/**
 * Price Analytics API Routes
 *
 * Endpoints for price history, specials, and price comparison analytics
 * Uses the new product_variants and product_variant_snapshots tables
 */

import { Router, Request, Response } from 'express';
import { pool } from '../db/pool';

const router = Router();

// ============================================================
// PRICE HISTORY
// ============================================================

/**
 * GET /api/price-analytics/products/:id/history
 * Get price and stock history for a product variant
 *
 * Query params:
 *   - days: Number of days to look back (default: 30, max: 90)
 *   - option: Specific variant option (e.g., "1g", "3.5g")
 */
router.get('/products/:id/history', async (req: Request, res: Response) => {
  try {
    const { id } = req.params;
    const { days = '30', option } = req.query;
    const daysNum = Math.min(parseInt(days as string, 10) || 30, 90);

    // Get product info
    const productResult = await pool.query(`
      SELECT
        sp.id, sp.name_raw as name, sp.brand_name_raw as brand,
        sp.category_raw as category, sp.dispensary_id,
        d.name as dispensary_name
      FROM store_products sp
      JOIN dispensaries d ON d.id = sp.dispensary_id
      WHERE sp.id = $1
    `, [id]);

    if (productResult.rows.length === 0) {
      return res.status(404).json({ error: 'Product not found' });
    }

    const product = productResult.rows[0];

    // Get variant history
    let variantQuery = `
      SELECT
        pv.id as variant_id,
        pv.option,
        pvs.price_rec,
        pvs.price_med,
        pvs.price_rec_special,
        pvs.price_med_special,
        pvs.quantity,
        pvs.in_stock,
        pvs.is_on_special,
        pvs.captured_at
      FROM product_variant_snapshots pvs
      JOIN product_variants pv ON pv.id = pvs.product_variant_id
      WHERE pv.store_product_id = $1
        AND pvs.captured_at >= NOW() - ($2 || ' days')::INTERVAL
    `;
    const params: any[] = [id, daysNum];

    if (option) {
      variantQuery += ` AND pv.option = $3`;
      params.push(option);
    }

    variantQuery += ` ORDER BY pv.option, pvs.captured_at ASC`;

    const historyResult = await pool.query(variantQuery, params);

    // Get current variants
    const currentResult = await pool.query(`
      SELECT
        id, option, price_rec, price_med, price_rec_special, price_med_special,
        quantity, in_stock, is_on_special, last_price_change_at, last_stock_change_at
      FROM product_variants
      WHERE store_product_id = $1
      ORDER BY option
    `, [id]);

    // Get sale stats using the function
    const saleStatsResult = await pool.query(`
      SELECT
        pv.option,
        (get_variant_sale_stats(pv.id, $2)).*
      FROM product_variants pv
      WHERE pv.store_product_id = $1
    `, [id, daysNum]);

    // Group history by variant
    const historyByVariant: Record<string, any[]> = {};
    for (const row of historyResult.rows) {
      if (!historyByVariant[row.option]) {
        historyByVariant[row.option] = [];
      }
      historyByVariant[row.option].push({
        price_rec: row.price_rec ? parseFloat(row.price_rec) : null,
        price_med: row.price_med ? parseFloat(row.price_med) : null,
        price_rec_special: row.price_rec_special ? parseFloat(row.price_rec_special) : null,
        quantity: row.quantity,
        in_stock: row.in_stock,
        is_on_special: row.is_on_special,
        captured_at: row.captured_at,
      });
    }

