/**
 * BrandPenetrationService
 *
 * Analytics for brand market presence and penetration trends.
 *
 * Data Sources:
 *   - store_products: Current brand presence by dispensary
 *   - store_product_snapshots: Historical brand tracking
 *   - states: Rec/med segmentation
 *
 * Key Metrics:
 *   - Dispensary count carrying brand (by state)
 *   - SKU count per dispensary
 *   - Market share within category
 *   - Penetration trends over time
 *   - Rec vs Med footprint comparison
 */

import { Pool } from 'pg';
import {
  TimeWindow,
  DateRange,
  getDateRangeFromWindow,
  BrandPenetrationResult,
  BrandStateBreakdown,
  PenetrationDataPoint,
  BrandMarketPosition,
  BrandRecVsMedFootprint,
  BrandPromotionalSummary,
  BrandPromotionalEvent,
} from './types';

export class BrandPenetrationService {
  constructor(private pool: Pool) {}

  /**
   * Get brand penetration metrics
   */
  async getBrandPenetration(
    brandName: string,
    options: { window?: TimeWindow; customRange?: DateRange } = {}
  ): Promise<BrandPenetrationResult | null> {
    const { window = '30d', customRange } = options;
    const { start, end } = getDateRangeFromWindow(window, customRange);

    // Get current brand presence
    const currentResult = await this.pool.query(`
      SELECT
        sp.brand_name_raw AS brand_name,
        COUNT(DISTINCT sp.dispensary_id) AS total_dispensaries,
        COUNT(*) AS total_skus,
        ROUND(COUNT(*)::NUMERIC / NULLIF(COUNT(DISTINCT sp.dispensary_id), 0), 2) AS avg_skus_per_dispensary,
        ARRAY_AGG(DISTINCT s.code) FILTER (WHERE s.code IS NOT NULL) AS states_present
      FROM store_products sp
      JOIN dispensaries d ON d.id = sp.dispensary_id
      LEFT JOIN states s ON s.id = d.state_id
      WHERE sp.brand_name_raw = $1
        AND sp.is_in_stock = TRUE
      GROUP BY sp.brand_name_raw
    `, [brandName]);

    if (currentResult.rows.length === 0) {
      return null;
    }

    const current = currentResult.rows[0];

    // Get state breakdown
    const stateBreakdown = await this.getBrandStateBreakdown(brandName);

    // Get penetration trend
    const trendResult = await this.pool.query(`
      WITH daily_presence AS (
        SELECT
          DATE(sps.captured_at) AS date,
          COUNT(DISTINCT sps.dispensary_id) AS dispensary_count
        FROM store_product_snapshots sps
        WHERE sps.brand_name_raw = $1
          AND sps.captured_at >= $2
          AND sps.captured_at <= $3
          AND sps.is_in_stock = TRUE
        GROUP BY DATE(sps.captured_at)
        ORDER BY date
      )
      SELECT
        date,
        dispensary_count,
        dispensary_count - LAG(dispensary_count) OVER (ORDER BY date) AS new_dispensaries
      FROM daily_presence
    `, [brandName, start, end]);

    const penetrationTrend: PenetrationDataPoint[] = trendResult.rows.map((row: any) => ({
      date: row.date.toISOString().split('T')[0],
      dispensary_count: parseInt(row.dispensary_count),
      new_dispensaries: row.new_dispensaries ? parseInt(row.new_dispensaries) : 0,
      dropped_dispensaries: row.new_dispensaries && row.new_dispensaries < 0
        ? Math.abs(parseInt(row.new_dispensaries))
        : 0,
    }));

    return {
      brand_name: brandName,
      total_dispensaries: parseInt(current.total_dispensaries),
      total_skus: parseInt(current.total_skus),
      avg_skus_per_dispensary: parseFloat(current.avg_skus_per_dispensary) || 0,
      states_present: current.states_present || [],
      state_breakdown: stateBreakdown,
      penetration_trend: penetrationTrend,
    };
  }

