require('dotenv').config();
const express = require('express');
const cors    = require('cors');
const { Pool, types } = require('pg');

// Return bigint (oid 20) and numeric (oid 1700) as JS numbers instead of strings,
// so apache-arrow's tableFromJSON infers Int/Float64 rather than Dictionary<Utf8>.
types.setTypeParser(20, v => v === null ? null : Number(v));
types.setTypeParser(1700, v => v === null ? null : Number(v));

const app = express();
app.use(cors());
app.use(express.json());
app.use(express.static('public/app'));

const pool = new Pool({
    host:     process.env.DB_HOST,
    port:     parseInt(process.env.DB_PORT) || 5432,
    database: process.env.DB_NAME,
    user:     process.env.DB_USER,
    password: process.env.DB_PASSWORD,
    ssl:      false
});

pool.on('error', (err) => {
    console.error('pg pool error', err);
});

app.use('/api', require('./routes/tables')(pool));
app.use('/api', require('./routes/sources')(pool));
app.use('/api', require('./routes/versions')(pool));
app.use('/api', require('./routes/operations')(pool));
app.use('/api', require('./routes/log')(pool));


// Refuse to start against a database whose schema is behind the migrations on
// disk. Without this the mismatch surfaces later as a confusing query error
// ('column "x" does not exist') deep inside an unrelated request.
// Set PF_SKIP_MIGRATION_CHECK=1 to bypass.
async function checkSchema() {
    if (process.env.PF_SKIP_MIGRATION_CHECK === '1') return;
    const { status } = require('./lib/migrations');
    const client = await pool.connect();
    try {
        const st = await status(client);
        const problems = [
            st.pending.length  && `${st.pending.length} pending: ${st.pending.map(m => m.filename).join(', ')}`,
            st.modified.length && `modified after being applied: ${st.modified.join(', ')}`,
            st.missing.length  && `applied but missing from disk: ${st.missing.join(', ')}`
        ].filter(Boolean);
        if (problems.length) {
            console.error('\n  Database schema is out of date:');
            for (const p of problems) console.error(`    - ${p}`);
            console.error('\n  Run "npm run migrate" (or "npm run migrate:status" for detail).');
            console.error('  For a database that already matches, "npm run migrate:baseline".\n');
            throw new Error('schema out of date');
        }
        console.log(`schema up to date (${st.applied.length} migrations applied)`);
    } finally {
        client.release();
    }
}

const port = process.env.PORT || 3010;
checkSchema()
    .then(() => app.listen(port, '0.0.0.0', () => console.log(`pf_app started on port ${port}`)))
    .catch((err) => {
        if (err.message !== 'schema out of date') console.error('startup failed:', err.message);
        process.exit(1);
    });