CREATE TABLE IF NOT EXISTS inventory_categories (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name_en VARCHAR(255) NOT NULL,
    name_ar VARCHAR(255) NOT NULL,
    description TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS inventory_items (
    id INT AUTO_INCREMENT PRIMARY KEY,
    category_id INT,
    name_en VARCHAR(255) NOT NULL,
    name_ar VARCHAR(255) NOT NULL,
    description TEXT,
    sku VARCHAR(100) UNIQUE,
    unit VARCHAR(50) DEFAULT 'piece',
    min_level INT DEFAULT 10,
    reorder_level INT DEFAULT 20,
    is_active BOOLEAN DEFAULT TRUE,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (category_id) REFERENCES inventory_categories(id) ON DELETE SET NULL
);

CREATE TABLE IF NOT EXISTS inventory_batches (
    id INT AUTO_INCREMENT PRIMARY KEY,
    item_id INT NOT NULL,
    batch_number VARCHAR(100),
    expiry_date DATE,
    quantity INT NOT NULL DEFAULT 0,
    cost_price DECIMAL(10, 2) DEFAULT 0.00,
    supplier_id INT,
    received_date DATE,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (item_id) REFERENCES inventory_items(id) ON DELETE CASCADE,
    FOREIGN KEY (supplier_id) REFERENCES suppliers(id) ON DELETE SET NULL
);

CREATE TABLE IF NOT EXISTS inventory_transactions (
    id INT AUTO_INCREMENT PRIMARY KEY,
    item_id INT NOT NULL,
    batch_id INT,
    transaction_type ENUM('in', 'out', 'adjustment') NOT NULL,
    quantity INT NOT NULL,
    reference_type VARCHAR(50), -- 'purchase', 'consumption', 'manual_adjustment'
    reference_id INT,
    user_id INT,
    transaction_date DATETIME DEFAULT CURRENT_TIMESTAMP,
    notes TEXT,
    FOREIGN KEY (item_id) REFERENCES inventory_items(id) ON DELETE CASCADE,
    FOREIGN KEY (batch_id) REFERENCES inventory_batches(id) ON DELETE SET NULL,
    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE SET NULL
);