/// Module d'upload et management de tracks SoundCloud-like
/// 
/// Features :
/// - Upload multi-format (MP3, WAV, FLAC, AIFF, OGG)
/// - Extraction automatique de métadonnées
/// - Génération de waveform avec peaks
/// - Traitement asynchrone
/// - Validation et sécurité

use std::sync::Arc;
use std::path::{Path, PathBuf};
use std::collections::HashMap;
use std::time::{Duration, SystemTime};

use serde::{Serialize, Deserialize};
use uuid::Uuid;
use tokio::fs;
use tokio::sync::{mpsc, RwLock};
// Note: Use tracing::info! macro directly instead of importing

use crate::error::AppError;
use crate::soundcloud::waveform::{WaveformGenerator, WaveformData};

/// Gestionnaire principal des uploads
#[derive(Debug)]
pub struct UploadManager {
    /// Processeurs d'upload actifs
    active_uploads: Arc<RwLock<HashMap<Uuid, UploadSession>>>,
    /// Configuration
    config: UploadConfig,
    /// Générateur de waveform
    waveform_generator: Arc<WaveformGenerator>,
    /// Extracteur de métadonnées
    metadata_extractor: Arc<MetadataExtractor>,
    /// Stockage des fichiers
    storage: Arc<dyn FileStorage + Send + Sync>,
    /// Événements d'upload
    event_sender: mpsc::UnboundedSender<UploadEvent>,
}

/// Session d'upload d'un fichier
#[derive(Debug, Clone)]
pub struct UploadSession {
    pub id: Uuid,
    pub user_id: i64,
    pub filename: String,
    pub file_size: u64,
    pub content_type: String,
    pub status: UploadStatus,
    pub progress: UploadProgress,
    pub metadata: Option<TrackMetadata>,
    pub waveform: Option<WaveformData>,
    pub created_at: SystemTime,
    pub updated_at: SystemTime,
}

/// Status de l'upload
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub enum UploadStatus {
    /// Upload en cours
    Uploading { bytes_received: u64 },
    /// Upload terminé, processing en cours
    Processing { stage: ProcessingStage },
    /// Upload et processing terminés avec succès
    Completed,
    /// Erreur pendant l'upload ou processing
    Failed { reason: String },
    /// Upload annulé par l'utilisateur
    Cancelled,
}

/// Étapes de processing
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub enum ProcessingStage {
    ValidatingFile,
    ExtractingMetadata,
    GeneratingWaveform,
    ConvertingFormats,
    UploadingToStorage,
    CreatingThumbnails,
    IndexingForSearch,
}

/// Progress de l'upload avec détails
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct UploadProgress {
    pub total_bytes: u64,
    pub uploaded_bytes: u64,
    pub processing_progress: f32, // 0.0 - 1.0
    pub current_stage: Option<ProcessingStage>,
    pub estimated_time_remaining: Option<Duration>,
    pub upload_speed_bps: u32,
}

/// Métadonnées extraites du fichier audio
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TrackMetadata {
    // Métadonnées de base
    pub title: Option<String>,
    pub artist: Option<String>,
    pub album: Option<String>,
    pub genre: Option<String>,
    pub year: Option<u32>,
    pub track_number: Option<u32>,
    pub duration: Option<Duration>,
    
    // Métadonnées techniques
    pub sample_rate: u32,
    pub bitrate: u32,
    pub channels: u8,
    pub bit_depth: Option<u8>,
    pub codec: String,
    pub file_format: String,
    
    // Métadonnées avancées
    pub bpm: Option<f32>,
    pub key: Option<String>,
    pub loudness_lufs: Option<f32>,
    pub peak_db: Option<f32>,
    pub dynamic_range: Option<f32>,
    
    // Identifiants
    pub isrc: Option<String>,
    pub mbid: Option<String>, // MusicBrainz ID
    
    // Artwork
    pub has_artwork: bool,
    pub artwork_size: Option<(u32, u32)>,
    
    // Métadonnées personnalisées
    pub custom_tags: HashMap<String, String>,
}

/// Configuration de l'upload
#[derive(Debug, Clone)]
pub struct UploadConfig {
    pub max_file_size: u64,           // bytes
    pub allowed_formats: Vec<String>,
    pub upload_directory: PathBuf,
    pub temp_directory: PathBuf,
    pub enable_waveform_generation: bool,
    pub enable_format_conversion: bool,
    pub max_concurrent_uploads: usize,
    pub chunk_size: usize,
    pub enable_virus_scan: bool,
}

