package api

import (
	"errors"
	"net/http"
	"strconv"

	"messenger/internal/store"
)

func (h *apiHandler) searchUsers(w http.ResponseWriter, r *http.Request) {
	query := r.URL.Query().Get("q")
	users, err := h.store.SearchUsers(r.Context(), query, 20)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "internal server error")
		return
	}
	out := make([]userJSON, 0, len(users))
	for i := range users {
		out = append(out, toUserJSON(&users[i]))
	}
	writeJSON(w, http.StatusOK, out)
}

type contactJSON struct {
	User    userJSON `json:"user"`
	AddedAt string   `json:"added_at"`
}

func (h *apiHandler) listContacts(w http.ResponseWriter, r *http.Request) {
	userID, _ := userIDFrom(r.Context())
	contacts, err := h.store.ListContacts(r.Context(), userID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "internal server error")
		return
	}
	out := make([]contactJSON, 0, len(contacts))
	for _, c := range contacts {
		u, err := h.store.GetUserByID(r.Context(), c.ContactID)
		if err != nil {
			continue
		}
		out = append(out, contactJSON{User: toUserJSON(u), AddedAt: c.CreatedAt.Format("2006-01-02T15:04:05Z07:00")})
	}
	writeJSON(w, http.StatusOK, out)
}

func (h *apiHandler) addContact(w http.ResponseWriter, r *http.Request) {
	userID, _ := userIDFrom(r.Context())
	var req struct {
		UserID int64 `json:"user_id"`
	}
	if !decodeJSON(w, r, &req) {
		return
	}
	if req.UserID <= 0 {
		writeError(w, http.StatusBadRequest, "invalid user_id")
		return
	}
	if req.UserID == userID {
		writeError(w, http.StatusBadRequest, "cannot add yourself")
		return
	}
	if _, err := h.store.GetUserByID(r.Context(), req.UserID); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			writeError(w, http.StatusNotFound, "user not found")
			return
		}
		writeError(w, http.StatusInternalServerError, "internal server error")
		return
	}
	if err := h.store.AddContact(r.Context(), userID, req.UserID); err != nil {
		if errors.Is(err, store.ErrDuplicate) {
			writeJSON(w, http.StatusOK, map[string]string{"status": "already a contact"})
			return
		}
		writeError(w, http.StatusInternalServerError, "internal server error")
		return
	}
	writeJSON(w, http.StatusCreated, map[string]string{"status": "ok"})
}

func (h *apiHandler) removeContact(w http.ResponseWriter, r *http.Request) {
	userID, _ := userIDFrom(r.Context())
	contactID, err := strconv.ParseInt(r.PathValue("user_id"), 10, 64)
	if err != nil || contactID <= 0 {
		writeError(w, http.StatusBadRequest, "invalid user_id")
		return
	}
	if err := h.store.RemoveContact(r.Context(), userID, contactID); err != nil {
		writeError(w, http.StatusInternalServerError, "internal server error")
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"status": "ok"})
}