USE inventory_db;

CREATE TABLE IF NOT EXISTS invoices (
    id INT(11) AUTO_INCREMENT PRIMARY KEY,
    client_id INT(11) NOT NULL,
    invoice_number VARCHAR(50) NOT NULL UNIQUE,
    issue_date DATE NOT NULL,
    due_date DATE NOT NULL,
    status ENUM('draft', 'sent', 'paid', 'overdue', 'cancelled') DEFAULT 'draft',
    subtotal DECIMAL(10,2) NOT NULL DEFAULT 0.00,
    tax_amount DECIMAL(10,2) NOT NULL DEFAULT 0.00,
    total_amount DECIMAL(10,2) NOT NULL DEFAULT 0.00,
    notes TEXT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    FOREIGN KEY (client_id) REFERENCES clients(id) ON DELETE RESTRICT,
    INDEX idx_client_status (client_id, status),
    INDEX idx_invoice_number (invoice_number),
    INDEX idx_due_date (due_date)
);

CREATE TABLE IF NOT EXISTS invoice_items (
    id INT(11) AUTO_INCREMENT PRIMARY KEY,
    invoice_id INT(11) NOT NULL,
    item_id INT(11) NOT NULL,
    description VARCHAR(255) NOT NULL,
    quantity DECIMAL(10,2) NOT NULL DEFAULT 1.00,
    unit_price DECIMAL(10,2) NOT NULL DEFAULT 0.00,
    line_total DECIMAL(10,2) NOT NULL DEFAULT 0.00,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    FOREIGN KEY (invoice_id) REFERENCES invoices(id) ON DELETE CASCADE,
    FOREIGN KEY (item_id) REFERENCES items(id) ON DELETE RESTRICT,
    INDEX idx_invoice (invoice_id),
    INDEX idx_item (item_id)
);

CREATE TABLE IF NOT EXISTS payments (
    id INT(11) AUTO_INCREMENT PRIMARY KEY,
    invoice_id INT(11) NULL,
    client_id INT(11) NOT NULL,
    payment_date DATE NOT NULL,
    amount DECIMAL(10,2) NOT NULL DEFAULT 0.00,
    payment_method ENUM('cash', 'check', 'credit_card', 'bank_transfer', 'other') DEFAULT 'cash',
    reference_number VARCHAR(50) NULL,
    notes TEXT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    FOREIGN KEY (invoice_id) REFERENCES invoices(id) ON DELETE SET NULL,
    FOREIGN KEY (client_id) REFERENCES clients(id) ON DELETE RESTRICT,
    INDEX idx_invoice (invoice_id),
    INDEX idx_client (client_id),
    INDEX idx_payment_date (payment_date)
);