#!/usr/bin/env tsx
/**
 * One-time migration script to process existing knowledge_items into AlloyDB
 * 
 * This script:
 * 1. Fetches all knowledge_items from Firestore
 * 2. For each item, chunks and embeds it into AlloyDB
 * 3. Shows progress and handles errors gracefully
 * 
 * Usage:
 *   npx tsx scripts/migrate-existing-knowledge-to-alloydb.ts [projectId]
 *   
 *   - If projectId is provided, processes only that project
 *   - If omitted, processes ALL projects
 */

import { getAdminDb } from '../lib/firebase/admin';
import { writeKnowledgeChunksForItem, getChunkCountForKnowledgeItem } from '../lib/server/vector-memory';

interface KnowledgeItem {
  id: string;
  projectId: string;
  content: string;
  sourceMeta?: {
    sourceType?: string;
    importance?: 'primary' | 'supporting' | 'irrelevant';
  };
}

async function getAllKnowledgeItems(projectId?: string): Promise<KnowledgeItem[]> {
  const adminDb = getAdminDb();
  const items: KnowledgeItem[] = [];

  if (projectId) {
    // Single project
    console.log(`[Migration] Fetching knowledge items for project ${projectId}...`);
    const snapshot = await adminDb
      .collection('knowledge_items')
      .where('projectId', '==', projectId)
      .get();

    snapshot.forEach((doc) => {
      const data = doc.data();
      items.push({
        id: doc.id,
        projectId: data.projectId,
        content: data.content || '',
        sourceMeta: data.sourceMeta,
      });
    });
  } else {
    // All projects
    console.log(`[Migration] Fetching ALL knowledge items...`);
    const snapshot = await adminDb.collection('knowledge_items').get();

    snapshot.forEach((doc) => {
      const data = doc.data();
      items.push({
        id: doc.id,
        projectId: data.projectId,
        content: data.content || '',
        sourceMeta: data.sourceMeta,
      });
    });
  }

  return items;
}

async function migrateKnowledgeItems(projectId?: string) {
  console.log('');
  console.log('='.repeat(60));
  console.log('🚀 AlloyDB Knowledge Migration');
  console.log('='.repeat(60));
  console.log('');

  try {
    // Fetch all items
    const items = await getAllKnowledgeItems(projectId);
    console.log(`✅ Found ${items.length} knowledge items to process`);
    console.log('');

    if (items.length === 0) {
      console.log('ℹ️  No knowledge items found. Nothing to migrate.');
      return;
    }

    let successCount = 0;
    let skipCount = 0;
    let errorCount = 0;

    // Process each item
    for (let i = 0; i < items.length; i++) {
      const item = items[i];
      const progress = `[${i + 1}/${items.length}]`;

      try {
        // Check if already processed (skip if chunks exist)
        const existingChunks = await getChunkCountForKnowledgeItem(item.id);
        if (existingChunks > 0) {
          console.log(`${progress} ⏭️  Skipping ${item.id} (already has ${existingChunks} chunks)`);
          skipCount++;
          continue;
        }

        console.log(`${progress} 🔄 Processing ${item.id}...`);

        // Chunk and embed
        await writeKnowledgeChunksForItem(item);

        const newChunks = await getChunkCountForKnowledgeItem(item.id);
        console.log(`${progress} ✅ Success! Created ${newChunks} chunks`);
        successCount++;

        // Small delay to avoid rate limiting
        if (i < items.length - 1) {
          await new Promise((resolve) => setTimeout(resolve, 100));
        }
      } catch (error) {
        console.error(`${progress} ❌ Failed to process ${item.id}:`, error);
        errorCount++;
      }
    }

    // Summary
    console.log('');
    console.log('='.repeat(60));
    console.log('📊 Migration Complete');
    console.log('='.repeat(60));
    console.log(`✅ Processed: ${successCount}`);
    console.log(`⏭️  Skipped (already exists): ${skipCount}`);
    console.log(`❌ Errors: ${errorCount}`);
    console.log(`📦 Total: ${items.length}`);
    console.log('');

    if (errorCount > 0) {
      console.log('⚠️  Some items failed. Check logs above for details.');
      process.exit(1);
    } else {
      console.log('🎉 All knowledge items successfully migrated to AlloyDB!');
      process.exit(0);
    }
  } catch (error) {
    console.error('');
    console.error('❌ Migration failed:', error);
    process.exit(1);
  }
}

// Parse command line arguments
const projectId = process.argv[2];

if (projectId) {
  console.log(`ℹ️  Processing single project: ${projectId}`);
} else {
  console.log('ℹ️  No projectId provided - processing ALL projects');
}

// Run migration
migrateKnowledgeItems(projectId);