/**
 * WS4: Competitor Intelligence — Alerts & Price Changes
 */
import { Router } from "express";
import { pool } from "../db/client";

export const competitorRouter = Router();

/**
 * GET /api/competitor-alerts?vendor=&type=&severity=&days=&limit=&offset=
 */
competitorRouter.get("/", async (req, res) => {
  try {
    const {
      vendor, type, severity, days = "7",
      acknowledged, limit = "50", offset = "0"
    } = req.query;

    let sql = `
      SELECT ca.*,
        v.name AS vendor_name,
        v.slug AS vendor_slug
      FROM competitor_alerts ca
      LEFT JOIN vendors v ON ca.vendor_id = v.id
      WHERE ca.created_at > NOW() - INTERVAL '1 day' * $1
    `;
    const params: any[] = [parseInt(days as string)];
    let idx = 2;

    if (vendor) { sql += ` AND v.slug = $${idx}`; params.push(vendor); idx++; }
    if (type) { sql += ` AND ca.alert_type = $${idx}`; params.push(type); idx++; }
    if (severity) { sql += ` AND ca.severity = $${idx}`; params.push(severity); idx++; }
    if (acknowledged === 'false') { sql += ` AND ca.acknowledged = false`; }

    sql += ` ORDER BY ca.created_at DESC LIMIT $${idx} OFFSET $${idx + 1}`;
    params.push(parseInt(limit as string), parseInt(offset as string));

    const result = await pool.query(sql, params);

    // Summary stats
    const stats = await pool.query(`
      SELECT
        alert_type,
        COUNT(*) AS count,
        COUNT(*) FILTER (WHERE acknowledged = false) AS unread
      FROM competitor_alerts
      WHERE created_at > NOW() - INTERVAL '1 day' * $1
      GROUP BY alert_type
      ORDER BY count DESC
    `, [parseInt(days as string)]);

    res.json({
      alerts: result.rows,
      total: result.rowCount,
      stats: stats.rows,
      period_days: parseInt(days as string),
    });
  } catch (err) {
    console.error("Competitor alerts error:", err);
    res.status(500).json({ error: "Internal server error" });
  }
});

/**
 * GET /api/competitor-alerts/price-changes?vendor=&speed=&days=
 */
competitorRouter.get("/price-changes", async (req, res) => {
  try {
    const { vendor, speed, days = "30", limit = "50" } = req.query;

    let sql = `
      SELECT pc.*,
        v.name AS vendor_name,
        t.slug, t.form_factor, t.speed_gbps, t.reach_label
      FROM price_changes pc
      JOIN vendors v ON pc.vendor_id = v.id
      JOIN transceivers t ON pc.transceiver_id = t.id
      WHERE pc.detected_at > NOW() - INTERVAL '1 day' * $1
    `;
    const params: any[] = [parseInt(days as string)];
    let idx = 2;

    if (vendor) { sql += ` AND v.slug = $${idx}`; params.push(vendor); idx++; }
    if (speed) { sql += ` AND t.speed_gbps = $${idx}`; params.push(parseFloat(speed as string)); idx++; }

    sql += ` ORDER BY ABS(pc.delta_pct) DESC LIMIT $${idx}`;
    params.push(parseInt(limit as string));

    const result = await pool.query(sql, params);
    res.json({ price_changes: result.rows, total: result.rowCount });
  } catch (err) {
    console.error("Price changes error:", err);
    res.status(500).json({ error: "Internal server error" });
  }
});

/**
 * PUT /api/competitor-alerts/:id/acknowledge
 */
competitorRouter.put("/:id/acknowledge", async (req, res) => {
  try {
    const { notes } = req.body || {};
    await pool.query(
      `UPDATE competitor_alerts SET acknowledged = true, notes = COALESCE($2, notes) WHERE id = $1`,
      [req.params.id, notes]
    );
    res.json({ success: true });
  } catch (err) {
    res.status(500).json({ error: "Internal server error" });
  }
});

/**
 * GET /api/competitor-alerts/summary
 *
 * High-level competitor intelligence overview
 */
competitorRouter.get("/summary", async (req, res) => {
  try {
    const [alertsByVendor, recentDrops, newProducts, coverage] = await Promise.all([
      pool.query(`
        SELECT v.name, v.slug, COUNT(*) AS alert_count,
          COUNT(*) FILTER (WHERE ca.alert_type = 'price_drop') AS drops,
          COUNT(*) FILTER (WHERE ca.alert_type = 'price_increase') AS increases,
          COUNT(*) FILTER (WHERE ca.alert_type = 'new_product') AS new_products
        FROM competitor_alerts ca
        JOIN vendors v ON ca.vendor_id = v.id
        WHERE ca.created_at > NOW() - INTERVAL '7 days'
        GROUP BY v.name, v.slug ORDER BY alert_count DESC LIMIT 20
      `),
      pool.query(`
        SELECT pc.*, v.name AS vendor_name, t.form_factor, t.speed_gbps, t.reach_label
        FROM price_changes pc
        JOIN vendors v ON pc.vendor_id = v.id
        JOIN transceivers t ON pc.transceiver_id = t.id
        WHERE pc.delta_pct < -5 AND pc.detected_at > NOW() - INTERVAL '7 days'
        ORDER BY pc.delta_pct ASC LIMIT 10
      `),
      pool.query(`
        SELECT ca.*, v.name AS vendor_name
        FROM competitor_alerts ca
        JOIN vendors v ON ca.vendor_id = v.id
        WHERE ca.alert_type = 'new_product' AND ca.created_at > NOW() - INTERVAL '30 days'
        ORDER BY ca.created_at DESC LIMIT 20
      `),
      pool.query(`SELECT * FROM v_price_coverage WHERE has_recent_price = false LIMIT 20`),
    ]);

    res.json({
      period: "7 days",
      by_vendor: alertsByVendor.rows,
      biggest_price_drops: recentDrops.rows,
      new_competitor_products: newProducts.rows,
      products_missing_prices: coverage.rows,
    });
  } catch (err) {
    console.error("Summary error:", err);
    res.status(500).json({ error: "Internal server error" });
  }
});