **deps;
            size_t deps_count;
        } sir;
        struct {
            const char *src;
            const char *compiler;
            const char **deps;
            size_t deps_count;
        } native;
    };
} build_t;

typedef struct {
    const char **items;
    size_t count;
    size_t capacity;
} str_da_t;

typedef struct run {
    const char *name;
    const char *interpreter;
} run_t;

bool run_target(const char *name, Nob_Cmd *args);
const char *build_target(const char *name);

static const char *build_exe(build_t *target) {
    Nob_Cmd cmd = {0};
    str_da_t objs = {0};
    str_da_t deps = {0};
    for (size_t i = 0; i < target->exe.srcs_count; ++i) {
        const char *src = target->exe.srcs[i];
        const char *obj = obj_path(src);
        if (!nob_file_exists(src)) {
            nob_log(NOB_ERROR, "source file `%s` does not exist", src);
            goto defer;
        }

        da_append(&objs, obj);

        da_append(&deps, src);
        da_append(&deps, CFLAGS_STAMP);
        for (size_t j = 0; j < target->exe.headers_count; ++j) {
            da_append(&deps, target->exe.headers[j]);
        }

        int needs = nob_needs_rebuild(obj, deps.items, deps.count);
        deps.count = 0; // 清空 deps，下一轮循环重新收集

        if (needs < 0)
            goto defer;
        if (needs == 0)
            continue;
        nob_cc(&cmd);
        nob_cc_flags(&cmd);
        nob_cmd_append(&cmd, "-c");
        nob_cc_inputs(&cmd, src);
        nob_cc_output(&cmd, obj);
        if (!nob_cmd_run(&cmd)) {
            nob_log(NOB_ERROR, "failed to compile `%s`", src);
            goto defer;
        }
        cmd.count = 0; // 清空 cmd，下一轮循环重新构建
    }

    const char *exe = exe_path(target->name);

    int needs = nob_needs_rebuild(exe, objs.items, objs.count);
    if (needs < 0)
        goto defer;
    if (needs == 0)
        return exe;

    nob_cc(&cmd);
    nob_cmd_append(&cmd, SPL_OPTIMIZATION_FLAG);
    for (size_t i = 0; i < objs.count; ++i) {
        nob_cc_inputs(&cmd, objs.items[i]);
    }
    nob_cc_output(&cmd, exe);
    if (!nob_cmd_run(&cmd)) {
        goto defer;
    }

    return exe;
defer:
    nob_cmd_free(cmd);
    da_free(objs);
    da_free(deps);
    return NULL;
}

static const char *build_native(const char *name) {
    const char *exe = exe_path(name);
    const char *cli = build_target("spl_cli");
    const char *sir = build_target("splc1");
    if (!cli || !sir) {
        nob_log(NOB_ERROR, "failed to build prerequisites for `%s`", name);
        return NULL;
    }
    const char *cpath = BUILD_FOLDER "splc1.c";
    const char *inputs[] = {sir,
                            "stage2/sys/spl_rt.h",
                            "stage2/sys/spl_vm_embed.h",
                            "stage2/sys/spl_vm_embed.c",
                            "stage0/spl_vm.c",
                            "stage0/spl_mcode.c",
                            "stage0/spl_syscall.c",
                            "stage0/spl_vm.h",
                            "stage0/spl_mcode.h"};
    int needs = nob_needs_rebuild(exe, inputs, NOB_ARRAY_LEN(inputs));
    if (needs < 0)
        return NULL;
    if (needs == 0)
        return exe;

    Nob_Cmd cmd = {0};
    if (nob_file_exists(exe)) {
        // 已有原生编译器：用原生自举重新生成 C（0.1s 级）
        nob_cmd_append(&cmd, exe, "--dump", "c", "stage2/splc1.spl", cpath);
    } else {
        // 冷启动：用 VM 版 splc1 生成 C
        nob_cmd_append(&cmd, cli, sir, "--dump", "c", "stage2/splc1.spl", cpath);
    }
    if (!nob_cmd_run(&cmd)) {
        nob_log(NOB_ERROR, "ir2c C generation failed");
        nob_cmd_free(cmd);
        return NULL;
    }
    cmd.count = 0;
    nob_cc(&cmd);
    nob_cc_inputs(&cmd, cpath);
    nob_cc_inputs(&cmd, "stage2/sys/spl_vm_embed.c");
    nob_cc_inputs(&cmd, "stage0/spl_vm.c");
    nob_cc_inputs(&cmd, "stage0/spl_mcode.c");
    nob_cc_inputs(&cmd, "stage0/spl_syscall.c");
    nob_cc_output(&cmd, exe);
    if (!nob_cmd_run(&cmd)) {
        nob_log(NOB_ERROR, "native link failed");
        nob_cmd_free(cmd);
        return NULL;
    }
    nob_cmd_free(cmd);
    return exe;
}

