/**
 * Neo4j Local to Cloud Sync Script
 *
 * Syncs data from local Neo4j (bruttopuljen/master) to AuraDB cloud
 * Run: npx tsx apps/backend/src/scripts/sync-neo4j-to-cloud.ts
 */

import neo4j, { Driver, Session, Record as Neo4jRecord, isNode, isRelationship } from 'neo4j-driver';
import dotenv from 'dotenv';
import path from 'path';

// Load environment
dotenv.config({ path: path.resolve(process.cwd(), '.env.production') });

interface SyncConfig {
  local: {
    uri: string;
    user: string;
    password: string;
    database: string;
  };
  cloud: {
    uri: string;
    user: string;
    password: string;
    database: string;
  };
}

interface NodeData {
  labels: string[];
  properties: Record<string, any>;
  elementId: string;
}

interface RelationshipData {
  type: string;
  properties: Record<string, any>;
  startElementId: string;
  endElementId: string;
}

interface SchemaItem {
  type: 'constraint' | 'index';
  name: string;
  definition: string;
}

const config: SyncConfig = {
  local: {
    uri: 'bolt://localhost:7687',
    user: 'neo4j',
    password: 'password',  // Update if different
    database: 'neo4j'
  },
  cloud: {
    uri: process.env.NEO4J_URI || 'neo4j+s://054eff27.databases.neo4j.io',
    user: process.env.NEO4J_USER || 'neo4j',
    password: process.env.NEO4J_PASSWORD || '',
    database: process.env.NEO4J_DATABASE || 'neo4j'
  }
};

async function createDriver(connectionConfig: SyncConfig['local'] | SyncConfig['cloud']): Promise<Driver> {
  return neo4j.driver(
    connectionConfig.uri,
    neo4j.auth.basic(connectionConfig.user, connectionConfig.password),
    {
      maxConnectionLifetime: 3 * 60 * 60 * 1000,
      connectionAcquisitionTimeout: 2 * 60 * 1000,
    }
  );
}

async function exportSchema(session: Session): Promise<SchemaItem[]> {
  console.log('📋 Exporting schema from local...');
  const schema: SchemaItem[] = [];

  // Export constraints
  const constraintResult = await session.run('SHOW CONSTRAINTS');
  for (const record of constraintResult.records) {
    const name = record.get('name');
    const type = record.get('type');
    const entityType = record.get('entityType');
    const labelsOrTypes = record.get('labelsOrTypes');
    const properties = record.get('properties');

    let definition = '';
    if (type === 'UNIQUENESS' && entityType === 'NODE') {
      const label = labelsOrTypes?.[0] || 'Unknown';
      const prop = properties?.[0] || 'id';
      definition = `CREATE CONSTRAINT ${name} IF NOT EXISTS FOR (n:${label}) REQUIRE n.${prop} IS UNIQUE`;
    }

    if (definition) {
      schema.push({ type: 'constraint', name, definition });
      console.log(`  ✓ Constraint: ${name}`);
    }
  }

  // Export indexes (excluding auto-generated and constraint-backed)
  const indexResult = await session.run('SHOW INDEXES');
  for (const record of indexResult.records) {
    const name = record.get('name');
    const type = record.get('type');
    const entityType = record.get('entityType');
    const labelsOrTypes = record.get('labelsOrTypes');
    const properties = record.get('properties');
    const owningConstraint = record.get('owningConstraint');

    // Skip constraint-backed indexes
    if (owningConstraint) continue;

    let definition = '';
    if (type === 'RANGE' && entityType === 'NODE') {
      const label = labelsOrTypes?.[0] || 'Unknown';
      const props = properties?.join(', ') || 'id';
      definition = `CREATE INDEX ${name} IF NOT EXISTS FOR (n:${label}) ON (n.${props.split(',')[0].trim()})`;
    } else if (type === 'FULLTEXT' && entityType === 'NODE') {
      const label = labelsOrTypes?.[0] || 'Unknown';
      const props = (properties || []).map((p: string) => `n.${p}`).join(', ');
      definition = `CREATE FULLTEXT INDEX ${name} IF NOT EXISTS FOR (n:${label}) ON EACH [${props}]`;
    } else if (type === 'VECTOR') {
      const label = labelsOrTypes?.[0] || 'Unknown';
      const prop = properties?.[0] || 'embedding';
      definition = `CREATE VECTOR INDEX ${name} IF NOT EXISTS FOR (n:${label}) ON (n.${prop}) OPTIONS {indexConfig: {\`vector.dimensions\`: 384, \`vector.similarity_function\`: 'cosine'}}`;
    }

    if (definition) {
      schema.push({ type: 'index', name, definition });
      console.log(`  ✓ Index: ${name} (${type})`);
    }
  }

  console.log(`  Total: ${schema.length} schema items`);
  return schema;
}

async function exportNodes(session: Session): Promise<NodeData[]> {
  console.log('\n📦 Exporting nodes from local...');
  const nodes: NodeData[] = [];

  const result = await session.run('MATCH (n) RETURN n, elementId(n) as elementId');

  for (const record of result.records) {
    const node = record.get('n');
    const elementId = record.get('elementId');

    if (isNode(node)) {
      // Clone properties and convert Neo4j types to JS types
      const properties: Record<string, any> = {};
      for (const [key, value] of Object.entries(node.properties)) {
        properties[key] = convertNeo4jValue(value);
      }

      nodes.push({
        labels: [...node.labels],
        properties,
        elementId
      });
    }
  }

  console.log(`  ✓ Exported ${nodes.length} nodes`);

