package useCases

import (
	"RenewCMS/internal/domain/article"
	"RenewCMS/internal/domain/site"
	"slices"
	"strings"
	"unicode/utf8"
)

func metaTitle(art article.Article) (string, string) {
	if art.SEOTitle != "" {
		return art.SEOTitle, article.SEOSourceSEOTitle
	}
	return art.Title, article.SEOSourceTitle
}

func resolveDescription(art article.Article, owner site.Site, facts bodyFacts) (string, string) {
	if art.SEODescription != "" {
		return art.SEODescription, article.SEOSourceSEODescription
	}
	if art.Excerpt != "" {
		return art.Excerpt, article.SEOSourceExcerpt
	}
	if sentence := firstSentence(facts.spacedText); sentence != "" {
		return sentence, article.SEOSourceBody
	}
	if owner.DefaultDescription != "" {
		return owner.DefaultDescription, article.SEOSourceSite
	}
	return "", article.SEOSourceNone
}

func suggestion(code string, field string, params map[string]int) article.SEOSuggestion {
	return article.SEOSuggestion{Code: code, Field: field, Params: params}
}

func rawSuggestions(art article.Article, owner site.Site, facts bodyFacts) []article.SEOSuggestion {
	suggestions := []article.SEOSuggestion{}
	title, _ := metaTitle(art)
	titleRunes := utf8.RuneCountInString(title)
	if titleRunes > article.SEOTitleMaxRunes {
		suggestions = append(suggestions, suggestion(article.DismissTitleLong, article.SEOFieldTitle, map[string]int{"length": titleRunes, "max": article.SEOTitleMaxRunes}))
	}
	if strings.TrimSpace(title) == "" {
		suggestions = append(suggestions, suggestion(article.DismissTitleEmpty, article.SEOFieldTitle, map[string]int{}))
	}
	description, _ := resolveDescription(art, owner, facts)
	descriptionRunes := utf8.RuneCountInString(description)
	if descriptionRunes < article.SEODescriptionMinRunes {
		suggestions = append(suggestions, suggestion(article.DismissDescShort, article.SEOFieldDescription, map[string]int{"length": descriptionRunes, "min": article.SEODescriptionMinRunes}))
	}
	if descriptionRunes > article.SEODescriptionMaxRunes {
		suggestions = append(suggestions, suggestion(article.DismissDescLong, article.SEOFieldDescription, map[string]int{"length": descriptionRunes, "max": article.SEODescriptionMaxRunes}))
	}
	if art.CoverImageID != nil && strings.TrimSpace(art.CoverImageAlt) == "" {
		suggestions = append(suggestions, suggestion(article.DismissCoverAlt, article.SEOFieldCoverAlt, map[string]int{}))
	}
	if art.CoverImageID == nil {
		suggestions = append(suggestions, suggestion(article.DismissCoverNone, article.SEOFieldCoverID, map[string]int{}))
	}
	slugRunes := utf8.RuneCountInString(art.Slug)
	if slugRunes > article.SEOSlugMaxRunes {
		suggestions = append(suggestions, suggestion(article.DismissSlugLong, article.SEOFieldSlug, map[string]int{"length": slugRunes, "max": article.SEOSlugMaxRunes}))
	}
	if len(art.Authors) == 0 {
		suggestions = append(suggestions, suggestion(article.DismissNoAuthor, article.SEOFieldAuthors, map[string]int{}))
	}
	if facts.textRunes >= article.SEOHeadingMinTextRunes && !facts.hasSubheading {
		suggestions = append(suggestions, suggestion(article.DismissNoHeading, article.SEOFieldBody, map[string]int{}))
	}
	if facts.imagesWithoutAlt > 0 {
		suggestions = append(suggestions, suggestion(article.DismissBodyAlt, article.SEOFieldBody, map[string]int{"count": facts.imagesWithoutAlt}))
	}
	if facts.textRunes < article.SEOShortBodyRunes {
		suggestions = append(suggestions, suggestion(article.DismissShort, article.SEOFieldBody, map[string]int{"length": facts.textRunes, "min": article.SEOShortBodyRunes}))
	}
	return suggestions
}

func assessSEO(art article.Article, owner site.Site) article.SEOAssessment {
	facts := analyzeBody(art.Body)
	kept := []article.SEOSuggestion{}
	for _, found := range rawSuggestions(art, owner, facts) {
		if !slices.Contains(art.SEODismissed, found.Code) {
			kept = append(kept, found)
		}
	}
	status := article.SEOStatusReady
	if len(kept) > 0 {
		status = article.SEOStatusSuggestions
	}
	if art.Noindex {
		status = article.SEOStatusHidden
	}
	return article.SEOAssessment{Status: status, Suggestions: kept}
}