static build_t targets[] = {
    {
        "spl_cli",
        BUILD_EXE_WITH_OPTIMIZATION,
        .exe = {.srcs = spl_cli_srcs,
                .srcs_count = NOB_ARRAY_LEN(spl_cli_srcs),
                .headers = NULL,
                .headers_count = 0},
    },
    {
        "spl_cli_g",
        BUILD_EXE,
        .exe = {.srcs = spl_cli_srcs,
                .srcs_count = NOB_ARRAY_LEN(spl_cli_srcs),
                .headers = NULL,
                .headers_count = 0},
    },
    {
        "vm_test",
        BUILD_EXE,
        .exe = {.srcs = vm_test_srcs,
                .srcs_count = NOB_ARRAY_LEN(vm_test_srcs),
                .headers = NULL,
                .headers_count = 0},
    },
    {
        "splc0",
        BUILD_EXE,
        .exe = {.srcs = splc0_srcs,
                .srcs_count = NOB_ARRAY_LEN(splc0_srcs),
                .headers = NULL,
                .headers_count = 0},
    },
    {
        "splc1",
        BUILD_SIR,
        .sir = {.src = "stage2/splc1.spl",
                .compiler = "splc0",
                .deps = splc1_deps,
                .deps_count = NOB_ARRAY_LEN(splc1_deps)},
    },
    {
        "splc1s",
        BUILD_SIR,
        .sir = {.src = "stage2/splc1.spl",
                .compiler = "splc1",
                .deps = splc1_deps,
                .deps_count = NOB_ARRAY_LEN(splc1_deps)},
    },
    {
        "splc1r",
        BUILD_SIR,
        .sir = {.src = "stage2/splc1.spl",
                .compiler = "splc1s",
                .deps = splc1_deps,
                .deps_count = NOB_ARRAY_LEN(splc1_deps)},
    },
    {
        "splc1n",
        BUILD_NATIVE,
        .native = {.src = "stage2/splc1.spl",
                   .compiler = "splc1",
                   .deps = splc1_deps,
                   .deps_count = NOB_ARRAY_LEN(splc1_deps)},
    },
    {
        "splc2",
        BUILD_SIR,
        .sir = {.src = "stage3/splc2.spl",
                .compiler = "splc1n",
                .deps = splc2_deps,
                .deps_count = NOB_ARRAY_LEN(splc2_deps)},
    },
    {
        "splc2n",
        BUILD_NATIVE,
        .native = {.src = "stage3/splc2.spl",
                   .compiler = "splc1n",
                   .deps = splc2_deps,
                   .deps_count = NOB_ARRAY_LEN(splc2_deps)},
    },
};

const char *build_target(const char *name) {
    if (!prepare_build())
        return NULL;
    for (size_t i = 0; i < NOB_ARRAY_LEN(targets); ++i) {
        if (name != NULL && strcmp(targets[i].name, name) != 0) {
            continue;
        }
        build_t *target = &targets[i];
        switch (target->kind) {
        case BUILD_EXE_WITH_OPTIMIZATION:
        case BUILD_EXE: {
            return build_exe(target);
        }
        case BUILD_SIR: {
            Nob_Cmd cmd = {0};
            const char *target_sir = sir_path(name);
            nob_cmd_append(&cmd, target->sir.src, target_sir);
            if (!run_target(target->sir.compiler, &cmd)) {
                nob_log(NOB_ERROR, "failed to build `%s`", name);
                nob_cmd_free(cmd);
                return NULL;
            }
            nob_cmd_free(cmd);
            return target_sir;
        }
        case BUILD_NATIVE: {
            Nob_Cmd cmd = {0};
            const char *target_exe = exe_path(name);
            const char *target_c = c_path(name);