  // Show label distribution
  const labelCounts: Record<string, number> = {};
  for (const node of nodes) {
    for (const label of node.labels) {
      labelCounts[label] = (labelCounts[label] || 0) + 1;
    }
  }
  for (const [label, count] of Object.entries(labelCounts)) {
    console.log(`    - ${label}: ${count}`);
  }

  return nodes;
}

async function exportRelationships(session: Session): Promise<RelationshipData[]> {
  console.log('\n🔗 Exporting relationships from local...');
  const relationships: RelationshipData[] = [];

  const result = await session.run(`
    MATCH (a)-[r]->(b)
    RETURN r, type(r) as type, elementId(a) as startId, elementId(b) as endId
  `);

  for (const record of result.records) {
    const rel = record.get('r');
    const type = record.get('type');
    const startId = record.get('startId');
    const endId = record.get('endId');

    // Clone properties and convert Neo4j types
    const properties: Record<string, any> = {};
    if (isRelationship(rel)) {
      for (const [key, value] of Object.entries(rel.properties)) {
        properties[key] = convertNeo4jValue(value);
      }
    }

    relationships.push({
      type,
      properties,
      startElementId: startId,
      endElementId: endId
    });
  }

  console.log(`  ✓ Exported ${relationships.length} relationships`);

  // Show relationship type distribution
  const typeCounts: Record<string, number> = {};
  for (const rel of relationships) {
    typeCounts[rel.type] = (typeCounts[rel.type] || 0) + 1;
  }
  for (const [type, count] of Object.entries(typeCounts)) {
    console.log(`    - ${type}: ${count}`);
  }

  return relationships;
}

function convertNeo4jValue(value: any): any {
  if (value === null || value === undefined) return value;

  // Handle Neo4j Integer
  if (typeof value === 'object' && value.constructor?.name === 'Integer') {
    return value.toNumber();
  }

  // Handle Neo4j DateTime
  if (typeof value === 'object' && value.constructor?.name === 'DateTime') {
    return value.toString();
  }

  // Handle Neo4j Date
  if (typeof value === 'object' && value.constructor?.name === 'Date') {
    return value.toString();
  }

  // Handle arrays
  if (Array.isArray(value)) {
    return value.map(convertNeo4jValue);
  }

  // Handle Float arrays (embeddings)
  if (typeof value === 'object' && value.constructor?.name === 'Float64Array') {
    return Array.from(value);
  }

  return value;
}

async function clearCloud(session: Session): Promise<void> {
  console.log('\n🗑️  Clearing cloud database...');

  // Delete in batches to avoid memory issues
  let deleted = 0;
  do {
    const result = await session.run(`
      MATCH (n)
      WITH n LIMIT 1000
      DETACH DELETE n
      RETURN count(*) as deleted
    `);
    deleted = result.records[0]?.get('deleted')?.toNumber() || 0;
    if (deleted > 0) {
      console.log(`  Deleted batch of ${deleted} nodes...`);
    }
  } while (deleted > 0);

  console.log('  ✓ Cloud database cleared');
}

async function applySchema(session: Session, schema: SchemaItem[]): Promise<void> {
  console.log('\n📋 Applying schema to cloud...');

  for (const item of schema) {
    try {
      await session.run(item.definition);
      console.log(`  ✓ ${item.type}: ${item.name}`);
    } catch (error: any) {
      if (error.message?.includes('already exists') || error.message?.includes('equivalent')) {
        console.log(`  ⚠ ${item.type} ${item.name} already exists`);
      } else {
        console.error(`  ✗ Failed to create ${item.type} ${item.name}: ${error.message}`);
      }
    }
  }
}

async function importNodes(session: Session, nodes: NodeData[], elementIdMap: Map<string, string>): Promise<void> {
  console.log('\n📦 Importing nodes to cloud...');

  let imported = 0;
  const batchSize = 100;

  for (let i = 0; i < nodes.length; i += batchSize) {
    const batch = nodes.slice(i, i + batchSize);

    for (const node of batch) {
      try {
        // Create node with labels and properties
        const labelStr = node.labels.join(':');

