package migrations

import (
	"strings"
	"testing"
)

// TestUserSettingValuesMigrationContract pins the parts of the canonical
// settings storage that the store code and the design both depend on: the scope
// CHECK constraints, the five partial unique indexes that enforce one explicit
// value per identity, and the covering indexes the one-query read path needs.
// A silent edit to any of them would not fail a store test until a duplicate row
// or a sequential-scan regression reached production.
func TestUserSettingValuesMigrationContract(t *testing.T) {
	migration := readMigration(t, "sql/20260727010621_user_setting_values.sql")

	for _, want := range []string{
		"CREATE TABLE public.user_setting_values",
		"value       jsonb NOT NULL",
		"revision    bigint NOT NULL DEFAULT 1",
		"CONSTRAINT user_setting_values_scope_check\n        CHECK (scope IN ('account', 'profile', 'profile_device', 'profile_library', 'profile_series'))",
		"(scope = 'account' AND profile_id IS NULL AND device_id IS NULL AND library_id IS NULL AND series_id IS NULL)",
		"(scope = 'profile' AND profile_id IS NOT NULL AND device_id IS NULL AND library_id IS NULL AND series_id IS NULL)",
		"(scope = 'profile_device' AND profile_id IS NOT NULL AND device_id IS NOT NULL AND library_id IS NULL AND series_id IS NULL)",
		"(scope = 'profile_library' AND profile_id IS NOT NULL AND device_id IS NULL AND library_id IS NOT NULL AND series_id IS NULL)",
		"(scope = 'profile_series' AND profile_id IS NOT NULL AND device_id IS NULL AND library_id IS NULL AND series_id IS NOT NULL)",

		// The cascades that exist today, and only those.
		"CONSTRAINT user_setting_values_user_id_fkey\n        FOREIGN KEY (user_id) REFERENCES public.users(id) ON DELETE CASCADE",
		"CONSTRAINT user_setting_values_profile_fkey\n        FOREIGN KEY (user_id, profile_id) REFERENCES public.user_profiles(user_id, id) ON DELETE CASCADE",

		// One explicit value per identity.
		"CREATE UNIQUE INDEX user_setting_values_account_uq\n  ON public.user_setting_values (user_id, key) WHERE scope = 'account'",
		"CREATE UNIQUE INDEX user_setting_values_profile_uq\n  ON public.user_setting_values (user_id, profile_id, key) WHERE scope = 'profile'",
		"CREATE UNIQUE INDEX user_setting_values_profile_device_uq\n  ON public.user_setting_values (user_id, profile_id, device_id, key) WHERE scope = 'profile_device'",
		"CREATE UNIQUE INDEX user_setting_values_profile_library_uq\n  ON public.user_setting_values (user_id, profile_id, library_id, key) WHERE scope = 'profile_library'",
		"CREATE UNIQUE INDEX user_setting_values_profile_series_uq\n  ON public.user_setting_values (user_id, profile_id, series_id, key) WHERE scope = 'profile_series'",

		// The hot read path.
		"ON public.user_setting_values (user_id, profile_id, key, scope)",
		"ON public.user_setting_values (user_id, profile_id, series_id)",
		"ON public.user_setting_values (user_id, profile_id, library_id)",

		// Idempotency and the inert migration audit table.
		"CREATE TABLE public.user_setting_mutations",
		"CONSTRAINT user_setting_mutations_pkey PRIMARY KEY (user_id, mutation_id)",
		"request_hash text NOT NULL",
		"expires_at   timestamptz NOT NULL",
		"ON public.user_setting_mutations (expires_at)",
		"CREATE TABLE public.user_setting_migration_rejects",
	} {
		if !strings.Contains(migration, want) {
			t.Fatalf("migration missing %q", want)
		}
	}

	// Library, series and device identity columns must stay reference-free: the
	// per-user SQLite store has no foreign keys at all, so inheriting cleanup
	// from constraints here would let the two backends drift.
	for _, forbidden := range []string{
		"REFERENCES public.library_folders",
		"REFERENCES public.media_items",
		"REFERENCES public.user_devices",
	} {
		if strings.Contains(migration, forbidden) {
			t.Fatalf("migration must not add %q; delete behavior is application-enforced", forbidden)
		}
	}
}

func readMigration(t *testing.T, path string) string {
	t.Helper()
	contents, err := FS.ReadFile(path)
	if err != nil {
		t.Fatalf("read migration %s: %v", path, err)
	}
	return string(contents)
}