            // TODO need_rebuild
            int needs =
                nob_needs_rebuild(target_exe, target->native.deps, target->native.deps_count);
            if (needs < 0)
                return NULL;
            if (needs == 0)
                return target_exe;

            nob_cmd_append(&cmd, "--dump", "c", target->native.src, target_c);
            if (!run_target(target->native.compiler, &cmd)) {
                nob_log(NOB_ERROR, "failed to build `%s`", name);
                nob_cmd_free(cmd);
                return NULL;
            }
            cmd.count = 0;
            nob_cc(&cmd);
            nob_cmd_append(&cmd, "-I./stage2/sys", "-O2", "-D_CRT_SECURE_NO_WARNINGS");
            nob_cc_inputs(&cmd, target_c);
            nob_cc_output(&cmd, target_exe);
            if (!nob_cmd_run(&cmd)) {
                nob_log(NOB_ERROR, "failed to build `%s`", name);
                nob_cmd_free(cmd);
                return NULL;
            }
            nob_cmd_free(cmd);
            return target_exe;
        }
        default:
            NOB_UNREACHABLE("build_t.kind");
        }
    }
    nob_log(NOB_ERROR, "unknown build target `%s`", name);
    return NULL;
}

static run_t runs[] = {
    {"spl_cli", NULL},    {"vm_test", NULL},     {"splc0", NULL},
    {"splc1", "spl_cli"}, {"splc1r", "spl_cli"}, {"splc1s", "spl_cli"},
    {"splc1n", NULL},     {"splc2", "spl_cli"},  {"splc2n", NULL},
};

bool run_target_dry(const char *name, Nob_Cmd *args, Nob_Cmd *result) {
    for (size_t i = 0; i < NOB_ARRAY_LEN(runs); ++i) {
        if (strcmp(runs[i].name, name) != 0) {
            continue;
        }
        const char *exe = build_target(runs[i].name);
        const char *interpreter = runs[i].interpreter;
        if (interpreter) {
            const char *inter = build_target(interpreter);
            if (!exe) {
                nob_log(NOB_ERROR, "failed to build interpreter `%s` for `%s`", interpreter, name);
                return false;
            }
            nob_cmd_append(result, inter);
        }
        nob_cmd_append(result, exe);
        nob_cmd_extend(result, args);
        return true;
    }
    nob_log(NOB_ERROR, "unknown run target `%s`", name);
    return false;
}

bool run_target(const char *name, Nob_Cmd *args) {
    Nob_Cmd result = {0};
    if (!run_target_dry(name, args, &result)) {
        return false;
    }
    nob_log(NOB_INFO, "running `%s`", name);
    bool ok = nob_cmd_run(&result);
    nob_cmd_free(result);
    return ok;
}

static void parse_expect(const char *name, Nob_Cmd_Result *expect) {
    Nob_String_Builder sb = {0};
    nob_read_entire_file(name, &sb);
    Nob_String_View sv = nob_sb_to_sv(sb);
    while (sv.count > 0) {
        Nob_String_View line = nob_sv_chop_by_delim(&sv, '\n');
        line = nob_sv_trim_left(line); // 去掉前导空格

        if (!nob_sv_starts_with(line, nob_sv_from_cstr("//"))) {
            break;
        }

        Nob_String_View rest = nob_sv_from_parts(line.data + 2, line.count - 2);
        rest = nob_sv_trim_left(rest);

        if (rest.count == 0)
            continue;

        if (!nob_sv_starts_with(rest, nob_sv_from_cstr("Expect"))) {
            break;
        }
        rest = nob_sv_from_parts(rest.data + 6, rest.count - 6);
        rest = nob_sv_trim_left(rest);

        // 按 '=' 分割
        Nob_String_View key = nob_sv_chop_by_delim(&rest, '=');
        key = nob_sv_trim(key);
        Nob_String_View value = nob_sv_trim(rest);

        if (nob_sv_eq(key, nob_sv_from_cstr("retcode"))) {
            int val = 0;
            for (size_t i = 0; i < value.count && isdigit(value.data[i]); ++i) {
                val = val * 10 + (value.data[i] - '0');
            }
            // printf("expected code %d\n", val);
            expect->exit_code = val;
        } else if (nob_sv_eq(key, nob_sv_from_cstr("stdout"))) {
        }
    }
}

static bool test_once(const char *fname, void *user_data) {
    (void)user_data;

    const char *compiler_path = "splc0";
    const char *cli_path = "spl_cli";
    const char *target_sir = BUILD_FOLDER "test.sir";

