CREATE EXTENSION IF NOT EXISTS "uuid-ossp";

CREATE TABLE IF NOT EXISTS schema_migrations (
    version BIGINT PRIMARY KEY,
    applied_at TIMESTAMPTZ DEFAULT NOW()
);

CREATE TABLE IF NOT EXISTS users (
    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
    username TEXT UNIQUE NOT NULL,
    password_hash TEXT NOT NULL,
    created_at TIMESTAMPTZ DEFAULT NOW(),
    updated_at TIMESTAMPTZ DEFAULT NOW()
);

CREATE TABLE IF NOT EXISTS notes (
    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    created_at TIMESTAMPTZ DEFAULT NOW(),
    updated_at TIMESTAMPTZ DEFAULT NOW()
);

CREATE TABLE IF NOT EXISTS note_versions (
    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
    note_id UUID NOT NULL REFERENCES notes(id) ON DELETE CASCADE,
    title TEXT NOT NULL,
    content TEXT NOT NULL,
    version_number INT NOT NULL,
    content_hash TEXT NOT NULL,
    created_at TIMESTAMPTZ DEFAULT NOW()
);

CREATE UNIQUE INDEX IF NOT EXISTS idx_note_version_unique ON note_versions(note_id, version_number);
CREATE UNIQUE INDEX IF NOT EXISTS idx_users_username ON users(username);
CREATE INDEX IF NOT EXISTS idx_note_versions_note ON note_versions(note_id);
CREATE INDEX IF NOT EXISTS idx_note_versions_number ON note_versions(version_number DESC);