  /**
   * Get brand breakdown by state
   */
  async getBrandStateBreakdown(brandName: string): Promise<BrandStateBreakdown[]> {
    const result = await this.pool.query(`
      WITH brand_state AS (
        SELECT
          s.code AS state_code,
          s.name AS state_name,
          CASE
            WHEN s.recreational_legal = TRUE THEN 'recreational'
            WHEN s.medical_legal = TRUE THEN 'medical_only'
            ELSE 'no_program'
          END AS legal_type,
          COUNT(DISTINCT sp.dispensary_id) AS dispensary_count,
          COUNT(*) AS sku_count
        FROM store_products sp
        JOIN dispensaries d ON d.id = sp.dispensary_id
        JOIN states s ON s.id = d.state_id
        WHERE sp.brand_name_raw = $1
          AND sp.is_in_stock = TRUE
        GROUP BY s.code, s.name, s.recreational_legal, s.medical_legal
      ),
      state_totals AS (
        SELECT
          s.code AS state_code,
          COUNT(DISTINCT sp.dispensary_id) AS total_dispensaries
        FROM store_products sp
        JOIN dispensaries d ON d.id = sp.dispensary_id
        JOIN states s ON s.id = d.state_id
        WHERE sp.is_in_stock = TRUE
        GROUP BY s.code
      )
      SELECT
        bs.*,
        ROUND(bs.sku_count::NUMERIC / NULLIF(bs.dispensary_count, 0), 2) AS avg_skus_per_dispensary,
        ROUND(bs.dispensary_count::NUMERIC * 100 / NULLIF(st.total_dispensaries, 0), 2) AS market_share_percent
      FROM brand_state bs
      LEFT JOIN state_totals st ON st.state_code = bs.state_code
      ORDER BY bs.dispensary_count DESC
    `, [brandName]);

    return result.rows.map((row: any) => ({
      state_code: row.state_code,
      state_name: row.state_name,
      legal_type: row.legal_type,
      dispensary_count: parseInt(row.dispensary_count),
      sku_count: parseInt(row.sku_count),
      avg_skus_per_dispensary: parseFloat(row.avg_skus_per_dispensary) || 0,
      market_share_percent: row.market_share_percent ? parseFloat(row.market_share_percent) : null,
    }));
  }

  /**
   * Get brand market position within a category
   */
  async getBrandMarketPosition(
    brandName: string,
    options: { category?: string; stateCode?: string } = {}
  ): Promise<BrandMarketPosition[]> {
    const params: any[] = [brandName];
    let paramIdx = 2;
    let filters = '';

    if (options.category) {
      filters += ` AND sp.category_raw = $${paramIdx}`;
      params.push(options.category);
      paramIdx++;
    }

    if (options.stateCode) {
      filters += ` AND s.code = $${paramIdx}`;
      params.push(options.stateCode);
      paramIdx++;
    }

    const result = await this.pool.query(`
      WITH brand_metrics AS (
        SELECT
          sp.brand_name_raw AS brand_name,
          sp.category_raw AS category,
          s.code AS state_code,
          COUNT(*) AS sku_count,
          COUNT(DISTINCT sp.dispensary_id) AS dispensary_count,
          AVG(sp.price_rec) AS avg_price
        FROM store_products sp
        JOIN dispensaries d ON d.id = sp.dispensary_id
        JOIN states s ON s.id = d.state_id
        WHERE sp.brand_name_raw = $1
          AND sp.is_in_stock = TRUE
          AND sp.category_raw IS NOT NULL
          ${filters}
        GROUP BY sp.brand_name_raw, sp.category_raw, s.code
      ),
      category_totals AS (
        SELECT
          sp.category_raw AS category,
          s.code AS state_code,
          COUNT(*) AS total_skus,
          AVG(sp.price_rec) AS category_avg_price
        FROM store_products sp
        JOIN dispensaries d ON d.id = sp.dispensary_id
        JOIN states s ON s.id = d.state_id
        WHERE sp.is_in_stock = TRUE
          AND sp.category_raw IS NOT NULL
        GROUP BY sp.category_raw, s.code
      )
      SELECT
        bm.*,
        ROUND(bm.sku_count::NUMERIC * 100 / NULLIF(ct.total_skus, 0), 2) AS category_share_percent,
        ct.category_avg_price,
        ROUND((bm.avg_price - ct.category_avg_price) / NULLIF(ct.category_avg_price, 0) * 100, 2) AS price_vs_category_avg
      FROM brand_metrics bm
      LEFT JOIN category_totals ct ON ct.category = bm.category AND ct.state_code = bm.state_code
      ORDER BY bm.sku_count DESC
    `, params);

