-- Migration 100: Fixed-Price Agreements
-- Creates table for monthly fixed-price hour agreements with binding periods
-- Ready for future subscription system integration (v2)

CREATE TABLE IF NOT EXISTS customer_fixed_price_agreements (
    id SERIAL PRIMARY KEY,
    agreement_number VARCHAR(50) UNIQUE NOT NULL,
    
    -- Future subscription system integration
    subscription_id INTEGER DEFAULT NULL,
    
    -- Customer linkage
    customer_id INTEGER NOT NULL,
    customer_name VARCHAR(255),
    
    -- Product definition (v2: move to subscription_products table)
    monthly_hours DECIMAL(8,2) NOT NULL CHECK (monthly_hours > 0),
    hourly_rate DECIMAL(10,2) NOT NULL CHECK (hourly_rate >= 0),
    overtime_rate DECIMAL(10,2) NOT NULL CHECK (overtime_rate >= 0),
    internal_cost_rate DECIMAL(10,2) DEFAULT 350.00,  -- For profit calculation
    rounding_minutes INTEGER DEFAULT 0 CHECK (rounding_minutes IN (0, 15, 30, 60)),
    
    -- Contract lifecycle
    start_date DATE NOT NULL,
    binding_months INTEGER DEFAULT 0 CHECK (binding_months >= 0),
    binding_end_date DATE,
    end_date DATE,
    notice_period_days INTEGER DEFAULT 30 CHECK (notice_period_days >= 0),
    auto_renew BOOLEAN DEFAULT false,
    
    -- Status tracking
    status VARCHAR(20) DEFAULT 'active' CHECK (status IN ('active', 'suspended', 'expired', 'cancelled', 'pending_cancellation')),
    cancellation_requested_date DATE,
    cancellation_effective_date DATE,
    cancelled_by_user_id INTEGER,
    cancellation_reason TEXT,
    
    -- Billing integration (v2: subscription_billing handles this)
    billing_enabled BOOLEAN DEFAULT true,
    last_billed_period DATE,
    
    -- e-conomic integration (v2: move to subscription product mapping)
    economic_product_number VARCHAR(50),
    economic_overtime_product_number VARCHAR(50),
    
    -- Metadata
    notes TEXT,
    created_by_user_id INTEGER,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Indexes for performance
CREATE INDEX IF NOT EXISTS idx_fpa_customer ON customer_fixed_price_agreements(customer_id);
CREATE INDEX IF NOT EXISTS idx_fpa_subscription ON customer_fixed_price_agreements(subscription_id);
CREATE INDEX IF NOT EXISTS idx_fpa_status ON customer_fixed_price_agreements(status);
CREATE INDEX IF NOT EXISTS idx_fpa_dates ON customer_fixed_price_agreements(start_date, end_date);

-- Trigger to auto-generate agreement_number
CREATE OR REPLACE FUNCTION generate_fpa_number()
RETURNS TRIGGER AS $$
DECLARE
    new_number VARCHAR(50);
    day_count INTEGER;
BEGIN
    -- Count agreements created today
    SELECT COUNT(*) INTO day_count
    FROM customer_fixed_price_agreements
    WHERE DATE(created_at) = CURRENT_DATE;
    
    -- Generate FPA-YYYYMMDD-XXX
    new_number := 'FPA-' || TO_CHAR(CURRENT_DATE, 'YYYYMMDD') || '-' || LPAD((day_count + 1)::TEXT, 3, '0');
    
    NEW.agreement_number := new_number;
    
    -- Calculate binding_end_date
    IF NEW.binding_months > 0 THEN
        NEW.binding_end_date := NEW.start_date + (NEW.binding_months || ' months')::INTERVAL;
    ELSE
        NEW.binding_end_date := NULL;
    END IF;
    
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER trigger_generate_fpa_number
    BEFORE INSERT OR UPDATE ON customer_fixed_price_agreements  
    FOR EACH ROW
    EXECUTE FUNCTION generate_fpa_number();

-- Update timestamp trigger
CREATE TRIGGER trigger_fpa_updated_at
    BEFORE UPDATE ON customer_fixed_price_agreements
    FOR EACH ROW
    EXECUTE FUNCTION update_updated_at_column();

COMMENT ON TABLE customer_fixed_price_agreements IS 
    'Fixed-price monthly hour agreements. Ready for v2 subscription system integration via subscription_id column.';

COMMENT ON COLUMN customer_fixed_price_agreements.subscription_id IS 
    'Future: Links to unified subscription system (Phase 2)';

COMMENT ON COLUMN customer_fixed_price_agreements.internal_cost_rate IS 
    'Internal hourly cost for profit margin calculation in reporting';

COMMENT ON COLUMN customer_fixed_price_agreements.binding_end_date IS 
    'Auto-calculated from start_date + binding_months. Enforced during cancellation.';