/// Événements d'upload
#[derive(Debug, Clone)]
pub enum UploadEvent {
    UploadStarted { session_id: Uuid, user_id: i64, filename: String },
    UploadProgress { session_id: Uuid, progress: UploadProgress },
    ProcessingStarted { session_id: Uuid, stage: ProcessingStage },
    MetadataExtracted { session_id: Uuid, metadata: TrackMetadata },
    WaveformGenerated { session_id: Uuid, waveform: WaveformData },
    UploadCompleted { session_id: Uuid, track_id: Uuid },
    UploadFailed { session_id: Uuid, reason: String },
    UploadCancelled { session_id: Uuid },
}

/// Extracteur de métadonnées audio
#[derive(Debug)]
pub struct MetadataExtractor {
    config: MetadataExtractorConfig,
}

/// Configuration de l'extracteur
#[derive(Debug, Clone)]
pub struct MetadataExtractorConfig {
    pub enable_fingerprinting: bool,
    pub enable_bpm_detection: bool,
    pub enable_key_detection: bool,
    pub enable_loudness_analysis: bool,
    pub musicbrainz_lookup: bool,
}

/// Trait pour le stockage de fichiers
pub trait FileStorage: std::fmt::Debug {
    async fn store_file(&self, file_path: &Path, metadata: &TrackMetadata) -> Result<StoredFile, AppError>;
    async fn get_file(&self, file_id: &str) -> Result<StoredFile, AppError>;
    async fn delete_file(&self, file_id: &str) -> Result<(), AppError>;
    async fn list_user_files(&self, user_id: i64) -> Result<Vec<StoredFile>, AppError>;
}

/// Fichier stocké
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct StoredFile {
    pub id: String,
    pub original_filename: String,
    pub content_type: String,
    pub size: u64,
    pub storage_path: String,
    pub public_url: Option<String>,
    pub cdn_url: Option<String>,
    pub checksum: String,
    pub created_at: SystemTime,
}

/// Stockage local pour développement
#[derive(Debug)]
pub struct LocalFileStorage {
    base_path: PathBuf,
    public_url_base: String,
}

impl Default for UploadConfig {
    fn default() -> Self {
        Self {
            max_file_size: 200 * 1024 * 1024, // 200MB
            allowed_formats: vec![
                "audio/mpeg".to_string(),     // MP3
                "audio/wav".to_string(),      // WAV
                "audio/flac".to_string(),     // FLAC
                "audio/aiff".to_string(),     // AIFF
                "audio/ogg".to_string(),      // OGG
                "audio/m4a".to_string(),      // M4A
                "audio/mp4".to_string(),      // MP4 audio
            ],
            upload_directory: PathBuf::from("uploads"),
            temp_directory: PathBuf::from("temp"),
            enable_waveform_generation: true,
            enable_format_conversion: true,
            max_concurrent_uploads: 10,
            chunk_size: 1024 * 1024, // 1MB chunks
            enable_virus_scan: false, // Désactivé par défaut en dev
        }
    }
}

impl UploadManager {
    /// Crée un nouveau gestionnaire d'uploads
    pub async fn new(config: UploadConfig) -> Result<Self, AppError> {
        let (event_sender, _) = mpsc::unbounded_channel();
        
        // Créer les répertoires si nécessaire
        fs::create_dir_all(&config.upload_directory).await?;
        fs::create_dir_all(&config.temp_directory).await?;
        
        let storage = Arc::new(LocalFileStorage::new(
            config.upload_directory.clone(),
            "http://localhost:8080/uploads".to_string(),
        ));
        
        Ok(Self {
            active_uploads: Arc::new(RwLock::new(HashMap::new())),
            waveform_generator: Arc::new(WaveformGenerator::new()),
            metadata_extractor: Arc::new(MetadataExtractor::new()),
            storage,
            config,
            event_sender,
        })
    }
    
    /// Démarre une session d'upload
    pub async fn start_upload(
        &self,
        user_id: i64,
        filename: String,
        file_size: u64,
        content_type: String,
    ) -> Result<Uuid, AppError> {
        // Validation de base
        self.validate_upload_request(&filename, file_size, &content_type)?;
        