    res.json({
      product: {
        id: product.id,
        name: product.name,
        brand: product.brand,
        category: product.category,
        dispensary_id: product.dispensary_id,
        dispensary_name: product.dispensary_name,
      },
      current_variants: currentResult.rows.map((v: any) => ({
        ...v,
        price_rec: v.price_rec ? parseFloat(v.price_rec) : null,
        price_med: v.price_med ? parseFloat(v.price_med) : null,
        price_rec_special: v.price_rec_special ? parseFloat(v.price_rec_special) : null,
      })),
      history: historyByVariant,
      sale_stats: saleStatsResult.rows.reduce((acc: any, row: any) => {
        acc[row.option] = {
          total_snapshots: parseInt(row.total_snapshots),
          times_on_special: parseInt(row.times_on_special),
          special_frequency_pct: row.special_frequency_pct ? parseFloat(row.special_frequency_pct) : 0,
          avg_discount_pct: row.avg_discount_pct ? parseFloat(row.avg_discount_pct) : null,
          min_price: row.min_price ? parseFloat(row.min_price) : null,
          max_price: row.max_price ? parseFloat(row.max_price) : null,
          avg_price: row.avg_price ? parseFloat(row.avg_price) : null,
        };
        return acc;
      }, {}),
      days: daysNum,
    });
  } catch (error: any) {
    console.error('Product history error:', error);
    res.status(500).json({ error: 'Failed to fetch product history', message: error.message });
  }
});

// ============================================================
// CURRENT SPECIALS
// ============================================================

/**
 * GET /api/price-analytics/specials
 * Get all products currently on special
 *
 * Query params:
 *   - state: Filter by state code
 *   - city: Filter by city
 *   - category: Filter by category
 *   - min_discount: Minimum discount percentage
 *   - limit: Max results (default: 100, max: 500)
 *   - offset: Pagination offset
 */
router.get('/specials', async (req: Request, res: Response) => {
  try {
    const {
      state,
      city,
      category,
      min_discount = '0',
      limit = '100',
      offset = '0',
    } = req.query;

    const limitNum = Math.min(parseInt(limit as string, 10) || 100, 500);
    const offsetNum = parseInt(offset as string, 10) || 0;
    const minDiscountNum = parseFloat(min_discount as string) || 0;

    let whereClause = `WHERE pv.is_on_special = TRUE AND pv.in_stock = TRUE`;
    const params: any[] = [];
    let paramIndex = 1;

    if (state) {
      whereClause += ` AND d.state = $${paramIndex}`;
      params.push(state);
      paramIndex++;
    }

    if (city) {
      whereClause += ` AND LOWER(d.city) LIKE LOWER($${paramIndex})`;
      params.push(`%${city}%`);
      paramIndex++;
    }

    if (category) {
      whereClause += ` AND LOWER(sp.category_raw) = LOWER($${paramIndex})`;
      params.push(category);
      paramIndex++;
    }

    // Calculate discount and filter
    const discountCalc = `ROUND(((pv.price_rec - pv.price_rec_special) / NULLIF(pv.price_rec, 0)) * 100, 1)`;

    if (minDiscountNum > 0) {
      whereClause += ` AND ${discountCalc} >= $${paramIndex}`;
      params.push(minDiscountNum);
      paramIndex++;
    }

    params.push(limitNum, offsetNum);

    const { rows: specials } = await pool.query(`
      SELECT
        pv.id as variant_id,
        sp.id as product_id,
        sp.name_raw as product_name,
        sp.brand_name_raw as brand_name,
        sp.category_raw as category,
        sp.image_url,
        d.id as dispensary_id,
        d.name as dispensary_name,
        d.city,
        d.state,
        pv.option,
        pv.price_rec,
        pv.price_rec_special,
        ${discountCalc} as discount_percent,
        pv.quantity,
        pv.last_seen_at
      FROM product_variants pv
      JOIN store_products sp ON sp.id = pv.store_product_id
      JOIN dispensaries d ON d.id = pv.dispensary_id
      ${whereClause}
        AND pv.price_rec_special IS NOT NULL
        AND pv.price_rec_special < pv.price_rec
      ORDER BY ${discountCalc} DESC
      LIMIT $${paramIndex} OFFSET $${paramIndex + 1}
    `, params);

