import { useEffect, useMemo, useState } from "react";
import { useAuthContext } from "@/providers/auth-context";
import { hasUserRole, isAdminUser } from "@/lib/auth/user-utils";
import { useVendorFacets } from "@/domain/vendors/use-cases/use-vendor-facets";
import type { Service, ServiceInput, ServiceWorkOrderType } from "@/domain/services/types/service";
import {
  useCreateService,
  useCompletionDocTemplates,
  useDeactivateService,
  useServices,
  useUpdateService,
} from "@/domain/services/use-cases/use-services";

export type ServiceStatus = "active" | "inactive";
export type ServiceForm = Omit<ServiceInput, "completionDocTemplateId"> & {
  completionDocTemplateId: string | number | null;
};

export const EMPTY_SERVICE_FORM: ServiceForm = {
  name: "",
  trade: "",
  iconKey: "",
  requiresCompletionDocument: false,
  completionDocTemplateId: null,
  supportedWorkOrderTypes: ["PM", "Reactive", "Emergency"],
};

// Keyed to the canonical TradeCatalog names the backend accepts (SH-247), not
// the legacy DropdownOptions seed. A trade with no explicit default falls back
// to "wrench" where this map is read.
export const DEFAULT_ICON_BY_TRADE: Record<string, string> = {
  HVAC: "droplets",
  "Plumbing & Water Systems": "droplets",
  Electrical: "zap",
  "General Building & Handyman": "hammer",
};

export function buildServiceInput(
  form: ServiceForm,
  includeActiveState = false,
): {
  input: ServiceInput | null;
  error: string;
} {
  const name = form.name.trim();
  if (!name || !form.trade || !form.iconKey) {
    return { input: null, error: "Service Name, Trade, and Icon are required." };
  }
  if (!form.supportedWorkOrderTypes.length) {
    return { input: null, error: "Select at least one Work Order Type." };
  }
  if (form.requiresCompletionDocument && form.completionDocTemplateId == null) {
    return {
      input: null,
      error: "Select a completion document template when the document is required.",
    };
  }
  const templateId = form.completionDocTemplateId;
  const { isActive, ...editableFields } = form;
  return {
    input: {
      ...editableFields,
      name,
      completionDocTemplateId: templateId == null || templateId === "" ? null : Number(templateId),
      ...(includeActiveState && isActive !== undefined ? { isActive } : {}),
    },
    error: "",
  };
}

function emptyForm(): ServiceForm {
  return {
    ...EMPTY_SERVICE_FORM,
    supportedWorkOrderTypes: [...EMPTY_SERVICE_FORM.supportedWorkOrderTypes],
  };
}

function formFromService(service: Service): ServiceForm {
  return {
    name: service.name,
    trade: service.trade,
    iconKey: service.iconKey,
    requiresCompletionDocument: service.requiresCompletionDocument,
    completionDocTemplateId: service.completionDocTemplate?.id ?? null,
    supportedWorkOrderTypes: [...service.supportedWorkOrderTypes],
    isActive: service.isActive,
  };
}

// Owns the add/edit form lifecycle so the top-level controller stays within the
// changed-file maintainability budget. Mutations are passed in so `isSaving` and
// `closeEditor` share the exact instances the controller reports on.
function useServiceEditor(
  canonicalTrades: string[],
  canDeactivate: boolean,
  createService: ReturnType<typeof useCreateService>,
  updateService: ReturnType<typeof useUpdateService>,
) {
  const [selected, setSelected] = useState<Service | null>(null);
  const [editorMode, setEditorMode] = useState<"add" | "edit" | null>(null);
  const [form, setForm] = useState<ServiceForm>(emptyForm);
  const [iconTouched, setIconTouched] = useState(false);
  const [formError, setFormError] = useState("");

  // Keep the trade stored on the service being edited selectable even if it was
  // later deactivated in the canonical Trade catalog, so editing never silently
  // blanks the field and forces an unrelated trade change.
  const trades = useMemo(() => {
    if (form.trade && !canonicalTrades.includes(form.trade)) {
      return [form.trade, ...canonicalTrades];
    }
    return canonicalTrades;
  }, [canonicalTrades, form.trade]);

  useEffect(() => {
    if (!iconTouched && form.trade) {
      setForm((current) => ({
        ...current,
        iconKey: DEFAULT_ICON_BY_TRADE[current.trade] ?? "wrench",
      }));
    }
  }, [form.trade, iconTouched]);

  const openCreate = () => {
    setSelected(null);
    setForm(emptyForm());
    setIconTouched(false);
    setFormError("");
    setEditorMode("add");
  };

