package command

import (
	"context"

	"golang.org/x/text/language"

	"github.com/zitadel/zitadel/internal/command/preparation"
	"github.com/zitadel/zitadel/internal/domain"
	"github.com/zitadel/zitadel/internal/eventstore"
	"github.com/zitadel/zitadel/internal/i18n"
	"github.com/zitadel/zitadel/internal/repository/instance"
	"github.com/zitadel/zitadel/internal/zerrors"
)

// SetDefaultMessageText only validates if the language is supported, not if it is allowed.
// This enables setting texts before allowing a language
func (c *Commands) SetDefaultMessageText(ctx context.Context, instanceID string, messageText *domain.CustomMessageText) (*domain.ObjectDetails, error) {
	instanceAgg := instance.NewAggregate(instanceID)
	events, existingMessageText, err := c.setDefaultMessageText(ctx, &instanceAgg.Aggregate, messageText)
	if err != nil {
		return nil, err
	}
	pushedEvents, err := c.eventstore.Push(ctx, events...)
	if err != nil {
		return nil, err
	}
	err = AppendAndReduce(existingMessageText, pushedEvents...)
	if err != nil {
		return nil, err
	}
	return writeModelToObjectDetails(&existingMessageText.WriteModel), nil
}

func (c *Commands) setDefaultMessageText(ctx context.Context, instanceAgg *eventstore.Aggregate, msg *domain.CustomMessageText) ([]eventstore.Command, *InstanceCustomMessageTextWriteModel, error) {
	if err := msg.IsValid(i18n.SupportedLanguages()); err != nil {
		return nil, nil, err
	}

	existingMessageText, err := c.defaultCustomMessageTextWriteModelByID(ctx, msg.MessageTextType, msg.Language)
	if err != nil {
		return nil, nil, err
	}

	events := make([]eventstore.Command, 0)
	if existingMessageText.Greeting != msg.Greeting {
		if msg.Greeting != "" {
			events = append(events, instance.NewCustomTextSetEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessageGreeting, msg.Greeting, msg.Language))
		} else {
			events = append(events, instance.NewCustomTextRemovedEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessageGreeting, msg.Language))
		}
	}
	if existingMessageText.Subject != msg.Subject {
		if msg.Subject != "" {
			events = append(events, instance.NewCustomTextSetEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessageSubject, msg.Subject, msg.Language))
		} else {
			events = append(events, instance.NewCustomTextRemovedEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessageSubject, msg.Language))
		}
	}
	if existingMessageText.Title != msg.Title {
		if msg.Title != "" {
			events = append(events, instance.NewCustomTextSetEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessageTitle, msg.Title, msg.Language))
		} else {
			events = append(events, instance.NewCustomTextRemovedEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessageTitle, msg.Language))
		}
	}
	if existingMessageText.PreHeader != msg.PreHeader {
		if msg.PreHeader != "" {
			events = append(events, instance.NewCustomTextSetEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessagePreHeader, msg.PreHeader, msg.Language))
		} else {
			events = append(events, instance.NewCustomTextRemovedEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessagePreHeader, msg.Language))
		}
	}
	if existingMessageText.Text != msg.Text {
		if msg.Text != "" {
			events = append(events, instance.NewCustomTextSetEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessageText, msg.Text, msg.Language))
		} else {
			events = append(events, instance.NewCustomTextRemovedEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessageText, msg.Language))
		}
	}
	if existingMessageText.ButtonText != msg.ButtonText {
		if msg.ButtonText != "" {
			events = append(events, instance.NewCustomTextSetEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessageButtonText, msg.ButtonText, msg.Language))
		} else {
			events = append(events, instance.NewCustomTextRemovedEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessageButtonText, msg.Language))
		}
	}
	if existingMessageText.FooterText != msg.FooterText {
		if msg.FooterText != "" {
			events = append(events, instance.NewCustomTextSetEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessageFooterText, msg.FooterText, msg.Language))
		} else {
			events = append(events, instance.NewCustomTextRemovedEvent(ctx, instanceAgg, msg.MessageTextType, domain.MessageFooterText, msg.Language))
		}
	}
	return events, existingMessageText, nil
}

