CREATE TABLE IF NOT EXISTS users (
    id SERIAL PRIMARY KEY,
    username TEXT NOT NULL UNIQUE,
    email TEXT NOT NULL UNIQUE,
    api_key TEXT UNIQUE,
    storage_limit_bytes BIGINT DEFAULT 1073741824,
    created_at TIMESTAMPTZ DEFAULT NOW()
);

CREATE TABLE IF NOT EXISTS buckets (
    id SERIAL PRIMARY KEY,
    name TEXT NOT NULL UNIQUE,
    owner_id INT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    storage_used_bytes BIGINT DEFAULT 0,
    created_at TIMESTAMPTZ DEFAULT NOW()
);

CREATE TABLE IF NOT EXISTS objects (
    id BIGSERIAL PRIMARY KEY,
    bucket_id INT NOT NULL REFERENCES buckets(id) ON DELETE CASCADE,
    key TEXT NOT NULL,
    size_bytes BIGINT NOT NULL,
    content_type TEXT,
    last_modified TIMESTAMPTZ DEFAULT NOW(),
    version_id TEXT UNIQUE,
    md5_checksum TEXT,
    custom_metadata JSONB DEFAULT '{}',
    UNIQUE (bucket_id, key)
);

CREATE INDEX IF NOT EXISTS idx_objects_bucket_id_key ON objects (bucket_id, key);
CREATE INDEX IF NOT EXISTS idx_objects_bucket_id_last_modified ON objects (bucket_id, last_modified DESC);
CREATE INDEX IF NOT EXISTS idx_objects_custom_metadata_gin ON objects USING GIN (custom_metadata);