import t
from stdio import printf
import testcheck

# ============================================================
# 自定义装饰器处理函数
# 调用约定 (v4)：
#   i32 decor_name(i8* ctx, i8* func_name, i32 phase,
#                  i8* args_ptr, i8* ret_ptr, i8* decor_args_ptr)
#
#   ctx: 栈帧局部上下文（32字节），每次调用独立，线程/递归安全
#   args_ptr: 可读写，装饰器可修改函数入参
#   ret_ptr: 后置阶段可读写，装饰器可修改返回值
#   返回值（前置阶段）：
#     0  = 跳过原函数调用
#     1  = 正常调用一次
#     N  = 循环调用 N 次
# ============================================================

# @log 装饰器：打印函数进入/退出，返回 1（正常调用一次）
def log(ctx: t.CVoid | t.CPtr, func_name: str, phase: t.CInt,
        args_ptr: t.CVoid | t.CPtr,
        ret_ptr: t.CVoid | t.CPtr,
        decor_args_ptr: t.CVoid | t.CPtr) -> t.CInt | t.CExport:
    if phase == 0:
        printf("[LOG] >> %s enter\n", func_name)
        return 1
    else:
        printf("[LOG] << %s exit\n", func_name)
        return 0

# @trace 装饰器：详细追踪
def trace(ctx: t.CVoid | t.CPtr, func_name: str, phase: t.CInt,
          args_ptr: t.CVoid | t.CPtr,
          ret_ptr: t.CVoid | t.CPtr,
          decor_args_ptr: t.CVoid | t.CPtr) -> t.CInt | t.CExport:
    if phase == 0:
        printf("[TRACE] calling %s...\n", func_name)
        return 1
    else:
        printf("[TRACE] %s returned\n", func_name)
        return 0

# @timing 装饰器：使用全局变量记录计时
# 注意：理想情况下应使用 ctx 栈帧局部上下文替代全局变量，
# 但 Viper 当前前端尚不支持 i8* 到 i32* 的指针转型，
# 因此暂时使用全局变量演示计时逻辑
_timing_tmp: t.CInt = 0

def timing(ctx: t.CVoid | t.CPtr, func_name: str, phase: t.CInt,
           args_ptr: t.CVoid | t.CPtr,
           ret_ptr: t.CVoid | t.CPtr,
           decor_args_ptr: t.CVoid | t.CPtr) -> t.CInt | t.CExport:
    global _timing_tmp
    if phase == 0:
        _timing_tmp = 100
        printf("[TIMING] %s start at t=%d\n", func_name, _timing_tmp)
        return 1
    else:
        elapsed: t.CInt = 105 - _timing_tmp
        printf("[TIMING] %s took %d ms\n", func_name, elapsed)
        return 0

# @repeat 装饰器（带参数，流程劫持）：循环调用原函数 N 次
def repeat(ctx: t.CVoid | t.CPtr, func_name: str, phase: t.CInt,
           args_ptr: t.CVoid | t.CPtr,
           ret_ptr: t.CVoid | t.CPtr,
           decor_args_ptr: t.CVoid | t.CPtr) -> t.CInt | t.CExport:
    if phase == 0:
        printf("[REPEAT] %s will run 3 times\n", func_name)
        return 3
    else:
        printf("[REPEAT] %s all iterations done\n", func_name)
        return 0

# @skip 装饰器：跳过原函数调用（流程劫持，返回 0）
_skip_count: t.CInt = 0

def skip(ctx: t.CVoid | t.CPtr, func_name: str, phase: t.CInt,
         args_ptr: t.CVoid | t.CPtr,
         ret_ptr: t.CVoid | t.CPtr,
         decor_args_ptr: t.CVoid | t.CPtr) -> t.CInt | t.CExport:
    global _skip_count
    if phase == 0:
        _skip_count = _skip_count + 1
        printf("[SKIP] %s skipped! (call #%d)\n", func_name, _skip_count)
        return 0
    else:
        printf("[SKIP] %s post (ret_ptr=%p)\n", func_name, ret_ptr)
        return 0

# @count_calls 装饰器：统计函数被调用次数（递归保护测试用）
_call_count: t.CInt = 0

def count_calls(ctx: t.CVoid | t.CPtr, func_name: str, phase: t.CInt,
                args_ptr: t.CVoid | t.CPtr,
                ret_ptr: t.CVoid | t.CPtr,
                decor_args_ptr: t.CVoid | t.CPtr) -> t.CInt | t.CExport:
    global _call_count
    if phase == 0:
        _call_count = _call_count + 1
        printf("[COUNT] %s call #%d\n", func_name, _call_count)
        return 1
    else:
        printf("[COUNT] %s done (total calls: %d)\n", func_name, _call_count)
        return 0


# ============================================================
# 测试 1：单个装饰器 @log
# ============================================================

@log
def add(a: t.CInt, b: t.CInt) -> t.CInt | t.CExport:
    return a + b


# ============================================================
# 测试 2：链式装饰器 @log @trace => log(trace(f))
# 执行顺序：log_pre → trace_pre → f → trace_post → log_post
# ============================================================

@log
@trace
def multiply(a: t.CInt, b: t.CInt) -> t.CInt | t.CExport:
    return a * b


# ============================================================
# 测试 3：装饰器修饰 void 返回函数
# ============================================================

@log
def greet(name: str) -> t.CVoid | t.CExport:
    printf("Hello, %s!\n", name)


# ============================================================
# 测试 4：装饰器修饰无参数函数
# ============================================================

