-- Migration: Add Messaging System
-- Creates tables for customer-admin conversations and messages

-- Conversations table
CREATE TABLE IF NOT EXISTS conversations (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT NOT NULL,
    product_id INT NULL,
    subject VARCHAR(255) NOT NULL,
    status ENUM('open', 'closed') DEFAULT 'open',
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
    FOREIGN KEY (product_id) REFERENCES products(id) ON DELETE SET NULL,
    INDEX idx_user_status (user_id, status),
    INDEX idx_updated (updated_at DESC)
);

-- Messages table
CREATE TABLE IF NOT EXISTS messages (
    id INT AUTO_INCREMENT PRIMARY KEY,
    conversation_id INT NOT NULL,
    sender_id INT NOT NULL,
    sender_role ENUM('customer', 'admin') NOT NULL,
    content TEXT NOT NULL,
    is_read BOOLEAN DEFAULT FALSE,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (conversation_id) REFERENCES conversations(id) ON DELETE CASCADE,
    FOREIGN KEY (sender_id) REFERENCES users(id) ON DELETE CASCADE,
    INDEX idx_conversation (conversation_id, created_at),
    INDEX idx_unread (conversation_id, is_read)
);