package landing

import (
	"context"
	"strings"
	"sync"
	"time"

	"github.com/google/uuid"
	"github.com/rs/zerolog"
	"go.uber.org/fx"
	"golang.org/x/sync/errgroup"

	domainAsset "base/internal/domain/asset"
	domainProfile "base/internal/domain/profile"
	"base/internal/dto"
	"base/pkg/cache"
)

const (
	defaultAssetsPerCategory = 6
	defaultSpecialistsLimit  = 6
	defaultRolesLimit        = 20
	landingCacheKey          = "landing:page"
	landingCacheTTL          = 5 * time.Minute
)

type Service interface {
	GetLanding(ctx context.Context) (*dto.Landing, error)
}

type service struct {
	logger       zerolog.Logger
	cache        cache.Cache[dto.Landing]
	categoryRepo domainAsset.CategoryRepository
	assetRepo    domainAsset.AssetRepository
	profileRepo  domainProfile.Repository
	roleRepo     domainProfile.RoleRepository
}

type Param struct {
	Logger       zerolog.Logger
	Cache        cache.Cache[dto.Landing]
	CategoryRepo domainAsset.CategoryRepository
	AssetRepo    domainAsset.AssetRepository
	ProfileRepo  domainProfile.Repository
	RoleRepo     domainProfile.RoleRepository

	fx.In
}

func New(param Param) Service {
	return &service{
		logger:       param.Logger,
		cache:        param.Cache,
		categoryRepo: param.CategoryRepo,
		assetRepo:    param.AssetRepo,
		profileRepo:  param.ProfileRepo,
		roleRepo:     param.RoleRepo,
	}
}

func (s *service) GetLanding(ctx context.Context) (*dto.Landing, error) {
	result, err := s.cache.WithCache(ctx, landingCacheKey, s.fetchLanding, landingCacheTTL)
	if err != nil {
		return nil, err
	}
	return &result, nil
}

func (s *service) fetchLanding(ctx context.Context) (dto.Landing, error) {
	data := &dto.LandingPageData{
		Categories:      []dto.CategoryDTO{},
		SpecialistRoles: []dto.ProfileRole{},
		Assets:          []dto.LandingAssetData{},
		Specialists:     []dto.Specialist{},
		Blogs:           []dto.Blog{},
	}

	g, gCtx := errgroup.WithContext(ctx)

	g.Go(func() error {
		categories, err := s.categoryRepo.FindAll(gCtx)
		if err != nil {
			return err
		}
		data.Categories = make([]dto.CategoryDTO, len(categories))
		for i, c := range categories {
			data.Categories[i] = dto.CategoryDTO{
				ID:          c.ID,
				Name:        c.Name,
				Icon:        c.Icon,
				Color:       c.Color,
				CardType:    c.CardType,
				Featured:    c.Featured,
				Description: c.Description,
			}
		}
		return nil
	})

	g.Go(func() error {
		domainRoles, err := s.roleRepo.List(gCtx, defaultRolesLimit, 0)
		if err != nil {
			return err
		}

		data.SpecialistRoles = make([]dto.ProfileRole, len(domainRoles))
		for i, r := range domainRoles {
			data.SpecialistRoles[i] = dto.ProfileRole{
				Id:    r.ID.String(),
				Title: r.Title,
			}
		}
		return nil
	})

	g.Go(func() error {
		profiles, _, err := s.profileRepo.FindAll(
			gCtx,
			domainProfile.Filter{
				Page:      1,
				PageSize:  defaultSpecialistsLimit,
				SortedBy:  "created_at",
				Ascending: false,
			})
		if err != nil {
			return err
		}

		data.Specialists = make([]dto.Specialist, len(profiles))
		for i, p := range profiles {
			data.Specialists[i] = dto.Specialist{
				Id:     p.ID.String(),
				Handle: p.Handle,
				Avatar: p.About.ProfilePicture,
			}
		}
		return nil
	})

	g.Go(func() error {
		categories, err := s.categoryRepo.FindAll(gCtx)
		if err != nil {
			return err
		}

		assetsByCat := make([]dto.LandingAssetData, len(categories))
		mu := &sync.Mutex{}
		eg, egCtx := errgroup.WithContext(gCtx)

		for index, category := range categories {
			i, cat := index, category

			eg.Go(func() error {
				assets, findLatestAssetErr := s.assetRepo.FindLatestByCategory(egCtx, cat.ID, defaultAssetsPerCategory)
				if findLatestAssetErr != nil {
					return findLatestAssetErr
				}

				assetResp := make([]dto.AssetResponse, len(assets))
				for j, a := range assets {
					assetResp[j] = *s.toAssetResponse(a)
				}

				mu.Lock()

				assetsByCat[i] = dto.LandingAssetData{
					AssetCategory: dto.AssetCategory{
						Id:    cat.ID.String(),
						Title: cat.Name,
						Icon:  cat.Icon,
					},
					Assets: assetResp,
				}

				mu.Unlock()
				return nil
			})
		}

		if err = eg.Wait(); err != nil {
			return err
		}
		data.Assets = assetsByCat
		return nil
	})

	if err := g.Wait(); err != nil {
		return dto.Landing{}, err
	}

	return dto.Landing{
		Message: "Landing page fetched successfully",
		Data:    *data,
	}, nil
}

func (s *service) toAssetResponse(a *domainAsset.Asset) *dto.AssetResponse {
	coverImage := ""
	for _, art := range a.AssetArtifacts {
		if strings.Contains(strings.ToLower(art.Type), "image") {
			coverImage = art.DownloadURL
			break
		}
	}
	resp := &dto.AssetResponse{
		ID:              a.ID,
		ProfileID:       a.ProfileID,
		AssetCategoryID: a.AssetCategoryID,
		Title:           a.Title,
		Description:     a.Description,
		Link:            a.Link,
		CoverImage:      coverImage,
		Status:          int(a.Status),
		CreatedAt:       formatTime(a.CreatedAt),
		UpdatedAt:       formatTime(a.UpdatedAt),
	}
	if a.AssetCategory.ID != uuid.Nil {
		resp.Category = dto.CategoryDTO{
			ID:          a.AssetCategory.ID,
			Name:        a.AssetCategory.Name,
			Icon:        a.AssetCategory.Icon,
			Color:       a.AssetCategory.Color,
			CardType:    a.AssetCategory.CardType,
			Featured:    a.AssetCategory.Featured,
			Description: a.AssetCategory.Description,
		}
	}
	return resp
}

func formatTime(t time.Time) string {
	if t.IsZero() {
		return ""
	}
	return t.Format(time.RFC3339)
}