CREATE TABLE IF NOT EXISTS background_jobs (
    id BIGSERIAL PRIMARY KEY,
    queue VARCHAR(100) NOT NULL DEFAULT 'default',
    job_type VARCHAR(150) NOT NULL,
    payload JSONB NOT NULL DEFAULT '{}',
    status VARCHAR(50) NOT NULL DEFAULT 'queued',
    priority INTEGER NOT NULL DEFAULT 0,
    attempts INTEGER NOT NULL DEFAULT 0,
    max_attempts INTEGER NOT NULL DEFAULT 3,
    scheduled_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT NOW(),
    locked_at TIMESTAMP WITH TIME ZONE,
    locked_by VARCHAR(150),
    idempotency_key VARCHAR(255),
    last_error TEXT,
    finished_at TIMESTAMP WITH TIME ZONE,
    failed_at TIMESTAMP WITH TIME ZONE,
    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
);

CREATE INDEX IF NOT EXISTS idx_background_jobs_ready
    ON background_jobs(status, queue, scheduled_at, priority DESC, id);
CREATE INDEX IF NOT EXISTS idx_background_jobs_job_type ON background_jobs(job_type);
CREATE INDEX IF NOT EXISTS idx_background_jobs_locked_at ON background_jobs(locked_at);
CREATE INDEX IF NOT EXISTS idx_background_jobs_idempotency_key ON background_jobs(idempotency_key);
CREATE UNIQUE INDEX IF NOT EXISTS idx_background_jobs_idempotency_key_unique
    ON background_jobs(idempotency_key)
    WHERE idempotency_key IS NOT NULL AND idempotency_key <> '';