    // Get count
    const countParams = params.slice(0, -2);
    const { rows: countRows } = await pool.query(`
      SELECT COUNT(*) as total
      FROM product_variants pv
      JOIN store_products sp ON sp.id = pv.store_product_id
      JOIN dispensaries d ON d.id = pv.dispensary_id
      ${whereClause}
        AND pv.price_rec_special IS NOT NULL
        AND pv.price_rec_special < pv.price_rec
    `, countParams);

    res.json({
      specials: specials.map((s: any) => ({
        ...s,
        price_rec: s.price_rec ? parseFloat(s.price_rec) : null,
        price_rec_special: s.price_rec_special ? parseFloat(s.price_rec_special) : null,
        discount_percent: s.discount_percent ? parseFloat(s.discount_percent) : null,
      })),
      pagination: {
        total: parseInt(countRows[0]?.total || '0', 10),
        limit: limitNum,
        offset: offsetNum,
        has_more: offsetNum + specials.length < parseInt(countRows[0]?.total || '0', 10),
      },
    });
  } catch (error: any) {
    console.error('Specials error:', error);
    res.status(500).json({ error: 'Failed to fetch specials', message: error.message });
  }
});

// ============================================================
// PRICE COMPARISON
// ============================================================

/**
 * GET /api/price-analytics/compare
 * Compare prices for a product across stores
 *
 * Query params:
 *   - name: Product name to search
 *   - option: Variant option (e.g., "1g", "3.5g")
 *   - state: Filter by state
 *   - limit: Max results (default: 50)
 */
router.get('/compare', async (req: Request, res: Response) => {
  try {
    const { name, option, state, limit = '50' } = req.query;

    if (!name) {
      return res.status(400).json({ error: 'Product name is required' });
    }

    const limitNum = Math.min(parseInt(limit as string, 10) || 50, 200);

    let whereClause = `WHERE sp.name_raw ILIKE $1 AND pv.in_stock = TRUE`;
    const params: any[] = [`%${name}%`];
    let paramIndex = 2;

    if (option) {
      whereClause += ` AND pv.option = $${paramIndex}`;
      params.push(option);
      paramIndex++;
    }

    if (state) {
      whereClause += ` AND d.state = $${paramIndex}`;
      params.push(state);
      paramIndex++;
    }

    params.push(limitNum);

    const { rows } = await pool.query(`
      SELECT
        sp.id as product_id,
        sp.name_raw as product_name,
        sp.brand_name_raw as brand_name,
        sp.category_raw as category,
        sp.image_url,
        d.id as dispensary_id,
        d.name as dispensary_name,
        d.city,
        d.state,
        pv.option,
        pv.price_rec,
        pv.price_rec_special,
        pv.is_on_special,
        pv.quantity,
        COALESCE(pv.price_rec_special, pv.price_rec) as effective_price,
        RANK() OVER (PARTITION BY pv.option ORDER BY COALESCE(pv.price_rec_special, pv.price_rec) ASC) as price_rank
      FROM product_variants pv
      JOIN store_products sp ON sp.id = pv.store_product_id
      JOIN dispensaries d ON d.id = pv.dispensary_id
      ${whereClause}
        AND (pv.price_rec IS NOT NULL OR pv.price_rec_special IS NOT NULL)
      ORDER BY pv.option, effective_price ASC
      LIMIT $${paramIndex}
    `, params);

    // Group by option
    const byOption: Record<string, any[]> = {};
    for (const row of rows) {
      if (!byOption[row.option]) {
        byOption[row.option] = [];
      }
      byOption[row.option].push({
        product_id: row.product_id,
        product_name: row.product_name,
        brand_name: row.brand_name,
        category: row.category,
        image_url: row.image_url,
        dispensary_id: row.dispensary_id,
        dispensary_name: row.dispensary_name,
        city: row.city,
        state: row.state,
        price_rec: row.price_rec ? parseFloat(row.price_rec) : null,
        price_rec_special: row.price_rec_special ? parseFloat(row.price_rec_special) : null,
        effective_price: row.effective_price ? parseFloat(row.effective_price) : null,
        is_on_special: row.is_on_special,
        quantity: row.quantity,
        price_rank: parseInt(row.price_rank),
      });
    }