    return result.rows.map((row: any) => ({
      brand_name: row.brand_name,
      category: row.category,
      state_code: row.state_code,
      sku_count: parseInt(row.sku_count),
      dispensary_count: parseInt(row.dispensary_count),
      category_share_percent: row.category_share_percent ? parseFloat(row.category_share_percent) : 0,
      avg_price: row.avg_price ? parseFloat(row.avg_price) : null,
      price_vs_category_avg: row.price_vs_category_avg ? parseFloat(row.price_vs_category_avg) : null,
    }));
  }

  /**
   * Get brand presence in rec vs med-only states
   */
  async getBrandRecVsMedFootprint(brandName: string): Promise<BrandRecVsMedFootprint> {
    const result = await this.pool.query(`
      WITH rec_presence AS (
        SELECT
          COUNT(DISTINCT s.code) AS state_count,
          ARRAY_AGG(DISTINCT s.code) AS states,
          COUNT(DISTINCT sp.dispensary_id) AS dispensary_count,
          ROUND(COUNT(*)::NUMERIC / NULLIF(COUNT(DISTINCT sp.dispensary_id), 0), 2) AS avg_skus
        FROM store_products sp
        JOIN dispensaries d ON d.id = sp.dispensary_id
        JOIN states s ON s.id = d.state_id
        WHERE sp.brand_name_raw = $1
          AND sp.is_in_stock = TRUE
          AND s.recreational_legal = TRUE
      ),
      med_presence AS (
        SELECT
          COUNT(DISTINCT s.code) AS state_count,
          ARRAY_AGG(DISTINCT s.code) AS states,
          COUNT(DISTINCT sp.dispensary_id) AS dispensary_count,
          ROUND(COUNT(*)::NUMERIC / NULLIF(COUNT(DISTINCT sp.dispensary_id), 0), 2) AS avg_skus
        FROM store_products sp
        JOIN dispensaries d ON d.id = sp.dispensary_id
        JOIN states s ON s.id = d.state_id
        WHERE sp.brand_name_raw = $1
          AND sp.is_in_stock = TRUE
          AND s.medical_legal = TRUE
          AND (s.recreational_legal = FALSE OR s.recreational_legal IS NULL)
      )
      SELECT
        rp.state_count AS rec_states_count,
        rp.states AS rec_states,
        rp.dispensary_count AS rec_dispensary_count,
        rp.avg_skus AS rec_avg_skus,
        mp.state_count AS med_only_states_count,
        mp.states AS med_only_states,
        mp.dispensary_count AS med_only_dispensary_count,
        mp.avg_skus AS med_only_avg_skus
      FROM rec_presence rp, med_presence mp
    `, [brandName]);

    const row = result.rows[0];

    return {
      brand_name: brandName,
      rec_states_count: parseInt(row.rec_states_count) || 0,
      rec_states: row.rec_states || [],
      rec_dispensary_count: parseInt(row.rec_dispensary_count) || 0,
      rec_avg_skus: parseFloat(row.rec_avg_skus) || 0,
      med_only_states_count: parseInt(row.med_only_states_count) || 0,
      med_only_states: row.med_only_states || [],
      med_only_dispensary_count: parseInt(row.med_only_dispensary_count) || 0,
      med_only_avg_skus: parseFloat(row.med_only_avg_skus) || 0,
    };
  }

