#![feature(c_variadic)]

use core::{ffi::*, ptr::null_mut};

extern "C" {
    fn asprintf(s: *mut *mut c_char, format: *const c_char, ...) -> c_int;
    fn free(p: *mut c_void);
}

unsafe extern "C" fn rust_fmt(str: *const c_char, mut args: ...) -> Box<(c_int, String)> {
    let mut s = String::new();
    let bytes_written = printf_compat::format(
        str,
        args.clone().as_va_list(),
        printf_compat::output::fmt_write(&mut s),
    );
    assert!(bytes_written >= 0);
    let mut s2 = std::io::Cursor::new(vec![]);
    assert_eq!(
        bytes_written,
        printf_compat::format(
            str,
            args.as_va_list(),
            printf_compat::output::io_write(&mut s2),
        )
    );
    assert_eq!(s.as_bytes(), s2.get_ref());
    Box::new((bytes_written, s))
}

macro_rules! c_fmt {
    ($format:literal $(, $p:expr)*) => {{
        let mut ptr = null_mut();
        let bytes_written = asprintf(&mut ptr, $format.as_ptr() $(, $p)*);
        assert!(bytes_written >= 0);
        let s: String = CStr::from_ptr(ptr).to_string_lossy().into();
        free(ptr.cast());
        (bytes_written, s)
    }};
}

/// Assert that `rust_fmt` produces the same output as C's `asprintf`,
/// and that both match the `expected` literal.
///
/// This takes a format literal, followed by optional printf arguments,
/// followed by `=>` and then the `expected` output.
///
/// Example usage:
///
/// ```
/// assert_eq_fmt!(c"%d %d", 1, 2 => "1 2");
/// ```
macro_rules! assert_eq_fmt {
    ($format:literal $(, $p:expr)* => $expected:literal) => {
        let (bytes_written, s) = c_fmt!($format $(, $p)*);
        assert_eq!(s, $expected);
        assert_eq!((bytes_written, s), *rust_fmt($format.as_ptr().cast(), $($p),*));
        assert_eq!(usize::try_from(bytes_written).unwrap(), $expected.len());
    };
}

/// Assert that a format string fails to parse. This checks that both
/// C's `asprintf` and `printf_compat::format` return -1.
fn assert_fmt_err(fmt: &CStr) {
    let mut ptr = null_mut();
    let bytes_written = unsafe { asprintf(&mut ptr, fmt.as_ptr()) };
    assert_eq!(bytes_written, -1, "asprintf parse unexpectedly succeeded");

    unsafe extern "C" fn format(str: *const c_char, args: ...) -> c_int {
        let mut s = String::new();
        let bytes_written = printf_compat::format(
            str,
            args.clone().as_va_list(),
            printf_compat::output::fmt_write(&mut s),
        );
        bytes_written
    }
    let bytes_written = unsafe { format(fmt.as_ptr()) };
    assert_eq!(
        bytes_written, -1,
        "printf_compat::output parse unexpectedly succeeded"
    );
}

#[test]
fn test_plain() {
    unsafe {
        assert_eq_fmt!(c"abc" => "abc");
        assert_eq_fmt!(c"" => "");
        assert_eq_fmt!(c"%%" => "%");
        assert_eq_fmt!(c"%% def" => "% def");
        assert_eq_fmt!(c"abc %%" => "abc %");
        assert_eq_fmt!(c"abc %% def" => "abc % def");
        assert_eq_fmt!(c"abc %%%% def" => "abc %% def");
        assert_eq_fmt!(c"%%%%%%" => "%%%");
    }
}

#[test]
fn test_str() {
    unsafe {
        assert_eq_fmt!(c"hello %s", c"world" => "hello world");
        assert_eq_fmt!(c"hello %%%s", c"world" => "hello %world");
        assert_eq_fmt!(c"%10s", c"world" => "     world");
        assert_eq_fmt!(c"%.4s", c"world" => "worl");
        assert_eq_fmt!(c"%10.4s", c"world" => "      worl");
        assert_eq_fmt!(c"%-10.4s", c"world" => "worl      ");
        assert_eq_fmt!(c"%-10s", c"world" => "world     ");
        assert_eq_fmt!(c"%s", null_mut::<c_char>() => "(null)");
    }
}