    // Calculate stats per option
    const stats: Record<string, any> = {};
    for (const [opt, items] of Object.entries(byOption)) {
      const prices = items.map((i: any) => i.effective_price).filter((p: any) => p !== null);
      stats[opt] = {
        count: items.length,
        min_price: Math.min(...prices),
        max_price: Math.max(...prices),
        avg_price: prices.reduce((a: number, b: number) => a + b, 0) / prices.length,
        cheapest_store: items[0]?.dispensary_name,
        on_special_count: items.filter((i: any) => i.is_on_special).length,
      };
    }

    res.json({
      search_term: name,
      results: byOption,
      stats,
      options: Object.keys(byOption),
    });
  } catch (error: any) {
    console.error('Price compare error:', error);
    res.status(500).json({ error: 'Failed to compare prices', message: error.message });
  }
});

// ============================================================
// MARKET SUMMARY
// ============================================================

/**
 * GET /api/price-analytics/market-summary
 * Get overall market analytics summary
 */
router.get('/market-summary', async (req: Request, res: Response) => {
  try {
    const { state } = req.query;

    let stateFilter = '';
    const params: any[] = [];
    if (state) {
      stateFilter = 'WHERE d.state = $1';
      params.push(state);
    }

    // Get variant counts
    const variantStats = await pool.query(`
      SELECT
        COUNT(DISTINCT pv.id) as total_variants,
        COUNT(DISTINCT pv.id) FILTER (WHERE pv.is_on_special) as on_special,
        COUNT(DISTINCT pv.id) FILTER (WHERE pv.in_stock) as in_stock,
        COUNT(DISTINCT pv.store_product_id) as total_products,
        COUNT(DISTINCT pv.dispensary_id) as total_stores
      FROM product_variants pv
      JOIN dispensaries d ON d.id = pv.dispensary_id
      ${stateFilter}
    `, params);

    // Get category breakdown
    const categoryStats = await pool.query(`
      SELECT
        sp.category_raw as category,
        COUNT(DISTINCT pv.id) as variant_count,
        AVG(COALESCE(pv.price_rec_special, pv.price_rec)) as avg_price,
        COUNT(DISTINCT pv.id) FILTER (WHERE pv.is_on_special) as on_special_count
      FROM product_variants pv
      JOIN store_products sp ON sp.id = pv.store_product_id
      JOIN dispensaries d ON d.id = pv.dispensary_id
      ${stateFilter}
      GROUP BY sp.category_raw
      ORDER BY variant_count DESC
      LIMIT 10
    `, params);

    // Get recent price changes (last 24h)
    const recentChanges = await pool.query(`
      SELECT COUNT(*) as price_changes_24h
      FROM product_variants pv
      JOIN dispensaries d ON d.id = pv.dispensary_id
      ${stateFilter ? stateFilter + ' AND' : 'WHERE'}
        pv.last_price_change_at >= NOW() - INTERVAL '24 hours'
    `, params);

    res.json({
      summary: {
        total_variants: parseInt(variantStats.rows[0]?.total_variants || '0'),
        on_special: parseInt(variantStats.rows[0]?.on_special || '0'),
        in_stock: parseInt(variantStats.rows[0]?.in_stock || '0'),
        total_products: parseInt(variantStats.rows[0]?.total_products || '0'),
        total_stores: parseInt(variantStats.rows[0]?.total_stores || '0'),
        price_changes_24h: parseInt(recentChanges.rows[0]?.price_changes_24h || '0'),
      },
      categories: categoryStats.rows.map((c: any) => ({
        category: c.category || 'Unknown',
        variant_count: parseInt(c.variant_count),
        avg_price: c.avg_price ? parseFloat(c.avg_price).toFixed(2) : null,
        on_special_count: parseInt(c.on_special_count),
      })),
    });
  } catch (error: any) {
    console.error('Market summary error:', error);
    res.status(500).json({ error: 'Failed to fetch market summary', message: error.message });
  }
});

export default router;