package api

import (
	"encoding/json"
	"net/http"
	"sort"
	"strings"
	"time"

	"github.com/ponzischeme89/memby/server/internal/cache"
	"github.com/ponzischeme89/memby/server/internal/recommend"
	"github.com/ponzischeme89/memby/server/internal/store"
)

type adminOnboardingRating struct {
	ItemID string `json:"itemId"`
	Title  string `json:"title"`
	Rating int    `json:"rating"`
}

type adminOnboardingPreferences struct {
	Completed    bool                    `json:"completed"`
	Updated      bool                    `json:"updated"`
	Ratings      []adminOnboardingRating `json:"ratings"`
	Genres       []string                `json:"genres"`
	Studios      []string                `json:"studios"`
	Actors       []string                `json:"actors"`
	Directors    []string                `json:"directors"`
	ContentTypes []string                `json:"contentTypes"`
}

type adminMembyAccount struct {
	ID              string                     `json:"id"`
	Username        string                     `json:"username"`
	CreatedAt       time.Time                  `json:"createdAt"`
	LastSeen        time.Time                  `json:"lastSeen"`
	Devices         []store.MembyDevice        `json:"devices"`
	Recommendations adminOnboardingPreferences `json:"recommendations"`
}

func (s *Server) handleAdminAccounts(w http.ResponseWriter, r *http.Request) {
	accounts, err := s.store.MembyAccounts(r.Context())
	if err != nil {
		s.log.Error("Memby account list failed", "error", err)
		writeError(w, http.StatusInternalServerError, "could not load Memby accounts")
		return
	}

	allRatingIDs := []string{}
	preferences := make(map[string]recommend.OnboardingPreferences, len(accounts))
	for _, account := range accounts {
		var pref recommend.OnboardingPreferences
		_ = json.Unmarshal(account.RecommendationPreferences, &pref)
		preferences[account.ID] = pref
		for id := range pref.Ratings {
			allRatingIDs = append(allRatingIDs, id)
		}
	}
	titles := map[string]string{}
	if raws, loadErr := s.store.LibraryItemsByID(r.Context(), allRatingIDs); loadErr == nil {
		for _, item := range recommend.Decode(raws) {
			titles[item.ID] = item.Name
		}
	}

	result := make([]adminMembyAccount, 0, len(accounts))
	for _, account := range accounts {
		pref := preferences[account.ID]
		ratings := make([]adminOnboardingRating, 0, len(pref.Ratings))
		for itemID, rating := range pref.Ratings {
			title := titles[itemID]
			if title == "" {
				title = itemID
			}
			ratings = append(ratings, adminOnboardingRating{ItemID: itemID, Title: title, Rating: rating})
		}
		sort.Slice(ratings, func(i, j int) bool {
			if ratings[i].Rating != ratings[j].Rating {
				return ratings[i].Rating > ratings[j].Rating
			}
			return strings.ToLower(ratings[i].Title) < strings.ToLower(ratings[j].Title)
		})
		result = append(result, adminMembyAccount{
			ID: account.ID, Username: account.Username, CreatedAt: account.CreatedAt,
			LastSeen: account.LastSeen, Devices: account.Devices,
			Recommendations: adminOnboardingPreferences{
				Completed: pref.Completed, Updated: len(account.RecommendationPreferences) > 2,
				Ratings: ratings, Genres: nonNilStrings(pref.Genres),
				Studios: nonNilStrings(pref.Studios), Actors: nonNilStrings(pref.Actors),
				Directors: nonNilStrings(pref.Directors), ContentTypes: nonNilStrings(pref.ContentTypes),
			},
		})
	}
	writeJSON(w, http.StatusOK, map[string]any{"accounts": result})
}

func (s *Server) handleAdminRenameDevice(w http.ResponseWriter, r *http.Request) {
	userID, deviceID := strings.TrimSpace(r.PathValue("userID")), strings.TrimSpace(r.PathValue("deviceID"))
	var req renameDeviceRequest
	if userID == "" || deviceID == "" || json.NewDecoder(http.MaxBytesReader(w, r.Body, 2<<10)).Decode(&req) != nil {
		writeError(w, http.StatusBadRequest, "user, device and name are required")
		return
	}
	req.DeviceName = strings.TrimSpace(req.DeviceName)
	if req.DeviceName == "" || len([]rune(req.DeviceName)) > 80 {
		writeError(w, http.StatusBadRequest, "device name must be between 1 and 80 characters")
		return
	}
	if err := s.store.RenameUserDevice(r.Context(), userID, deviceID, req.DeviceName); err == store.ErrNotFound {
		writeError(w, http.StatusNotFound, "Memby device not found")
		return
	} else if err != nil {
		writeError(w, http.StatusInternalServerError, "could not rename Memby device")
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

func (s *Server) handleAdminDeleteDevice(w http.ResponseWriter, r *http.Request) {
	userID, deviceID := strings.TrimSpace(r.PathValue("userID")), strings.TrimSpace(r.PathValue("deviceID"))
	if userID == "" || deviceID == "" {
		writeError(w, http.StatusBadRequest, "user and device are required")
		return
	}
	hash, err := s.store.DeleteUserDevice(r.Context(), userID, deviceID)
	if err == store.ErrNotFound {
		writeError(w, http.StatusNotFound, "Memby device not found")
		return
	}
	if err != nil {
		writeError(w, http.StatusInternalServerError, "could not sign out Memby device")
		return
	}
	if s.cache != nil {
		_ = s.cache.Delete(r.Context(), cache.SessionKey(hexHash(hash)))
	}
	w.WriteHeader(http.StatusNoContent)
}

func (s *Server) handleAdminDeleteAccount(w http.ResponseWriter, r *http.Request) {
	userID := strings.TrimSpace(r.PathValue("userID"))
	if userID == "" {
		writeError(w, http.StatusBadRequest, "user is required")
		return
	}
	hashes, err := s.store.DeleteUserSessions(r.Context(), userID)
	if err == store.ErrNotFound {
		writeError(w, http.StatusNotFound, "Memby account not found")
		return
	}
	if err != nil {
		writeError(w, http.StatusInternalServerError, "could not revoke Memby account access")
		return
	}
	if s.cache != nil {
		keys := make([]string, 0, len(hashes))
		for _, hash := range hashes {
			keys = append(keys, cache.SessionKey(hexHash(hash)))
		}
		_ = s.cache.Delete(r.Context(), keys...)
		_ = s.cache.InvalidateUser(r.Context(), userID)
	}
	w.WriteHeader(http.StatusNoContent)
}

func (s *Server) handleAdminResetRecommendations(w http.ResponseWriter, r *http.Request) {
	userID := strings.TrimSpace(r.PathValue("userID"))
	if userID == "" {
		writeError(w, http.StatusBadRequest, "user is required")
		return
	}
	if err := s.store.ClearRecommendationOnboarding(r.Context(), userID); err != nil {
		writeError(w, http.StatusInternalServerError, "could not reset recommendation choices")
		return
	}
	if s.cache != nil {
		_ = s.cache.Delete(r.Context(), cache.RecommendationsKey(userID))
	}
	w.WriteHeader(http.StatusNoContent)
}