    Nob_Cmd cmd = {0};
    if (!build_target(compiler_path)) {
        return 1;
    }
    cmd.count = 0;

    nob_cmd_append(&cmd, exe_path(compiler_path));
    nob_cmd_append(&cmd, fname, target_sir);
    if (!nob_cmd_run(&cmd)) {
        return false;
    }

    if (!build_target(cli_path)) {
        return 1;
    }
    cmd.count = 0;
    nob_cmd_append(&cmd, exe_path(cli_path));
    nob_cmd_append(&cmd, target_sir);
    // nob_cmd_run(&cmd);

    Nob_Cmd_Result result = {0};
    Nob_String_Builder cmd_str = {0};
    nob_cmd_render(cmd, &cmd_str);

    Nob_String_View sv = nob_sb_to_sv(cmd_str);
    nob_cmd_capture_popen(nob_temp_sv_to_cstr(sv), &result);
    // Expect retcode = number

    Nob_Cmd_Result expect = {0};
    parse_expect(fname, &expect);

    if (expect.exit_code != result.exit_code) {
        nob_log(NOB_ERROR, "Expect code `%d`, Result code `%d`", expect.exit_code,
                result.exit_code);
        return false;
    }

    nob_cmd_result_free(result);
    return true;
}

static bool test_once_with_dump(const char *fname, void *user_data) {
    const char *target_name = "splc0";
    if (!prepare_build())
        return 1;
    if (!build_target(target_name))
        return 1;
    Nob_Cmd cmd = {0};
    nob_cmd_append(&cmd, exe_path(target_name));
    nob_cmd_append(&cmd, "--dump", (char *)user_data, fname, BUILD_FOLDER "t.sir");
    return nob_cmd_run(&cmd);
}

// 由源路径派生构建产物路径：build/<basename>.sir
static const char *artifact_sir(const char *src) {
    const char *base = src;
    for (const char *p = src; *p; ++p)
        if (*p == '/' || *p == '\\')
            base = p + 1;
    const char *dot = strrchr(base, '.');
    size_t len = dot ? (size_t)(dot - base) : strlen(base);
    return nob_temp_sprintf(BUILD_FOLDER "%.*s.sir", (int)len, base);
}

static bool run_capture(Nob_Cmd *cmd, Nob_Cmd_Result *result) {
    Nob_String_Builder rendered = {0};
    nob_cmd_render(*cmd, &rendered);
    Nob_String_View sv = nob_sb_to_sv(rendered);
    bool ok = nob_cmd_capture_popen(nob_temp_sv_to_cstr(sv), result);
    nob_sb_free(rendered);
    return ok;
}

// diff 测试：对同一文件跑 `splc0 --dump <mode>` 与 `spl_cli splc1.sir --dump <mode>`，
// 逐字节比较 stdout。
static bool test_once_diff(const char *fname, void *user_data) {
    const char *mode = (const char *)user_data;
    if (!mode) {
        nob_log(NOB_ERROR, "diff test requires a mode: lex|ast|sema|ir|vm");
        return false;
    }
    if (!build_target("splc0"))
        return false;
    if (!build_target("spl_cli"))
        return false;
    if (!build_target("splc1"))
        return false;

    Nob_Cmd c_cmd = {0};
    nob_cmd_append(&c_cmd, exe_path("splc0"), "--dump", (char *)mode, (char *)fname,
                   BUILD_FOLDER "diff_c.sir");
    Nob_Cmd_Result c_res = {0};
    if (!run_capture(&c_cmd, &c_res)) {
        nob_cmd_result_free(c_res);
        return false;
    }

    Nob_Cmd s_cmd = {0};
    nob_cmd_append(&s_cmd, exe_path("spl_cli"), BUILD_FOLDER "splc1.sir", "--dump", (char *)mode,
                   (char *)fname);
    Nob_Cmd_Result s_res = {0};
    if (!run_capture(&s_cmd, &s_res)) {
        nob_cmd_result_free(c_res);
        nob_cmd_result_free(s_res);
        return false;
    }

