package pages

import (
	"context"
	"time"

	"lmika.dev/lmika/weiro/models"
	"lmika.dev/lmika/weiro/providers/db"
	"lmika.dev/lmika/weiro/services/publisher"
)

type CreatePageParams struct {
	GUID      string `form:"guid" json:"guid"`
	Title     string `form:"title" json:"title"`
	Slug      string `form:"slug" json:"slug"`
	Body      string `form:"body" json:"body"`
	PageType  int    `form:"page_type" json:"page_type"`
	ShowInNav bool   `form:"show_in_nav" json:"show_in_nav"`
}

type Service struct {
	db        *db.Provider
	publisher *publisher.Queue
}

func New(db *db.Provider, publisher *publisher.Queue) *Service {
	return &Service{db: db, publisher: publisher}
}

func (s *Service) ListPages(ctx context.Context) ([]*models.Page, error) {
	site, ok := models.GetSite(ctx)
	if !ok {
		return nil, models.SiteRequiredError
	}
	return s.db.SelectPagesOfSite(ctx, site.ID)
}

func (s *Service) GetPage(ctx context.Context, id int64) (*models.Page, error) {
	site, ok := models.GetSite(ctx)
	if !ok {
		return nil, models.SiteRequiredError
	}

	page, err := s.db.SelectPage(ctx, id)
	if err != nil {
		return nil, err
	}
	if page.SiteID != site.ID {
		return nil, models.NotFoundError
	}
	return page, nil
}

func (s *Service) CreatePage(ctx context.Context, params CreatePageParams) (*models.Page, error) {
	site, ok := models.GetSite(ctx)
	if !ok {
		return nil, models.SiteRequiredError
	}

	now := time.Now()
	slug := params.Slug
	if slug == "" {
		slug = models.GeneratePageSlug(params.Title)
	}

	// Check slug collision
	if _, err := s.db.SelectPageBySlugAndSite(ctx, site.ID, slug); err == nil {
		return nil, models.SlugConflictError
	} else if !db.ErrorIsNoRows(err) {
		return nil, err
	}

	// Determine sort order: place at end
	existingPages, err := s.db.SelectPagesOfSite(ctx, site.ID)
	if err != nil {
		return nil, err
	}
	sortOrder := len(existingPages)

	page := &models.Page{
		SiteID:    site.ID,
		GUID:      params.GUID,
		Title:     params.Title,
		Slug:      slug,
		Body:      params.Body,
		PageType:  params.PageType,
		ShowInNav: params.ShowInNav,
		SortOrder: sortOrder,
		CreatedAt: now,
		UpdatedAt: now,
	}
	if page.GUID == "" {
		page.GUID = models.NewNanoID()
	}

	if err := s.db.SavePage(ctx, page); err != nil {
		return nil, err
	}

	s.publisher.Queue(site)
	return page, nil
}

func (s *Service) UpdatePage(ctx context.Context, id int64, params CreatePageParams) (*models.Page, error) {
	site, ok := models.GetSite(ctx)
	if !ok {
		return nil, models.SiteRequiredError
	}

	page, err := s.db.SelectPage(ctx, id)
	if err != nil {
		return nil, err
	}
	if page.SiteID != site.ID {
		return nil, models.NotFoundError
	}

	slug := params.Slug
	if slug == "" {
		slug = models.GeneratePageSlug(params.Title)
	}

	// Check slug collision (exclude self)
	if existing, err := s.db.SelectPageBySlugAndSite(ctx, site.ID, slug); err == nil && existing.ID != page.ID {
		return nil, models.SlugConflictError
	} else if err != nil && !db.ErrorIsNoRows(err) {
		return nil, err
	}

	page.Title = params.Title
	page.Slug = slug
	page.Body = params.Body
	page.PageType = params.PageType
	page.ShowInNav = params.ShowInNav
	page.UpdatedAt = time.Now()

	if err := s.db.SavePage(ctx, page); err != nil {
		return nil, err
	}

	s.publisher.Queue(site)
	return page, nil
}

func (s *Service) DeletePage(ctx context.Context, id int64) error {
	site, ok := models.GetSite(ctx)
	if !ok {
		return models.SiteRequiredError
	}

	page, err := s.db.SelectPage(ctx, id)
	if err != nil {
		return err
	}
	if page.SiteID != site.ID {
		return models.NotFoundError
	}

	if err := s.db.DeletePage(ctx, id); err != nil {
		return err
	}

	s.publisher.Queue(site)
	return nil
}

func (s *Service) ReorderPages(ctx context.Context, pageIDs []int64) error {
	site, ok := models.GetSite(ctx)
	if !ok {
		return models.SiteRequiredError
	}

	// Verify all pages belong to this site
	for i, id := range pageIDs {
		page, err := s.db.SelectPage(ctx, id)
		if err != nil {
			return err
		}
		if page.SiteID != site.ID {
			return models.NotFoundError
		}
		if err := s.db.UpdatePageSortOrder(ctx, id, i); err != nil {
			return err
		}
	}

	s.publisher.Queue(site)
	return nil
}