-- Enterprise AI Assistant - E-commerce Database Schema

CREATE TABLE IF NOT EXISTS customers (
    customer_id INTEGER PRIMARY KEY AUTOINCREMENT,
    first_name TEXT NOT NULL,
    last_name TEXT NOT NULL,
    email TEXT UNIQUE NOT NULL,
    phone TEXT,
    address TEXT,
    city TEXT,
    state TEXT,
    zip_code TEXT,
    country TEXT DEFAULT 'US',
    segment TEXT CHECK(segment IN ('Consumer', 'Corporate', 'Enterprise')),
    lifetime_value REAL DEFAULT 0,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS products (
    product_id INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT NOT NULL,
    category TEXT NOT NULL,
    subcategory TEXT,
    brand TEXT,
    price REAL NOT NULL,
    cost REAL NOT NULL,
    stock_quantity INTEGER DEFAULT 0,
    rating REAL DEFAULT 0,
    review_count INTEGER DEFAULT 0,
    is_active BOOLEAN DEFAULT 1,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS orders (
    order_id INTEGER PRIMARY KEY AUTOINCREMENT,
    customer_id INTEGER NOT NULL REFERENCES customers(customer_id),
    order_date TIMESTAMP NOT NULL,
    status TEXT CHECK(status IN ('Pending', 'Processing', 'Shipped', 'Delivered', 'Cancelled', 'Returned')),
    total_amount REAL NOT NULL,
    discount_amount REAL DEFAULT 0,
    shipping_cost REAL DEFAULT 0,
    payment_method TEXT CHECK(payment_method IN ('Credit Card', 'Debit Card', 'PayPal', 'Bank Transfer', 'Gift Card')),
    shipping_address TEXT,
    tracking_number TEXT
);

CREATE TABLE IF NOT EXISTS order_items (
    item_id INTEGER PRIMARY KEY AUTOINCREMENT,
    order_id INTEGER NOT NULL REFERENCES orders(order_id),
    product_id INTEGER NOT NULL REFERENCES products(product_id),
    quantity INTEGER NOT NULL,
    unit_price REAL NOT NULL,
    discount_percent REAL DEFAULT 0
);

CREATE TABLE IF NOT EXISTS reviews (
    review_id INTEGER PRIMARY KEY AUTOINCREMENT,
    product_id INTEGER NOT NULL REFERENCES products(product_id),
    customer_id INTEGER NOT NULL REFERENCES customers(customer_id),
    rating INTEGER CHECK(rating BETWEEN 1 AND 5),
    title TEXT,
    body TEXT,
    helpful_votes INTEGER DEFAULT 0,
    verified_purchase BOOLEAN DEFAULT 1,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS inventory_log (
    log_id INTEGER PRIMARY KEY AUTOINCREMENT,
    product_id INTEGER NOT NULL REFERENCES products(product_id),
    change_type TEXT CHECK(change_type IN ('Restock', 'Sale', 'Return', 'Adjustment', 'Damaged')),
    quantity_change INTEGER NOT NULL,
    previous_stock INTEGER NOT NULL,
    new_stock INTEGER NOT NULL,
    notes TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS cost_tracking (
    tracking_id INTEGER PRIMARY KEY AUTOINCREMENT,
    request_id TEXT UNIQUE NOT NULL,
    query TEXT NOT NULL,
    model_name TEXT NOT NULL,
    prompt_tokens INTEGER NOT NULL,
    completion_tokens INTEGER NOT NULL,
    total_tokens INTEGER NOT NULL,
    estimated_cost_usd REAL NOT NULL,
    latency_ms REAL,
    tools_used TEXT,
    guardrail_flags TEXT,
    success BOOLEAN DEFAULT 1,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Indexes for common queries
CREATE INDEX IF NOT EXISTS idx_orders_customer ON orders(customer_id);
CREATE INDEX IF NOT EXISTS idx_orders_date ON orders(order_date);
CREATE INDEX IF NOT EXISTS idx_orders_status ON orders(status);
CREATE INDEX IF NOT EXISTS idx_order_items_order ON order_items(order_id);
CREATE INDEX IF NOT EXISTS idx_order_items_product ON order_items(product_id);
CREATE INDEX IF NOT EXISTS idx_reviews_product ON reviews(product_id);
CREATE INDEX IF NOT EXISTS idx_reviews_customer ON reviews(customer_id);
CREATE INDEX IF NOT EXISTS idx_inventory_product ON inventory_log(product_id);
CREATE INDEX IF NOT EXISTS idx_products_category ON products(category);
CREATE INDEX IF NOT EXISTS idx_customers_segment ON customers(segment);
CREATE INDEX IF NOT EXISTS idx_cost_tracking_date ON cost_tracking(created_at);