CREATE TABLE IF NOT EXISTS participants (
    id SERIAL PRIMARY KEY,
    name TEXT NOT NULL UNIQUE,
    created_at TIMESTAMPTZ DEFAULT NOW()
);
INSERT INTO participants (name) VALUES ('Me') ON CONFLICT DO NOTHING;

CREATE TABLE IF NOT EXISTS transaction_splits (
    id SERIAL PRIMARY KEY,
    transaction_id INTEGER NOT NULL REFERENCES transactions(id) ON DELETE CASCADE,
    participant_id INTEGER NOT NULL REFERENCES participants(id) ON DELETE CASCADE,
    share_percent NUMERIC(5,2) NOT NULL CHECK (share_percent > 0 AND share_percent <= 100),
    settled BOOLEAN DEFAULT FALSE,
    settled_at TIMESTAMPTZ,
    created_at TIMESTAMPTZ DEFAULT NOW(),
    UNIQUE (transaction_id, participant_id)
);
CREATE INDEX IF NOT EXISTS idx_splits_txn ON transaction_splits(transaction_id);
CREATE INDEX IF NOT EXISTS idx_splits_participant ON transaction_splits(participant_id);