package useCases

import (
	"RenewCMS/internal/domain/article"
	"RenewCMS/internal/domain/image"
	"RenewCMS/internal/domain/site"
)

type CheckArticleSEOUseCase struct {
	articleRepository article.Repository
	sites             site.Repository
	images            image.Repository
}

type CheckArticleSEOCommand struct {
	Body              *string
	Slug              *string
	Excerpt           *string
	SEOTitle          *string
	SEODescription    *string
	CoverImageID      article.Nullable[uint32]
	CoverImageAlt     *string
	SocialTitle       *string
	SocialDescription *string
	SocialImageID     article.Nullable[uint32]
	CanonicalURL      *string
	Noindex           *bool
	SEODismissed      *[]string
}

func NewCheckArticleSEOUseCase(articleRepository article.Repository, sites site.Repository, images image.Repository) *CheckArticleSEOUseCase {
	return &CheckArticleSEOUseCase{articleRepository: articleRepository, sites: sites, images: images}
}

func (u *CheckArticleSEOUseCase) Check(id uint32, command CheckArticleSEOCommand) (article.SEOCheck, error) {
	saved, err := u.articleRepository.Get(id)
	if err != nil {
		return article.SEOCheck{}, err
	}
	if err := u.validate(command); err != nil {
		return article.SEOCheck{}, err
	}
	owner, err := u.sites.Get(saved.SiteID)
	if err != nil {
		return article.SEOCheck{}, err
	}
	candidate := command.applyTo(saved)
	slugCheck, err := u.checkSlug(candidate)
	if err != nil {
		return article.SEOCheck{}, err
	}
	assessment := assessSEO(candidate, owner)
	return article.SEOCheck{Status: assessment.Status, Suggestions: assessment.Suggestions, Slug: slugCheck}, nil
}

func (u *CheckArticleSEOUseCase) validate(command CheckArticleSEOCommand) error {
	if command.Slug != nil && *command.Slug != "" && !article.IsValidSlug(*command.Slug) {
		return article.ErrInvalidSlug
	}
	if command.CanonicalURL != nil {
		if err := article.ValidateCanonicalURL(*command.CanonicalURL); err != nil {
			return err
		}
	}
	if command.CoverImageID.Set {
		if err := ensureImageExists(u.images, command.CoverImageID.Value); err != nil {
			return err
		}
	}
	if command.SocialImageID.Set {
		return ensureImageExists(u.images, command.SocialImageID.Value)
	}
	return nil
}

func overrideText(current string, override *string) string {
	if override == nil {
		return current
	}
	return *override
}

func overrideImage(current *uint32, override article.Nullable[uint32]) *uint32 {
	if override.Set {
		return override.Value
	}
	return current
}

func (c CheckArticleSEOCommand) applyTo(saved article.Article) article.Article {
	saved.Body = overrideText(saved.Body, c.Body)
	saved.Excerpt = overrideText(saved.Excerpt, c.Excerpt)
	saved.SEOTitle = overrideText(saved.SEOTitle, c.SEOTitle)
	saved.SEODescription = overrideText(saved.SEODescription, c.SEODescription)
	saved.CoverImageID = overrideImage(saved.CoverImageID, c.CoverImageID)
	saved.CoverImageAlt = overrideText(saved.CoverImageAlt, c.CoverImageAlt)
	saved.SocialTitle = overrideText(saved.SocialTitle, c.SocialTitle)
	saved.SocialDescription = overrideText(saved.SocialDescription, c.SocialDescription)
	saved.SocialImageID = overrideImage(saved.SocialImageID, c.SocialImageID)
	saved.CanonicalURL = overrideText(saved.CanonicalURL, c.CanonicalURL)
	if c.Noindex != nil {
		saved.Noindex = *c.Noindex
	}
	if c.SEODismissed != nil {
		saved.SEODismissed = article.NormalizeDismissed(*c.SEODismissed)
	}
	if c.Slug != nil {
		saved.Slug = *c.Slug
		if saved.Slug == "" {
			saved.Slug = article.GenerateSlug(saved.Title)
		}
	}
	return saved
}

func (u *CheckArticleSEOUseCase) checkSlug(candidate article.Article) (article.SEOSlugCheck, error) {
	available := article.SEOSlugCheck{Available: true}
	if candidate.Slug == "" {
		return available, nil
	}
	taken, err := u.articleRepository.SlugTaken(candidate.SiteID, candidate.Slug, candidate.ID)
	if err != nil || !taken {
		return available, err
	}
	suggestion, err := freeSlug(u.articleRepository, candidate.SiteID, candidate.Slug, candidate.ID, firstSuggestedAttempt)
	if err != nil {
		return article.SEOSlugCheck{}, err
	}
	return article.SEOSlugCheck{Suggestion: &suggestion}, nil
}