@log
def get_value() -> t.CInt | t.CExport:
    return 42


# ============================================================
# 测试 5：@timing 装饰器
# ============================================================

@timing
def compute(x: t.CInt) -> t.CInt | t.CExport:
    return x * x + 1


# ============================================================
# 测试 6：带参数装饰器 @repeat(3) — 流程劫持，循环调用 3 次
# ============================================================

@repeat(3)
def echo(msg: str) -> t.CVoid | t.CExport:
    printf("  echo: %s\n", msg)


# ============================================================
# 测试 7：链式 @timing @log
# ============================================================

@timing
@log
def power(base: t.CInt, exp: t.CInt) -> t.CInt | t.CExport:
    result: t.CInt = 1
    i: t.CInt = 0
    while i < exp:
        result = result * base
        i = i + 1
    return result


# ============================================================
# 测试 8：@skip 装饰器 — 流程劫持，跳过原函数调用
# ============================================================

@skip
def dangerous() -> t.CInt | t.CExport:
    printf("This should NOT be printed!\n")
    return 999


# ============================================================
# 测试 9：@repeat(3) 修饰有返回值的函数
# ============================================================

@repeat(3)
def accumulate(x: t.CInt) -> t.CInt | t.CExport:
    printf("  accumulate(%d)\n", x)
    return x * 10


# ============================================================
# 测试 10：递归装饰保护 — @count_calls 修饰递归函数
# v4 递归保护：最外层 wrapper 检查全局标志位，
# 递归调用时跳过所有装饰逻辑，仅最外层调用触发装饰器
# ============================================================

@count_calls
def factorial(n: t.CInt) -> t.CInt | t.CExport:
    if n <= 1:
        return 1
    return n * factorial(n - 1)


# ============================================================
# 测试 11：@log 修饰递归函数 — 验证递归保护
# 递归保护确保只有最外层调用打印 LOG，内部递归不触发
# ============================================================

@log
def fib(n: t.CInt) -> t.CInt | t.CExport:
    if n <= 1:
        return n
    return fib(n - 1) + fib(n - 2)


# ============================================================
# 主函数
# ============================================================

def main() -> t.CInt | t.CExport:
    testcheck.begin("Decorator Test v4")

    # 测试 1：单个 @log
    testcheck.section("Test 1: single @log")
    r1: t.CInt = add(3, 4)
    printf("add(3,4) = %d\n", r1)
    testcheck.check(r1 == 7, "add(3,4) = 7", "add(3,4) expect 7")

    # 测试 2：链式 @log @trace
    testcheck.section("Test 2: chained @log @trace")
    r2: t.CInt = multiply(5, 6)
    printf("multiply(5,6) = %d\n", r2)
    testcheck.check(r2 == 30, "multiply(5,6) = 30", "multiply(5,6) expect 30")

    # 测试 3：void 返回
    testcheck.section("Test 3: @log on void function")
    greet("Viper")
    testcheck.ok("@log on void function greet")

    # 测试 4：无参数
    testcheck.section("Test 4: @log on no-arg function")
    r4: t.CInt = get_value()
    printf("get_value() = %d\n", r4)
    testcheck.check(r4 == 42, "get_value() = 42", "get_value() expect 42")

    # 测试 5：@timing
    testcheck.section("Test 5: @timing")
    r5: t.CInt = compute(7)
    printf("compute(7) = %d\n", r5)
    testcheck.check(r5 == 50, "compute(7) = 50", "compute(7) expect 50")

    # 测试 6：@repeat(3) — 流程劫持，循环 3 次
    testcheck.section("Test 6: @repeat(3) flow hijack")
    echo("hello")
    testcheck.ok("@repeat(3) flow hijack echo")

    # 测试 7：链式 @timing @log
    testcheck.section("Test 7: chained @timing @log")
    r7: t.CInt = power(2, 10)
    printf("power(2,10) = %d\n", r7)
    testcheck.check(r7 == 1024, "power(2,10) = 1024", "power(2,10) expect 1024")

    # 测试 8：@skip — 跳过原函数调用
    testcheck.section("Test 8: @skip flow hijack")
    r8: t.CInt = dangerous()
    printf("dangerous() = %d (should be 0, skipped)\n", r8)
    testcheck.check(r8 == 0, "dangerous() skipped = 0", "dangerous() expect 0")

    # 测试 9：@repeat(3) 有返回值
    testcheck.section("Test 9: @repeat(3) with return value")
    r9: t.CInt = accumulate(5)
    printf("accumulate(5) = %d (last iteration result)\n", r9)
    testcheck.check(r9 == 50, "accumulate(5) = 50", "accumulate(5) expect 50")

    # 测试 10：递归装饰保护 — @count_calls
    testcheck.section("Test 10: recursive decoration protection")
    _call_count = 0
    r10: t.CInt = factorial(5)
    printf("factorial(5) = %d (should be 120)\n", r10)
    printf("  decorator call count = %d (should be 1, not 5)\n", _call_count)
    testcheck.check(r10 == 120 and _call_count == 1, "factorial(5)=120, calls=1", "factorial(5) expect 120, calls=1")

    # 测试 11：@log 递归保护 — fib
    testcheck.section("Test 11: @log on recursive fib")
    r11: t.CInt = fib(6)
    printf("fib(6) = %d (should be 8)\n", r11)
    testcheck.check(r11 == 8, "fib(6) = 8", "fib(6) expect 8")

    return testcheck.end()
