//  Copyright (C) 2016 Sebastian Dröge <sebastian@centricular.com>
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Library General Public
//  License as published by the Free Software Foundation; either
//  version 2 of the License, or (at your option) any later version.
//
//  This library is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//  Library General Public License for more details.
//
//  You should have received a copy of the GNU Library General Public
//  License along with this library; if not, write to the
//  Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
//  Boston, MA 02110-1301, USA.

use std::u64;
use std::io::{Read, Seek, SeekFrom};
use std::fs::File;
use std::path::PathBuf;
use std::sync::Mutex;
use url::Url;

use std::io::Write;

use utils::*;
use rssource::*;

#[derive(Debug)]
struct Settings {
    location: Option<PathBuf>,
}

#[derive(Debug)]
enum StreamingState {
    Stopped,
    Started { file: File, position: u64 },
}

#[derive(Debug)]
pub struct FileSrc {
    controller: SourceController,
    settings: Mutex<Settings>,
    streaming_state: Mutex<StreamingState>,
}

unsafe impl Sync for FileSrc {}
unsafe impl Send for FileSrc {}

impl FileSrc {
    pub fn new(controller: SourceController) -> FileSrc {
        FileSrc {
            controller: controller,
            settings: Mutex::new(Settings { location: None }),
            streaming_state: Mutex::new(StreamingState::Stopped),
        }
    }

    pub fn new_boxed(controller: SourceController) -> Box<Source> {
        Box::new(FileSrc::new(controller))
    }
}

impl Source for FileSrc {
    fn set_uri(&self, uri: Option<Url>) -> bool {
        let location = &mut self.settings.lock().unwrap().location;

        match uri {
            None => {
                *location = None;
                true
            }
            Some(ref uri) => {
                match uri.to_file_path().ok() {
                    Some(p) => {
                        *location = Some(p);
                        true
                    }
                    None => {
                        *location = None;
                        println_err!("Unsupported file URI '{}'", uri.as_str());
                        false
                    }
                }
            }
        }
    }

    fn get_uri(&self) -> Option<Url> {
        let location = &self.settings.lock().unwrap().location;

        location.as_ref()
            .map(|l| Url::from_file_path(l).ok())
            .and_then(|i| i) // join()
    }

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

    fn get_size(&self) -> u64 {
        let streaming_state = self.streaming_state.lock().unwrap();

        if let StreamingState::Started { ref file, .. } = *streaming_state {
            file.metadata()
                .ok()
                .map_or(u64::MAX, |m| m.len())
        } else {
            u64::MAX
        }
    }

    fn start(&self) -> bool {
        let location = &self.settings.lock().unwrap().location;
        let mut streaming_state = self.streaming_state.lock().unwrap();

        if let StreamingState::Started { .. } = *streaming_state {
            return false;
        }

        match *location {
            None => false,
            Some(ref location) => {
                match File::open(location.as_path()) {
                    Ok(file) => {
                        *streaming_state = StreamingState::Started {
                            file: file,
                            position: 0,
                        };
                        true
                    }
                    Err(err) => {
                        println_err!("Could not open file for writing '{}': {}",
                                     location.to_str().unwrap_or("Non-UTF8 path"),
                                     err.to_string());
                        false
                    }
                }
            }
        }
    }

    fn stop(&self) -> bool {
        let mut streaming_state = self.streaming_state.lock().unwrap();
        *streaming_state = StreamingState::Stopped;

        true
    }

    fn fill(&self, offset: u64, data: &mut [u8]) -> Result<usize, GstFlowReturn> {
        let mut streaming_state = self.streaming_state.lock().unwrap();

        if let StreamingState::Started { ref mut file, ref mut position } = *streaming_state {
            if *position != offset {
                match file.seek(SeekFrom::Start(offset)) {
                    Ok(_) => {
                        *position = offset;
                    }
                    Err(err) => {
                        println_err!("Failed to seek to {}: {}", offset, err.to_string());
                        return Err(GstFlowReturn::Error);
                    }
                }
            }

            match file.read(data) {
                Ok(size) => {
                    *position += size as u64;
                    Ok(size)
                }
                Err(err) => {
                    println_err!("Failed to read at {}: {}", offset, err.to_string());
                    Err(GstFlowReturn::Error)
                }
            }
        } else {
            Err(GstFlowReturn::Error)
        }
    }

    fn do_seek(&self, _: u64, _: u64) -> bool {
        true
    }
}