  /**
   * Get top brands by penetration
   */
  async getTopBrandsByPenetration(
    options: { limit?: number; stateCode?: string; category?: string } = {}
  ): Promise<Array<{
    brand_name: string;
    dispensary_count: number;
    sku_count: number;
    state_count: number;
  }>> {
    const { limit = 25, stateCode, category } = options;
    const params: any[] = [limit];
    let paramIdx = 2;
    let filters = '';

    if (stateCode) {
      filters += ` AND s.code = $${paramIdx}`;
      params.push(stateCode);
      paramIdx++;
    }

    if (category) {
      filters += ` AND sp.category_raw = $${paramIdx}`;
      params.push(category);
      paramIdx++;
    }

    const result = await this.pool.query(`
      SELECT
        sp.brand_name_raw AS brand_name,
        COUNT(DISTINCT sp.dispensary_id) AS dispensary_count,
        COUNT(*) AS sku_count,
        COUNT(DISTINCT s.code) AS state_count
      FROM store_products sp
      JOIN dispensaries d ON d.id = sp.dispensary_id
      LEFT JOIN states s ON s.id = d.state_id
      WHERE sp.brand_name_raw IS NOT NULL
        AND sp.is_in_stock = TRUE
        ${filters}
      GROUP BY sp.brand_name_raw
      ORDER BY dispensary_count DESC, sku_count DESC
      LIMIT $1
    `, params);

    return result.rows.map((row: any) => ({
      brand_name: row.brand_name,
      dispensary_count: parseInt(row.dispensary_count),
      sku_count: parseInt(row.sku_count),
      state_count: parseInt(row.state_count),
    }));
  }

  /**
   * Get brands that have expanded/contracted in the window
   */
  async getBrandExpansionContraction(
    options: { window?: TimeWindow; customRange?: DateRange; limit?: number } = {}
  ): Promise<Array<{
    brand_name: string;
    start_dispensaries: number;
    end_dispensaries: number;
    change: number;
    change_percent: number;
  }>> {
    const { window = '30d', customRange, limit = 25 } = options;
    const { start, end } = getDateRangeFromWindow(window, customRange);

    const result = await this.pool.query(`
      WITH start_counts AS (
        SELECT
          brand_name_raw AS brand_name,
          COUNT(DISTINCT dispensary_id) AS dispensary_count
        FROM store_product_snapshots
        WHERE captured_at >= $1 AND captured_at < $1 + INTERVAL '1 day'
          AND brand_name_raw IS NOT NULL
          AND is_in_stock = TRUE
        GROUP BY brand_name_raw
      ),
      end_counts AS (
        SELECT
          brand_name_raw AS brand_name,
          COUNT(DISTINCT dispensary_id) AS dispensary_count
        FROM store_product_snapshots
        WHERE captured_at >= $2 - INTERVAL '1 day' AND captured_at <= $2
          AND brand_name_raw IS NOT NULL
          AND is_in_stock = TRUE
        GROUP BY brand_name_raw
      )
      SELECT
        COALESCE(sc.brand_name, ec.brand_name) AS brand_name,
        COALESCE(sc.dispensary_count, 0) AS start_dispensaries,
        COALESCE(ec.dispensary_count, 0) AS end_dispensaries,
        COALESCE(ec.dispensary_count, 0) - COALESCE(sc.dispensary_count, 0) AS change,
        ROUND(
          (COALESCE(ec.dispensary_count, 0) - COALESCE(sc.dispensary_count, 0))::NUMERIC * 100
          / NULLIF(COALESCE(sc.dispensary_count, 0), 0),
          2
        ) AS change_percent
      FROM start_counts sc
      FULL OUTER JOIN end_counts ec ON ec.brand_name = sc.brand_name
      WHERE COALESCE(ec.dispensary_count, 0) != COALESCE(sc.dispensary_count, 0)
      ORDER BY ABS(COALESCE(ec.dispensary_count, 0) - COALESCE(sc.dispensary_count, 0)) DESC
      LIMIT $3
    `, [start, end, limit]);

    return result.rows.map((row: any) => ({
      brand_name: row.brand_name,
      start_dispensaries: parseInt(row.start_dispensaries),
      end_dispensaries: parseInt(row.end_dispensaries),
      change: parseInt(row.change),
      change_percent: row.change_percent ? parseFloat(row.change_percent) : 0,
    }));
  }

  /**
   * Get brand promotional history
   *
   * Tracks when products went on special, how long, what discount,
   * and estimated quantity sold during the promotion.
   */
  async getBrandPromotionalHistory(
    brandName: string,
    options: { window?: TimeWindow; customRange?: DateRange; stateCode?: string; category?: string } = {}
  ): Promise<BrandPromotionalSummary> {
    const { window = '90d', customRange, stateCode, category } = options;
    const { start, end } = getDateRangeFromWindow(window, customRange);

