CREATE OR REPLACE FUNCTION update_updated_at_column()
RETURNS TRIGGER AS $$
BEGIN
    NEW.updated_at = NOW();
    RETURN NEW;
END;
$$ language 'plpgsql';

CREATE TYPE dropout_risk_level AS ENUM ('low', 'medium', 'high', 'critical');

CREATE TABLE IF NOT EXISTS dropout_risks (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    organization_id UUID NOT NULL REFERENCES organizations(id),
    course_id UUID NOT NULL REFERENCES courses(id),
    user_id UUID NOT NULL REFERENCES users(id),
    risk_level dropout_risk_level NOT NULL DEFAULT 'low',
    score REAL NOT NULL DEFAULT 0.0,
    reasons JSONB,
    last_calculated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    UNIQUE(course_id, user_id)
);

-- Trigger for updated_at
CREATE TRIGGER update_dropout_risks_updated_at
BEFORE UPDATE ON dropout_risks
FOR EACH ROW
EXECUTE FUNCTION update_updated_at_column();