package admin

import (
	"context"
	"strconv"

	"git.dmitriygnatenko.ru/dima/go-common/logger"
	"github.com/go-playground/validator/v10"
	"github.com/gofiber/fiber/v2"

	"git.dmitriygnatenko.ru/dima/dmitriygnatenko-v2/internal/dto"
	helper "git.dmitriygnatenko.ru/dima/dmitriygnatenko-v2/internal/helpers/i18n"
	"git.dmitriygnatenko.ru/dima/dmitriygnatenko-v2/internal/helpers/request"
	"git.dmitriygnatenko.ru/dima/dmitriygnatenko-v2/internal/mapper"
	"git.dmitriygnatenko.ru/dima/dmitriygnatenko-v2/internal/services/handler"
	"git.dmitriygnatenko.ru/dima/dmitriygnatenko-v2/internal/services/i18n"
)

type articleEditPage struct {
	tm                   TransactionManager
	articleRepository    ArticleRepository
	tagRepository        TagRepository
	articleTagRepository ArticleTagRepository
	cacheService         CacheService
}

func NewArticleEditPageHandler(
	tm TransactionManager,
	articleRepository ArticleRepository,
	tagRepository TagRepository,
	articleTagRepository ArticleTagRepository,
	cacheService CacheService,
) fiber.Handler {
	h := articleEditPage{
		tm:                   tm,
		articleRepository:    articleRepository,
		tagRepository:        tagRepository,
		articleTagRepository: articleTagRepository,
		cacheService:         cacheService,
	}

	return h.handler()
}

func (h articleEditPage) handler() fiber.Handler {
	return func(fctx *fiber.Ctx) error {
		ctx := fctx.Context()
		lang := i18n.LanguageFromContext(fctx)

		var validate = validator.New()
		validateErrors := make(map[string]string)

		trans, err := helper.GetDefaultTranslator(validate)
		if err != nil {
			logger.Error(ctx, err.Error())
			return err
		}

		id, err := request.ConvertToUint64(fctx, "id")
		if err != nil {
			logger.Error(ctx, err.Error())
			return err
		}

		article, err := h.articleRepository.GetByID(ctx, id)
		if err != nil {
			logger.Error(ctx, err.Error())
			return err
		}

		if article == nil {
			return fiber.ErrNotFound
		}

		articleTags, err := h.tagRepository.GetByArticleID(ctx, id)
		if err != nil {
			logger.Error(ctx, err.Error())
			return err
		}

		tags, err := h.tagRepository.GetAll(ctx)
		if err != nil {
			logger.Error(ctx, err.Error())
			return err
		}

		tagsDTO := mapper.ToTagsList(tags)

		var form *dto.ArticleForm
		if fctx.Method() == fiber.MethodGet {
			form = mapper.ToArticleForm(*article, articleTags)
		} else if fctx.Method() == fiber.MethodPost {
			form = &dto.ArticleForm{
				ID:         id,
				ActiveTags: make(map[uint64]bool),
			}

			if err = fctx.BodyParser(form); err != nil {
				logger.Info(ctx, err.Error())
				return err
			}

			if err = validate.Struct(*form); err != nil {
				validateErrors = helper.FormatValidateErrors(err, trans)
			}

			if res, _ := h.articleRepository.GetByURL(ctx, form.URL); res != nil {
				if res.ID != id {
					validateErrors["ArticleForm.URL"] = i18n.T(lang, "admin_err_article_exists")
				}
			}

			tagIDs := make([]uint64, 0, len(form.Tags))
			for i := range form.Tags {
				tagID, tagErr := strconv.ParseUint(form.Tags[i], 10, 64)
				if tagErr != nil {
					return tagErr
				}

				tagIDs = append(tagIDs, tagID)
			}

			for i := range tagIDs {
				form.ActiveTags[tagIDs[i]] = true
			}

			if len(validateErrors) == 0 {
				articleModel, err := mapper.ToArticleModel(*form)
				if err != nil {
					logger.Error(ctx, err.Error())
					return err
				}

				var tagsToAdd, tagsToDelete []uint64

				oldTagsMap := make(map[int]struct{}, len(articleTags))
				for i := range articleTags {
					oldTagsMap[int(articleTags[i].ID)] = struct{}{}
					if _, ok := form.ActiveTags[articleTags[i].ID]; !ok {
						tagsToDelete = append(tagsToDelete, articleTags[i].ID)
					}
				}

				for i := range tagIDs {
					if _, ok := oldTagsMap[int(tagIDs[i])]; !ok {
						tagsToAdd = append(tagsToAdd, tagIDs[i])
					}
				}

				err = h.tm.ReadCommitted(ctx, func(ctx context.Context) error {
					txErr := h.articleRepository.Update(ctx, *articleModel)
					if txErr != nil {
						return txErr
					}

					if len(tagsToAdd) > 0 {
						if txErr = h.articleTagRepository.Add(ctx, id, tagsToAdd); txErr != nil {
							return txErr
						}
					}

					if len(tagsToDelete) > 0 {
						if txErr = h.articleTagRepository.Delete(ctx, id, tagsToDelete); txErr != nil {
							return txErr
						}
					}

					return nil
				})

				if err != nil {
					logger.Error(ctx, err.Error())
					return err
				}

				h.cacheService.Delete(handler.ArticleCacheKey + string(lang) + article.URL)

				if fctx.FormValue("action", "save") == "save" {
					return fctx.Redirect("/admin")
				}
			}
		}

		return fctx.Render("admin/article_edit", fiber.Map{
			"section":    "article",
			"lang":       lang,
			"form":       form,
			"errors":     validateErrors,
			"tags":       tagsDTO,
			"show_apply": true,
			"title":      i18n.T(lang, "admin_edit_article_title"),
		}, "admin/_layout")
	}
}