package api

import (
	"net/http"
	"strconv"

	"github.com/go-chi/chi/v5"

	"geniusrun/backend/internal/store"
)

// activityListItem is one row of the activities list, enriched with its
// current classification so the frontend can show what kind it's assigned
// to and whether that assignment is locked (see Locked's doc comment).
type activityListItem struct {
	activityResponse
	WorkoutKindID    *int64  `json:"workout_kind_id"`
	WorkoutKindName  *string `json:"workout_kind_name"`
	AssignmentSource *string `json:"assignment_source"`
	AssignmentStatus *string `json:"assignment_status"`
	// Locked is true when a global reclassify pass will never touch this
	// activity again: a manual assignment is the user's definitive word, and
	// a Race assignment comes from a hard Garmin fact, not a retunable rule.
	Locked bool `json:"locked"`
}

func (s *Server) handleListActivities(w http.ResponseWriter, r *http.Request) {
	userID := userIDFromContext(r.Context())
	q := r.URL.Query()
	filter := store.ActivityFilter{
		FromDate: q.Get("from"),
		ToDate:   q.Get("to"),
	}
	if limit, err := strconv.Atoi(q.Get("limit")); err == nil {
		filter.Limit = limit
	}
	if offset, err := strconv.Atoi(q.Get("offset")); err == nil {
		filter.Offset = offset
	}

	activities, err := s.DB.ListActivities(r.Context(), userID, filter)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	kinds, err := s.DB.ListWorkoutKinds(r.Context(), userID, false)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	kindNames := make(map[int64]string, len(kinds))
	for _, k := range kinds {
		kindNames[k.ID] = k.Name
	}

	resp := make([]activityListItem, 0, len(activities))
	for _, a := range activities {
		item := activityListItem{activityResponse: toActivityResponse(a)}
		assignment, ok, err := s.DB.CurrentAssignment(r.Context(), userID, a.ID)
		if err != nil {
			writeError(w, http.StatusInternalServerError, err.Error())
			return
		}
		if ok {
			source, status := assignment.AssignmentSource, assignment.Status
			item.AssignmentSource, item.AssignmentStatus = &source, &status
			if assignment.WorkoutKindID != nil {
				item.WorkoutKindID = assignment.WorkoutKindID
				if name, found := kindNames[*assignment.WorkoutKindID]; found {
					item.WorkoutKindName = &name
				}
			}
			item.Locked = source == store.AssignmentSourceManual ||
				(item.WorkoutKindName != nil && *item.WorkoutKindName == "Race")
		}
		resp = append(resp, item)
	}
	writeJSON(w, http.StatusOK, resp)
}

func (s *Server) handleGetActivity(w http.ResponseWriter, r *http.Request) {
	userID := userIDFromContext(r.Context())
	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid activity id")
		return
	}

	activity, ok, err := s.DB.GetActivity(r.Context(), userID, id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	if !ok {
		writeError(w, http.StatusNotFound, "activity not found")
		return
	}

	laps, err := s.DB.LapsForActivity(r.Context(), userID, id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	assignment, hasAssignment, err := s.DB.CurrentAssignment(r.Context(), userID, id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	resp := map[string]any{"activity": toActivityResponse(activity), "laps": toLapResponses(laps)}
	if hasAssignment {
		resp["assignment"] = assignment
	}
	writeJSON(w, http.StatusOK, resp)
}