        // Vérifier le nombre d'uploads actifs
        let active_count = self.active_uploads.read().await.len();
        if active_count >= self.config.max_concurrent_uploads {
            return Err(AppError::RateLimitExceeded);
        }
        
        let session_id = Uuid::new_v4();
        let session = UploadSession {
            id: session_id,
            user_id,
            filename: filename.clone(),
            file_size,
            content_type,
            status: UploadStatus::Uploading { bytes_received: 0 },
            progress: UploadProgress {
                total_bytes: file_size,
                uploaded_bytes: 0,
                processing_progress: 0.0,
                current_stage: None,
                estimated_time_remaining: None,
                upload_speed_bps: 0,
            },
            metadata: None,
            waveform: None,
            created_at: SystemTime::now(),
            updated_at: SystemTime::now(),
        };
        
        // Enregistrer la session
        self.active_uploads.write().await.insert(session_id, session);
        
        // Émettre l'événement
        let _ = self.event_sender.send(UploadEvent::UploadStarted {
            session_id,
            user_id,
            filename,
        });
        
        tracing::info!("Session d'upload démarrée: {} pour utilisateur {}", session_id, user_id);
        Ok(session_id)
    }
    
    /// Reçoit un chunk de données
    pub async fn receive_chunk(
        &self,
        session_id: Uuid,
        chunk_data: &[u8],
        chunk_offset: u64,
    ) -> Result<(), AppError> {
        let mut sessions = self.active_uploads.write().await;
        let session = sessions.get_mut(&session_id)
            .ok_or_else(|| AppError::UploadSessionNotFound { session_id })?;
        
        // Vérifier le status
        match &session.status {
            UploadStatus::Uploading { .. } => {},
            _ => return Err(AppError::InvalidUploadState { 
                session_id, 
                current_state: format!("{:?}", session.status) 
            }),
        }
        
        // Mettre à jour le progress
        let new_uploaded = chunk_offset + chunk_data.len() as u64;
        session.progress.uploaded_bytes = new_uploaded;
        session.updated_at = SystemTime::now();
        
        // Calculer la vitesse d'upload
        let elapsed = session.updated_at.duration_since(session.created_at).unwrap_or_default();
        if elapsed.as_secs() > 0 {
            session.progress.upload_speed_bps = (new_uploaded / elapsed.as_secs()) as u32;
        }
        
        // Émettre l'événement de progress
        let _ = self.event_sender.send(UploadEvent::UploadProgress {
            session_id,
            progress: session.progress.clone(),
        });
        
        // Si upload terminé, démarrer le processing
        if new_uploaded >= session.file_size {
            session.status = UploadStatus::Processing { 
                stage: ProcessingStage::ValidatingFile 
            };
            
            // Démarrer le processing en arrière-plan
            let self_clone = self.clone();
            tokio::spawn(async move {
                if let Err(e) = self_clone.process_uploaded_file(session_id).await {
                    tracing::error!("Erreur processing fichier {}: {:?}", session_id, e);
                }
            });
        } else {
            session.status = UploadStatus::Uploading { 
                bytes_received: new_uploaded 
            };
        }
        
        Ok(())
    }
    
    /// Traite un fichier uploadé
    async fn process_uploaded_file(&self, session_id: Uuid) -> Result<(), AppError> {
        // Étape 1: Extraction des métadonnées
        self.update_processing_stage(session_id, ProcessingStage::ExtractingMetadata).await?;
        let metadata = self.extract_metadata(session_id).await?;
        
        // Étape 2: Génération de waveform
        if self.config.enable_waveform_generation {
            self.update_processing_stage(session_id, ProcessingStage::GeneratingWaveform).await?;
            let waveform = self.generate_waveform(session_id, &metadata).await?;
            self.update_session_waveform(session_id, waveform).await?;
        }
        
        // Étape 3: Stockage final
        self.update_processing_stage(session_id, ProcessingStage::UploadingToStorage).await?;
        let stored_file = self.store_file(session_id, &metadata).await?;
        
        // Marquer comme terminé
        self.complete_upload(session_id, stored_file.id).await?;
        
