using NetDocsForLLM.Models;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Threading.Tasks;

namespace NetDocsForLLM.Services
{
    public interface IDocFxService
    {
        Task<string> GenerateMetadataAsync(IEnumerable<AssemblyModel> assemblies);
    }

    public class DocFxService : IDocFxService
    {
        private readonly string _workingDirectory;
        private readonly string _docfxPath;

        public DocFxService()
        {
            // Create a temporary working directory
            _workingDirectory = Path.Combine(Path.GetTempPath(), "NetDocsForLLM_" + Guid.NewGuid().ToString("N"));
            Directory.CreateDirectory(_workingDirectory);

            // Locate DocFX executable in the packages directory
            var baseDir = AppDomain.CurrentDomain.BaseDirectory;
            _docfxPath = Path.Combine(baseDir, "docfx", "docfx.exe");

            // If not found in the default location, try to locate it in the packages directory
            if (!File.Exists(_docfxPath))
            {
                var packagesDir = Path.Combine(baseDir, "..", "..", "..", "packages");
                var docfxPaths = Directory.GetFiles(packagesDir, "docfx.exe", SearchOption.AllDirectories);
                if (docfxPaths.Length > 0)
                {
                    _docfxPath = docfxPaths[0];
                }
                else
                {
                    throw new FileNotFoundException("No se pudo encontrar docfx.exe. Asegúrese de que el paquete docfx.console esté instalado.");
                }
            }
        }

        public async Task<string> GenerateMetadataAsync(IEnumerable<AssemblyModel> assemblies)
        {
            try
            {
                // Create DocFX configuration
                var configPath = Path.Combine(_workingDirectory, "docfx.json");
                var config = CreateDocFxConfig(assemblies);
                File.WriteAllText(configPath, config);

                // Run DocFX metadata
                var result = await RunDocFxMetadataAsync(configPath);

                // Return path to the generated metadata
                var apiPath = Path.Combine(_workingDirectory, "obj", "api");
                return apiPath;
            }
            catch (Exception ex)
            {
                throw new InvalidOperationException($"Error al generar metadatos con DocFX: {ex.Message}", ex);
            }
        }

        private string CreateDocFxConfig(IEnumerable<AssemblyModel> assemblies)
        {
            var assemblyPaths = new List<string>();
            var xmlPaths = new List<string>();

            foreach (var assembly in assemblies)
            {
                assemblyPaths.Add(assembly.FilePath);
                if (assembly.HasXmlDocumentation)
                {
                    xmlPaths.Add(assembly.XmlDocPath);
                }
            }

            return $@"
{{
  ""metadata"": [
    {{
      ""src"": [
        {{
          ""files"": [
            ""{string.Join("\",\n            \"", assemblyPaths.Select(p => p.Replace("\\", "\\\\")))}"" 
          ],
          ""src"": "".""
        }}
      ],
      ""dest"": ""obj/api"",
      ""properties"": {{
        ""TargetFramework"": ""net6.0""
      }},
      ""disableGitFeatures"": true,
      ""disableDefaultFilter"": false
    }}
  ],
  ""build"": {{
    ""content"": [
      {{
        ""files"": [""*.yml""],
        ""src"": ""obj/api"",
        ""dest"": ""api""
      }}
    ],
    ""resource"": [
      {{
        ""files"": [""images/**""],
        ""exclude"": [""obj/**"", ""_site/**""]
      }}
    ],
    ""dest"": ""_site"",
    ""globalMetadataFiles"": [],
    ""fileMetadataFiles"": [],
    ""template"": [""default""],
    ""postProcessors"": [],
    ""markdownEngineName"": ""markdig"",
    ""noLangKeyword"": false,
    ""keepFileLink"": false,
    ""cleanupCacheHistory"": false,
    ""disableGitFeatures"": false
  }}
}}";
        }

        private async Task<string> RunDocFxMetadataAsync(string configPath)
        {
            var startInfo = new ProcessStartInfo
            {
                FileName = _docfxPath,
                Arguments = $"metadata \"{configPath}\"",
                RedirectStandardOutput = true,
                RedirectStandardError = true,
                UseShellExecute = false,
                CreateNoWindow = true,
                WorkingDirectory = _workingDirectory
            };

            using var process = new Process { StartInfo = startInfo };
            var outputBuilder = new System.Text.StringBuilder();
            var errorBuilder = new System.Text.StringBuilder();

            process.OutputDataReceived += (sender, e) => 
            {
                if (!string.IsNullOrEmpty(e.Data))
                    outputBuilder.AppendLine(e.Data);
            };

            process.ErrorDataReceived += (sender, e) => 
            {
                if (!string.IsNullOrEmpty(e.Data))
                    errorBuilder.AppendLine(e.Data);
            };

            process.Start();
            process.BeginOutputReadLine();
            process.BeginErrorReadLine();

            await process.WaitForExitAsync();

            if (process.ExitCode != 0)
            {
                throw new InvalidOperationException(
                    $"DocFX metadata falló con código de salida {process.ExitCode}. Error: {errorBuilder}");
            }

            return outputBuilder.ToString();
        }
    }
}