        // Generate a unique ID if not present
        const nodeId = node.properties.id || `node_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`;
        node.properties.id = nodeId;

        const query = `
          MERGE (n:${labelStr} {id: $nodeId})
          SET n = $props
          RETURN elementId(n) as newElementId
        `;

        const result = await session.run(query, {
          nodeId,
          props: node.properties
        });

        const newElementId = result.records[0]?.get('newElementId');
        if (newElementId) {
          elementIdMap.set(node.elementId, newElementId);
        }

        imported++;
      } catch (error: any) {
        console.error(`  ✗ Failed to import node: ${error.message?.slice(0, 100)}`);
      }
    }

    console.log(`  Progress: ${imported}/${nodes.length} nodes`);
  }

  console.log(`  ✓ Imported ${imported} nodes`);
}

async function importRelationships(
  session: Session,
  relationships: RelationshipData[],
  elementIdMap: Map<string, string>,
  nodes: NodeData[]
): Promise<void> {
  console.log('\n🔗 Importing relationships to cloud...');

  // Create a map from old elementId to node id (for relationship matching)
  const elementIdToNodeId = new Map<string, string>();
  for (const node of nodes) {
    elementIdToNodeId.set(node.elementId, node.properties.id);
  }

  let imported = 0;
  let skipped = 0;

  for (const rel of relationships) {
    try {
      const startNodeId = elementIdToNodeId.get(rel.startElementId);
      const endNodeId = elementIdToNodeId.get(rel.endElementId);

      if (!startNodeId || !endNodeId) {
        skipped++;
        continue;
      }

      const query = `
        MATCH (a {id: $startId})
        MATCH (b {id: $endId})
        MERGE (a)-[r:${rel.type}]->(b)
        SET r = $props
      `;

      await session.run(query, {
        startId: startNodeId,
        endId: endNodeId,
        props: rel.properties
      });

      imported++;
    } catch (error: any) {
      console.error(`  ✗ Failed to import relationship: ${error.message?.slice(0, 100)}`);
    }
  }

  console.log(`  ✓ Imported ${imported} relationships (skipped ${skipped})`);
}

async function syncNeo4jToCloud() {
  console.log('═'.repeat(60));
  console.log('🔄 Neo4j Local → Cloud Sync');
  console.log('═'.repeat(60));
  console.log(`\nLocal:  ${config.local.uri}`);
  console.log(`Cloud:  ${config.cloud.uri}`);
  console.log('');

  let localDriver: Driver | null = null;
  let cloudDriver: Driver | null = null;

  try {
    // Connect to local
    console.log('📡 Connecting to local Neo4j...');
    localDriver = await createDriver(config.local);
    await localDriver.verifyConnectivity();
    console.log('  ✓ Connected to local');

    // Connect to cloud
    console.log('☁️  Connecting to AuraDB cloud...');
    cloudDriver = await createDriver(config.cloud);
    await cloudDriver.verifyConnectivity();
    console.log('  ✓ Connected to cloud');

    // Export from local
    const localSession = localDriver.session({ database: config.local.database });

    const schema = await exportSchema(localSession);
    const nodes = await exportNodes(localSession);
    const relationships = await exportRelationships(localSession);

    await localSession.close();

    // Confirm before clearing cloud
    console.log('\n⚠️  This will REPLACE all data in cloud with local data!');
    console.log(`    Nodes to sync: ${nodes.length}`);
    console.log(`    Relationships to sync: ${relationships.length}`);

    // Import to cloud
    const cloudSession = cloudDriver.session({ database: config.cloud.database });

    await clearCloud(cloudSession);
    await applySchema(cloudSession, schema);

    const elementIdMap = new Map<string, string>();
    await importNodes(cloudSession, nodes, elementIdMap);
    await importRelationships(cloudSession, relationships, elementIdMap, nodes);

    await cloudSession.close();

    // Verify sync
    console.log('\n✅ Verifying sync...');
    const verifySession = cloudDriver.session({ database: config.cloud.database });

    const nodeCountResult = await verifySession.run('MATCH (n) RETURN count(n) as count');
    const cloudNodeCount = nodeCountResult.records[0]?.get('count')?.toNumber() || 0;

    const relCountResult = await verifySession.run('MATCH ()-[r]->() RETURN count(r) as count');
    const cloudRelCount = relCountResult.records[0]?.get('count')?.toNumber() || 0;

    await verifySession.close();

    console.log(`  Cloud nodes: ${cloudNodeCount} (expected: ${nodes.length})`);
    console.log(`  Cloud relationships: ${cloudRelCount} (expected: ${relationships.length})`);

    console.log('\n' + '═'.repeat(60));
    console.log('✅ SYNC COMPLETE');
    console.log('═'.repeat(60));

  } catch (error: any) {
    console.error('\n❌ Sync failed:', error.message);
    throw error;
  } finally {
    if (localDriver) await localDriver.close();
    if (cloudDriver) await cloudDriver.close();
  }
}

// Run
syncNeo4jToCloud()
  .then(() => process.exit(0))
  .catch(() => process.exit(1));