// Copyright 2015  Emmanuele Bassi. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#![crate_name = "taglib"]
#![crate_type = "lib"]

extern crate libc;
extern crate taglib_sys as sys;

use libc::c_char;
use std::ffi::{CString, CStr};
use std::path::Path;

use sys as ll;

fn c_str_to_str(c_str: *const c_char) -> Option<String> {
    if c_str.is_null() {
        None
    } else {
        let bytes = unsafe { CStr::from_ptr(c_str).to_bytes() };

        if bytes.is_empty() { None } else { Some(String::from_utf8_lossy(bytes).to_string()) }
    }
}

fn u32_to_option(n: u32) -> Option<u32> {
    if n == 0 { None } else { Some(n) }
}

/// A representation of an audio file, with meta-data and properties.
pub struct File {
    raw: *mut ll::TagLib_File,
}

/// The abstract meta-data container for audio files
///
/// Each `Tag` instance can only be created by the `taglib::File::tag()`
/// method.
#[allow(dead_code)]
pub struct Tag<'a> {
    raw: *mut ll::TagLib_Tag,
    file: &'a File,
}

/// Common audio file properties.
///
/// Instances of `AudioProperties` can only be created through the
/// `taglib::File::audioproperties()` method.
#[allow(dead_code)]
pub struct AudioProperties<'a> {
    raw: *const ll::TagLib_AudioProperties,
    file: &'a File,
}

impl<'a> Tag<'a> {
    /// Returns the track name, if any.
    pub fn title(&self) -> Option<String> {
        let res = unsafe { ll::taglib_tag_title(self.raw) };
        c_str_to_str(res)
    }

    /// Sets the track name.
    pub fn set_title(&mut self, title: &str) {
        let cs = CString::new(title).unwrap();
        let s = cs.as_ptr();
        unsafe {
            ll::taglib_tag_set_title(self.raw, s);
        }
    }

    /// Returns the artist name, if any.
    pub fn artist(&self) -> Option<String> {
        let res = unsafe { ll::taglib_tag_artist(self.raw) };
        c_str_to_str(res)
    }

    /// Sets the artist name.
    pub fn set_artist(&mut self, artist: &str) {
        let cs = CString::new(artist).unwrap();
        let s = cs.as_ptr();
        unsafe {
            ll::taglib_tag_set_artist(self.raw, s);
        }
    }

    /// Returns the album name, if any.
    pub fn album(&self) -> Option<String> {
        let res = unsafe { ll::taglib_tag_album(self.raw) };
        c_str_to_str(res)
    }

    /// Sets the album name.
    pub fn set_album(&mut self, album: &str) {
        let cs = CString::new(album).unwrap();
        let s = cs.as_ptr();
        unsafe {
            ll::taglib_tag_set_album(self.raw, s);
        }
    }

    /// Returns the track comment, if any.
    pub fn comment(&self) -> Option<String> {
        let res = unsafe { ll::taglib_tag_comment(self.raw) };
        c_str_to_str(res)
    }

    /// Sets the track comment.
    pub fn set_comment(&mut self, comment: &str) {
        let cs = CString::new(comment).unwrap();
        let s = cs.as_ptr();
        unsafe {
            ll::taglib_tag_set_comment(self.raw, s);
        }
    }

    /// Returns the genre name, if any.
    pub fn genre(&self) -> Option<String> {
        let res = unsafe { ll::taglib_tag_genre(self.raw) };
        c_str_to_str(res)
    }

    /// Sets the genre name.
    pub fn set_genre(&mut self, genre: &str) {
        let cs = CString::new(genre).unwrap();
        let s = cs.as_ptr();
        unsafe {
            ll::taglib_tag_set_genre(self.raw, s);
        }
    }

    /// Returns the year, if any.
    pub fn year(&self) -> Option<u32> {
        u32_to_option(unsafe { ll::taglib_tag_year(self.raw) as u32 })
    }

    /// Sets the year.
    pub fn set_year(&mut self, year: u32) {
        unsafe {
            ll::taglib_tag_set_year(self.raw, year);
        }
    }

    /// Returns the track number, if any.
    pub fn track(&self) -> Option<u32> {
        u32_to_option(unsafe { ll::taglib_tag_track(self.raw) as u32 })
    }

    /// Sets the track number.
    pub fn set_track(&mut self, track: u32) {
        unsafe {
            ll::taglib_tag_set_track(self.raw, track);
        }
    }
}

impl<'a> AudioProperties<'a> {
    /// Returns the length, in seconds, of the track.
    pub fn length(&self) -> u32 {
        unsafe { ll::taglib_audioproperties_length(self.raw) as u32 }
    }

    /// Returns the most appropriate bit rate for the track, in kB/s.
    /// For constant bit rate formats, the returned value is the bit
    /// rate of the file; for variable bit rate formats this is either
    /// the average or the nominal bit rate.
    pub fn bitrate(&self) -> u32 {
        unsafe { ll::taglib_audioproperties_bitrate(self.raw) as u32 }
    }

    /// Returns the sample rate, in Hz.
    pub fn samplerate(&self) -> u32 {
        unsafe { ll::taglib_audioproperties_samplerate(self.raw) as u32 }
    }

    /// Returns the number of audio channels.
    pub fn channels(&self) -> u32 {
        unsafe { ll::taglib_audioproperties_channels(self.raw) as u32 }
    }
}

