-- Subscription agreement overview, approval workflow and invoice idempotency.

ALTER TABLE sag_subscriptions
    ADD COLUMN IF NOT EXISTS billing_schedule_type VARCHAR(30) NOT NULL DEFAULT 'fixed_day',
    ADD COLUMN IF NOT EXISTS version INTEGER NOT NULL DEFAULT 1;

ALTER TABLE sag_subscriptions DROP CONSTRAINT IF EXISTS sag_subscriptions_status_check;
ALTER TABLE sag_subscriptions ADD CONSTRAINT sag_subscriptions_status_check
    CHECK (status IN ('draft','scheduled','active','paused','terminating','cancelled','expired','blocked')) NOT VALID;
ALTER TABLE sag_subscriptions VALIDATE CONSTRAINT sag_subscriptions_status_check;

ALTER TABLE sag_subscriptions DROP CONSTRAINT IF EXISTS sag_subscriptions_billing_schedule_type_check;
ALTER TABLE sag_subscriptions ADD CONSTRAINT sag_subscriptions_billing_schedule_type_check
    CHECK (billing_schedule_type IN ('fixed_day','first_business_day','last_business_day','interval_anchor'));

CREATE TABLE IF NOT EXISTS subscription_change_requests (
    id BIGSERIAL PRIMARY KEY,
    main_sag_id INTEGER NOT NULL REFERENCES sag_sager(id) ON DELETE CASCADE,
    change_sag_id INTEGER NOT NULL REFERENCES sag_sager(id) ON DELETE RESTRICT,
    status VARCHAR(30) NOT NULL DEFAULT 'draft'
        CHECK (status IN ('draft','pending','approved_scheduled','applying','partially_applied','applied','rejected','failed','cancellation_pending','cancelled')),
    reason TEXT,
    effective_date DATE NOT NULL DEFAULT CURRENT_DATE,
    created_by_user_id INTEGER NOT NULL REFERENCES users(user_id),
    submitted_at TIMESTAMP,
    approved_by_user_id INTEGER REFERENCES users(user_id),
    approved_at TIMESTAMP,
    rejected_by_user_id INTEGER REFERENCES users(user_id),
    rejected_at TIMESTAMP,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE UNIQUE INDEX IF NOT EXISTS uq_subscription_change_request_open_per_sag
    ON subscription_change_requests(main_sag_id)
    WHERE status IN ('draft','pending','approved_scheduled','applying','partially_applied','failed','cancellation_pending');
CREATE UNIQUE INDEX IF NOT EXISTS uq_subscription_change_request_case
    ON subscription_change_requests(change_sag_id);

CREATE TABLE IF NOT EXISTS subscription_change_request_items (
    id BIGSERIAL PRIMARY KEY,
    change_request_id BIGINT NOT NULL REFERENCES subscription_change_requests(id) ON DELETE CASCADE,
    subscription_id INTEGER NOT NULL REFERENCES sag_subscriptions(id) ON DELETE RESTRICT,
    base_version INTEGER NOT NULL,
    before_snapshot JSONB NOT NULL,
    proposed_snapshot JSONB NOT NULL,
    apply_status VARCHAR(20) NOT NULL DEFAULT 'pending'
        CHECK (apply_status IN ('pending','applied','failed','abandoned')),
    error_message TEXT,
    applied_at TIMESTAMP,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    UNIQUE(change_request_id, subscription_id)
);

CREATE INDEX IF NOT EXISTS idx_subscription_change_items_subscription
    ON subscription_change_request_items(subscription_id);

CREATE TABLE IF NOT EXISTS subscription_change_cancellations (
    id BIGSERIAL PRIMARY KEY,
    change_request_id BIGINT NOT NULL REFERENCES subscription_change_requests(id) ON DELETE CASCADE,
    reason TEXT NOT NULL,
    status VARCHAR(20) NOT NULL DEFAULT 'pending' CHECK (status IN ('pending','approved','rejected')),
    requested_by_user_id INTEGER NOT NULL REFERENCES users(user_id),
    decided_by_user_id INTEGER REFERENCES users(user_id),
    decided_at TIMESTAMP,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);
CREATE UNIQUE INDEX IF NOT EXISTS uq_subscription_change_cancellation_pending
    ON subscription_change_cancellations(change_request_id) WHERE status = 'pending';

CREATE TABLE IF NOT EXISTS subscription_events (
    id BIGSERIAL PRIMARY KEY,
    main_sag_id INTEGER NOT NULL REFERENCES sag_sager(id) ON DELETE CASCADE,
    subscription_id INTEGER REFERENCES sag_subscriptions(id) ON DELETE SET NULL,
    change_request_id BIGINT REFERENCES subscription_change_requests(id) ON DELETE SET NULL,
    event_type VARCHAR(50) NOT NULL,
    actor_user_id INTEGER REFERENCES users(user_id),
    details JSONB NOT NULL DEFAULT '{}'::jsonb,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);
CREATE INDEX IF NOT EXISTS idx_subscription_events_sag_created
    ON subscription_events(main_sag_id, created_at DESC);

CREATE TABLE IF NOT EXISTS subscription_billing_runs (
    id BIGSERIAL PRIMARY KEY,
    subscription_id INTEGER NOT NULL REFERENCES sag_subscriptions(id) ON DELETE RESTRICT,
    period_start DATE NOT NULL,
    ordre_draft_id INTEGER REFERENCES ordre_drafts(id) ON DELETE SET NULL,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    UNIQUE(subscription_id, period_start)
);

INSERT INTO permissions (code, description, category) VALUES
    ('subscriptions.view', 'View subscriptions and agreement history', 'subscriptions'),
    ('subscriptions.change_request', 'Create subscription change requests', 'subscriptions'),
    ('subscriptions.approve', 'Approve and retry subscription changes', 'subscriptions')
ON CONFLICT (code) DO UPDATE SET
    description = EXCLUDED.description,
    category = EXCLUDED.category;

WITH permission_map(subscription_code, case_code) AS (
    VALUES
        ('subscriptions.view', 'cases.view'),
        ('subscriptions.change_request', 'cases.edit')
)
INSERT INTO group_permissions (group_id, permission_id)
SELECT DISTINCT gp.group_id, subscription_permission.id
FROM group_permissions gp
JOIN permissions case_permission ON case_permission.id = gp.permission_id
JOIN permission_map mapping ON mapping.case_code = case_permission.code
JOIN permissions subscription_permission ON subscription_permission.code = mapping.subscription_code
ON CONFLICT DO NOTHING;

-- Existing out-of-range days need an explicit review instead of silent correction.
UPDATE sag_subscriptions
SET billing_blocked = TRUE,
    billing_block_reason = CONCAT_WS('; ', NULLIF(billing_block_reason, ''), 'Fakturadag 29-31 kræver manuel gennemgang')
WHERE billing_day > 28
  AND COALESCE(billing_block_reason, '') NOT LIKE '%Fakturadag 29-31 kræver manuel gennemgang%';

CREATE INDEX IF NOT EXISTS idx_sag_subscriptions_sag_lifecycle
    ON sag_subscriptions(sag_id, status, start_date, end_date);