package command

import (
	"context"
	"crypto/md5"
	"encoding/hex"
	"fmt"

	"golang.org/x/text/language"

	"github.com/zitadel/zitadel/internal/api/authz"
	"github.com/zitadel/zitadel/internal/eventstore"
	"github.com/zitadel/zitadel/internal/repository/instance"
	"github.com/zitadel/zitadel/internal/repository/org"
	"github.com/zitadel/zitadel/internal/telemetry/tracing"
	"github.com/zitadel/zitadel/internal/zerrors"
	"github.com/zitadel/zitadel/pkg/grpc/settings/v2"
)

func (c *Commands) SetHostedLoginTranslation(ctx context.Context, req *settings.SetHostedLoginTranslationRequest) (res *settings.SetHostedLoginTranslationResponse, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	var agg eventstore.Aggregate
	switch t := req.GetLevel().(type) {
	case *settings.SetHostedLoginTranslationRequest_Instance:
		agg = instance.NewAggregate(authz.GetInstance(ctx).InstanceID()).Aggregate
	case *settings.SetHostedLoginTranslationRequest_OrganizationId:
		agg = org.NewAggregate(t.OrganizationId).Aggregate
	default:
		return nil, zerrors.ThrowInvalidArgument(nil, "COMMA-YB6Sri", "Errors.Arguments.Level.Invalid")
	}

	lang, err := language.Parse(req.GetLocale())
	if err != nil || lang.IsRoot() {
		return nil, zerrors.ThrowInvalidArgument(nil, "COMMA-xmjATA", "Errors.Arguments.Locale.Invalid")
	}

	commands, wm, err := c.setTranslationEvents(ctx, agg, lang, req.GetTranslations().AsMap())
	if err != nil {
		return nil, err
	}

	pushedEvents, err := c.eventstore.Push(ctx, commands...)
	if err != nil {
		return nil, zerrors.ThrowInternal(err, "COMMA-i8nqFl", "Errors.Internal")
	}

	err = AppendAndReduce(wm, pushedEvents...)
	if err != nil {
		return nil, err
	}

	etag := md5.Sum(fmt.Append(nil, wm.Translation))
	return &settings.SetHostedLoginTranslationResponse{
		Etag: hex.EncodeToString(etag[:]),
	}, nil
}

func (c *Commands) setTranslationEvents(ctx context.Context, agg eventstore.Aggregate, lang language.Tag, translations map[string]any) ([]eventstore.Command, *HostedLoginTranslationWriteModel, error) {
	wm := NewHostedLoginTranslationWriteModel(agg.ID)
	events := []eventstore.Command{}
	switch agg.Type {
	case instance.AggregateType:
		events = append(events, instance.NewHostedLoginTranslationSetEvent(ctx, &agg, translations, lang))
	case org.AggregateType:
		events = append(events, org.NewHostedLoginTranslationSetEvent(ctx, &agg, translations, lang))
	default:
		return nil, nil, zerrors.ThrowInvalidArgument(nil, "COMMA-0aw7In", "Errors.Arguments.LevelType.Invalid")
	}

	return events, wm, nil
}