  const openEdit = (service: Service) => {
    setSelected(service);
    setForm(formFromService(service));
    setIconTouched(true);
    setFormError("");
    setEditorMode("edit");
  };

  const closeEditor = () => {
    if (!createService.isPending && !updateService.isPending) setEditorMode(null);
  };

  const updateForm = <K extends keyof ServiceForm>(key: K, value: ServiceForm[K]) => {
    if (key === "trade") setIconTouched(false);
    setFormError("");
    setForm((current) => ({ ...current, [key]: value }));
  };

  const toggleType = (type: ServiceWorkOrderType) => {
    setForm((current) => {
      const supported = current.supportedWorkOrderTypes.includes(type)
        ? current.supportedWorkOrderTypes.filter((item) => item !== type)
        : [...current.supportedWorkOrderTypes, type];
      return { ...current, supportedWorkOrderTypes: supported };
    });
  };

  const save = () => {
    const validation = buildServiceInput(form, canDeactivate);
    if (!validation.input) {
      setFormError(validation.error);
      return;
    }
    const input = validation.input;
    if (editorMode === "add") {
      createService.mutate(input, {
        onSuccess: (created) => {
          setEditorMode(null);
          setSelected(created);
        },
      });
    } else if (editorMode === "edit" && selected) {
      updateService.mutate(
        { id: selected.id, input },
        {
          onSuccess: (updated) => {
            setEditorMode(null);
            setSelected(updated);
          },
        },
      );
    }
  };

  return {
    selected,
    setSelected,
    editorMode,
    form,
    formError,
    trades,
    openCreate,
    openEdit,
    closeEditor,
    updateForm,
    toggleType,
    save,
  };
}

export function useServicesRegistryController() {
  const { user } = useAuthContext();
  const canManage = hasUserRole(user?.userRoles, "scheduler") || isAdminUser(user?.userRoles);
  const canDeactivate = isAdminUser(user?.userRoles);
  const [status, setStatus] = useState<ServiceStatus>("active");
  const [search, setSearch] = useState("");
  const [deactivateTarget, setDeactivateTarget] = useState<Service | null>(null);

  const servicesQuery = useServices();
  // The backend rejects any Trade outside the canonical TradeCatalog (400
  // TradeInvalid), so the picker is sourced from the server-owned canonical
  // Trade reference exposed on Vendor/facets — the same list the vendor roster
  // form uses — never the editable DropdownOptions "Trade" category, whose
  // legacy seed values ("Plumbing", "General", ...) would fail on save.
  const facetsQuery = useVendorFacets();
  const canonicalTrades = useMemo(() => facetsQuery.data?.trades ?? [], [facetsQuery.data]);
  const { data: templates = [] } = useCompletionDocTemplates();
  const createService = useCreateService();
  const updateService = useUpdateService();
  const deactivateService = useDeactivateService();

  const editor = useServiceEditor(canonicalTrades, canDeactivate, createService, updateService);

  const services = useMemo(() => servicesQuery.data ?? [], [servicesQuery.data]);
  const activeCount = services.filter((service) => service.isActive).length;
  const inactiveCount = services.length - activeCount;

  const filteredServices = useMemo(() => {
    const needle = search.trim().toLowerCase();
    return services
      .filter((service) => (status === "active" ? service.isActive : !service.isActive))
      .filter(
        (service) =>
          !needle ||
          service.name.toLowerCase().includes(needle) ||
          service.trade.toLowerCase().includes(needle),
      );
  }, [search, services, status]);

  const confirmDeactivate = () => {
    if (!deactivateTarget) return;
    deactivateService.mutate(deactivateTarget.id, {
      onSuccess: () => {
        setDeactivateTarget(null);
        editor.setSelected(null);
      },
    });
  };

  return {
    canManage,
    canDeactivate,
    status,
    setStatus,
    search,
    setSearch,
    selected: editor.selected,
    setSelected: editor.setSelected,
    editorMode: editor.editorMode,
    form: editor.form,
    formError: editor.formError,
    trades: editor.trades,
    templates,
    filteredServices,
    services,
    activeCount,
    inactiveCount,
    isLoading: servicesQuery.isLoading,
    error: servicesQuery.error,
    openCreate: editor.openCreate,
    openEdit: editor.openEdit,
    closeEditor: editor.closeEditor,
    updateForm: editor.updateForm,
    toggleType: editor.toggleType,
    save: editor.save,
    deactivateTarget,
    setDeactivateTarget,
    confirmDeactivate,
    isSaving: createService.isPending || updateService.isPending,
    isDeactivating: deactivateService.isPending,
  };
}