    // Build filters
    const params: any[] = [brandName, start, end];
    let paramIdx = 4;
    let filters = '';

    if (stateCode) {
      filters += ` AND s.code = $${paramIdx}`;
      params.push(stateCode);
      paramIdx++;
    }

    if (category) {
      filters += ` AND sp.category_raw = $${paramIdx}`;
      params.push(category);
      paramIdx++;
    }

    // Find promotional events by detecting when is_on_special transitions to TRUE
    // and tracking until it transitions back to FALSE
    const eventsResult = await this.pool.query(`
      WITH snapshot_with_lag AS (
        SELECT
          sps.id,
          sps.store_product_id,
          sps.dispensary_id,
          sps.brand_name_raw,
          sps.name_raw,
          sps.category_raw,
          sps.is_on_special,
          sps.price_rec,
          sps.price_rec_special,
          sps.stock_quantity,
          sps.captured_at,
          LAG(sps.is_on_special) OVER (
            PARTITION BY sps.store_product_id
            ORDER BY sps.captured_at
          ) AS prev_is_on_special,
          LAG(sps.stock_quantity) OVER (
            PARTITION BY sps.store_product_id
            ORDER BY sps.captured_at
          ) AS prev_stock_quantity
        FROM store_product_snapshots sps
        JOIN store_products sp ON sp.id = sps.store_product_id
        JOIN dispensaries dd ON dd.id = sp.dispensary_id
        LEFT JOIN states s ON s.id = dd.state_id
        WHERE sps.brand_name_raw = $1
          AND sps.captured_at >= $2
          AND sps.captured_at <= $3
          ${filters}
      ),
      special_starts AS (
        -- Find when specials START (transition from not-on-special to on-special)
        SELECT
          store_product_id,
          dispensary_id,
          name_raw,
          category_raw,
          captured_at AS special_start,
          price_rec AS regular_price,
          price_rec_special AS special_price,
          stock_quantity AS quantity_at_start
        FROM snapshot_with_lag
        WHERE is_on_special = TRUE
          AND (prev_is_on_special = FALSE OR prev_is_on_special IS NULL)
          AND price_rec_special IS NOT NULL
          AND price_rec IS NOT NULL
      ),
      special_ends AS (
        -- Find when specials END (transition from on-special to not-on-special)
        SELECT
          store_product_id,
          captured_at AS special_end,
          prev_stock_quantity AS quantity_at_end
        FROM snapshot_with_lag
        WHERE is_on_special = FALSE
          AND prev_is_on_special = TRUE
      ),
      matched_events AS (
        SELECT
          ss.store_product_id,
          ss.dispensary_id,
          ss.name_raw AS product_name,
          ss.category_raw AS category,
          ss.special_start,
          se.special_end,
          ss.regular_price,
          ss.special_price,
          ss.quantity_at_start,
          COALESCE(se.quantity_at_end, ss.quantity_at_start) AS quantity_at_end
        FROM special_starts ss
        LEFT JOIN special_ends se ON se.store_product_id = ss.store_product_id
          AND se.special_end > ss.special_start
          AND se.special_end = (
            SELECT MIN(se2.special_end)
            FROM special_ends se2
            WHERE se2.store_product_id = ss.store_product_id
              AND se2.special_end > ss.special_start
          )
      )
      SELECT
        me.store_product_id,
        me.dispensary_id,
        d.name AS dispensary_name,
        s.code AS state_code,
        me.product_name,
        me.category,
        me.special_start,
        me.special_end,
        EXTRACT(DAY FROM COALESCE(me.special_end, NOW()) - me.special_start)::INT AS duration_days,
        me.regular_price,
        me.special_price,
        ROUND(((me.regular_price - me.special_price) / NULLIF(me.regular_price, 0)) * 100, 1) AS discount_percent,
        me.quantity_at_start,
        me.quantity_at_end,
        GREATEST(0, COALESCE(me.quantity_at_start, 0) - COALESCE(me.quantity_at_end, 0)) AS quantity_sold_estimate
      FROM matched_events me
      JOIN dispensaries d ON d.id = me.dispensary_id
      LEFT JOIN states s ON s.id = d.state_id
      ORDER BY me.special_start DESC
    `, params);