func (c *Commands) RemoveInstanceMessageTexts(ctx context.Context, messageTextType string, lang language.Tag) (*domain.ObjectDetails, error) {
	if messageTextType == "" || lang == language.Und {
		return nil, zerrors.ThrowInvalidArgument(nil, "INSTANCE-fjw9b", "Errors.CustomMessageText.Invalid")
	}
	customText, err := c.defaultCustomMessageTextWriteModelByID(ctx, messageTextType, lang)
	if err != nil {
		return nil, err
	}
	if customText.State == domain.PolicyStateUnspecified || customText.State == domain.PolicyStateRemoved {
		return nil, zerrors.ThrowNotFound(nil, "INSTANCE-fju90", "Errors.CustomMessageText.NotFound")
	}
	instanceAgg := InstanceAggregateFromWriteModel(&customText.WriteModel)
	pushedEvents, err := c.eventstore.Push(ctx, instance.NewCustomTextTemplateRemovedEvent(ctx, instanceAgg, messageTextType, lang))
	if err != nil {
		return nil, err
	}
	err = AppendAndReduce(customText, pushedEvents...)
	if err != nil {
		return nil, err
	}
	return writeModelToObjectDetails(&customText.WriteModel), nil
}

func (c *Commands) defaultCustomMessageTextWriteModelByID(ctx context.Context, messageType string, lang language.Tag) (*InstanceCustomMessageTextWriteModel, error) {
	writeModel := NewInstanceCustomMessageTextWriteModel(ctx, messageType, lang)
	err := c.eventstore.FilterToQueryReducer(ctx, writeModel)
	if err != nil {
		return nil, err
	}
	return writeModel, nil
}

func prepareSetInstanceCustomMessageTexts(
	a *instance.Aggregate,
	msg *domain.CustomMessageText,
) preparation.Validation {
	return func() (preparation.CreateCommands, error) {
		if err := msg.IsValid(i18n.SupportedLanguages()); err != nil {
			return nil, err
		}
		return func(ctx context.Context, filter preparation.FilterToQueryReducer) ([]eventstore.Command, error) {
			existing, err := existingInstanceCustomMessageText(ctx, filter, msg.MessageTextType, msg.Language)
			if err != nil {
				return nil, err
			}

			cmds := make([]eventstore.Command, 0, 7)
			if existing.Greeting != msg.Greeting {
				if msg.Greeting != "" {
					cmds = append(cmds, instance.NewCustomTextSetEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessageGreeting, msg.Greeting, msg.Language))
				} else {
					cmds = append(cmds, instance.NewCustomTextRemovedEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessageGreeting, msg.Language))
				}
			}
			if existing.Subject != msg.Subject {
				if msg.Subject != "" {
					cmds = append(cmds, instance.NewCustomTextSetEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessageSubject, msg.Subject, msg.Language))
				} else {
					cmds = append(cmds, instance.NewCustomTextRemovedEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessageSubject, msg.Language))
				}
			}
			if existing.Title != msg.Title {
				if msg.Title != "" {
					cmds = append(cmds, instance.NewCustomTextSetEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessageTitle, msg.Title, msg.Language))
				} else {
					cmds = append(cmds, instance.NewCustomTextRemovedEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessageTitle, msg.Language))
				}
			}
			if existing.PreHeader != msg.PreHeader {
				if msg.PreHeader != "" {
					cmds = append(cmds, instance.NewCustomTextSetEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessagePreHeader, msg.PreHeader, msg.Language))
				} else {
					cmds = append(cmds, instance.NewCustomTextRemovedEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessagePreHeader, msg.Language))
				}
			}
			if existing.Text != msg.Text {
				if msg.Text != "" {
					cmds = append(cmds, instance.NewCustomTextSetEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessageText, msg.Text, msg.Language))
				} else {
					cmds = append(cmds, instance.NewCustomTextRemovedEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessageText, msg.Language))
				}
			}
			if existing.ButtonText != msg.ButtonText {
				if msg.ButtonText != "" {
					cmds = append(cmds, instance.NewCustomTextSetEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessageButtonText, msg.ButtonText, msg.Language))
				} else {
					cmds = append(cmds, instance.NewCustomTextRemovedEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessageButtonText, msg.Language))
				}
			}
			if existing.FooterText != msg.FooterText {
				if msg.FooterText != "" {
					cmds = append(cmds, instance.NewCustomTextSetEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessageFooterText, msg.FooterText, msg.Language))
				} else {
					cmds = append(cmds, instance.NewCustomTextRemovedEvent(ctx, &a.Aggregate, msg.MessageTextType, domain.MessageFooterText, msg.Language))
				}
			}
			return cmds, nil
		}, nil
	}
}

func existingInstanceCustomMessageText(ctx context.Context, filter preparation.FilterToQueryReducer, textType string, lang language.Tag) (*InstanceCustomMessageTextWriteModel, error) {
	writeModel := NewInstanceCustomMessageTextWriteModel(ctx, textType, lang)
	events, err := filter(ctx, writeModel.Query())
	if err != nil {
		return nil, err
	}
	writeModel.AppendEvents(events...)
	writeModel.Reduce()
	return writeModel, nil
}