-- ============================================================================
-- MIGRACIÓN: Sistema de Ranking de Partners (Clientes/Proveedores)
-- Fecha: 2025-12-12
-- Descripción: Crea tablas y funciones para clasificación ABC de partners
-- Impacto: Verticales que usan módulo de partners/ventas/compras
-- Rollback: DROP TABLE y DROP FUNCTION incluidos al final
-- ============================================================================

-- ============================================================================
-- 1. TABLA DE RANKINGS POR PERÍODO
-- ============================================================================

CREATE TABLE IF NOT EXISTS core.partner_rankings (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  tenant_id UUID NOT NULL REFERENCES auth.tenants(id) ON DELETE CASCADE,
  partner_id UUID NOT NULL REFERENCES core.partners(id) ON DELETE CASCADE,
  company_id UUID REFERENCES auth.companies(id) ON DELETE SET NULL,

  -- Período de análisis
  period_start DATE NOT NULL,
  period_end DATE NOT NULL,

  -- Métricas de Cliente
  total_sales DECIMAL(16,2) DEFAULT 0,
  sales_order_count INTEGER DEFAULT 0,
  avg_order_value DECIMAL(16,2) DEFAULT 0,

  -- Métricas de Proveedor
  total_purchases DECIMAL(16,2) DEFAULT 0,
  purchase_order_count INTEGER DEFAULT 0,
  avg_purchase_value DECIMAL(16,2) DEFAULT 0,

  -- Métricas de Pago
  avg_payment_days INTEGER,
  on_time_payment_rate DECIMAL(5,2),  -- Porcentaje 0-100

  -- Rankings (posición relativa dentro del período)
  sales_rank INTEGER,
  purchase_rank INTEGER,

  -- Clasificación ABC
  customer_abc CHAR(1) CHECK (customer_abc IN ('A', 'B', 'C', NULL)),
  supplier_abc CHAR(1) CHECK (supplier_abc IN ('A', 'B', 'C', NULL)),

  -- Scores calculados (0-100)
  customer_score DECIMAL(5,2) CHECK (customer_score IS NULL OR customer_score BETWEEN 0 AND 100),
  supplier_score DECIMAL(5,2) CHECK (supplier_score IS NULL OR supplier_score BETWEEN 0 AND 100),
  overall_score DECIMAL(5,2) CHECK (overall_score IS NULL OR overall_score BETWEEN 0 AND 100),

  -- Tendencia vs período anterior
  sales_trend DECIMAL(5,2),  -- % cambio
  purchase_trend DECIMAL(5,2),

  -- Metadatos
  calculated_at TIMESTAMPTZ DEFAULT NOW(),
  created_at TIMESTAMPTZ DEFAULT NOW(),

  -- Constraints
  UNIQUE(tenant_id, partner_id, company_id, period_start, period_end),
  CHECK (period_end >= period_start)
);

-- ============================================================================
-- 2. CAMPOS DESNORMALIZADOS EN PARTNERS (para consultas rápidas)
-- ============================================================================

DO $$
BEGIN
  -- Agregar columnas si no existen
  IF NOT EXISTS (SELECT 1 FROM information_schema.columns
                 WHERE table_schema = 'core' AND table_name = 'partners'
                 AND column_name = 'customer_rank') THEN
    ALTER TABLE core.partners ADD COLUMN customer_rank INTEGER;
  END IF;

  IF NOT EXISTS (SELECT 1 FROM information_schema.columns
                 WHERE table_schema = 'core' AND table_name = 'partners'
                 AND column_name = 'supplier_rank') THEN
    ALTER TABLE core.partners ADD COLUMN supplier_rank INTEGER;
  END IF;

  IF NOT EXISTS (SELECT 1 FROM information_schema.columns
                 WHERE table_schema = 'core' AND table_name = 'partners'
                 AND column_name = 'customer_abc') THEN
    ALTER TABLE core.partners ADD COLUMN customer_abc CHAR(1);
  END IF;

  IF NOT EXISTS (SELECT 1 FROM information_schema.columns
                 WHERE table_schema = 'core' AND table_name = 'partners'
                 AND column_name = 'supplier_abc') THEN
    ALTER TABLE core.partners ADD COLUMN supplier_abc CHAR(1);
  END IF;

