//
//  rhimportd
//
//  The Radio Helsinki Rivendell Import Daemon
//
//
//  Copyright (C) 2015-2016 Christian Pointner <equinox@helsinki.at>
//
//  This file is part of rhimportd.
//
//  rhimportd is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  any later version.
//
//  rhimportd 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 General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with rhimportd. If not, see <http://www.gnu.org/licenses/>.
//

package rhimport

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"
)

type FetchConverter interface {
	io.WriteCloser
	GetResult(ctx *Context, res *Result) (result string, err error)
}

type FetchConverterResult struct {
	output       string
	err          error
	loudnessCorr float64
}

func NewFetchConverter(convType, filename string, metadata map[string]string, channels uint) (FetchConverter, string, error) {
	switch convType {
	case "null":
		return NewNullFetchConverter(filename, metadata, channels)
	case "ffmpeg":
		return NewFFMpegFetchConverter(filename, metadata, channels)
	case "bs1770":
		return NewBS1770FetchConverter(filename, metadata, channels)
	case "ffmpeg-bs1770":
		return NewFFMpegBS1770FetchConverter(filename, metadata, channels)
	}
	return nil, "", errors.New("unknown fetch converter type: " + convType)
}

//
// NUll Converter aka File Writer
//

type NullFetchConverter struct {
	file *os.File
}

func NewNullFetchConverter(filename string, metadata map[string]string, channels uint) (n *NullFetchConverter, newFilename string, err error) {
	n = &NullFetchConverter{}
	rhl.Printf("null-converter: opening file '%s'", filename)
	newFilename = filename
	n.file, err = os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0600)
	return
}

func (c *NullFetchConverter) Write(p []byte) (n int, err error) {
	return c.file.Write(p)
}

func (c *NullFetchConverter) Close() (err error) {
	return c.file.Close()
}

func (c *NullFetchConverter) GetResult(ctx *Context, res *Result) (result string, err error) {
	return "", nil
}

//
// FFMpeg Converter: converts all files into flac
//

type FFMpegFetchConverter struct {
	cmd    *exec.Cmd
	pipe   io.WriteCloser
	result chan FetchConverterResult
}

func NewFFMpegFetchConverter(filename string, metadata map[string]string, channels uint) (ff *FFMpegFetchConverter, filenameFlac string, err error) {
	ff = &FFMpegFetchConverter{}
	ext := filepath.Ext(filename)
	filenameFlac = strings.TrimSuffix(filename, ext) + ".flac"
	rhl.Printf("ffmpeg-converter: starting ffmpeg for file '%s' (had extension: '%s')", filenameFlac, ext)
	ff.cmd = exec.Command("ffmpeg", "-loglevel", "warning", "-i", "-", "-map_metadata", "0")
	if metadata != nil {
		for key, value := range metadata {
			ff.cmd.Args = append(ff.cmd.Args, "-metadata", fmt.Sprintf("%s=%s", key, value))
		}
	}
	ff.cmd.Args = append(ff.cmd.Args, "-ac", strconv.FormatUint(uint64(channels), 10), "-f", "flac", filenameFlac)
	if ff.pipe, err = ff.cmd.StdinPipe(); err != nil {
		return nil, "", err
	}

	ff.result = make(chan FetchConverterResult, 1)
	go func() {
		output, err := ff.cmd.CombinedOutput()
		ff.result <- FetchConverterResult{strings.TrimSpace(string(output)), err, 0.0}
	}()
	return
}

func (ff *FFMpegFetchConverter) Write(p []byte) (n int, err error) {
	return ff.pipe.Write(p)
}

func (ff *FFMpegFetchConverter) Close() (err error) {
	return ff.pipe.Close()
}

func (ff *FFMpegFetchConverter) GetResult(ctx *Context, res *Result) (result string, err error) {
	if ff.result != nil {
		r := <-ff.result
		ctx.LoudnessCorr = r.loudnessCorr
		return r.output, r.err
	}
	return "", nil
}

//
// BS1770 Converter: calculates loudness correction value using ITU BS1770 (EBU R128)
//

type BS1770FetchConverter struct {
	cmd    *exec.Cmd
	file   *os.File
	pipe   io.WriteCloser
	multi  io.Writer
	result chan FetchConverterResult
}

func NewBS1770FetchConverter(filename string, metadata map[string]string, channels uint) (bs *BS1770FetchConverter, newFilename string, err error) {
	bs = &BS1770FetchConverter{}
	rhl.Printf("bs1770-converter: opening file '%s'", filename)
	newFilename = filename
	bs.file, err = os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0600)

	bs.cmd = exec.Command("bs1770gain", "--ebu", "-i", "--xml", "-")
	if bs.pipe, err = bs.cmd.StdinPipe(); err != nil {
		return nil, "", err
	}
	bs.multi = io.MultiWriter(bs.file, bs.pipe)

	var bsStdout, bsStderr bytes.Buffer
	bs.cmd.Stdout = &bsStdout
	bs.cmd.Stderr = &bsStderr

	bs.result = make(chan FetchConverterResult, 1)
	go func() {
		if err := bs.cmd.Run(); err != nil {
			bs.result <- FetchConverterResult{strings.TrimSpace(string(bsStderr.String())), err, 0.0}
		}

