package cabana

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"reflect"
	"strings"
	"testing"
	"testing/fstest"

	"git.golem15.com/golem15/summercms/modules/phrasebook"
	"git.golem15.com/golem15/summercms/modules/towel"
)

const (
	menuURLScheme = "acme.menu::lang.errors.url_scheme"
	menuTarget    = "acme.menu::lang.errors.target"
	menuMissing   = "acme.menu::lang.errors.missing"
)

var menuTexts = map[string][2]string{
	"en": {"The link must start with http or https.", "Choose where the link opens."},
	"pl": {"Link musi zaczynać się od http lub https.", "Wybierz, gdzie otwiera się link."},
}

// menuTranslator has the acme.menu error keys in en and pl.
func menuTranslator(t *testing.T) *phrasebook.Translator {
	t.Helper()
	cat := phrasebook.NewCatalog()
	files := fstest.MapFS{}
	for locale, texts := range menuTexts {
		files["lang/"+locale+"/lang.yaml"] = &fstest.MapFile{Data: []byte(fmt.Sprintf("errors:\n  url_scheme: %q\n  target: %q\n", texts[0], texts[1]))}
	}
	if err := cat.Load("acme.menu", files); err != nil {
		t.Fatal(err)
	}
	return phrasebook.NewTranslator(cat, phrasebook.Options{Locale: "en", Fallback: "en"})
}

// menuInvalid is a ValidationError with every Details shape a plugin uses.
func menuInvalid() *ValidationError {
	return &ValidationError{Details: map[string]any{
		"url":    []string{menuURLScheme},
		"target": menuTarget,
		"mixed":  []any{menuURLScheme, 7},
		"title":  []string{"The title field is required."},
		"nested": map[string]any{"pl": []string{menuURLScheme}},
		"absent": []string{menuMissing},
	}}
}

func TestLocalizeControllerErrorValidation(t *testing.T) {
	tr := menuTranslator(t)
	shared := menuInvalid()
	before := menuInvalid()
	for _, locale := range []string{"pl", "en", "pl"} {
		ctx := towel.WithLocale(context.Background(), locale)
		got := localizeControllerError(ctx, tr, shared)
		var ve *ValidationError
		if !errors.As(got, &ve) {
			t.Fatalf("%s: got %T, want *ValidationError", locale, got)
		}
		if ve == shared {
			t.Fatalf("%s: the plugin's value was returned, not a copy", locale)
		}
		want := map[string]any{
			"url":    []string{menuTexts[locale][0]},
			"target": []string{menuTexts[locale][1]},
			"mixed":  []any{menuTexts[locale][0], 7},
			"title":  []string{"The title field is required."},
			"nested": map[string]any{"pl": []string{menuURLScheme}},
			"absent": []string{menuMissing},
		}
		if !reflect.DeepEqual(ve.Details, want) {
			t.Fatalf("%s: details = %#v, want %#v", locale, ve.Details, want)
		}
		// New slices: writing into the result does not reach the plugin's value.
		ve.Details["url"].([]string)[0] = "changed"
		ve.Details["title"].([]string)[0] = "changed"
		ve.Details["mixed"].([]any)[0] = "changed"
		if !reflect.DeepEqual(shared, before) {
			t.Fatalf("%s: the plugin's value was modified: %#v", locale, shared.Details)
		}
	}
}

func TestLocalizeControllerErrorUnchanged(t *testing.T) {
	tr := menuTranslator(t)
	ctx := towel.WithLocale(context.Background(), "pl")
	if got := localizeControllerError(ctx, tr, nil); got != nil {
		t.Fatalf("nil error = %v", got)
	}
	plain := errors.New("x")
	if got := localizeControllerError(ctx, tr, plain); got != plain {
		t.Fatalf("plain error = %#v, want the identical value", got)
	}
	empty := &ValidationError{}
	if got := localizeControllerError(ctx, tr, empty); got != empty {
		t.Fatalf("nil details = %#v, want the identical value", got)
	}
	noDetails := &ValidationError{Details: map[string]any{}}
	if got := localizeControllerError(ctx, tr, noDetails); got != noDetails {
		t.Fatalf("empty details = %#v, want the identical value", got)
	}
	var nilVE *ValidationError
	if got := localizeControllerError(ctx, tr, nilVE); got != error(nilVE) {
		t.Fatalf("nil *ValidationError = %#v", got)
	}
	// A wrapped ValidationError is found and localized.
	got := localizeControllerError(ctx, tr, fmt.Errorf("save: %w", &ValidationError{Details: map[string]any{"url": []string{menuURLScheme}}}))
	ve, ok := got.(*ValidationError)
	if !ok || !reflect.DeepEqual(ve.Details, map[string]any{"url": []string{menuTexts["pl"][0]}}) {
		t.Fatalf("wrapped = %#v", got)
	}
	// Without a translator the keys stay.
	got = localizeControllerError(nil, nil, &ValidationError{Details: map[string]any{"url": menuURLScheme}})
	if ve, ok := got.(*ValidationError); !ok || !reflect.DeepEqual(ve.Details, map[string]any{"url": []string{menuURLScheme}}) {
		t.Fatalf("nil translator = %#v", got)
	}
}