  IF NOT EXISTS (SELECT 1 FROM information_schema.columns
                 WHERE table_schema = 'core' AND table_name = 'partners'
                 AND column_name = 'last_ranking_date') THEN
    ALTER TABLE core.partners ADD COLUMN last_ranking_date DATE;
  END IF;

  IF NOT EXISTS (SELECT 1 FROM information_schema.columns
                 WHERE table_schema = 'core' AND table_name = 'partners'
                 AND column_name = 'total_sales_ytd') THEN
    ALTER TABLE core.partners ADD COLUMN total_sales_ytd DECIMAL(16,2) DEFAULT 0;
  END IF;

  IF NOT EXISTS (SELECT 1 FROM information_schema.columns
                 WHERE table_schema = 'core' AND table_name = 'partners'
                 AND column_name = 'total_purchases_ytd') THEN
    ALTER TABLE core.partners ADD COLUMN total_purchases_ytd DECIMAL(16,2) DEFAULT 0;
  END IF;
END $$;

-- ============================================================================
-- 3. ÍNDICES
-- ============================================================================

CREATE INDEX IF NOT EXISTS idx_partner_rankings_tenant_period
  ON core.partner_rankings(tenant_id, period_start, period_end);

CREATE INDEX IF NOT EXISTS idx_partner_rankings_partner
  ON core.partner_rankings(partner_id);

CREATE INDEX IF NOT EXISTS idx_partner_rankings_abc
  ON core.partner_rankings(tenant_id, customer_abc)
  WHERE customer_abc IS NOT NULL;

CREATE INDEX IF NOT EXISTS idx_partners_customer_rank
  ON core.partners(tenant_id, customer_rank)
  WHERE customer_rank IS NOT NULL;

CREATE INDEX IF NOT EXISTS idx_partners_supplier_rank
  ON core.partners(tenant_id, supplier_rank)
  WHERE supplier_rank IS NOT NULL;

-- ============================================================================
-- 4. RLS (Row Level Security)
-- ============================================================================

ALTER TABLE core.partner_rankings ENABLE ROW LEVEL SECURITY;

DROP POLICY IF EXISTS partner_rankings_tenant_isolation ON core.partner_rankings;
CREATE POLICY partner_rankings_tenant_isolation ON core.partner_rankings
  USING (tenant_id = current_setting('app.current_tenant_id', true)::uuid);

-- ============================================================================
-- 5. FUNCIÓN: Calcular rankings de partners
-- ============================================================================

CREATE OR REPLACE FUNCTION core.calculate_partner_rankings(
  p_tenant_id UUID,
  p_company_id UUID DEFAULT NULL,
  p_period_start DATE DEFAULT (CURRENT_DATE - INTERVAL '1 year')::date,
  p_period_end DATE DEFAULT CURRENT_DATE
)
RETURNS TABLE (
  partners_processed INTEGER,
  customers_ranked INTEGER,
  suppliers_ranked INTEGER
) AS $$
DECLARE
  v_partners_processed INTEGER := 0;
  v_customers_ranked INTEGER := 0;
  v_suppliers_ranked INTEGER := 0;
BEGIN
  -- 1. Calcular métricas de ventas por partner
  INSERT INTO core.partner_rankings (
    tenant_id, partner_id, company_id, period_start, period_end,
    total_sales, sales_order_count, avg_order_value
  )
  SELECT
    p_tenant_id,
    so.partner_id,
    COALESCE(p_company_id, so.company_id),
    p_period_start,
    p_period_end,
    COALESCE(SUM(so.amount_total), 0),
    COUNT(*),
    COALESCE(AVG(so.amount_total), 0)
  FROM sales.sales_orders so
  WHERE so.tenant_id = p_tenant_id
    AND so.status IN ('sale', 'done')
    AND so.order_date BETWEEN p_period_start AND p_period_end
    AND (p_company_id IS NULL OR so.company_id = p_company_id)
  GROUP BY so.partner_id, so.company_id
  ON CONFLICT (tenant_id, partner_id, company_id, period_start, period_end)
  DO UPDATE SET
    total_sales = EXCLUDED.total_sales,
    sales_order_count = EXCLUDED.sales_order_count,
    avg_order_value = EXCLUDED.avg_order_value,
    calculated_at = NOW();

