CREATE TABLE users (
    user_id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(100) UNIQUE NOT NULL,
    email VARCHAR(255) UNIQUE NOT NULL,
    password_hash CHAR(64) DEFAULT NULL, -- SHA256 hash or similar
    api_key CHAR(64) UNIQUE NOT NULL, -- for API authentication
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    last_login TIMESTAMP NULL DEFAULT NULL,
    status ENUM('active','inactive','banned') NOT NULL DEFAULT 'active'
);

CREATE TABLE device_tokens (
    token_id CHAR(36) NOT NULL PRIMARY KEY, -- UUID
    user_id BIGINT NOT NULL,                -- Foreign key
    platform ENUM('ios','android','web') NOT NULL,
    token VARBINARY(512) NOT NULL,          -- encrypted token
    status ENUM('active','invalid','expired') NOT NULL DEFAULT 'active',
    app_version VARCHAR(50),
    locale VARCHAR(10),
    topics VARCHAR(255),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    last_seen_at TIMESTAMP NULL DEFAULT NULL,
    last_successful_delivery TIMESTAMP NULL DEFAULT NULL,
    last_failed_delivery TIMESTAMP NULL DEFAULT NULL,

    CONSTRAINT fk_user FOREIGN KEY (user_id) REFERENCES users(user_id)
        ON DELETE CASCADE
);

-- Indexes for performance
CREATE INDEX idx_user_id ON device_tokens(user_id);
CREATE INDEX idx_platform ON device_tokens(platform);
CREATE INDEX idx_topics ON device_tokens(topics);