#region License Information (GPL v3)

/*
    ShareX - A program that allows you to take screenshots and share any file type
    Copyright (c) 2007-2019 ShareX Team

    This program 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 2
    of the License, or (at your option) any later version.

    This program 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 this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

    Optionally you can also view the license at <http://www.gnu.org/licenses/>.
*/

#endregion License Information (GPL v3)

using ShareX.HelpersLib;
using ShareX.ScreenCaptureLib.Properties;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;

namespace ShareX.ScreenCaptureLib
{
    public class FFmpegHelper : ExternalCLIManager
    {
        public const string SourceNone = "None";
        public const string SourceGDIGrab = "GDI grab";
        public const string SourceVideoDevice = "screen-capture-recorder";
        public const string SourceAudioDevice = "virtual-audio-capturer";
        public const string DeviceSetupPath = "Recorder-devices-setup.exe";

        public const int libmp3lame_qscale_end = 9;

        public event Action RecordingStarted;

        public StringBuilder Output { get; private set; }
        public ScreencastOptions Options { get; private set; }

        private bool recordingStarted;
        private int closeTryCount = 0;

        public FFmpegHelper(ScreencastOptions options)
        {
            Output = new StringBuilder();
            OutputDataReceived += FFmpegHelper_DataReceived;
            ErrorDataReceived += FFmpegHelper_DataReceived;
            Options = options;
            Helpers.CreateDirectoryFromFilePath(Options.OutputPath);
        }

        private void FFmpegHelper_DataReceived(object sender, DataReceivedEventArgs e)
        {
            lock (this)
            {
                if (!string.IsNullOrEmpty(e.Data))
                {
                    Output.AppendLine(e.Data);

                    if (!recordingStarted && e.Data.Contains("Press [q] to stop", StringComparison.InvariantCultureIgnoreCase))
                    {
                        recordingStarted = true;
                        OnRecordingStarted();
                    }
                }
            }
        }

        public bool Record()
        {
            recordingStarted = false;
            return Run(Options.FFmpeg.FFmpegPath, Options.GetFFmpegCommands());
        }

        protected void OnRecordingStarted()
        {
            if (RecordingStarted != null)
            {
                RecordingStarted();
            }
        }

        public bool EncodeVideo(string input, string output)
        {
            Options.IsRecording = false;
            Options.IsLossless = false;
            Options.InputPath = input;
            Options.OutputPath = output;
            return Run(Options.FFmpeg.FFmpegPath, Options.GetFFmpegCommands());
        }

        public bool EncodeGIF(string input, string output)
        {
            // https://ffmpeg.org/ffmpeg-filters.html#palettegen-1
            // https://ffmpeg.org/ffmpeg-filters.html#paletteuse
            return Run(Options.FFmpeg.FFmpegPath,
                $"-y -i \"{input}\" -lavfi \"palettegen=stats_mode={Options.FFmpeg.GIFStatsMode}[palette]," +
                $"[0:v][palette]paletteuse=dither={Options.FFmpeg.GIFDither}\" \"{output}\"");
        }

        private bool Run(string path, string args = null)
        {
            int errorCode = Open(path, args);
            bool result = errorCode == 0;
            if (Options.FFmpeg.ShowError && !result)
            {
                new OutputBox(Output.ToString(), Resources.FFmpegHelper_Record_FFmpeg_error).ShowDialog();
            }
            return result;
        }

        public DirectShowDevices GetDirectShowDevices()
        {
            DirectShowDevices devices = new DirectShowDevices();

            if (File.Exists(Options.FFmpeg.FFmpegPath))
            {
                string arg = "-list_devices true -f dshow -i dummy";
                Open(Options.FFmpeg.FFmpegPath, arg);
                string output = Output.ToString();
                string[] lines = output.Lines();
                bool isVideo = true;
                Regex regex = new Regex("\\[dshow @ \\w+\\]  \"(.+)\"", RegexOptions.Compiled | RegexOptions.CultureInvariant);
                foreach (string line in lines)
                {
                    if (line.EndsWith("] DirectShow video devices", StringComparison.InvariantCulture))
                    {
                        isVideo = true;
                        continue;
                    }

                    if (line.EndsWith("] DirectShow audio devices", StringComparison.InvariantCulture))
                    {
                        isVideo = false;
                        continue;
                    }

                    Match match = regex.Match(line);

                    if (match.Success)
                    {
                        string value = match.Groups[1].Value;

                        if (isVideo)
                        {
                            devices.VideoDevices.Add(value);
                        }
                        else
                        {
                            devices.AudioDevices.Add(value);
                        }
                    }
                }
            }

            return devices;
        }

        public override void Close()
        {
            if (processRunning)
            {
                if (closeTryCount >= 2)
                {
                    process.Kill();
                }
                else
                {
                    WriteInput("q");
                    closeTryCount++;
                }
            }
        }
    }

    public class DirectShowDevices
    {
        public List<string> VideoDevices = new List<string>();
        public List<string> AudioDevices = new List<string>();
    }
}