use libc::{c_char};
use std::ffi::{CStr, CString};
use std::ptr;
use std::u64;
use std::slice;
use std::io::Read;
use std::fs::File;
use std::path::Path;

#[repr(C)]
pub enum GstFlowReturn {
    Ok = 0,
    NotLinked = -1,
    Flushing = -2,
    Eos = -3,
    NotNegotiated = -4,
    Error = -5,
}

#[repr(C)]
pub enum GBoolean {
    False = 0,
    True = 1,
}

impl GBoolean {
    fn from_bool(v: bool) -> GBoolean {
        match v {
            true => GBoolean::True,
            false => GBoolean::False,
        }
    }
}

#[derive(Debug)]
pub struct FileSrc {
    location: Option<String>,
    file: Option<File>,
}

impl FileSrc {
    fn new() -> FileSrc {
        FileSrc { location: None, file: None }
    }

    fn set_location(&mut self, location: &Option<String>) {
        self.location = location.clone();
    }

    fn get_location(&self) -> &Option<String> {
        &self.location
    }

    fn is_seekable(&self) -> bool {
        true
    }

    fn get_size(&self) -> u64 {
        match self.file {
            None => return u64::MAX,
            Some(ref f) => {
                return f.metadata().unwrap().len();
            },
        }
    }

    fn start(&mut self) -> bool {
        if self.location.is_none() { return false; }

        self.file = Some(File::open(Path::new(&self.location.clone().unwrap())).unwrap());

        return true;
    }

    fn stop(&mut self) -> bool {
        self.file = None;

        true
    }

    fn fill(&mut self, data: &mut [u8]) -> GstFlowReturn {
        match self.file {
            None => return GstFlowReturn::Error,
            Some(ref mut f) => {
                // FIXME: Need to return the actual size, handle EOF, etc
                f.read(data);
                return GstFlowReturn::Ok;
            },
        }
    }
}

impl Drop for FileSrc {
    fn drop(&mut self) {
        println!("drop");
    }
}

#[no_mangle]
pub extern "C" fn filesrc_new() -> *mut FileSrc {
    let instance = Box::new(FileSrc::new());
    return Box::into_raw(instance);
}

#[no_mangle]
pub extern "C" fn filesrc_drop(ptr: *mut FileSrc) {
    unsafe { Box::from_raw(ptr) };
}

#[no_mangle]
pub extern "C" fn filesrc_set_location(ptr: *mut FileSrc, location_ptr: *const c_char) {
    let filesrc: &mut FileSrc = unsafe { &mut *ptr };

    if location_ptr.is_null() {
        filesrc.set_location(&None)
    } else {
        let location = unsafe { CStr::from_ptr(location_ptr) };
        filesrc.set_location(&Some(String::from(location.to_str().unwrap())));
    }
}

#[no_mangle]
pub extern "C" fn filesrc_get_location(ptr: *mut FileSrc) -> *mut c_char {
    let filesrc: &mut FileSrc = unsafe { &mut *ptr };

    match *filesrc.get_location() {
        Some(ref location) =>
            CString::new(location.clone().into_bytes()).unwrap().into_raw(),
        None =>
            ptr::null_mut()
    }
}

#[no_mangle]
pub extern "C" fn filesrc_fill(ptr: *mut FileSrc, data_ptr: *mut u8, data_len: usize) -> GstFlowReturn {
    let filesrc: &mut FileSrc = unsafe { &mut *ptr };

    println!("{:?}", filesrc);
    let mut data = unsafe { slice::from_raw_parts_mut(data_ptr, data_len) };
    return filesrc.fill(data);
}

#[no_mangle]
pub extern "C" fn filesrc_get_size(ptr: *mut FileSrc) -> u64 {
    let filesrc: &mut FileSrc = unsafe { &mut *ptr };

    return filesrc.get_size();
}

#[no_mangle]
pub extern "C" fn filesrc_start(ptr: *mut FileSrc) -> GBoolean {
    let filesrc: &mut FileSrc = unsafe { &mut *ptr };

    GBoolean::from_bool(filesrc.start())
}

#[no_mangle]
pub extern "C" fn filesrc_stop(ptr: *mut FileSrc) -> GBoolean {
    let filesrc: &mut FileSrc = unsafe { &mut *ptr };

    GBoolean::from_bool(filesrc.stop())
}

#[no_mangle]
pub extern "C" fn filesrc_is_seekable(ptr: *mut FileSrc) -> GBoolean {
    let filesrc: &mut FileSrc = unsafe { &mut *ptr };

    GBoolean::from_bool(filesrc.is_seekable())
}