//go:build test && dev

package payments

import (
	"os"
	"path/filepath"
	"regexp"
	"strconv"
	"testing"

	"github.com/stretchr/testify/require"
)

// policyTSValue extracts the numeric value of a `NAME: value,` entry from the
// frontend's POLICY object literal (policy.ts), tolerating the tab-indented
// formatting the file uses. Returns "" when the name is absent.
func policyTSValue(t *testing.T, src, name string) string {
	t.Helper()
	re := regexp.MustCompile(`(?m)^\s*` + regexp.QuoteMeta(name) + `:\s*(\d+(?:\.\d+)?),`)
	m := re.FindStringSubmatch(src)
	if m == nil {
		return ""
	}
	return m[1]
}

// TestPolicyTS_CrossCheck pins the frontend's single-source policy constants
// (frontend/src/lib/constants/policy.ts) to THIS package's refund_policy.go
// values by REACTING to drift: the test reads the .ts file and asserts each
// entry equals the backend constant, so a one-sided change on either side fails
// CI. The frontend's own vitest suite (policy.test.ts) pins the same values in
// the other direction, closing the drift loop both ways.
func TestPolicyTS_CrossCheck(t *testing.T) {
	path := filepath.Join("..", "..", "..", "frontend", "src", "lib", "constants", "policy.ts")
	data, err := os.ReadFile(path)
	require.NoError(t, err, "policy.ts not found at %s (tests run from the package dir; repo layout is <repo>/backend/handlers/payments + <repo>/frontend)", path)
	src := string(data)

	cases := []struct {
		name string
		want string
	}{
		{"REQUIRED_DEPOSIT_PCT", "0.2"},
		{"PROTECTED_DEPOSIT_MAX_PCT", "0.5"},
		{"FULL_REFUND_THRESHOLD_HOURS", "72"},
		{"PARTIAL_REFUND_THRESHOLD_HOURS", "24"},
		{"NO_SHOW_THRESHOLD_HOURS", "24"},
		{"DEPOSIT_ADVANCE_HOURS", "36"},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			got := policyTSValue(t, src, tc.name)
			require.NotEmpty(t, got, "policy.ts no longer declares %q — the constant may have been renamed or removed", tc.name)
			require.Equal(t, tc.want, got, "%s drifted from backend/handlers/payments/refund_policy.go", tc.name)
		})
	}

	// The backend has no named reschedule constants; the frontend values must
	// track the refund tiers they were derived from.
	for _, tc := range []struct {
		name string
		want string
	}{
		{"RESCHEDULE_BLOCK_HOURS_WITH_PAYMENTS", strconv.Itoa(int(FullRefundThreshold.Hours()))},
		{"RESCHEDULE_BLOCK_HOURS_NO_PAYMENTS", strconv.Itoa(int(PartialRefundThreshold.Hours()))},
	} {
		t.Run(tc.name, func(t *testing.T) {
			got := policyTSValue(t, src, tc.name)
			require.NotEmpty(t, got, "policy.ts no longer declares %q", tc.name)
			require.Equal(t, tc.want, got, "%s must track the backend refund threshold", tc.name)
		})
	}
}