-- Migration 106: Banner Email Linking + Consent Proof
-- Phase 3: linked_email for DSR ↔ Banner-Consent correlation
-- Phase 6: banner_config_hash + consent_version for Art. 7(1) DSGVO proof

-- 1. Add linked_email to banner consents (optional, nullable)
-- Allows correlating device-based consents with user email for DSR processing
ALTER TABLE compliance_banner_consents
    ADD COLUMN IF NOT EXISTS linked_email TEXT;

CREATE INDEX IF NOT EXISTS idx_banner_consent_email
    ON compliance_banner_consents (linked_email)
    WHERE linked_email IS NOT NULL;

-- 2. Add consent proof columns to audit log
-- banner_config_hash: SHA256 of the site config at consent time (Art. 7(1) DSGVO)
-- consent_version: incremented per site on config change, tracks which banner version was shown
ALTER TABLE compliance_banner_consent_audit_log
    ADD COLUMN IF NOT EXISTS banner_config_hash TEXT,
    ADD COLUMN IF NOT EXISTS consent_version INTEGER;

-- 3. Add config_version counter to site configs (auto-incremented on config change)
ALTER TABLE compliance_banner_site_configs
    ADD COLUMN IF NOT EXISTS config_version INTEGER NOT NULL DEFAULT 1;