use std::os::raw::{c_char, c_void};
use std::ffi::CString;

/// # TIFF Internal Structure
/// An opaque type
#[repr(C)]
pub struct TIFF {
    _unused: [u8; 0],
}

/// # TIFF Warning Handler Definition
pub type TIFFWarningHandler = Option<unsafe extern "C" fn(module: *const c_char, fmt: *const c_char, ap: *mut c_void)>;

/// # TIFF Ignore Warnings Handle
unsafe extern "C" fn tiff_ignore_warning_handle(_module: *const c_char, _fmt: *const c_char, _ap: *mut std::ffi::c_void) {
    // Do nothing
}

#[link(name = "tiff")]
unsafe extern "C" {
    pub fn TIFFSetWarningHandler(handler: TIFFWarningHandler) -> TIFFWarningHandler;
    pub fn TIFFOpen(filename: *const c_char, mode: *const c_char) -> *mut TIFF;
    pub fn TIFFClose(tiff_ptr: *mut TIFF);
}

/// # Ignore TIFF Warnings
pub fn tiff_ignore_warnings() {
    unsafe {
        let _ = TIFFSetWarningHandler(Some(tiff_ignore_warning_handle));
    }
}

/// # Open TIFF File
pub fn tiff_open(filename: &str) -> *mut TIFF {
    let c_filename = CString::new(filename).expect("Cast error");
    let c_mode = CString::new("r").expect("Cast error");
    unsafe {
        TIFFOpen(c_filename.as_ptr(), c_mode.as_ptr())
    }
}

/// # Close TIFF File
pub fn tiff_close(tiff_ptr: *mut TIFF) {
    unsafe {
        TIFFClose(tiff_ptr);
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn it_works() {
        assert_eq!(0, 0);
    }

    #[test]
    fn ignore_warning_test() {
        tiff_ignore_warnings();
        assert_eq!(1, 1);
    }

    #[test]
    fn tiff_open_test() {
        tiff_ignore_warnings();
        let result = tiff_open("../test.tif");
        assert!(!result.is_null());
        tiff_close(result);
        assert_eq!(1, 1);
    }
}