		res, err := NewBS1770ResultFromXML(&bsStdout)
		if err != nil {
			bs.result <- FetchConverterResult{bsStdout.String(), err, 0.0}
		}
		if len(res.Album.Tracks) == 0 {
			bs.result <- FetchConverterResult{bsStdout.String(), fmt.Errorf("bs1770gain returned no/invalid result"), 0.0}
		}
		bs.result <- FetchConverterResult{"", nil, res.Album.Tracks[0].Integrated.LU}
	}()
	return
}

func (bs *BS1770FetchConverter) Write(p []byte) (n int, err error) {
	return bs.multi.Write(p)
}

func (bs *BS1770FetchConverter) Close() (err error) {
	errPipe := bs.pipe.Close()
	errFile := bs.file.Close()
	if errFile != nil {
		return errFile
	}
	return errPipe
}

func (bs *BS1770FetchConverter) GetResult(ctx *Context, res *Result) (result string, err error) {
	if bs.result != nil {
		r := <-bs.result
		ctx.LoudnessCorr = r.loudnessCorr
		return r.output, r.err
	}
	return "", nil
}

//
// FFMpeg/BS1770 Converter: converts all files into flac and calculates loudness correction value
// using ITU BS1770 (EBU R128)
//

type FFMpegBS1770FetchConverter struct {
	ffmpeg   *exec.Cmd
	bs1770   *exec.Cmd
	pipe     io.WriteCloser
	resultFF chan FetchConverterResult
	resultBS chan FetchConverterResult
}

func NewFFMpegBS1770FetchConverter(filename string, metadata map[string]string, channels uint) (ff *FFMpegBS1770FetchConverter, filenameFlac string, err error) {
	ff = &FFMpegBS1770FetchConverter{}
	ext := filepath.Ext(filename)
	filenameFlac = strings.TrimSuffix(filename, ext) + ".flac"
	rhl.Printf("ffmpeg-bs1770-converter: starting ffmpeg for file '%s' (had extension: '%s')", filenameFlac, ext)
	ff.ffmpeg = exec.Command("ffmpeg", "-loglevel", "warning", "-i", "pipe:0", "-map_metadata", "0")
	if metadata != nil {
		for key, value := range metadata {
			ff.ffmpeg.Args = append(ff.ffmpeg.Args, "-metadata", fmt.Sprintf("%s=%s", key, value))
		}
	}
	ff.ffmpeg.Args = append(ff.ffmpeg.Args, "-ac", strconv.FormatUint(uint64(channels), 10), "-f", "flac", filenameFlac)
	ff.ffmpeg.Args = append(ff.ffmpeg.Args, "-ac", strconv.FormatUint(uint64(channels), 10), "-f", "flac", "pipe:1")
	if ff.pipe, err = ff.ffmpeg.StdinPipe(); err != nil {
		return nil, "", err
	}
	var ffStderr bytes.Buffer
	ff.ffmpeg.Stderr = &ffStderr

	ff.bs1770 = exec.Command("bs1770gain", "--ebu", "-i", "--xml", "-")
	var ffstdout io.WriteCloser
	if ffstdout, err = ff.bs1770.StdinPipe(); err != nil {
		return nil, "", err
	}
	ff.ffmpeg.Stdout = ffstdout

	var bsStdout, bsStderr bytes.Buffer
	ff.bs1770.Stdout = &bsStdout
	ff.bs1770.Stderr = &bsStderr

	ff.resultFF = make(chan FetchConverterResult, 1)
	ff.resultBS = make(chan FetchConverterResult, 1)
	go func() {
		err := ff.ffmpeg.Run()
		ffstdout.Close()
		ff.resultFF <- FetchConverterResult{strings.TrimSpace(string(ffStderr.String())), err, 0.0}
	}()
	go func() {
		if err := ff.bs1770.Run(); err != nil {
			ff.resultBS <- FetchConverterResult{strings.TrimSpace(string(bsStderr.String())), err, 0.0}
		}

		res, err := NewBS1770ResultFromXML(&bsStdout)
		if err != nil {
			ff.resultBS <- FetchConverterResult{bsStdout.String(), err, 0.0}
		}
		if len(res.Album.Tracks) == 0 {
			ff.resultBS <- FetchConverterResult{bsStdout.String(), fmt.Errorf("bs1770gain returned no/invalid result"), 0.0}
		}
		ff.resultBS <- FetchConverterResult{"", nil, res.Album.Tracks[0].Integrated.LU}
	}()
	return
}

func (ff *FFMpegBS1770FetchConverter) Write(p []byte) (n int, err error) {
	return ff.pipe.Write(p)
}

func (ff *FFMpegBS1770FetchConverter) Close() (err error) {
	return ff.pipe.Close()
}

func (ff *FFMpegBS1770FetchConverter) GetResult(ctx *Context, res *Result) (result string, err error) {
	var rff, rbs FetchConverterResult
	if ff.resultFF != nil {
		rff = <-ff.resultFF
	}
	if ff.resultBS != nil {
		rbs = <-ff.resultBS
	}
	if rff.err != nil {
		return rff.output, fmt.Errorf("ffmpeg: %v", rff.err)
	}
	if rbs.err != nil {
		return rbs.output, fmt.Errorf("bs1770gain: %v", rbs.err)
	}
	ctx.LoudnessCorr = rbs.loudnessCorr
	return "", nil
}