package admin

import (
	"errors"
	"log/slog"
	"net/http"

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

	"github.com/jackc/pgx/v5/pgxpool"
	"github.com/ultisuite/ulti-backend/internal/api/apiresponse"
	"github.com/ultisuite/ulti-backend/internal/api/apivalidate"
	"github.com/ultisuite/ulti-backend/internal/api/middleware"
	"github.com/ultisuite/ulti-backend/internal/api/query"
	"github.com/ultisuite/ulti-backend/internal/permission"
	"github.com/ultisuite/ulti-backend/internal/securityaudit"
)

type Handler struct {
	svc    *Service
	logger *slog.Logger
}

func NewHandler(db *pgxpool.Pool, audit *securityaudit.Logger) *Handler {
	return &Handler{
		svc:    NewService(db, audit),
		logger: slog.Default().With("component", "admin-api"),
	}
}

func (h *Handler) Routes() chi.Router {
	r := chi.NewRouter()
	r.Use(middleware.RequireRole(permission.RoleAdmin))

	r.Get("/users", h.ListUsers)
	r.Get("/users/{userID}", h.GetUser)
	r.Put("/users/{userID}/quota", h.SetQuota)
	r.Delete("/users/{userID}", h.DeleteUser)

	r.Get("/audit", h.ListAuditLogs)
	r.Get("/stats", h.GetStats)

	return r
}

func (h *Handler) ListUsers(w http.ResponseWriter, r *http.Request) {
	params, err := query.ParseListRequest(r)
	if err != nil {
		apivalidate.WriteQueryError(w, r, err)
		return
	}

	result, err := h.svc.ListUsers(r.Context(), params)
	if err != nil {
		h.logger.Error("list users", "error", err)
		apivalidate.WriteInternal(w, r)
		return
	}
	apiresponse.WriteJSON(w, http.StatusOK, result)
}

func (h *Handler) GetUser(w http.ResponseWriter, r *http.Request) {
	userID := chi.URLParam(r, "userID")
	if verr := validateUserID(userID); verr != nil {
		apivalidate.WriteValidationError(w, r, verr)
		return
	}

	user, err := h.svc.GetUser(r.Context(), userID)
	if err != nil {
		if errors.Is(err, ErrNotFound) {
			apivalidate.WriteNotFound(w, r, "not found")
			return
		}
		h.logger.Error("get user", "error", err)
		apivalidate.WriteInternal(w, r)
		return
	}
	apiresponse.WriteJSON(w, http.StatusOK, user)
}

func (h *Handler) SetQuota(w http.ResponseWriter, r *http.Request) {
	userID := chi.URLParam(r, "userID")
	if verr := validateUserID(userID); verr != nil {
		apivalidate.WriteValidationError(w, r, verr)
		return
	}

	claims := middleware.ClaimsFromContext(r.Context())

	var req setQuotaRequest
	if err := apivalidate.DecodeJSON(w, r, maxQuotaRequestBody, &req); err != nil {
		return
	}
	if verr := validateSetQuota(&req); verr != nil {
		apivalidate.WriteValidationError(w, r, verr)
		return
	}

	if err := h.svc.SetQuota(r.Context(), claims.Sub, userID, req.MaxStorageBytes); err != nil {
		h.logger.Error("set quota", "error", err)
		apivalidate.WriteInternal(w, r)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

func (h *Handler) DeleteUser(w http.ResponseWriter, r *http.Request) {
	userID := chi.URLParam(r, "userID")
	if verr := validateUserID(userID); verr != nil {
		apivalidate.WriteValidationError(w, r, verr)
		return
	}

	claims := middleware.ClaimsFromContext(r.Context())
	if err := h.svc.DeleteUser(r.Context(), claims.Sub, userID); err != nil {
		if errors.Is(err, ErrNotFound) {
			apivalidate.WriteNotFound(w, r, "not found")
			return
		}
		h.logger.Error("delete user", "error", err)
		apivalidate.WriteInternal(w, r)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

func (h *Handler) ListAuditLogs(w http.ResponseWriter, r *http.Request) {
	params, err := query.ParseListRequest(r)
	if err != nil {
		apivalidate.WriteQueryError(w, r, err)
		return
	}

	result, err := h.svc.ListAuditLogs(r.Context(), params)
	if err != nil {
		h.logger.Error("list audit logs", "error", err)
		apivalidate.WriteInternal(w, r)
		return
	}
	apiresponse.WriteJSON(w, http.StatusOK, result)
}

func (h *Handler) GetStats(w http.ResponseWriter, r *http.Request) {
	stats, err := h.svc.GetStats(r.Context())
	if err != nil {
		h.logger.Error("get stats", "error", err)
		apivalidate.WriteInternal(w, r)
		return
	}
	apiresponse.WriteJSON(w, http.StatusOK, stats)
}