#[derive(Copy, Clone, PartialEq)]
pub enum FileType {
    /// MPEG file
    MPEG = ll::TAGLIB_FILE_MPEG as isize,
    /// Ogg/Vorbis file
    OggVorbis = ll::TAGLIB_FILE_OGG_VORBIS as isize,
    /// FLAC file
    FLAC = ll::TAGLIB_FILE_FLAC as isize,
    /// MPC file
    MPC = ll::TAGLIB_FILE_MPC as isize,
    /// Ogg/FLAC file
    OggFlac = ll::TAGLIB_FILE_OGG_FLAC as isize,
    /// WavPack file
    WavPack = ll::TAGLIB_FILE_WAV_PACK as isize,
    /// Ogg/Speex file
    Speex = ll::TAGLIB_FILE_SPEEX as isize,
    /// TrueAudio file
    TrueAudio = ll::TAGLIB_FILE_TRUE_AUDIO as isize,
    /// MP4 file
    MP4 = ll::TAGLIB_FILE_MP4 as isize,
    /// ASF file
    ASF = ll::TAGLIB_FILE_ASF as isize,
}

#[derive(Debug)]
pub enum FileError {
    /// The file is an invalid or an unrecognized audio container
    InvalidFile,
    /// The file name is invalid
    InvalidFileName,
    /// No meta-data is available
    NoAvailableTag,
    /// No audio properties are available
    NoAvailableAudioProperties,
}

impl Drop for File {
    fn drop(&mut self) {
        unsafe {
            ll::taglib_file_free(self.raw);
        }
    }
}

impl File {
    /// Creates a new `taglib::File` for the given `filename`.
    pub fn new<P: AsRef<Path>>(path: P) -> Result<File, FileError> {
        let filename = path.as_ref().to_str().ok_or(FileError::InvalidFileName)?;
        let filename_c = CString::new(filename).ok().ok_or(FileError::InvalidFileName)?;
        let filename_c_ptr = filename_c.as_ptr();

        let f = unsafe { ll::taglib_file_new(filename_c_ptr) };
        if f.is_null() {
            return Err(FileError::InvalidFile);
        }

        Ok(File { raw: f })
    }

    /// Creates a new `taglib::File` for the given `filename` and type of file.
    pub fn new_type(filename: &str, filetype: FileType) -> Result<File, FileError> {
        let filename_c = match CString::new(filename) {
            Ok(s) => s,
            _ => return Err(FileError::InvalidFileName),
        };

        let filename_c_ptr = filename_c.as_ptr();
        let f = unsafe { ll::taglib_file_new_type(filename_c_ptr, filetype as u32) };
        if f.is_null() {
            return Err(FileError::InvalidFile);
        }

        Ok(File { raw: f })
    }

    /// Returns the `taglib::Tag` instance for the given file.
    pub fn tag(&self) -> Result<Tag, FileError> {
        let res = unsafe { ll::taglib_file_tag(self.raw) };

        if res.is_null() {
            Err(FileError::NoAvailableTag)
        } else {
            Ok(Tag {
                raw: res,
                file: self,
            })
        }
    }

    /// Returns whether the file is valid.
    pub fn is_valid(&self) -> bool {
        unsafe { ll::taglib_file_is_valid(self.raw) != 0 }
    }

    /// Returns the `taglib::AudioProperties` instance for the given file.
    pub fn audioproperties(&self) -> Result<AudioProperties, FileError> {
        let res = unsafe { ll::taglib_file_audioproperties(self.raw) };

        if res.is_null() {
            Err(FileError::NoAvailableAudioProperties)
        } else {
            Ok(AudioProperties {
                raw: res,
                file: self,
            })
        }
    }

    /// Updates the meta-data of the file.
    pub fn save(&self) -> bool {
        unsafe { ll::taglib_file_save(self.raw) != 0 }
    }
}


/// Fixture creation:
/// ffmpeg -t 0.01 -f s16le -i /dev/zero test.mp3
/// kid3-cli -c 'set artist "Artist"' test.mp3
#[cfg(test)]
mod test {
    const TEST_MP3: &'static str = "fixtures/test.mp3";

    use super::*;
    use std::fs;
    use std::path::PathBuf;

    #[test]
    fn test_get_tag() {
        let file = File::new(TEST_MP3).unwrap();
        let tag = file.tag().unwrap();
        assert_eq!(tag.artist().unwrap(), "Artist");
    }

    #[test]
    fn test_get_pathbuf() {
        let file = File::new(PathBuf::from(TEST_MP3)).unwrap();
        let tag = file.tag().unwrap();
        assert_eq!(tag.artist().unwrap(), "Artist");
    }

    #[test]
    fn test_get_no_tag() {
        let file = File::new(TEST_MP3).unwrap();
        let tag = file.tag().unwrap();
        assert_eq!(tag.album(), None);
    }

    #[test]
    fn test_get_tag_new_type() {
        let file = File::new_type(TEST_MP3, FileType::MPEG).unwrap();
        let tag = file.tag().unwrap();
        assert_eq!(tag.artist().unwrap(), "Artist");
    }

    #[test]
    fn test_get_audioproperties() {
        let file = File::new(TEST_MP3).unwrap();
        let ap = file.audioproperties().unwrap();
        assert_eq!(ap.length(), 0);
    }

    #[test]
    fn test_set_tag() {
        let temp_fn = "fixtures/temp.mp3";
        fs::copy(TEST_MP3, temp_fn).unwrap();
        let file = File::new(temp_fn).unwrap();
        let mut tag = file.tag().unwrap();
        tag.set_artist("Not Artist");
        assert_eq!(tag.artist().unwrap(), "Not Artist");

        file.save();

        let file = File::new(temp_fn).unwrap();
        let tag = file.tag().unwrap();
        assert_eq!(tag.artist().unwrap(), "Not Artist");

        fs::remove_file(temp_fn).unwrap();
    }
}