  GET DIAGNOSTICS v_customers_ranked = ROW_COUNT;

  -- 2. Calcular métricas de compras por partner
  INSERT INTO core.partner_rankings (
    tenant_id, partner_id, company_id, period_start, period_end,
    total_purchases, purchase_order_count, avg_purchase_value
  )
  SELECT
    p_tenant_id,
    po.partner_id,
    COALESCE(p_company_id, po.company_id),
    p_period_start,
    p_period_end,
    COALESCE(SUM(po.amount_total), 0),
    COUNT(*),
    COALESCE(AVG(po.amount_total), 0)
  FROM purchase.purchase_orders po
  WHERE po.tenant_id = p_tenant_id
    AND po.status IN ('confirmed', 'done')
    AND po.order_date BETWEEN p_period_start AND p_period_end
    AND (p_company_id IS NULL OR po.company_id = p_company_id)
  GROUP BY po.partner_id, po.company_id
  ON CONFLICT (tenant_id, partner_id, company_id, period_start, period_end)
  DO UPDATE SET
    total_purchases = EXCLUDED.total_purchases,
    purchase_order_count = EXCLUDED.purchase_order_count,
    avg_purchase_value = EXCLUDED.avg_purchase_value,
    calculated_at = NOW();

  GET DIAGNOSTICS v_suppliers_ranked = ROW_COUNT;

  -- 3. Calcular rankings de clientes (por total de ventas)
  WITH ranked AS (
    SELECT
      id,
      ROW_NUMBER() OVER (ORDER BY total_sales DESC) as rank,
      total_sales,
      SUM(total_sales) OVER () as grand_total,
      SUM(total_sales) OVER (ORDER BY total_sales DESC) as cumulative_total
    FROM core.partner_rankings
    WHERE tenant_id = p_tenant_id
      AND period_start = p_period_start
      AND period_end = p_period_end
      AND total_sales > 0
  )
  UPDATE core.partner_rankings pr
  SET
    sales_rank = r.rank,
    customer_abc = CASE
      WHEN r.cumulative_total / NULLIF(r.grand_total, 0) <= 0.80 THEN 'A'
      WHEN r.cumulative_total / NULLIF(r.grand_total, 0) <= 0.95 THEN 'B'
      ELSE 'C'
    END,
    customer_score = CASE
      WHEN r.rank = 1 THEN 100
      ELSE GREATEST(0, 100 - (r.rank - 1) * 5)
    END
  FROM ranked r
  WHERE pr.id = r.id;

  -- 4. Calcular rankings de proveedores (por total de compras)
  WITH ranked AS (
    SELECT
      id,
      ROW_NUMBER() OVER (ORDER BY total_purchases DESC) as rank,
      total_purchases,
      SUM(total_purchases) OVER () as grand_total,
      SUM(total_purchases) OVER (ORDER BY total_purchases DESC) as cumulative_total
    FROM core.partner_rankings
    WHERE tenant_id = p_tenant_id
      AND period_start = p_period_start
      AND period_end = p_period_end
      AND total_purchases > 0
  )
  UPDATE core.partner_rankings pr
  SET
    purchase_rank = r.rank,
    supplier_abc = CASE
      WHEN r.cumulative_total / NULLIF(r.grand_total, 0) <= 0.80 THEN 'A'
      WHEN r.cumulative_total / NULLIF(r.grand_total, 0) <= 0.95 THEN 'B'
      ELSE 'C'
    END,
    supplier_score = CASE
      WHEN r.rank = 1 THEN 100
      ELSE GREATEST(0, 100 - (r.rank - 1) * 5)
    END
  FROM ranked r
  WHERE pr.id = r.id;

