from stdio import printf
import testcheck

# Custom decorator handler calling convention (v4): i32 decor(ctx, func_name, phase, args_ptr, ret_ptr, decor_args_ptr).
# ctx: per-call frame-local context (32 bytes); args_ptr/ret_ptr are read-write; pre-phase returns 0=skip, 1=call once, N=loop N.

# @log: print enter/exit, return 1 (call once)
export def log(ctx: rawptr, func_name: str, phase: int,
        args_ptr: rawptr,
        ret_ptr: rawptr,
        decor_args_ptr: rawptr) -> int:
    if phase == 0:
        printf("[LOG] >> %s enter\n", func_name)
        return 1
    else:
        printf("[LOG] << %s exit\n", func_name)
        return 0

# @trace: verbose tracing
export def trace(ctx: rawptr, func_name: str, phase: int,
          args_ptr: rawptr,
          ret_ptr: rawptr,
          decor_args_ptr: rawptr) -> int:
    if phase == 0:
        printf("[TRACE] calling %s...\n", func_name)
        return 1
    else:
        printf("[TRACE] %s returned\n", func_name)
        return 0

# @timing: measures elapsed time using a global counter.
# A global is used because i8* to i32* pointer casts are not supported yet.
_timing_tmp: int = 0

export def timing(ctx: rawptr, func_name: str, phase: int,
           args_ptr: rawptr,
           ret_ptr: rawptr,
           decor_args_ptr: rawptr) -> int:
    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: int = 105 - _timing_tmp
        printf("[TIMING] %s took %d ms\n", func_name, elapsed)
        return 0

# @repeat (with args, flow hijack): call the original function N times
export def repeat(ctx: rawptr, func_name: str, phase: int,
           args_ptr: rawptr,
           ret_ptr: rawptr,
           decor_args_ptr: rawptr) -> int:
    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: skip the original call (flow hijack, returns 0)
_skip_count: int = 0

export def skip(ctx: rawptr, func_name: str, phase: int,
         args_ptr: rawptr,
         ret_ptr: rawptr,
         decor_args_ptr: rawptr) -> int:
    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: count invocations (used to test recursion guard)
_call_count: int = 0

export def count_calls(ctx: rawptr, func_name: str, phase: int,
                args_ptr: rawptr,
                ret_ptr: rawptr,
                decor_args_ptr: rawptr) -> int:
    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


# --- Test 1: single @log ---
@log
export def add(a: int, b: int) -> int:
    return a + b


# --- Test 2: chained @log @trace (log(trace(f))) ---
@log
@trace
export def multiply(a: int, b: int) -> int:
    return a * b


# --- Test 3: @log on void function ---
@log
export def greet(name: str):
    printf("Hello, %s!\n", name)


# --- Test 4: @log on no-arg function ---
@log
export def get_value() -> int:
    return 42


# --- Test 5: @timing ---
@timing
export def compute(x: int) -> int:
    return x * x + 1


# --- Test 6: @repeat(3) flow hijack ---
@repeat(3)
export def echo(msg: str):
    printf("  echo: %s\n", msg)


# --- Test 7: chained @timing @log ---
@timing
@log
export def power(base: int, exp: int) -> int:
    result: int = 1
    for i in range(exp):
        result = result * base
    return result


# --- Test 8: @skip flow hijack ---
@skip
export def dangerous() -> int:
    printf("This should NOT be printed!\n")
    return 999


# --- Test 9: @repeat(3) with return value ---
@repeat(3)
export def accumulate(x: int) -> int:
    printf("  accumulate(%d)\n", x)
    return x * 10


# --- Test 10: recursion guard, @count_calls on recursive fn ---
@count_calls
export def factorial(n: int) -> int:
    if n <= 1:
        return 1
    return n * factorial(n - 1)


# --- Test 11: @log on recursive fib ---
@log
export def fib(n: int) -> int:
    if n <= 1:
        return n
    return fib(n - 1) + fib(n - 2)


# --- main ---
export def main() -> int:
    testcheck.begin("Decorator Test v4")

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

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

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

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

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

    # Test 6: @repeat(3) flow hijack, loops 3 times
    testcheck.section("Test 6: @repeat(3) flow hijack")
    echo("hello")
    testcheck.ok("@repeat(3) flow hijack echo")

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

    # Test 8: @skip, skips the original call
    testcheck.section("Test 8: @skip flow hijack")
    r8: int = dangerous()
    printf("dangerous() = %d (should be 0, skipped)\n", r8)
    testcheck.check(r8 == 0, "dangerous() skipped = 0", "dangerous() expect 0")

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

    # Test 10: recursion guard, @count_calls
    testcheck.section("Test 10: recursive decoration protection")
    global _call_count
    _call_count = 0
    r10: int = 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")

    # Test 11: @log recursion guard, fib
    testcheck.section("Test 11: @log on recursive fib")
    r11: int = 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()