using Microsoft.AspNetCore.Mvc;
using TuneRipper.Shared.Models;
using TuneRipper.Api.Services;
using System.Collections.Concurrent;

namespace TuneRipper.Api.Controllers;

[ApiController]
[Route("api/[controller]")]
public class VideoController : ControllerBase
{
    private readonly IVideoService _videoService;
    private readonly ISessionService _sessionService;
    private readonly ILogger<VideoController> _logger;
    
    // In-memory storage for processing status (in production, use database or Redis)
    private static readonly ConcurrentDictionary<string, ProcessingJob> _processingJobs = new();
    
    private class ProcessingJob
    {
        public string Id { get; set; } = string.Empty;
        public string SessionId { get; set; } = string.Empty; // Add session tracking
        public ProcessVideoRequest Request { get; set; } = new();
        public DownloadProgress Progress { get; set; } = new();
        public ProcessVideoResponse? Result { get; set; }
        public YouTubeVideoDetails? VideoDetails { get; set; } // Add video details to job
        public string? DownloadedFileName { get; set; } // Store actual downloaded file name
        public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
    }

    public VideoController(IVideoService videoService, ISessionService sessionService, ILogger<VideoController> logger)
    {
        _videoService = videoService;
        _sessionService = sessionService;
        _logger = logger;
    }

    [HttpPost("process")]
    public async Task<ActionResult<ProcessVideoResponse>> StartProcessing([FromBody] ProcessVideoRequest request)
    {
        if (request == null || string.IsNullOrWhiteSpace(request.Url))
        {
            return BadRequest("Invalid request");
        }

        if (!_videoService.IsValidYouTubeUrl(request.Url))
        {
            return BadRequest("Invalid YouTube URL");
        }

        try
        {
            _logger.LogInformation("Starting video processing for URL: {Url}", request.Url);
            
            // Get or create session
            var sessionId = _sessionService.GetOrCreateSession(request.SessionId);
            
            // Generate a job ID
            var jobId = Guid.NewGuid().ToString();
            
            // Create processing job
            var job = new ProcessingJob
            {
                Id = jobId,
                SessionId = sessionId,
                Request = request,
                Progress = new DownloadProgress
                {
                    PercentageComplete = 0,
                    Status = "Queued",
                    Message = "Processing request queued"
                }
            };

            _processingJobs[jobId] = job;

            // Start processing in background (fire and forget)
            _ = Task.Run(() => ProcessVideoAsync(jobId));

            var response = new ProcessVideoResponse
            {
                Success = true,
                Message = "Processing started",
                FileName = jobId, // Use job ID as temporary filename
                DownloadUrl = null, // Will be available when processing completes
                VideoDetails = null, // Will be populated during processing
                SessionId = sessionId // Return session ID to client
            };

            return Accepted(response);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error starting video processing for URL: {Url}", request.Url);
            return StatusCode(500, $"Error starting video processing: {ex.Message}");
        }
    }

    [HttpGet("status/{jobId}")]
    public ActionResult<DownloadProgress> GetProcessingStatus(string jobId)
    {
        if (string.IsNullOrWhiteSpace(jobId))
        {
            return BadRequest("Job ID is required");
        }

        if (!_processingJobs.TryGetValue(jobId, out var job))
        {
            return NotFound("Job not found");
        }

        // Return progress with video details if available
        var progress = job.Progress;
        
        // If we have video details and we're past the first step, include them in a custom response
        if (job.VideoDetails != null && job.Progress.PercentageComplete >= 15)
        {
            return Ok(new
            {
                PercentageComplete = progress.PercentageComplete,
                Status = progress.Status,
                Message = progress.Message,
                VideoDetails = job.VideoDetails
            });
        }

        return Ok(progress);
    }

    [HttpGet("result/{jobId}")]
    public ActionResult<ProcessVideoResponse> GetProcessingResult(string jobId)
    {
        if (string.IsNullOrWhiteSpace(jobId))
        {
            return BadRequest("Job ID is required");
        }

        if (!_processingJobs.TryGetValue(jobId, out var job))
        {
            return NotFound("Job not found");
        }

        if (job.Result == null)
        {
            return Accepted("Processing not completed yet");
        }

        return Ok(job.Result);
    }

    [HttpGet("jobs/{sessionId?}")]
    public ActionResult<IEnumerable<JobStatusResponse>> GetJobsBySession(string? sessionId = null)
    {
        var jobsQuery = _processingJobs.Values.AsEnumerable();
        
