-- : SKIP
-- ============================================================
-- v3.5 WhatsApp State Machine
-- Reorganización del chatbot de AI libre a flujo estructurado
--
-- NOTE: This migration requires the WhatsApp tables (whatsapp_sessions,
-- whatsapp_messages) to be present. Tenant DBs without WhatsApp enabled
-- should skip this file.
-- Marked with ': SKIP' so the runner skips it unless WhatsApp is configured.
-- To apply manually on a tenant with WhatsApp tables:
--   psql <tenant_db> -f pos/migrations/v3.5_whatsapp_state_machine.sql
-- (Remove the ': SKIP' line above before manual execution.)
-- ============================================================

DO $$
BEGIN
    -- 1. Extender whatsapp_sessions con estado y contexto
    IF EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'whatsapp_sessions') THEN
        ALTER TABLE whatsapp_sessions
        ADD COLUMN IF NOT EXISTS state VARCHAR(50) DEFAULT 'idle',
        ADD COLUMN IF NOT EXISTS state_data JSONB DEFAULT '{}',
        ADD COLUMN IF NOT EXISTS customer_id INTEGER REFERENCES customers(id),
        ADD COLUMN IF NOT EXISTS branch_id INTEGER REFERENCES branches(id),
        ADD COLUMN IF NOT EXISTS learning_cycle INTEGER DEFAULT 0,
        ADD COLUMN IF NOT EXISTS created_at TIMESTAMPTZ DEFAULT NOW();

        CREATE INDEX IF NOT EXISTS idx_wa_sessions_state ON whatsapp_sessions(state);
        CREATE INDEX IF NOT EXISTS idx_wa_sessions_customer ON whatsapp_sessions(customer_id);
        CREATE INDEX IF NOT EXISTS idx_wa_sessions_updated ON whatsapp_sessions(updated_at);
    END IF;

    -- 2. Tabla de vínculo persistente WA ID ↔ Cliente
    IF EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'customers') THEN
        CREATE TABLE IF NOT EXISTS wa_customer_links (
            phone VARCHAR(50) PRIMARY KEY,
            customer_id INTEGER NOT NULL REFERENCES customers(id),
            created_at TIMESTAMPTZ DEFAULT NOW(),
            updated_at TIMESTAMPTZ DEFAULT NOW()
        );

        CREATE INDEX IF NOT EXISTS idx_wa_cust_link_customer ON wa_customer_links(customer_id);

        CREATE OR REPLACE FUNCTION update_wa_link_timestamp()
        RETURNS TRIGGER AS $$
        BEGIN
            NEW.updated_at = NOW();
            RETURN NEW;
        END;
        $$ LANGUAGE plpgsql;

        DROP TRIGGER IF EXISTS trg_wa_link_updated ON wa_customer_links;
        CREATE TRIGGER trg_wa_link_updated
            BEFORE UPDATE ON wa_customer_links
            FOR EACH ROW EXECUTE FUNCTION update_wa_link_timestamp();
    END IF;

    -- 3. Tabla de sesiones de aprendizaje (piezas no resueltas)
    IF EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'customers')
       AND EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'inventory')
       AND EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'sales') THEN
        CREATE TABLE IF NOT EXISTS wa_learning_sessions (
            id SERIAL PRIMARY KEY,
            phone VARCHAR(50) NOT NULL,
            customer_id INTEGER REFERENCES customers(id),
            description TEXT NOT NULL,
            offered_parts JSONB DEFAULT '[]',
            status VARCHAR(20) DEFAULT 'pending',
            resolved_part_id INTEGER REFERENCES inventory(id),
            resolution_sale_id INTEGER REFERENCES sales(id),
            created_at TIMESTAMPTZ DEFAULT NOW(),
            resolved_at TIMESTAMPTZ
        );

        CREATE INDEX IF NOT EXISTS idx_wa_learn_phone ON wa_learning_sessions(phone);
        CREATE INDEX IF NOT EXISTS idx_wa_learn_status ON wa_learning_sessions(status);
        CREATE INDEX IF NOT EXISTS idx_wa_learn_customer ON wa_learning_sessions(customer_id);
        CREATE INDEX IF NOT EXISTS idx_wa_learn_created ON wa_learning_sessions(created_at);
    END IF;

    -- 4. Tabla de configuración de envío por sucursal
    IF EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'branches') THEN
        CREATE TABLE IF NOT EXISTS branch_delivery_config (
            id SERIAL PRIMARY KEY,
            branch_id INTEGER NOT NULL UNIQUE REFERENCES branches(id),
            is_enabled BOOLEAN DEFAULT FALSE,
            delivery_fee NUMERIC(12,2) DEFAULT 0,
            free_delivery_threshold NUMERIC(12,2) DEFAULT NULL,
            coverage_radius_km INTEGER DEFAULT NULL,
            delivery_hours VARCHAR(100) DEFAULT 'Lun-Vie 9:00-18:00',
            notes TEXT,
            created_at TIMESTAMPTZ DEFAULT NOW(),
            updated_at TIMESTAMPTZ DEFAULT NOW()
        );
    END IF;

    -- 5. Agregar push_name a whatsapp_messages
    IF EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'whatsapp_messages') THEN
        ALTER TABLE whatsapp_messages
        ADD COLUMN IF NOT EXISTS push_name VARCHAR(200);
    END IF;

    -- 6. Migrar datos existentes
    IF EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'whatsapp_sessions')
       AND EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'wa_customer_links')
       AND EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'customers') THEN
        INSERT INTO wa_customer_links (phone, customer_id)
        SELECT ws.phone, c.id
        FROM whatsapp_sessions ws
        JOIN customers c ON c.phone = ws.phone
        WHERE ws.phone IS NOT NULL AND c.phone IS NOT NULL
        ON CONFLICT (phone) DO NOTHING;

        UPDATE whatsapp_sessions ws
        SET customer_id = wcl.customer_id
        FROM wa_customer_links wcl
        WHERE ws.phone = wcl.phone AND ws.customer_id IS NULL;
    END IF;
END $$;