-- Add referral tracking columns to purchase_attempts table
ALTER TABLE purchase_attempts 
ADD COLUMN IF NOT EXISTS referral_source TEXT,
ADD COLUMN IF NOT EXISTS utm_campaign TEXT,
ADD COLUMN IF NOT EXISTS utm_medium TEXT,
ADD COLUMN IF NOT EXISTS utm_source TEXT,
ADD COLUMN IF NOT EXISTS utm_term TEXT,
ADD COLUMN IF NOT EXISTS utm_content TEXT,
ADD COLUMN IF NOT EXISTS referrer_url TEXT,
ADD COLUMN IF NOT EXISTS landing_page TEXT;

-- Add indexes for better query performance
CREATE INDEX IF NOT EXISTS idx_purchase_attempts_referral_source ON purchase_attempts(referral_source);
CREATE INDEX IF NOT EXISTS idx_purchase_attempts_utm_source ON purchase_attempts(utm_source);
CREATE INDEX IF NOT EXISTS idx_purchase_attempts_utm_campaign ON purchase_attempts(utm_campaign);

-- Add comments to explain the columns
COMMENT ON COLUMN purchase_attempts.referral_source IS 'High-level referral source (e.g., google, facebook, direct, email)';
COMMENT ON COLUMN purchase_attempts.utm_campaign IS 'Campaign name from UTM parameters';
COMMENT ON COLUMN purchase_attempts.utm_medium IS 'Medium from UTM parameters (e.g., email, social, paid)';
COMMENT ON COLUMN purchase_attempts.utm_source IS 'Source from UTM parameters (e.g., google, facebook, newsletter)';
COMMENT ON COLUMN purchase_attempts.utm_term IS 'Term from UTM parameters (paid search keywords)';
COMMENT ON COLUMN purchase_attempts.utm_content IS 'Content from UTM parameters (ad variant)';
COMMENT ON COLUMN purchase_attempts.referrer_url IS 'Full HTTP referrer URL';
COMMENT ON COLUMN purchase_attempts.landing_page IS 'Page where user first landed on the site';