        // Filter by session if provided
        if (!string.IsNullOrWhiteSpace(sessionId))
        {
            jobsQuery = jobsQuery.Where(job => job.SessionId == sessionId);
        }

        var jobs = jobsQuery.Select(job => new JobStatusResponse
        {
            JobId = job.Id,
            Status = job.Progress.Status,
            PercentageComplete = job.Progress.PercentageComplete,
            Message = job.Progress.Message,
            CreatedAt = job.CreatedAt,
            CompletedAt = job.Result != null ? job.CreatedAt.AddMinutes(5) : null, // Simulated completion time
            Result = job.Result
        }).OrderByDescending(j => j.CreatedAt);

        return Ok(jobs);
    }

    // Keep the old endpoint for backward compatibility
    [HttpGet("jobs")]
    public ActionResult<IEnumerable<JobStatusResponse>> GetAllJobs()
    {
        return GetJobsBySession(null);
    }

    private async Task ProcessVideoAsync(string jobId)
    {
        if (!_processingJobs.TryGetValue(jobId, out var job))
            return;

        try
        {
            _logger.LogInformation("Processing video for job {JobId} in session {SessionId}", jobId, job.SessionId);
            
            // Step 1: Fetch video details
            job.Progress.Status = "Processing";
            job.Progress.Message = "Fetching video details...";
            job.Progress.PercentageComplete = 5;
            
            _logger.LogInformation("Job {JobId}: Fetching video details", jobId);
            
            var videoDetails = await _videoService.GetVideoDetailsAsync(job.Request.Url!);
            
            if (videoDetails == null)
            {
                throw new Exception("Unable to fetch video details. Invalid URL or video unavailable.");
            }
            
            // Store video details in the job
            job.VideoDetails = videoDetails;
            job.Progress.Message = "Video details retrieved successfully";
            job.Progress.PercentageComplete = 15;
            
            _logger.LogInformation("Job {JobId}: Video details retrieved - Title: {Title}", jobId, videoDetails.Title);
            
            // Step 2: Process video with yt-dlp
            job.Progress.Message = "Starting download and conversion...";
            job.Progress.PercentageComplete = 20;
            
            var downloadedFileName = await _videoService.ProcessVideoWithProgressAsync(
                job.Request.Url!, 
                job.Request.Format ?? "mp3", 
                jobId, // Pass the job ID for filename generation
                job.SessionId, // Pass the session ID for directory organization
                (percentage, message) =>
                {
                    // Update progress from yt-dlp
                    job.Progress.PercentageComplete = Math.Max(20, percentage); // Ensure minimum 20%
                    job.Progress.Message = message;
                    _logger.LogDebug("Job {JobId}: Progress {Percentage}% - {Message}", jobId, percentage, message);
                }
            );

            if (string.IsNullOrEmpty(downloadedFileName))
            {
                throw new Exception("Processing completed but no file was generated");
            }

            // Store the downloaded file name
            job.DownloadedFileName = downloadedFileName;

            // Complete processing
            job.Progress.Status = "Completed";
            job.Progress.Message = "Processing completed successfully";
            job.Progress.PercentageComplete = 100;

            // Create download URL for the actual file within session
            var downloadUrl = $"/api/download/{job.SessionId}/{jobId}";

            job.Result = new ProcessVideoResponse
            {
                Success = true,
                Message = "Video processed successfully",
                FileName = downloadedFileName,
                DownloadUrl = downloadUrl,
                VideoDetails = videoDetails,
                SessionId = job.SessionId
            };
            
            _logger.LogInformation("Successfully completed processing for job {JobId} in session {SessionId}. File: {FileName}", jobId, job.SessionId, downloadedFileName);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error processing video for job {JobId} in session {SessionId}", jobId, job.SessionId);
            
            job.Progress.Status = "Failed";
            job.Progress.Message = $"Processing failed: {ex.Message}";
            job.Progress.PercentageComplete = 0;

            job.Result = new ProcessVideoResponse
            {
                Success = false,
                Message = ex.Message,
                FileName = null,
                DownloadUrl = null,
                VideoDetails = job.VideoDetails, // Include video details even on failure if we got them
                SessionId = job.SessionId
            };
        }
    }
}