using System;
using System.Diagnostics;
using System.IO;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;

namespace Sozsoft.Platform.Controllers;

/// <summary>
/// DB hazır olduğunda bile /setup sayfasından migration çalıştırmaya olanak tanır.
/// </summary>
[Route("api/setup")]
[Authorize(Roles = "admin")]
public class SetupController : ControllerBase
{
    private readonly IConfiguration _configuration;
    private readonly IHostEnvironment _env;

    public SetupController(
        IConfiguration configuration,
        IHostEnvironment env)
    {
        _configuration = configuration;
        _env = env;
    }

    [HttpGet("application-status")]
    [AllowAnonymous]
    public IActionResult Status()
    {
        return Ok(new { dbExists = SetupAppRunner.DatabaseIsReady(_configuration) });
    }

    [HttpPost("migrate")]
    public async Task Migrate(CancellationToken ct)
    {
        Response.ContentType = "text/event-stream; charset=utf-8";
        Response.Headers["Cache-Control"] = "no-cache, no-store";
        Response.Headers["X-Accel-Buffering"] = "no";
        await Response.Body.FlushAsync(ct);

        async Task Send(string level, string message)
        {
            try
            {
                var payload = JsonSerializer.Serialize(new { level, message });
                await Response.WriteAsync($"data: {payload}\n\n", ct);
                await Response.Body.FlushAsync(ct);
            }
            catch { }
        }

        var migratorPath = _configuration["Setup:MigratorPath"]
            ?? Path.GetFullPath(Path.Combine(_env.ContentRootPath, "..", "Sozsoft.Platform.DbMigrator"));

        await Send("info", "Database migration and seeding are being initiated...");
        await Send("info", $"Migrator path: {migratorPath}");

        var extraArgs = _configuration["Setup:MigratorArgs"] ?? "--Seed=true";

        string fileName;
        string arguments;
        string workingDirectory;

        if (migratorPath.EndsWith(".dll", StringComparison.OrdinalIgnoreCase) && System.IO.File.Exists(migratorPath))
        {
            fileName = "dotnet";
            arguments = $"\"{migratorPath}\" {extraArgs}";
            workingDirectory = Path.GetDirectoryName(migratorPath)!;
        }
        else if (Directory.Exists(migratorPath))
        {
            var dllFiles = Directory.GetFiles(migratorPath, "*.DbMigrator.dll", SearchOption.TopDirectoryOnly);
            if (dllFiles.Length == 0)
                dllFiles = Directory.GetFiles(migratorPath, "*Migrator*.dll", SearchOption.TopDirectoryOnly);

            if (dllFiles.Length > 0)
            {
                fileName = "dotnet";
                arguments = $"\"{dllFiles[0]}\" {extraArgs}";
                workingDirectory = migratorPath;
            }
            else
            {
                fileName = "dotnet";
                arguments = $"run --project \"{migratorPath}\" -- {extraArgs}";
                workingDirectory = migratorPath;
            }
        }
        else
        {
            await Send("error", $"Migrator path not found or invalid: {migratorPath}");
            await Send("done", "Failed.");
            return;
        }

        await Send("info", $"Running: {fileName} {arguments}");

        Process? process = null;
        try
        {
            process = new Process
            {
                StartInfo = new ProcessStartInfo
                {
                    FileName = fileName,
                    Arguments = arguments,
                    RedirectStandardOutput = true,
                    RedirectStandardError = true,
                    UseShellExecute = false,
                    CreateNoWindow = true,
                    WorkingDirectory = workingDirectory,
                }
            };

            process.Start();

            async Task ReadStream(StreamReader reader, string level)
            {
                try
                {
                    while (await reader.ReadLineAsync(ct) is { } line)
                    {
                        await Send(level, line);
                    }
                }
                catch (OperationCanceledException) { }
            }

            await Task.WhenAll(
                ReadStream(process.StandardOutput, "info"),
                ReadStream(process.StandardError, "warn"));

            await process.WaitForExitAsync(ct);

            if (process.ExitCode == 0)
            {
                await Send("success", "Migration and seed completed successfully.");
                await Send("done", "Completed.");
            }
            else
            {
                await Send("error", $"Migration failed. Exit code: {process.ExitCode}");
                await Send("done", "Failed.");
            }
        }
        catch (OperationCanceledException)
        {
            await Send("warn", "Migration request was canceled.");
        }
        catch (Exception ex)
        {
            await Send("error", $"Migration failed: {ex.Message}");
            await Send("done", "Failed.");
        }
        finally
        {
            process?.Dispose();
        }
    }
}