package useCases

import (
	"RenewCMS/internal/domain/audit"
	"RenewCMS/internal/domain/author"
	"RenewCMS/internal/domain/image"
	"RenewCMS/internal/domain/user"
	"errors"
	"strconv"
	"strings"
)

const authorChangeSeparator = ", "

type AuthorCaller struct {
	UserID uint32
	Role   user.Role
}

func isAdminRole(role user.Role) bool {
	return role == user.RoleOwner || role == user.RoleAdmin
}

func (c AuthorCaller) isAdmin() bool {
	return isAdminRole(c.Role)
}

func authorTarget(a author.Author) audit.Target {
	return audit.NewTarget(audit.TargetAuthor, a.ID, a.Name)
}

func isSlugTaken(authors author.Repository, slug string) (bool, error) {
	_, err := authors.GetBySlug(slug)
	if errors.Is(err, author.ErrAuthorNotFound) {
		return false, nil
	}
	return err == nil, err
}

func ensureUserCanBeLinked(users user.Repository, authors author.Repository, userID uint32) error {
	if _, err := users.Get(userID); err != nil {
		return err
	}
	_, err := authors.GetByUserID(userID)
	if err == nil {
		return author.ErrUserAlreadyLinked
	}
	if errors.Is(err, author.ErrAuthorNotFound) {
		return nil
	}
	return err
}

func withUserEmail(users user.Repository, a author.Author) author.Author {
	a.UserEmail = nil
	if a.UserID == nil {
		return a
	}
	linked, err := users.Get(*a.UserID)
	if err != nil {
		return a
	}
	email := linked.Email
	a.UserEmail = &email
	return a
}

func linksLabel(links []author.SocialLink) string {
	labels := make([]string, 0, len(links))
	for _, link := range links {
		labels = append(labels, link.Type+": "+link.URL)
	}
	return strings.Join(labels, authorChangeSeparator)
}

func websiteLabel(website *string) string {
	if website == nil {
		return ""
	}
	return *website
}

func usernameLabel(users user.Repository, id *uint32) string {
	if id == nil {
		return ""
	}
	found, err := users.Get(*id)
	if err != nil {
		return strconv.FormatUint(uint64(*id), 10)
	}
	return found.Username
}

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

func authorChanges(users user.Repository, images image.Repository, before author.Author, after author.Author) []audit.Change {
	changes := []audit.Change{}
	changes = appendTextChange(changes, audit.FieldName, before.Name, after.Name)
	changes = appendTextChange(changes, audit.FieldSlug, before.Slug, after.Slug)
	changes = appendTextChange(changes, audit.FieldBio, before.Bio, after.Bio)
	changes = appendTextChange(changes, audit.FieldWebsite, websiteLabel(before.Website), websiteLabel(after.Website))
	changes = appendTextChange(changes, audit.FieldSocialLinks, linksLabel(before.SocialLinks), linksLabel(after.SocialLinks))
	if !sameID(before.AvatarID, after.AvatarID) {
		changes = append(changes, audit.TextChange(audit.FieldAvatar, imageLabel(images, before.AvatarID), imageLabel(images, after.AvatarID)))
	}
	if !sameID(before.UserID, after.UserID) {
		changes = append(changes, audit.TextChange(audit.FieldUser, usernameLabel(users, before.UserID), usernameLabel(users, after.UserID)))
	}
	return changes
}