    Nob_String_View c_out = nob_sb_to_sv(c_res.out);
    Nob_String_View s_out = nob_sb_to_sv(s_res.out);
    bool same = nob_sv_eq(c_out, s_out);
    if (!same) {
        nob_log(NOB_ERROR, "diff mismatch: %s (c=%zu bytes, spl=%zu bytes)", fname, c_out.count,
                s_out.count);
        // 打印首个不相同行（按行比较）。
        Nob_String_View ca = c_out;
        Nob_String_View sa = s_out;
        size_t lineno = 1;
        while (ca.count > 0 || sa.count > 0) {
            Nob_String_View cl = nob_sv_chop_by_delim(&ca, '\n');
            Nob_String_View sl = nob_sv_chop_by_delim(&sa, '\n');
            if (!nob_sv_eq(cl, sl)) {
                nob_log(NOB_ERROR, "  line %zu:", lineno);
                nob_log(NOB_ERROR, "    c  : %.*s", (int)cl.count, cl.data);
                nob_log(NOB_ERROR, "    spl: %.*s", (int)sl.count, sl.data);
                break;
            }
            lineno++;
        }
        nob_log(NOB_ERROR, "--- c stderr/stdout merged above; exit=%d vs spl exit=%d ---",
                c_res.exit_code, s_res.exit_code);
    }

    nob_cmd_result_free(c_res);
    nob_cmd_result_free(s_res);
    return same;
}

static bool is_stage_name(const char *s) {
    return strcmp(s, "stage1") == 0 || strcmp(s, "stage2") == 0 || strcmp(s, "diff") == 0;
}

static bool is_dump_mode(const char *s) {
    return strcmp(s, "lex") == 0 || strcmp(s, "ast") == 0 || strcmp(s, "sema") == 0 ||
           strcmp(s, "ir") == 0 || strcmp(s, "vm") == 0;
}

static const char *stage_dir_of(const char *stage) {
    if (strcmp(stage, "stage2") == 0)
        return "./stage2/";
    return "./tests/stage1/";
}

typedef bool (*test_fn_t)(const char *fname, void *user_data);
typedef struct {
    Nob_Files *files;
    test_fn_t test_once;
    void *user_data;
} test_walk_ctx_t;

static bool test_walk_entry(Nob_Walk_Entry entry) {
    if (entry.type != NOB_FILE_REGULAR)
        return true;

    const char *dot = strrchr(entry.path, '.');
    if (!dot || strcmp(dot, ".spl") != 0)
        return true;

    test_walk_ctx_t *ctx = (test_walk_ctx_t *)entry.data;
    bool run_all = (ctx->files->count == 0);
    bool matched = run_all;
    for (int i = 0; !matched && i < ctx->files->count; i += 1) {
        if (strstr(entry.path, ctx->files->items[i]))
            matched = true;
    }
    if (!matched)
        return true;

    printf("--- test %s ---\n", entry.path);
    if (ctx->test_once(entry.path, ctx->user_data) == false)
        return false;
    return true;
}

static bool run_test(const char *stage, Nob_Files *files, test_fn_t test_once, void *user_data) {
    const char *test_folder = stage_dir_of(stage);

    if (!prepare_build())
        return false;

    if (!nob_file_exists(test_folder)) {
        nob_log(NOB_INFO, "%s does not exist, skip", test_folder);
        return true;
    }

    test_walk_ctx_t ctx = {
        .files = files,
        .test_once = test_once,
        .user_data = user_data,
    };
    return nob_walk_dir(test_folder, test_walk_entry, .data = &ctx);
}

static bool delete_walk_entry(Nob_Walk_Entry entry) { return nob_delete_file(entry.path); }

static bool delete_directory_recursively(const char *dir_path) {
    return nob_walk_dir(dir_path, delete_walk_entry, .post_order = true);
}