#[test]
fn test_int() {
    unsafe {
        assert_eq_fmt!(c"% 0*i", 17, 23125 => " 0000000000023125");
        assert_eq_fmt!(c"% 010i", 23125 => " 000023125");
        assert_eq_fmt!(c"% 10i", 23125 => "     23125");
        assert_eq_fmt!(c"% 5i", 23125 => " 23125");
        assert_eq_fmt!(c"% 4i", 23125 => " 23125");
        assert_eq_fmt!(c"%- 010i", 23125 => " 23125    ");
        assert_eq_fmt!(c"%- 10i", 23125 => " 23125    ");
        assert_eq_fmt!(c"%- 5i", 23125 => " 23125");
        assert_eq_fmt!(c"%- 4i", 23125 => " 23125");
        assert_eq_fmt!(c"%+ 010i", 23125 => "+000023125");
        assert_eq_fmt!(c"%+ 10i", 23125 => "    +23125");
        assert_eq_fmt!(c"%+ 5i", 23125 => "+23125");
        assert_eq_fmt!(c"%+ 4i", 23125 => "+23125");
        assert_eq_fmt!(c"%-010i", 23125 => "23125     ");
        assert_eq_fmt!(c"%-10i", 23125 => "23125     ");
        assert_eq_fmt!(c"%-5i", 23125 => "23125");
        assert_eq_fmt!(c"%-4i", 23125 => "23125");
    }
}

#[test]
fn test_int_length_signed() {
    unsafe {
        assert_eq_fmt!(c"%hhi", -125 => "-125");
        assert_eq_fmt!(c"%hi", -23125 => "-23125");
        assert_eq_fmt!(c"%li", -211_126_823_125i64 => "-211126823125");
        assert_eq_fmt!(c"%lli", -211_126_823_125i64 => "-211126823125");
        assert_eq_fmt!(c"%ti", -211_126_823_125isize => "-211126823125");
        assert_eq_fmt!(c"%zi", 211_126_823_125usize => "211126823125");

        assert_eq_fmt!(c"% 5hhi", -125 => " -125");
        assert_eq_fmt!(c"% 7hi", -23125 => " -23125");
        assert_eq_fmt!(c"% 14li", -211_126_823_125i64 => " -211126823125");
        assert_eq_fmt!(c"% 14lli", -211_126_823_125i64 => " -211126823125");
        assert_eq_fmt!(c"% 14ti", -211_126_823_125isize => " -211126823125");
        assert_eq_fmt!(c"% 13zi", 211_126_823_125usize => " 211126823125");
    }
}

#[test]
fn test_int_length_unsigned() {
    unsafe {
        assert_eq_fmt!(c"%hhu", 125 => "125");
        assert_eq_fmt!(c"%hu", 23125 => "23125");
        assert_eq_fmt!(c"%lu", 211_126_823_125u64 => "211126823125");
        assert_eq_fmt!(c"%llu", 211_126_823_125u64 => "211126823125");
        assert_eq_fmt!(c"%tu", 211_126_823_125isize => "211126823125");
        assert_eq_fmt!(c"%zu", 211_126_823_125usize => "211126823125");
    }
}

#[test]
fn test_octal() {
    unsafe {
        assert_eq_fmt!(c"% 010o", 23125 => "0000055125");
        assert_eq_fmt!(c"% 10o", 23125 => "     55125");
        assert_eq_fmt!(c"% 5o", 23125 => "55125");
        assert_eq_fmt!(c"% 4o", 23125 => "55125");
        assert_eq_fmt!(c"%- 010o", 23125 => "55125     ");
        assert_eq_fmt!(c"%- 10o", 23125 => "55125     ");
        assert_eq_fmt!(c"%- 5o", 23125 => "55125");
        assert_eq_fmt!(c"%- 4o", 23125 => "55125");
        assert_eq_fmt!(c"%+ 010o", 23125 => "0000055125");
        assert_eq_fmt!(c"%+ 10o", 23125 => "     55125");
        assert_eq_fmt!(c"%+ 5o", 23125 => "55125");
        assert_eq_fmt!(c"%+ 4o", 23125 => "55125");
        assert_eq_fmt!(c"%-010o", 23125 => "55125     ");
        assert_eq_fmt!(c"%-10o", 23125 => "55125     ");
        assert_eq_fmt!(c"%-5o", 23125 => "55125");
        assert_eq_fmt!(c"%-4o", 23125 => "55125");
    }
}