func TestLocalizeControllerErrorForbidden(t *testing.T) {
	tr := menuTranslator(t)
	shared := &ForbiddenError{Message: menuTarget, Details: map[string]any{"url": []string{menuURLScheme}, "plain": "Text."}}
	for _, locale := range []string{"en", "pl"} {
		got := localizeControllerError(towel.WithLocale(context.Background(), locale), tr, shared)
		fe, ok := got.(*ForbiddenError)
		if !ok || fe == shared {
			t.Fatalf("%s: got %#v", locale, got)
		}
		want := &ForbiddenError{Message: menuTexts[locale][1], Details: map[string]any{"url": []string{menuTexts[locale][0]}, "plain": []string{"Text."}}}
		if !reflect.DeepEqual(fe, want) {
			t.Fatalf("%s: got %#v, want %#v", locale, fe, want)
		}
	}
	if shared.Message != menuTarget || !reflect.DeepEqual(shared.Details, map[string]any{"url": []string{menuURLScheme}, "plain": "Text."}) {
		t.Fatalf("the plugin's value was modified: %#v", shared)
	}
	// An empty Message stays empty and no Details stay nil.
	got := localizeControllerError(context.Background(), tr, &ForbiddenError{})
	if fe, ok := got.(*ForbiddenError); !ok || fe.Message != "" || fe.Details != nil {
		t.Fatalf("empty refusal = %#v", got)
	}
}

func TestWriteCRUDErrorLocalized(t *testing.T) {
	tr := menuTranslator(t)
	err := localizeControllerError(towel.WithLocale(context.Background(), "pl"), tr, menuInvalid())
	rec := httptest.NewRecorder()
	writeCRUDError(rec, err)
	var env ErrorEnvelope
	if jerr := json.Unmarshal(rec.Body.Bytes(), &env); jerr != nil {
		t.Fatal(jerr)
	}
	if rec.Code != http.StatusUnprocessableEntity || env.Error.Code != "validation_failed" {
		t.Fatalf("status=%d body=%s", rec.Code, rec.Body.String())
	}
	if !reflect.DeepEqual(env.Error.Details["url"], []any{menuTexts["pl"][0]}) {
		t.Fatalf("details.url = %#v", env.Error.Details["url"])
	}
}

// TestLocalizeControllerErrorPlainTextNotLookedUp: text without "::" is
// never looked up, so the development log has no missing-key warning for it;
// an unknown key does warn, which proves the capture works. Not parallel: it
// swaps the default logger.
func TestLocalizeControllerErrorPlainTextNotLookedUp(t *testing.T) {
	var buf bytes.Buffer
	previous := slog.Default()
	slog.SetDefault(slog.New(slog.NewTextHandler(&buf, nil)))
	t.Cleanup(func() { slog.SetDefault(previous) })

	tr := menuTranslator(t)
	ctx := towel.WithLocale(context.Background(), "en")
	localizeControllerError(ctx, tr, &ValidationError{Details: map[string]any{"title": []string{"The title field is required."}, "body": "Too long."}})
	if strings.Contains(buf.String(), "missing translation key") {
		t.Fatalf("plain text was looked up: %s", buf.String())
	}
	localizeControllerError(ctx, tr, &ValidationError{Details: map[string]any{"url": []string{menuMissing}}})
	if !strings.Contains(buf.String(), "missing translation key") {
		t.Fatalf("an unknown key logged nothing; the capture does not work: %q", buf.String())
	}
}