static void print_help(const char *program_name) {
    nob_log(NOB_INFO, "SPL C-side bootstrap build system (nob)");
    nob_log(NOB_INFO, "%s", " ");
    nob_log(NOB_INFO, "Usage: %s <command> [args...]", program_name);
    nob_log(NOB_INFO, "%s", " ");
    nob_log(NOB_INFO, "Commands:");
    nob_log(NOB_INFO, "    build [targets...]  build all targets or the given ones");
    nob_log(NOB_INFO, "    run <target> [args] build and run a target");
    nob_log(NOB_INFO, "    test <kind>         build and run tests");
    nob_log(NOB_INFO, "    clean               remove build artifacts");
    nob_log(NOB_INFO, "    list                list all targets");
    nob_log(NOB_INFO, "    help/-h/--help      print this help message");
}

int main(int argc, char **argv) {
#ifdef _WIN32
    SetConsoleOutputCP(CP_UTF8);
    SetConsoleCP(CP_UTF8);
#endif
    NOB_GO_REBUILD_URSELF_PLUS(argc, argv, "nob.h", "nob_popen.h");
    set_log_handler(nob_cancer_log_handler);

    const char *program_name = nob_shift(argv, argc);
    const char *command_name = "build";
    if (argc > 0) {
        command_name = nob_shift(argv, argc);
    }

    if (strcmp(command_name, "build") == 0) {
        if (!prepare_build())
            return 1;
        if (argc > 0) {
            while (argc > 0) {
                const char *target_name = nob_shift(argv, argc);
                if (!build_target(target_name))
                    return 1;
            }
        } else {
            if (!build_target(NULL))
                return 1;
        }
        return 0;
    }

    if (strcmp(command_name, "run") == 0) {
        if (argc <= 0) {
            nob_log(NOB_ERROR, "usage: %s run <target> [args...]", program_name);
            return 1;
        }
        const char *target_name = nob_shift(argv, argc);
        Nob_Cmd runcmd = {0};
        while (argc > 0) {
            nob_cmd_append(&runcmd, nob_shift(argv, argc));
        }
        return !run_target(target_name, &runcmd);
    }

    if (strcmp(command_name, "test") == 0) {
        // 1. stage（可选，默认 stage1）
        const char *stage = "stage1";
        if (argc > 0 && is_stage_name(argv[0])) {
            stage = nob_shift(argv, argc);
        }

        // 2. mode（可选）
        test_fn_t tfn = test_once;
        const char *mode_name = NULL;
        if (argc > 0) {
            if (is_dump_mode(argv[0])) {
                tfn = test_once_with_dump;
                mode_name = nob_shift(argv, argc);
            } else if (strcmp(argv[0], "run") == 0) {
                nob_shift(argv, argc);
                // HACK：只对 stage1 有意义，跑上次生成的 build/test.sir
                Nob_Cmd cmd = {0};
                nob_cmd_append(&cmd, BUILD_FOLDER "spl_cli", "-d");
                nob_cmd_append(&cmd, BUILD_FOLDER "test.sir");
                return nob_cmd_run(&cmd) ? 0 : 1;
            }
        }

        // diff 需要显式 mode，且使用专门的双编译器比较函数。
        if (strcmp(stage, "diff") == 0) {
            if (!mode_name) {
                nob_log(NOB_ERROR, "diff requires a mode: lex|ast|sema|ir|vm");
                return 1;
            }
            tfn = test_once_diff;
        }

        // 3. 剩下的都当 pattern
        Nob_Files files = {0};
        while (argc > 0) {
            da_append(&files, nob_shift(argv, argc));
        }

        return run_test(stage, &files, tfn, (void *)mode_name) ? 0 : 1;
    }

    if (strcmp(command_name, "clean") == 0) {
        if (nob_file_exists(BUILD_FOLDER)) {
            if (!delete_directory_recursively(BUILD_FOLDER))
                return 1;
        }
        nob_log(NOB_INFO, "cleaned %s", BUILD_FOLDER);
        return 0;
    }

    if (strcmp(command_name, "list") == 0) {
        for (size_t i = 0; i < NOB_ARRAY_LEN(targets); ++i) {
            nob_log(NOB_INFO, "%s:", targets[i].name);
        }
        return 0;
    }

    if (strcmp(command_name, "help") == 0 || strcmp(command_name, "-h") == 0 ||
        strcmp(command_name, "--help") == 0) {
        print_help(program_name);
        return 0;
    }

    nob_log(NOB_ERROR, "unknown command `%s`", command_name);
    print_help(program_name);
    return 1;
}