package useCases

import (
	"RenewCMS/internal/domain/audit"
	"RenewCMS/internal/domain/image"
	"RenewCMS/internal/domain/site"
	"context"
)

type UpdateSiteUseCase struct {
	siteRepository  site.Repository
	imageRepository image.Repository
	recorder        audit.Recorder
}

func NewUpdateSiteUseCase(siteRepository site.Repository, imageRepository image.Repository, recorder audit.Recorder) *UpdateSiteUseCase {
	return &UpdateSiteUseCase{siteRepository, imageRepository, recorder}
}

func (u *UpdateSiteUseCase) Update(ctx context.Context, id uint32, patch site.Patch) (site.Site, error) {
	before, err := u.siteRepository.Get(id)
	if err != nil {
		return site.Site{}, err
	}

	event := audit.NewEvent(audit.ActionSiteEdit, audit.CategorySites)
	event.Target = siteTarget(before)
	after, err := u.apply(before, patch)
	if err != nil {
		recordFailure(ctx, u.recorder, event, err)
		return site.Site{}, err
	}

	changes := u.changes(before, after)
	if len(changes) == 0 {
		return before, nil
	}
	saved, err := u.siteRepository.Update(after)
	if err != nil {
		recordFailure(ctx, u.recorder, event, err)
		return site.Site{}, err
	}
	event.Target = siteTarget(saved)
	event.Changes = changes
	u.recorder.Record(ctx, event)
	return saved, nil
}

func (u *UpdateSiteUseCase) apply(before site.Site, patch site.Patch) (site.Site, error) {
	after := before
	if patch.IsDefault != nil {
		return site.Site{}, site.ErrUseSetDefault
	}
	if patch.Key != nil && *patch.Key != before.Key {
		return site.Site{}, site.ErrKeyImmutable
	}
	if patch.Name != nil {
		after.Name = *patch.Name
	}
	if patch.BaseURL != nil {
		baseURL, err := site.NormalizeBaseURL(*patch.BaseURL)
		if err != nil {
			return site.Site{}, err
		}
		after.BaseURL = baseURL
	}
	if patch.DefaultRobots != nil {
		after.DefaultRobots = *patch.DefaultRobots
	}
	if patch.Locale.Set {
		locale, err := site.NormalizeLocale(patch.Locale.Value)
		if err != nil {
			return site.Site{}, err
		}
		after.Locale = locale
	}
	if patch.DefaultSocialImageID.Set {
		if err := ensureImageExists(u.imageRepository, patch.DefaultSocialImageID.Value); err != nil {
			return site.Site{}, err
		}
		after.DefaultSocialImageID = patch.DefaultSocialImageID.Value
	}
	return after, nil
}

func (u *UpdateSiteUseCase) changes(before site.Site, after site.Site) []audit.Change {
	changes := []audit.Change{}
	changes = appendTextChange(changes, audit.FieldName, before.Name, after.Name)
	changes = appendTextChange(changes, audit.FieldBaseURL, before.BaseURL, after.BaseURL)
	changes = appendTextChange(changes, audit.FieldDefaultRobots, before.DefaultRobots, after.DefaultRobots)
	changes = appendTextChange(changes, audit.FieldLocale, localeLabel(before.Locale), localeLabel(after.Locale))
	if !sameImage(before.DefaultSocialImageID, after.DefaultSocialImageID) {
		changes = append(changes, audit.TextChange(audit.FieldSocialImage, imageLabel(u.imageRepository, before.DefaultSocialImageID), imageLabel(u.imageRepository, after.DefaultSocialImageID)))
	}
	return changes
}

func appendTextChange(changes []audit.Change, field string, before string, after string) []audit.Change {
	if before == after {
		return changes
	}
	return append(changes, audit.TextChange(field, before, after))
}

func sameImage(a *uint32, b *uint32) bool {
	if a == nil || b == nil {
		return a == b
	}
	return *a == *b
}