use alloc::boxed::Box;

use crate::fs::File;
use crate::header::errno;
use crate::header::fcntl::*;
use crate::header::string::strchr;
use crate::io::LineWriter;
use crate::platform;
use crate::platform::types::*;
use crate::sync::Mutex;

use super::constants::*;
use super::{Buffer, FILE};

/// Parse mode flags as a string and output a mode flags integer
pub unsafe fn parse_mode_flags(mode_str: *const c_char) -> i32 {
    let mut flags = if !strchr(mode_str, b'+' as i32).is_null() {
        O_RDWR
    } else if (*mode_str) == b'r' as i8 {
        O_RDONLY
    } else {
        O_WRONLY
    };
    if !strchr(mode_str, b'x' as i32).is_null() {
        flags |= O_EXCL;
    }
    if !strchr(mode_str, b'e' as i32).is_null() {
        flags |= O_CLOEXEC;
    }
    if (*mode_str) != b'r' as i8 {
        flags |= O_CREAT;
    }
    if (*mode_str) == b'w' as i8 {
        flags |= O_TRUNC;
    } else if (*mode_str) == b'a' as i8 {
        flags |= O_APPEND;
    }

    flags
}

/// Open a file with the file descriptor `fd` in the mode `mode`
pub unsafe fn _fdopen(fd: c_int, mode: *const c_char) -> Option<*mut FILE> {
    if *mode != b'r' as i8 && *mode != b'w' as i8 && *mode != b'a' as i8 {
        platform::errno = errno::EINVAL;
        return None;
    }

    let mut flags = 0;
    if strchr(mode, b'+' as i32).is_null() {
        flags |= if *mode == b'r' as i8 { F_NOWR } else { F_NORD };
    }

    if !strchr(mode, b'e' as i32).is_null() {
        sys_fcntl(fd, F_SETFD, FD_CLOEXEC);
    }

    if *mode == 'a' as i8 {
        let f = sys_fcntl(fd, F_GETFL, 0);
        if (f & O_APPEND) == 0 {
            sys_fcntl(fd, F_SETFL, f | O_APPEND);
        }
        flags |= F_APP;
    }

    let file = File::new(fd);
    let writer = LineWriter::new(file.get_ref());

    Some(Box::into_raw(Box::new(FILE {
        lock: Mutex::new(()),

        file,
        flags,
        read_buf: Buffer::Owned(vec![0; BUFSIZ as usize]),
        read_pos: 0,
        read_size: 0,
        unget: None,
        writer,

        pid: None,
    })))
}