package transcoding

import (
	"database/sql"
	"fmt"
	"log"
	"os"
	"os/exec"
	"path/filepath"
)

// Manager coordinates transcoding with the existing storage system
type Manager struct {
	transcoder *Transcoder
	db         *sql.DB
	enabled    bool
}

// NewManager creates a new transcoding manager
func NewManager(transcoder *Transcoder, db *sql.DB) *Manager {
	return &Manager{
		transcoder: transcoder,
		db:         db,
		enabled:    transcoder != nil && transcoder.IsEnabled(),
	}
}

// QueueVideoForTranscoding adds a video file to the transcoding queue
func (tm *Manager) QueueVideoForTranscoding(fileHash, fileName, filePath string, fileSize int64) {
	if !tm.enabled {
		return
	}

	// Check if already transcoded
	if tm.HasTranscodedVersion(fileHash) {
		log.Printf("File %s already has transcoded version, skipping", fileHash)
		return
	}

	// Check if file needs transcoding
	needsTranscoding, err := tm.transcoder.NeedsTranscoding(filePath)
	if err != nil {
		log.Printf("Error checking if %s needs transcoding: %v", fileName, err)
		// Continue anyway - better to try and fail than skip
	}

	if !needsTranscoding {
		log.Printf("File %s doesn't need transcoding (already web-compatible)", fileName)
		tm.markAsWebCompatible(fileHash)
		return
	}

	// Create transcoding job
	job := Job{
		ID:        fmt.Sprintf("transcode_%s", fileHash),
		InputPath: filePath,
		OutputDir: filepath.Join(tm.transcoder.workDir, fileHash),
		FileHash:  fileHash,
		Qualities: DefaultQualities,
		Priority:  tm.calculatePriority(fileSize),
		Callback: func(err error) {
			if err != nil {
				log.Printf("Transcoding failed for %s: %v", fileName, err)
				tm.markTranscodingFailed(fileHash, err.Error())
			} else {
				log.Printf("Transcoding completed successfully for %s", fileName)
				tm.markTranscodingCompleted(fileHash)
			}
		},
	}

	log.Printf("Queuing %s for transcoding (size: %.2f MB)", fileName, float64(fileSize)/1024/1024)
	tm.transcoder.SubmitJob(job)
	tm.markTranscodingQueued(fileHash)
}

// HasTranscodedVersion checks if a file has a transcoded version available
func (tm *Manager) HasTranscodedVersion(fileHash string) bool {
	if !tm.enabled {
		return false
	}

	// Check file system
	transcodedPath := tm.transcoder.GetTranscodedPath(fileHash)
	if transcodedPath != "" {
		return true
	}

	// Check database record
	var status string
	err := tm.db.QueryRow(`
		SELECT status FROM transcoding_status 
		WHERE file_hash = ? AND status IN ('completed', 'web_compatible')
	`, fileHash).Scan(&status)
	
	return err == nil && (status == "completed" || status == "web_compatible")
}

// GetTranscodedPath returns the path to transcoded version if available
func (tm *Manager) GetTranscodedPath(fileHash string) string {
	if !tm.enabled {
		return ""
	}

	return tm.transcoder.GetTranscodedPath(fileHash)
}

// GetQualityPath returns the path to a specific quality version
func (tm *Manager) GetQualityPath(fileHash, quality string) string {
	if !tm.enabled {
		return ""
	}

	return tm.transcoder.GetQualityPath(fileHash, quality)
}

// GetAvailableQualities returns available quality versions for a file
func (tm *Manager) GetAvailableQualities(fileHash string) []Quality {
	if !tm.enabled {
		return nil
	}

	return tm.transcoder.GetAvailableQualities(fileHash)
}

// GetAvailableQualitiesInterface returns available quality versions as interface{} for API compatibility
func (tm *Manager) GetAvailableQualitiesInterface(fileHash string) []interface{} {
	qualities := tm.GetAvailableQualities(fileHash)
	result := make([]interface{}, len(qualities))
	for i, q := range qualities {
		result[i] = q
	}
	return result
}

// GetTranscodingStatus returns the current status of transcoding for a file
func (tm *Manager) GetTranscodingStatus(fileHash string) string {
	if !tm.enabled {
		return "disabled"
	}

	// First check if job is in progress
	if job, exists := tm.transcoder.GetJobStatus(fmt.Sprintf("transcode_%s", fileHash)); exists {
		return job.Status
	}

	// Check database
	var status string
	err := tm.db.QueryRow(`
		SELECT status FROM transcoding_status WHERE file_hash = ?
	`, fileHash).Scan(&status)
	
	if err != nil {
		return "unknown"
	}

	return status
}

// GetJobProgress returns the progress percentage and whether the job exists
func (tm *Manager) GetJobProgress(fileHash string) (float64, bool) {
	if !tm.enabled {
		return 0.0, false
	}

	jobID := fmt.Sprintf("transcode_%s", fileHash)
	job, exists := tm.transcoder.GetJobStatus(jobID)
	if !exists {
		return 0.0, false
	}

	return job.Progress, true
}

// calculatePriority determines transcoding priority based on file characteristics
func (tm *Manager) calculatePriority(fileSize int64) int {
	priority := 5 // Default medium priority

	if fileSize < 500*1024*1024 { // < 500MB
		priority = 8 // Higher priority for smaller files (faster to transcode)
	}

	if fileSize > 5*1024*1024*1024 { // > 5GB
		priority = 2 // Lower priority for very large files
	}

	return priority
}

// markTranscodingQueued records that a file has been queued for transcoding
func (tm *Manager) markTranscodingQueued(fileHash string) {
	tm.updateTranscodingStatus(fileHash, "queued")
}

