-- Migration 110: Create delivered_status table (v0.502 CH1-01)
CREATE TABLE IF NOT EXISTS delivered_status (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    message_id UUID NOT NULL REFERENCES messages(id) ON DELETE CASCADE,
    delivered_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
    CONSTRAINT uq_delivered_status_user_message UNIQUE (user_id, message_id)
);
CREATE INDEX idx_delivered_status_message_id ON delivered_status(message_id);
CREATE INDEX idx_delivered_status_user_id ON delivered_status(user_id);