#!/usr/bin/env node

/**
 * Script zur Analyse des knowledge_pkey Problems
 * 
 * Prüft warum knowledge_pkey nicht verwendet wird
 */

import './config/loadEnv.js';
import { sequelize } from './utils/sequelize.js';

async function main() {
    try {
        console.log('🔍 Analyse knowledge_pkey Problem\n');
        console.log('='.repeat(60) + '\n');

        // Prüfe ob knowledge einen Primary Key hat
        const [pkInfo] = await sequelize.query(`
            SELECT 
                a.attname as column_name,
                t.conname as constraint_name,
                t.contype as constraint_type
            FROM pg_constraint t
            JOIN pg_class c ON c.oid = t.conrelid
            JOIN pg_namespace n ON n.oid = c.relnamespace
            JOIN pg_attribute a ON a.attrelid = c.oid AND a.attnum = ANY(t.conkey)
            WHERE n.nspname = 'falukant_data'
            AND c.relname = 'knowledge'
            AND t.contype = 'p';
        `);

        console.log('📋 Primary Key Information:');
        if (pkInfo.length > 0) {
            pkInfo.forEach(pk => {
                console.log(`   Constraint: ${pk.constraint_name}`);
                console.log(`   Spalte: ${pk.column_name}`);
                console.log(`   Typ: ${pk.constraint_type === 'p' ? 'PRIMARY KEY' : pk.constraint_type}`);
            });
        } else {
            console.log('   ⚠️  Kein Primary Key gefunden!');
        }
        console.log('');

        // Prüfe alle Indizes auf knowledge
        const [allIndexes] = await sequelize.query(`
            SELECT 
                indexname,
                indexdef,
                idx_scan,
                idx_tup_read,
                idx_tup_fetch
            FROM pg_indexes
            LEFT JOIN pg_stat_user_indexes 
                ON pg_stat_user_indexes.indexrelname = pg_indexes.indexname
                AND pg_stat_user_indexes.schemaname = pg_indexes.schemaname
            WHERE pg_indexes.schemaname = 'falukant_data'
            AND pg_indexes.tablename = 'knowledge'
            ORDER BY indexname;
        `);

        console.log('📊 Alle Indizes auf knowledge:');
        allIndexes.forEach(idx => {
            console.log(`\n   ${idx.indexname}:`);
            console.log(`      Definition: ${idx.indexdef}`);
            console.log(`      Scans: ${idx.idx_scan ? parseInt(idx.idx_scan).toLocaleString() : 'N/A'}`);
            console.log(`      Zeilen gelesen: ${idx.idx_tup_read ? parseInt(idx.idx_tup_read).toLocaleString() : 'N/A'}`);
        });
        console.log('');

        // Prüfe Tabellenstruktur
        const [tableStructure] = await sequelize.query(`
            SELECT 
                column_name,
                data_type,
                is_nullable,
                column_default
            FROM information_schema.columns
            WHERE table_schema = 'falukant_data'
            AND table_name = 'knowledge'
            ORDER BY ordinal_position;
        `);

        console.log('📋 Tabellenstruktur:');
        tableStructure.forEach(col => {
            console.log(`   ${col.column_name}: ${col.data_type} ${col.is_nullable === 'NO' ? 'NOT NULL' : 'NULL'}`);
        });
        console.log('');

        // Erklärung: Warum knowledge_pkey ungenutzt ist
        const pkUnused = allIndexes.find(i => i.indexname === 'knowledge_pkey' && (i.idx_scan == null || parseInt(i.idx_scan) === 0));
        if (pkUnused) {
            console.log('💡 Warum knowledge_pkey (0 Scans) ungenutzt ist:');
            console.log('   Alle Zugriffe filtern nach (character_id, product_id), nie nach id.');
            console.log('   Der PK-Index wird nur für Eindeutigkeit/Referenzen genutzt, nicht für Lookups.');
            console.log('   idx_knowledge_character_product deckt die tatsächlichen Queries ab.\n');
        }

        // Prüfe ob Queries mit id (Primary Key) gemacht werden
        let idUsage = [];
        try {
            const [rows] = await sequelize.query(`
            SELECT 
                query,
                calls,
                total_exec_time,
                mean_exec_time
            FROM pg_stat_statements
            WHERE query LIKE '%knowledge%'
            AND (query LIKE '%knowledge.id%' OR query LIKE '%knowledge%id%')
            ORDER BY calls DESC
            LIMIT 5;
        `);
            idUsage = rows;
        } catch (e) {
            console.log('   ℹ️  pg_stat_statements nicht verfügbar – keine Query-Statistik.\n');
        }

        if (idUsage.length > 0) {
            console.log('🔍 Queries die knowledge.id verwenden:');
            idUsage.forEach(q => {
                console.log(`   Aufrufe: ${parseInt(q.calls).toLocaleString()}`);
                console.log(`   Query: ${q.query.substring(0, 150)}...`);
                console.log('');
            });
        }

        await sequelize.close();
        process.exit(0);

    } catch (error) {
        if (error.message.includes('pg_stat_statements')) {
            console.log('   ⚠️  pg_stat_statements ist nicht aktiviert oder nicht verfügbar\n');
        } else {
            console.error('❌ Fehler:', error.message);
            console.error(error.stack);
        }
        await sequelize.close();
        process.exit(1);
    }
}

main();