import { TFile } from 'obsidian';
import { IndexingQueueItem, IndexingProgress } from '../types';
import { ExtractorManager } from '../extractors';
import { HybridChunker } from '../chunking/chunker';
import { EmbeddingProviderInterface } from '../types';
import { CollectionManager } from '../qdrant/collection';
import { CollectionManager as QdrantCollectionManager } from '../qdrant/collection';
import { generateDeterministicUUID } from '../utils/hash';

export class IndexingQueue {
  private queue: IndexingQueueItem[] = [];
  private isProcessing = false;
  private progress: IndexingProgress;
  private extractorManager: ExtractorManager;
  private chunker: HybridChunker;
  private embeddingProvider: EmbeddingProviderInterface;
  private collectionManager: QdrantCollectionManager;
  private onProgressUpdate?: (progress: IndexingProgress) => void;
  private onError?: (error: string) => void;
  private maxConcurrency = 3;
  private batchSize = 10;

  constructor(
    extractorManager: ExtractorManager,
    chunker: HybridChunker,
    embeddingProvider: EmbeddingProviderInterface,
    collectionManager: QdrantCollectionManager
  ) {
    this.extractorManager = extractorManager;
    this.chunker = chunker;
    this.embeddingProvider = embeddingProvider;
    this.collectionManager = collectionManager;
    
    this.progress = {
      totalFiles: 0,
      processedFiles: 0,
      totalChunks: 0,
      processedChunks: 0,
      errors: [],
      isRunning: false
    };
  }

  /**
   * Add files to the indexing queue
   */
  addFiles(files: TFile[], action: 'create' | 'update' | 'delete' = 'update'): void {
    for (const file of files) {
      this.addFile(file, action);
    }
  }

  /**
   * Add a single file to the indexing queue
   */
  addFile(file: TFile, action: 'create' | 'update' | 'delete' = 'update'): void {
    const priority = action === 'delete' ? 0 : (action === 'create' ? 2 : 1);
    
    const item: IndexingQueueItem = {
      file,
      action,
      priority
    };

    // Remove existing entry for this file
    this.queue = this.queue.filter(item => item.file.path !== file.path);
    
    // Add new entry
    this.queue.push(item);
    
    // Sort by priority (higher priority first)
    this.queue.sort((a, b) => b.priority - a.priority);
  }

  /**
   * Start processing the queue
   */
  async startProcessing(): Promise<void> {
    if (this.isProcessing) {
      return;
    }

    this.isProcessing = true;
    this.progress.isRunning = true;
    this.progress.totalFiles = this.queue.length;
    this.progress.processedFiles = 0;
    this.progress.errors = [];

    this.updateProgress();

    try {
      await this.processQueue();
    } finally {
      this.isProcessing = false;
      this.progress.isRunning = false;
      this.updateProgress();
    }
  }

  /**
   * Stop processing the queue
   */
  stopProcessing(): void {
    this.isProcessing = false;
    this.progress.isRunning = false;
    this.updateProgress();
  }

  /**
   * Clear the queue
   */
  clearQueue(): void {
    this.queue = [];
    this.progress.totalFiles = 0;
    this.progress.processedFiles = 0;
    this.updateProgress();
  }

  /**
   * Get current progress
   */
  getProgress(): IndexingProgress {
    return { ...this.progress };
  }

  /**
   * Set progress update callback
   */
  setProgressCallback(callback: (progress: IndexingProgress) => void): void {
    this.onProgressUpdate = callback;
  }

