using System;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;

namespace Convert_It_Online.Services
{
    public class TextToSpeechService : ITextToSpeechService
    {
        private readonly ILogger<TextToSpeechService> _logger;
        private readonly string? _espeakPath;
        private readonly string? _ffmpegPath;

        public TextToSpeechService(ILogger<TextToSpeechService> logger)
        {
            _logger = logger;
            _espeakPath = FindExecutable("espeak-ng");
            _ffmpegPath = FindExecutable("ffmpeg");

            if (_espeakPath != null)
                _logger.LogInformation("espeak-ng encontrado em: {Path}", _espeakPath);
            else
                _logger.LogWarning("espeak-ng não encontrado. TTS pode não funcionar.");

            if (_ffmpegPath != null)
                _logger.LogInformation("FFmpeg encontrado em: {Path}", _ffmpegPath);
            else
                _logger.LogWarning("FFmpeg não encontrado. Conversão para OGG pode não funcionar.");
        }

        private string? FindExecutable(string name)
        {
            var isWindows = RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
            var executable = isWindows ? $"{name}.exe" : name;

            // Caminhos comuns
            string[] searchPaths;
            if (isWindows)
            {
                searchPaths = new[]
                {
                    Path.Combine(AppContext.BaseDirectory, name),
                    @"C:\Program Files\eSpeak NG",
                    @"C:\Program Files (x86)\eSpeak NG",
                    @"C:\Apps\espeak-ng",
                    @"C:\Apps\ffmpeg\bin",
                    @"C:\ffmpeg\bin",
                    @"C:\Program Files\ffmpeg\bin"
                };
            }
            else
            {
                searchPaths = new[]
                {
                    "/usr/bin",
                    "/usr/local/bin",
                    "/opt/homebrew/bin"
                };
            }

            foreach (var path in searchPaths)
            {
                var fullPath = Path.Combine(path, executable);
                if (File.Exists(fullPath))
                    return fullPath;
            }

            // Tentar encontrar via PATH
            var pathEnv = Environment.GetEnvironmentVariable("PATH");
            if (!string.IsNullOrEmpty(pathEnv))
            {
                var separator = isWindows ? ';' : ':';
                foreach (var path in pathEnv.Split(separator))
                {
                    var fullPath = Path.Combine(path.Trim(), executable);
                    if (File.Exists(fullPath))
                        return fullPath;
                }
            }

            return null;
        }

        public async Task<byte[]> GenerateAudioAsync(string text, string language = "pt-BR", float rate = 1.0f, float pitch = 1.0f)
        {
            if (_espeakPath == null)
                throw new InvalidOperationException("espeak-ng não está instalado no servidor.");

            if (_ffmpegPath == null)
                throw new InvalidOperationException("FFmpeg não está instalado no servidor.");

            var tempWavPath = Path.Combine(Path.GetTempPath(), $"{Guid.NewGuid()}.wav");
            var tempOggPath = Path.Combine(Path.GetTempPath(), $"{Guid.NewGuid()}.ogg");

            try
            {
                // Mapear código de idioma para espeak
                var espeakLang = MapLanguageCode(language);

                // Calcular velocidade (espeak usa words per minute, padrão ~175)
                var wordsPerMinute = (int)(175 * rate);
                if (wordsPerMinute < 80) wordsPerMinute = 80;
                if (wordsPerMinute > 450) wordsPerMinute = 450;

                // Calcular pitch (espeak usa 0-99, padrão 50)
                var espeakPitch = (int)(50 * pitch);
                if (espeakPitch < 0) espeakPitch = 0;
                if (espeakPitch > 99) espeakPitch = 99;

                // Gerar WAV com espeak-ng
                var espeakArgs = $"-v {espeakLang} -s {wordsPerMinute} -p {espeakPitch} -w \"{tempWavPath}\" \"{EscapeText(text)}\"";

                _logger.LogInformation("Executando espeak-ng: {Args}", espeakArgs);

                var espeakProcess = new Process
                {
                    StartInfo = new ProcessStartInfo
                    {
                        FileName = _espeakPath,
                        Arguments = espeakArgs,
                        RedirectStandardOutput = true,
                        RedirectStandardError = true,
                        UseShellExecute = false,
                        CreateNoWindow = true
                    }
                };

                espeakProcess.Start();
                await espeakProcess.WaitForExitAsync();

                if (espeakProcess.ExitCode != 0)
                {
                    var error = await espeakProcess.StandardError.ReadToEndAsync();
                    throw new Exception($"espeak-ng falhou: {error}");
                }

                if (!File.Exists(tempWavPath))
                    throw new Exception("espeak-ng não gerou o arquivo WAV.");

                // Converter WAV para OGG com FFmpeg
                var ffmpegArgs = $"-i \"{tempWavPath}\" -c:a libvorbis -q:a 4 -y \"{tempOggPath}\"";

                _logger.LogInformation("Executando FFmpeg: {Args}", ffmpegArgs);

                var ffmpegProcess = new Process
                {
                    StartInfo = new ProcessStartInfo
                    {
                        FileName = _ffmpegPath,
                        Arguments = ffmpegArgs,
                        RedirectStandardOutput = true,
                        RedirectStandardError = true,
                        UseShellExecute = false,
                        CreateNoWindow = true
                    }
                };

                ffmpegProcess.Start();
                await ffmpegProcess.WaitForExitAsync();

                if (ffmpegProcess.ExitCode != 0)
                {
                    var error = await ffmpegProcess.StandardError.ReadToEndAsync();
                    throw new Exception($"FFmpeg falhou: {error}");
                }

                if (!File.Exists(tempOggPath))
                    throw new Exception("FFmpeg não gerou o arquivo OGG.");

                return await File.ReadAllBytesAsync(tempOggPath);
            }
            finally
            {
                // Limpar arquivos temporários
                if (File.Exists(tempWavPath))
                    File.Delete(tempWavPath);
                if (File.Exists(tempOggPath))
                    File.Delete(tempOggPath);
            }
        }

        private string MapLanguageCode(string language)
        {
            // Mapear códigos de idioma para vozes espeak-ng
            return language.ToLower() switch
            {
                "pt-br" => "pt-br",
                "pt" => "pt",
                "pt-pt" => "pt-pt",
                "es" or "es-mx" or "es-cl" or "es-py" or "es-es" => "es",
                "en" or "en-us" => "en-us",
                "en-gb" => "en-gb",
                _ => "pt-br" // Padrão
            };
        }

        private string EscapeText(string text)
        {
            // Escapar aspas e caracteres especiais para linha de comando
            return text
                .Replace("\\", "\\\\")
                .Replace("\"", "\\\"")
                .Replace("\n", " ")
                .Replace("\r", "");
        }
    }
}