        Ok(())
    }
    
    /// Valide une demande d'upload
    fn validate_upload_request(
        &self,
        filename: &str,
        file_size: u64,
        content_type: &str,
    ) -> Result<(), AppError> {
        // Vérifier la taille
        if file_size > self.config.max_file_size {
            return Err(AppError::ValidationError(format!(
                "File too large: {} bytes, max: {} bytes", 
                file_size, 
                self.config.max_file_size
            )));
        }
        
        // Vérifier le format
        if !self.config.allowed_formats.contains(&content_type.to_string()) {
            return Err(AppError::ValidationError(format!(
                "Unsupported format: {}, supported: {:?}", 
                content_type,
                self.config.allowed_formats
            )));
        }
        
        // Vérifier l'extension
        if let Some(extension) = Path::new(filename).extension() {
            let ext_str = extension.to_string_lossy().to_lowercase();
            let valid_extensions = ["mp3", "wav", "flac", "aiff", "ogg", "m4a", "mp4"];
            if !valid_extensions.contains(&ext_str.as_str()) {
                return Err(AppError::ValidationError(format!(
                    "Unsupported extension: {}, supported: {:?}", 
                    ext_str,
                    valid_extensions
                )));
            }
        }
        
        Ok(())
    }
    
    /// Met à jour l'étape de processing
    async fn update_processing_stage(
        &self,
        session_id: Uuid,
        stage: ProcessingStage,
    ) -> Result<(), AppError> {
        let mut sessions = self.active_uploads.write().await;
        if let Some(session) = sessions.get_mut(&session_id) {
            session.status = UploadStatus::Processing { stage: stage.clone() };
            session.progress.current_stage = Some(stage.clone());
            session.updated_at = SystemTime::now();
            
            let _ = self.event_sender.send(UploadEvent::ProcessingStarted {
                session_id,
                stage,
            });
        }
        Ok(())
    }
    
    /// Extrait les métadonnées d'un fichier
    async fn extract_metadata(&self, session_id: Uuid) -> Result<TrackMetadata, AppError> {
        // Simulation d'extraction - en production, utiliser des libs comme `lofty` ou `mp3-metadata`
        let metadata = TrackMetadata {
            title: Some("Uploaded Track".to_string()),
            artist: Some("Unknown Artist".to_string()),
            album: None,
            genre: Some("Electronic".to_string()),
            year: Some(2024),
            track_number: None,
            duration: Some(Duration::from_secs(180)), // 3 minutes
            
            sample_rate: 44100,
            bitrate: 320000,
            channels: 2,
            bit_depth: Some(16),
            codec: "MP3".to_string(),
            file_format: "MPEG".to_string(),
            
            bpm: Some(128.0),
            key: Some("C major".to_string()),
            loudness_lufs: Some(-14.0),
            peak_db: Some(-1.0),
            dynamic_range: Some(8.5),
            
            isrc: None,
            mbid: None,
            
            has_artwork: false,
            artwork_size: None,
            
            custom_tags: HashMap::new(),
        };
        
        // Mettre à jour la session
        self.update_session_metadata(session_id, metadata.clone()).await?;
        
        let _ = self.event_sender.send(UploadEvent::MetadataExtracted {
            session_id,
            metadata: metadata.clone(),
        });
        
        Ok(metadata)
    }
    
    /// Génère la waveform d'un fichier
    async fn generate_waveform(
        &self,
        session_id: Uuid,
        _metadata: &TrackMetadata,
    ) -> Result<WaveformData, AppError> {
        // Utiliser le générateur de waveform
        let waveform = self.waveform_generator.generate_from_file("dummy_path").await?;
        
        let _ = self.event_sender.send(UploadEvent::WaveformGenerated {
            session_id,
            waveform: waveform.clone(),
        });
        
        Ok(waveform)
    }
    
    /// Met à jour les métadonnées d'une session
    async fn update_session_metadata(
        &self,
        session_id: Uuid,
        metadata: TrackMetadata,
    ) -> Result<(), AppError> {
        let mut sessions = self.active_uploads.write().await;
        if let Some(session) = sessions.get_mut(&session_id) {
            session.metadata = Some(metadata);
            session.updated_at = SystemTime::now();
        }
        Ok(())
    }
    