  /**
   * Set error callback
   */
  setErrorCallback(callback: (error: string) => void): void {
    this.onError = callback;
  }

  private async processQueue(): Promise<void> {
    while (this.queue.length > 0 && this.isProcessing) {
      const batch = this.queue.splice(0, this.batchSize);
      await this.processBatch(batch);
    }
  }

  private async processBatch(batch: IndexingQueueItem[]): Promise<void> {
    const promises = batch.map(item => this.processItem(item));
    await Promise.allSettled(promises);
  }

  private async processItem(item: IndexingQueueItem): Promise<void> {
    try {
      this.progress.currentFile = item.file.path;
      this.updateProgress();

      if (item.action === 'delete') {
        await this.deleteFile(item.file);
      } else {
        await this.indexFile(item.file);
      }

      this.progress.processedFiles++;
      this.updateProgress();
    } catch (error) {
      const errorMessage = `Failed to process ${item.file.path}: ${error}`;
      this.progress.errors.push(errorMessage);
      this.onError?.(errorMessage);
      console.error(errorMessage, error);
    }
  }

  private async indexFile(file: TFile): Promise<void> {
    try {
      // Check if file can be handled
      if (!this.extractorManager.canHandle(file)) {
        console.log(`Skipping file ${file.path} - no suitable extractor`);
        return;
      }

      // Extract content
      const extractedContent = await this.extractorManager.extract(file);

      if (!extractedContent.text.trim()) {
        console.log(`Skipping file ${file.path} - no text content`);
        return;
      }

      // Chunk content
      const chunks = await this.chunker.chunk(extractedContent);

      if (chunks.length === 0) {
        console.log(`Skipping file ${file.path} - no chunks created`);
        return;
      }

      this.progress.totalChunks += chunks.length;

      // Extract chunk texts and generate embeddings
      const texts = chunks.map(chunk => extractedContent.text.substring(chunk.chunk_start, chunk.chunk_end));
      const embeddings = await this.embeddingProvider.embed(texts);

      // Get model name from the embedding provider
      const modelName = this.embeddingProvider.getName();

      // Prepare points for Qdrant
      const points = chunks.map((chunk, index) => ({
        id: this.generatePointId(file, chunk.chunk_index),
        vector: embeddings[index],
        metadata: {
          ...chunk,
          model: modelName, // Set the model name for each chunk
          chunk_text: texts[index] // Include the actual text content
        }
      }));

      // Index in Qdrant
      await this.collectionManager.indexChunks(points);

      this.progress.processedChunks += chunks.length;
      this.updateProgress();

    } catch (error) {
      throw new Error(`Failed to index file ${file.path}: ${error}`);
    }
  }

  private async deleteFile(file: TFile): Promise<void> {
    try {
      // Delete all chunks for this file from Qdrant
      await this.collectionManager.deleteFileChunks(file.path);
    } catch (error) {
      throw new Error(`Failed to delete file ${file.path}: ${error}`);
    }
  }

  private generatePointId(file: TFile, chunkIndex: number): string {
    // Generate a deterministic UUID based on file path and chunk index
    // This ensures the same file+chunk always gets the same ID
    const idString = `${file.path}:${chunkIndex}`;
    return generateDeterministicUUID(idString);
  }

  private updateProgress(): void {
    this.onProgressUpdate?.(this.getProgress());
  }

  /**
   * Get queue statistics
   */
  getQueueStats(): {
    queueLength: number;
    isProcessing: boolean;
    estimatedTimeRemaining: number;
  } {
    const averageTimePerFile = 2000; // 2 seconds per file (rough estimate)
    const estimatedTimeRemaining = this.queue.length * averageTimePerFile;

    return {
      queueLength: this.queue.length,
      isProcessing: this.isProcessing,
      estimatedTimeRemaining
    };
  }

  /**
   * Get files in queue by action type
   */
  getFilesByAction(action: 'create' | 'update' | 'delete'): TFile[] {
    return this.queue
      .filter(item => item.action === action)
      .map(item => item.file);
  }

  /**
   * Remove files from queue
   */
  removeFiles(filePaths: string[]): void {
    this.queue = this.queue.filter(item => !filePaths.includes(item.file.path));
    this.progress.totalFiles = this.queue.length;
    this.updateProgress();
  }
}