// markTranscodingCompleted records that transcoding completed successfully
func (tm *Manager) markTranscodingCompleted(fileHash string) {
	tm.updateTranscodingStatus(fileHash, "completed")
	log.Printf("DEBUG: Marked transcoding completed for file %s", fileHash)
}

// markTranscodingFailed records that transcoding failed
func (tm *Manager) markTranscodingFailed(fileHash string, errorMsg string) {
	_, err := tm.db.Exec(`
		INSERT OR REPLACE INTO transcoding_status 
		(file_hash, status, error_message, updated_at) 
		VALUES (?, ?, ?, datetime('now'))
	`, fileHash, "failed", errorMsg)
	
	if err != nil {
		log.Printf("Warning: Failed to update transcoding status for %s: %v", fileHash, err)
	}
}

// markAsWebCompatible records that a file doesn't need transcoding
func (tm *Manager) markAsWebCompatible(fileHash string) {
	tm.updateTranscodingStatus(fileHash, "web_compatible")
}

// updateTranscodingStatus updates the transcoding status in database
func (tm *Manager) updateTranscodingStatus(fileHash, status string) {
	if tm.db == nil {
		return
	}

	_, err := tm.db.Exec(`
		INSERT OR REPLACE INTO transcoding_status 
		(file_hash, status, updated_at) 
		VALUES (?, ?, datetime('now'))
	`, fileHash, status)
	
	if err != nil {
		log.Printf("Warning: Failed to update transcoding status for %s: %v", fileHash, err)
	}
}

// InitializeDatabase creates the transcoding status table if it doesn't exist
func (tm *Manager) InitializeDatabase() error {
	if tm.db == nil {
		return fmt.Errorf("no database connection")
	}

	_, err := tm.db.Exec(`
		CREATE TABLE IF NOT EXISTS transcoding_status (
			file_hash TEXT PRIMARY KEY,
			status TEXT NOT NULL,
			error_message TEXT,
			created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
			updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
		)
	`)

	if err != nil {
		return fmt.Errorf("failed to create transcoding_status table: %w", err)
	}

	return nil
}


// GetFailedJobsCount returns the count of failed transcoding jobs
func (tm *Manager) GetFailedJobsCount() (int, error) {
	if !tm.enabled {
		return 0, nil
	}

	var count int
	err := tm.db.QueryRow(`
		SELECT COUNT(*) FROM transcoding_status WHERE status = 'failed'
	`).Scan(&count)
	
	return count, err
}

// Admin Methods for monitoring and management

// GetAllJobs returns information about all transcoding jobs
func (tm *Manager) GetAllJobs() map[string]interface{} {
	if !tm.enabled || tm.transcoder == nil {
		return map[string]interface{}{"enabled": false}
	}

	// Get in-memory jobs from transcoder
	jobs := tm.transcoder.GetAllJobs()
	
	return map[string]interface{}{
		"enabled": true,
		"jobs":    jobs,
	}
}

// Note: RetryFailedJob is now handled by admin handlers which have access to Gateway reconstruction

// ClearFailedJobs removes all failed job records
func (tm *Manager) ClearFailedJobs() error {
	if !tm.enabled {
		return fmt.Errorf("transcoding is disabled")
	}

	_, err := tm.db.Exec(`DELETE FROM transcoding_status WHERE status = 'failed'`)
	if err != nil {
		return fmt.Errorf("failed to clear failed jobs: %w", err)
	}
	
	return nil
}

// PauseQueue pauses the transcoding queue
func (tm *Manager) PauseQueue() error {
	if !tm.enabled || tm.transcoder == nil {
		return fmt.Errorf("transcoding is disabled")
	}

	// TODO: Implement queue pausing in transcoder
	return fmt.Errorf("pause queue not implemented yet")
}

// ResumeQueue resumes the transcoding queue
func (tm *Manager) ResumeQueue() error {
	if !tm.enabled || tm.transcoder == nil {
		return fmt.Errorf("transcoding is disabled")
	}

	// TODO: Implement queue resuming in transcoder
	return fmt.Errorf("resume queue not implemented yet")
}

// GetSystemHealth returns system health information
func (tm *Manager) GetSystemHealth() map[string]interface{} {
	health := map[string]interface{}{}
	
	if !tm.enabled {
		health["enabled"] = false
		health["ffmpeg_status"] = "Disabled"
		return health
	}
	
	health["enabled"] = true
	
	// Check FFmpeg availability
	_, err := exec.LookPath("ffmpeg")
	if err != nil {
		health["ffmpeg_status"] = "Not Found"
	} else {
		// Try running ffmpeg to check if it works
		cmd := exec.Command("ffmpeg", "-version")
		err := cmd.Run()
		if err != nil {
			health["ffmpeg_status"] = "Error"
		} else {
			health["ffmpeg_status"] = "Available"
		}
	}
	
	// Calculate transcoded storage usage
	if tm.transcoder != nil {
		storageGB := tm.calculateTranscodedStorage()
		health["transcoded_storage_gb"] = storageGB
	}
	
	return health
}

// calculateTranscodedStorage calculates disk space used by transcoded files
func (tm *Manager) calculateTranscodedStorage() float64 {
	workDir := tm.transcoder.workDir
	if workDir == "" {
		return 0.0
	}
	
	var totalSize int64
	
	filepath.Walk(workDir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return nil
		}
		if !info.IsDir() {
			totalSize += info.Size()
		}
		return nil
	})
	
	// Convert bytes to gigabytes
	return float64(totalSize) / (1024 * 1024 * 1024)
}