/**
 * AAMOS API v1 — Shared utilities
 * Bildhantering, DB, auth helpers
 */
import { createHash } from 'crypto';
import { Pool } from 'pg';

// ── PostgreSQL pool ──────────────────────────────────────────
const DB_URL = process.env.AMOS_DB_URL || process.env.DATABASE_URL;
export const dbPool = new Pool({
  connectionString: DB_URL,
  ssl: false,
  max: 5,
  idleTimeoutMillis: 30000,
});

// ── Ensure aamos_api_results table exists ───────────────────
export async function ensureTable() {
  await dbPool.query(`
    CREATE TABLE IF NOT EXISTS aamos_api_results (
      id SERIAL PRIMARY KEY,
      endpoint VARCHAR(32) NOT NULL,
      request_id VARCHAR(64) NOT NULL,
      input_hash VARCHAR(64),
      result JSONB NOT NULL,
      confidence NUMERIC(5,4),
      metadata JSONB,
      created_at TIMESTAMPTZ DEFAULT NOW()
    )
  `);
}

// ── Save result to DB ────────────────────────────────────────
export async function saveResult(endpoint, requestId, inputHash, result, confidence, metadata = {}) {
  await ensureTable();
  await dbPool.query(
    `INSERT INTO aamos_api_results (endpoint, request_id, input_hash, result, confidence, metadata)
     VALUES ($1,$2,$3,$4,$5,$6)`,
    [endpoint, requestId, inputHash, JSON.stringify(result), confidence, JSON.stringify(metadata)]
  );
}

// ── Fetch image from URL or base64 ───────────────────────────
export async function fetchImage(input) {
  if (!input) throw new Error('No image input provided');
  if (input.image_base64) {
    const buf = Buffer.from(input.image_base64.replace(/^data:image\/\w+;base64,/, ''), 'base64');
    return { buffer: buf, source: 'base64' };
  }
  if (input.image_url) {
    const r = await fetch(input.image_url, { signal: AbortSignal.timeout(15000) });
    if (!r.ok) throw new Error(`Failed to fetch image: ${r.status}`);
    const buf = Buffer.from(await r.arrayBuffer());
    return { buffer: buf, source: 'url' };
  }
  throw new Error('image_url or image_base64 required');
}

// ── Simple hash for input dedup ──────────────────────────────
export function hashInput(buf) {
  return createHash('sha256').update(buf).digest('hex');
}

// ── JWT auth middleware (Bearer token) ───────────────────────
export function requireAuth(req, res, next) {
  const auth = req.headers.authorization || '';
  const token = auth.replace(/^Bearer\s+/i, '');
  if (!token || token.length < 20) {
    return res.status(401).json({ error: 'Unauthorized', message: 'Bearer token required' });
  }
  // Validate JWT structure (3 parts)
  const parts = token.split('.');
  if (parts.length !== 3) {
    return res.status(401).json({ error: 'Unauthorized', message: 'Invalid token format' });
  }
  req.token = token;
  next();
}

// ── Request ID generator ─────────────────────────────────────
export function genReqId() {
  return `req_${Date.now()}_${Math.random().toString(36).slice(2, 8)}`;
}