    /// Met à jour la waveform d'une session
    async fn update_session_waveform(
        &self,
        session_id: Uuid,
        waveform: WaveformData,
    ) -> Result<(), AppError> {
        let mut sessions = self.active_uploads.write().await;
        if let Some(session) = sessions.get_mut(&session_id) {
            session.waveform = Some(waveform);
            session.updated_at = SystemTime::now();
        }
        Ok(())
    }
    
    /// Stocke le fichier final
    async fn store_file(
        &self,
        session_id: Uuid,
        metadata: &TrackMetadata,
    ) -> Result<StoredFile, AppError> {
        // Simulation - en production, uploader vers S3/GCS/etc.
        let file_path = self.config.upload_directory.join(format!("{}.mp3", session_id));
        self.storage.store_file(&file_path, metadata).await
    }
    
    /// Termine un upload avec succès
    async fn complete_upload(
        &self,
        session_id: Uuid,
        track_id: String,
    ) -> Result<(), AppError> {
        let mut sessions = self.active_uploads.write().await;
        if let Some(session) = sessions.get_mut(&session_id) {
            session.status = UploadStatus::Completed;
            session.progress.processing_progress = 1.0;
            session.updated_at = SystemTime::now();
            
            let _ = self.event_sender.send(UploadEvent::UploadCompleted {
                session_id,
                track_id: Uuid::parse_str(&track_id).unwrap_or_else(|_| Uuid::new_v4()),
            });
        }
        Ok(())
    }
    
    /// Obtient le status d'un upload
    pub async fn get_upload_status(&self, session_id: Uuid) -> Option<UploadSession> {
        self.active_uploads.read().await.get(&session_id).cloned()
    }
    
    /// Annule un upload
    pub async fn cancel_upload(&self, session_id: Uuid) -> Result<(), AppError> {
        let mut sessions = self.active_uploads.write().await;
        if let Some(session) = sessions.get_mut(&session_id) {
            session.status = UploadStatus::Cancelled;
            session.updated_at = SystemTime::now();
            
            let _ = self.event_sender.send(UploadEvent::UploadCancelled { session_id });
        }
        Ok(())
    }
}

impl Clone for UploadManager {
    fn clone(&self) -> Self {
        Self {
            active_uploads: self.active_uploads.clone(),
            config: self.config.clone(),
            waveform_generator: self.waveform_generator.clone(),
            metadata_extractor: self.metadata_extractor.clone(),
            storage: self.storage.clone(),
            event_sender: self.event_sender.clone(),
        }
    }
}

impl MetadataExtractor {
    pub fn new() -> Self {
        Self {
            config: MetadataExtractorConfig {
                enable_fingerprinting: true,
                enable_bpm_detection: true,
                enable_key_detection: true,
                enable_loudness_analysis: true,
                musicbrainz_lookup: false, // Désactivé par défaut
            },
        }
    }
}

impl LocalFileStorage {
    pub fn new(base_path: PathBuf, public_url_base: String) -> Self {
        Self {
            base_path,
            public_url_base,
        }
    }
}

impl FileStorage for LocalFileStorage {
    async fn store_file(&self, file_path: &Path, metadata: &TrackMetadata) -> Result<StoredFile, AppError> {
        let file_id = Uuid::new_v4().to_string();
        let stored_path = self.base_path.join(&file_id);
        
        // Copier le fichier (simulation)
        let file_size = 1024 * 1024; // 1MB simulé
        
        Ok(StoredFile {
            id: file_id.clone(),
            original_filename: file_path.file_name()
                .unwrap_or_default()
                .to_string_lossy()
                .to_string(),
            content_type: "audio/mpeg".to_string(),
            size: file_size,
            storage_path: stored_path.to_string_lossy().to_string(),
            public_url: Some(format!("{}/{}", self.public_url_base, file_id)),
            cdn_url: None,
            checksum: "abc123".to_string(),
            created_at: SystemTime::now(),
        })
    }
    
    async fn get_file(&self, file_id: &str) -> Result<StoredFile, AppError> {
        // Simulation de récupération
        Err(AppError::NotFound(format!("File not found: {}", file_id)))
    }
    
    async fn delete_file(&self, _file_id: &str) -> Result<(), AppError> {
        // Simulation de suppression
        Ok(())
    }
    
    async fn list_user_files(&self, _user_id: i64) -> Result<Vec<StoredFile>, AppError> {
        // Simulation de listing
        Ok(Vec::new())
    }
} 