    const events: BrandPromotionalEvent[] = eventsResult.rows.map((row: any) => ({
      product_name: row.product_name,
      store_product_id: parseInt(row.store_product_id),
      dispensary_id: parseInt(row.dispensary_id),
      dispensary_name: row.dispensary_name,
      state_code: row.state_code || 'Unknown',
      category: row.category,
      special_start: row.special_start.toISOString().split('T')[0],
      special_end: row.special_end ? row.special_end.toISOString().split('T')[0] : null,
      duration_days: row.duration_days ? parseInt(row.duration_days) : null,
      regular_price: parseFloat(row.regular_price) || 0,
      special_price: parseFloat(row.special_price) || 0,
      discount_percent: parseFloat(row.discount_percent) || 0,
      quantity_at_start: row.quantity_at_start ? parseInt(row.quantity_at_start) : null,
      quantity_at_end: row.quantity_at_end ? parseInt(row.quantity_at_end) : null,
      quantity_sold_estimate: row.quantity_sold_estimate ? parseInt(row.quantity_sold_estimate) : null,
    }));

    // Calculate summary stats
    const totalEvents = events.length;
    const uniqueProducts = new Set(events.map(e => e.store_product_id)).size;
    const uniqueDispensaries = new Set(events.map(e => e.dispensary_id)).size;
    const uniqueStates = [...new Set(events.map(e => e.state_code))];

    const avgDiscount = totalEvents > 0
      ? events.reduce((sum, e) => sum + e.discount_percent, 0) / totalEvents
      : 0;

    const durations = events.filter(e => e.duration_days !== null).map(e => e.duration_days!);
    const avgDuration = durations.length > 0
      ? durations.reduce((sum, d) => sum + d, 0) / durations.length
      : null;

    const totalQuantitySold = events
      .filter(e => e.quantity_sold_estimate !== null)
      .reduce((sum, e) => sum + (e.quantity_sold_estimate || 0), 0);

    // Calculate frequency
    const windowDays = Math.ceil((end.getTime() - start.getTime()) / (1000 * 60 * 60 * 24));
    const weeklyAvg = windowDays > 0 ? (totalEvents / windowDays) * 7 : 0;
    const monthlyAvg = windowDays > 0 ? (totalEvents / windowDays) * 30 : 0;

    // Group by category
    const categoryMap = new Map<string, { count: number; discounts: number[]; quantity: number }>();
    for (const event of events) {
      const cat = event.category || 'Uncategorized';
      if (!categoryMap.has(cat)) {
        categoryMap.set(cat, { count: 0, discounts: [], quantity: 0 });
      }
      const entry = categoryMap.get(cat)!;
      entry.count++;
      entry.discounts.push(event.discount_percent);
      if (event.quantity_sold_estimate !== null) {
        entry.quantity += event.quantity_sold_estimate;
      }
    }

    const byCategory = Array.from(categoryMap.entries()).map(([category, data]) => ({
      category,
      event_count: data.count,
      avg_discount_percent: data.discounts.length > 0
        ? Math.round((data.discounts.reduce((a, b) => a + b, 0) / data.discounts.length) * 10) / 10
        : 0,
      quantity_sold_estimate: data.quantity > 0 ? data.quantity : null,
    })).sort((a, b) => b.event_count - a.event_count);

    return {
      brand_name: brandName,
      window,
      total_promotional_events: totalEvents,
      total_products_on_special: uniqueProducts,
      total_dispensaries_with_specials: uniqueDispensaries,
      states_with_specials: uniqueStates,
      avg_discount_percent: Math.round(avgDiscount * 10) / 10,
      avg_duration_days: avgDuration !== null ? Math.round(avgDuration * 10) / 10 : null,
      total_quantity_sold_estimate: totalQuantitySold > 0 ? totalQuantitySold : null,
      promotional_frequency: {
        weekly_avg: Math.round(weeklyAvg * 10) / 10,
        monthly_avg: Math.round(monthlyAvg * 10) / 10,
      },
      by_category: byCategory,
      events,
    };
  }
}

export default BrandPenetrationService;