  -- 5. Calcular score overall
  UPDATE core.partner_rankings
  SET overall_score = COALESCE(
    (COALESCE(customer_score, 0) + COALESCE(supplier_score, 0)) /
    NULLIF(
      CASE WHEN customer_score IS NOT NULL THEN 1 ELSE 0 END +
      CASE WHEN supplier_score IS NOT NULL THEN 1 ELSE 0 END,
      0
    ),
    0
  )
  WHERE tenant_id = p_tenant_id
    AND period_start = p_period_start
    AND period_end = p_period_end;

  -- 6. Actualizar campos desnormalizados en partners
  UPDATE core.partners p
  SET
    customer_rank = pr.sales_rank,
    supplier_rank = pr.purchase_rank,
    customer_abc = pr.customer_abc,
    supplier_abc = pr.supplier_abc,
    total_sales_ytd = pr.total_sales,
    total_purchases_ytd = pr.total_purchases,
    last_ranking_date = CURRENT_DATE
  FROM core.partner_rankings pr
  WHERE p.id = pr.partner_id
    AND p.tenant_id = p_tenant_id
    AND pr.tenant_id = p_tenant_id
    AND pr.period_start = p_period_start
    AND pr.period_end = p_period_end;

  GET DIAGNOSTICS v_partners_processed = ROW_COUNT;

  RETURN QUERY SELECT v_partners_processed, v_customers_ranked, v_suppliers_ranked;
END;
$$ LANGUAGE plpgsql;

COMMENT ON FUNCTION core.calculate_partner_rankings IS
'Calcula rankings ABC de partners basado en ventas/compras.
Parámetros:
  - p_tenant_id: Tenant obligatorio
  - p_company_id: Opcional, filtrar por empresa
  - p_period_start: Inicio del período (default: hace 1 año)
  - p_period_end: Fin del período (default: hoy)';

-- ============================================================================
-- 6. VISTA: Top Partners
-- ============================================================================

CREATE OR REPLACE VIEW core.top_partners_view AS
SELECT
  p.id,
  p.tenant_id,
  p.name,
  p.email,
  p.is_customer,
  p.is_supplier,
  p.customer_rank,
  p.supplier_rank,
  p.customer_abc,
  p.supplier_abc,
  p.total_sales_ytd,
  p.total_purchases_ytd,
  p.last_ranking_date,
  CASE
    WHEN p.customer_abc = 'A' THEN 'Cliente VIP'
    WHEN p.customer_abc = 'B' THEN 'Cliente Regular'
    WHEN p.customer_abc = 'C' THEN 'Cliente Ocasional'
    ELSE NULL
  END as customer_category,
  CASE
    WHEN p.supplier_abc = 'A' THEN 'Proveedor Estratégico'
    WHEN p.supplier_abc = 'B' THEN 'Proveedor Regular'
    WHEN p.supplier_abc = 'C' THEN 'Proveedor Ocasional'
    ELSE NULL
  END as supplier_category
FROM core.partners p
WHERE p.deleted_at IS NULL
  AND (p.customer_rank IS NOT NULL OR p.supplier_rank IS NOT NULL);

-- ============================================================================
-- ROLLBACK SCRIPT
-- ============================================================================
/*
DROP VIEW IF EXISTS core.top_partners_view;
DROP FUNCTION IF EXISTS core.calculate_partner_rankings(UUID, UUID, DATE, DATE);
DROP TABLE IF EXISTS core.partner_rankings;

ALTER TABLE core.partners
  DROP COLUMN IF EXISTS customer_rank,
  DROP COLUMN IF EXISTS supplier_rank,
  DROP COLUMN IF EXISTS customer_abc,
  DROP COLUMN IF EXISTS supplier_abc,
  DROP COLUMN IF EXISTS last_ranking_date,
  DROP COLUMN IF EXISTS total_sales_ytd,
  DROP COLUMN IF EXISTS total_purchases_ytd;
*/

-- ============================================================================
-- VERIFICACIÓN
-- ============================================================================

DO $$
BEGIN
  IF NOT EXISTS (SELECT 1 FROM pg_tables WHERE schemaname = 'core' AND tablename = 'partner_rankings') THEN
    RAISE EXCEPTION 'Error: Tabla partner_rankings no fue creada';
  END IF;

  RAISE NOTICE 'Migración completada exitosamente: Partner Rankings';
END $$;