CREATE TABLE users (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    username VARCHAR(32) UNIQUE NOT NULL,
    display_name VARCHAR(64) NOT NULL,
    avatar_url TEXT,
    password_hash TEXT NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE TABLE conversations (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    next_sequence BIGINT NOT NULL DEFAULT 0
);

CREATE TABLE conversation_participants (
    conversation_id UUID REFERENCES conversations(id),
    user_id UUID REFERENCES users(id),
    last_read_seq BIGINT NOT NULL DEFAULT 0,
    joined_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    PRIMARY KEY (conversation_id, user_id),
    UNIQUE (conversation_id, user_id)
);

CREATE TABLE messages (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    conversation_id UUID REFERENCES conversations(id) NOT NULL,
    sender_id UUID REFERENCES users(id) NOT NULL,
    sequence BIGINT NOT NULL,
    message_type VARCHAR(16) NOT NULL,
    body TEXT,
    media_metadata JSONB,
    client_msg_id UUID NOT NULL,
    status VARCHAR(16) NOT NULL DEFAULT 'sent',
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    UNIQUE (conversation_id, sequence),
    UNIQUE (client_msg_id)
);

CREATE TABLE sticker_packs (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    name VARCHAR(64) NOT NULL,
    author VARCHAR(64),
    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE TABLE stickers (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    pack_id UUID REFERENCES sticker_packs(id) NOT NULL,
    emoji_tag VARCHAR(8),
    image_url TEXT NOT NULL,
    thumbnail_url TEXT NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);