package useCases

import (
	"RenewCMS/internal/domain/article"
	"RenewCMS/internal/domain/audit"
	"RenewCMS/internal/domain/author"
	"RenewCMS/internal/domain/builtintype"
	"RenewCMS/internal/domain/language"
	"RenewCMS/internal/domain/localization"
	"RenewCMS/internal/domain/role"
	"RenewCMS/internal/domain/site"
	"RenewCMS/internal/domain/transaction"
	"context"
	"errors"
)

type CreateArticleUseCase struct {
	transactor   transaction.Transactor
	bodyRenderer article.BodyRenderer
	recorder     audit.Recorder
	sites        site.Repository
	authors      author.Repository
}

type CreateArticleCommand struct {
	Title  string
	Body   string
	Format article.BodyFormat
	Lang   string
	Site   *string
	Caller ContentCaller
}

func NewCreateArticleUseCase(transactor transaction.Transactor, bodyRenderer article.BodyRenderer, recorder audit.Recorder, sites site.Repository, authors author.Repository) *CreateArticleUseCase {
	return &CreateArticleUseCase{transactor: transactor, bodyRenderer: bodyRenderer, recorder: recorder, sites: sites, authors: authors}
}

func (g *CreateArticleUseCase) targetSite(key *string) (site.Site, error) {
	if key == nil {
		return g.sites.GetDefault()
	}
	return g.sites.GetByKey(*key)
}

func (g *CreateArticleUseCase) creatorBylines(userID uint32) ([]author.Byline, error) {
	found, err := g.authors.GetByUserID(userID)
	if errors.Is(err, author.ErrAuthorNotFound) {
		return []author.Byline{}, nil
	}
	if err != nil {
		return nil, err
	}
	return []author.Byline{found.Byline()}, nil
}

func (g *CreateArticleUseCase) CreateArticle(ctx context.Context, createArticle CreateArticleCommand) (article.Article, error) {
	if err := createArticle.Caller.requireHolding(role.KeyContentCreate, builtintype.KeyArticle); err != nil {
		return article.Article{}, err
	}
	event := audit.NewEvent(audit.ActionArticleCreate, audit.CategoryArticles)
	if err := article.ValidateTitle(createArticle.Title); err != nil {
		recordFailure(ctx, g.recorder, event, err)
		return article.Article{}, err
	}
	requested, err := requestedLanguage(createArticle.Lang)
	if err != nil {
		recordFailure(ctx, g.recorder, event, err)
		return article.Article{}, err
	}

	target, err := g.targetSite(createArticle.Site)
	if errors.Is(err, site.ErrSiteNotFound) {
		failFrom(ctx, g.recorder, event, reasonFor(err))
		return article.Article{}, err
	}
	if err != nil {
		recordFailure(ctx, g.recorder, event, err)
		return article.Article{}, err
	}

	creditedAuthors, err := g.creatorBylines(createArticle.Caller.UserID)
	if err != nil {
		recordFailure(ctx, g.recorder, event, err)
		return article.Article{}, err
	}

	created, err := g.createWithFreeSlug(ctx, requested, article.Article{
		Title:        createArticle.Title,
		Body:         createArticle.Body,
		IsOnline:     false,
		SiteID:       target.ID,
		CreatedBy:    createArticle.Caller.UserID,
		Authors:      creditedAuthors,
		SEODismissed: []string{},
	})
	if err != nil {
		recordFailure(ctx, g.recorder, event, err)
		return article.Article{}, err
	}

	event = articleEvent(audit.ActionArticleCreate, created)
	event.Params[audit.ParamSite] = target.Key
	g.recorder.Record(ctx, event)
	return renderArticle(g.bodyRenderer, created, createArticle.Format)
}

func requestedLanguage(raw string) (string, error) {
	if raw == "" {
		return language.Unassigned, nil
	}
	return language.Normalize(raw)
}

func (g *CreateArticleUseCase) createWithFreeSlug(ctx context.Context, requested string, draft article.Article) (article.Article, error) {
	for attempt := 0; attempt < maxCreateSlugAttempts; attempt++ {
		created, err := g.createInTransaction(ctx, requested, draft)
		if !isSlugTakenError(err) {
			return created, err
		}
	}
	return article.Article{}, article.ErrSlugTaken
}

func (g *CreateArticleUseCase) createInTransaction(ctx context.Context, requested string, draft article.Article) (article.Article, error) {
	var created article.Article
	err := g.transactor.Run(ctx, func(tx transaction.Repositories) error {
		err := tx.Sites.LockSite(draft.SiteID)
		if errors.Is(err, site.ErrSiteNotFound) {
			return article.ErrTargetSiteDeleted
		}
		if err != nil {
			return err
		}
		rows, err := tx.Localization.Rows(draft.SiteID)
		if err != nil {
			return err
		}
		if draft.Lang, err = chooseLanguage(rows, requested); err != nil {
			return err
		}
		draft.Slug, err = freeSlug(tx.Articles, draft.SiteID, draft.Lang, article.GenerateSlug(draft.Title), 0, firstSlugAttempt)
		if err != nil {
			return err
		}
		created, err = tx.Articles.Create(draft)
		return err
	})
	return created, err
}

func chooseLanguage(rows []localization.Row, requested string) (string, error) {
	if requested == language.Unassigned {
		return localization.ConfirmedDefaultTag(rows), nil
	}
	if localization.NeedsSetup(rows) {
		return "", localization.ErrSetupRequired
	}
	if !localization.HasRow(rows, requested) {
		return "", &article.LanguageNotEnabledError{}
	}
	if !localization.EnabledTag(rows, requested) {
		return "", article.ErrLanguageUnavailable
	}
	return requested, nil
}