#[test]
fn test_hex() {
    unsafe {
        assert_eq_fmt!(c"% 010x", 23125 => "0000005a55");
        assert_eq_fmt!(c"% 10x", 23125 => "      5a55");
        assert_eq_fmt!(c"% 5x", 23125 => " 5a55");
        assert_eq_fmt!(c"% 4x", 23125 => "5a55");
        assert_eq_fmt!(c"%- 010x", 23125 => "5a55      ");
        assert_eq_fmt!(c"%- 10x", 23125 => "5a55      ");
        assert_eq_fmt!(c"%- 5x", 23125 => "5a55 ");
        assert_eq_fmt!(c"%- 4x", 23125 => "5a55");
        assert_eq_fmt!(c"%+ 010x", 23125 => "0000005a55");
        assert_eq_fmt!(c"%+ 10x", 23125 => "      5a55");
        assert_eq_fmt!(c"%+ 5x", 23125 => " 5a55");
        assert_eq_fmt!(c"%+ 4x", 23125 => "5a55");
        assert_eq_fmt!(c"%-010x", 23125 => "5a55      ");
        assert_eq_fmt!(c"%-10x", 23125 => "5a55      ");
        assert_eq_fmt!(c"%-5x", 23125 => "5a55 ");
        assert_eq_fmt!(c"%-4x", 23125 => "5a55");

        assert_eq_fmt!(c"%# 010x", 23125 => "0x00005a55");
        assert_eq_fmt!(c"%# 10x", 23125 => "    0x5a55");
        assert_eq_fmt!(c"%# 5x", 23125 => "0x5a55");
        assert_eq_fmt!(c"%# 4x", 23125 => "0x5a55");
        assert_eq_fmt!(c"%#- 010x", 23125 => "0x5a55    ");
        assert_eq_fmt!(c"%#- 10x", 23125 => "0x5a55    ");
        assert_eq_fmt!(c"%#- 5x", 23125 => "0x5a55");
        assert_eq_fmt!(c"%#- 4x", 23125 => "0x5a55");
        assert_eq_fmt!(c"%#+ 010x", 23125 => "0x00005a55");
        assert_eq_fmt!(c"%#+ 10x", 23125 => "    0x5a55");
        assert_eq_fmt!(c"%#+ 5x", 23125 => "0x5a55");
        assert_eq_fmt!(c"%#+ 4x", 23125 => "0x5a55");
        assert_eq_fmt!(c"%#-010x", 23125 => "0x5a55    ");
        assert_eq_fmt!(c"%#-10x", 23125 => "0x5a55    ");
        assert_eq_fmt!(c"%#-5x", 23125 => "0x5a55");
        assert_eq_fmt!(c"%#-4x", 23125 => "0x5a55");

        assert_eq_fmt!(c"% 010X", 23125 => "0000005A55");
        assert_eq_fmt!(c"% 10X", 23125 => "      5A55");
        assert_eq_fmt!(c"% 5X", 23125 => " 5A55");
        assert_eq_fmt!(c"% 4X", 23125 => "5A55");
        assert_eq_fmt!(c"%- 010X", 23125 => "5A55      ");
        assert_eq_fmt!(c"%- 10X", 23125 => "5A55      ");
        assert_eq_fmt!(c"%- 5X", 23125 => "5A55 ");
        assert_eq_fmt!(c"%- 4X", 23125 => "5A55");
        assert_eq_fmt!(c"%+ 010X", 23125 => "0000005A55");
        assert_eq_fmt!(c"%+ 10X", 23125 => "      5A55");
        assert_eq_fmt!(c"%+ 5X", 23125 => " 5A55");
        assert_eq_fmt!(c"%+ 4X", 23125 => "5A55");
        assert_eq_fmt!(c"%-010X", 23125 => "5A55      ");
        assert_eq_fmt!(c"%-10X", 23125 => "5A55      ");
        assert_eq_fmt!(c"%-5X", 23125 => "5A55 ");
        assert_eq_fmt!(c"%-4X", 23125 => "5A55");
    }
}

#[test]
fn test_float() {
    unsafe {
        assert_eq_fmt!(c"%f", 1234f64 => "1234.000000");
        assert_eq_fmt!(c"%.5f", 1234f64 => "1234.00000");
        assert_eq_fmt!(c"%.*f", 1234f64, 3 => "1234.000");
    }
}

#[test]
fn test_char() {
    unsafe {
        assert_eq_fmt!(c"%c", b'a' as c_int => "a");
        assert_eq_fmt!(c"%10c", b'a' as c_int => "         a");
        assert_eq_fmt!(c"%-10c", b'a' as c_int => "a         ");
    }
}

#[test]
fn test_errors() {
    assert_fmt_err(c"%");
    assert_fmt_err(c"%1");
}