import {
  useMutation,
  useQueryClient,
  type QueryClient,
  type UseMutationResult,
} from "@tanstack/react-query";
import { isHTTPError } from "ky";
import { toast } from "react-toastify";
import { completionTemplatesApi } from "@/domain/completion-templates/api/completion-templates-api";
import { COMPLETION_TEMPLATE_COPY } from "@/domain/completion-templates/constants/completion-template-constants";
import type {
  CompletionTemplate,
  CompletionTemplateInput,
} from "@/domain/completion-templates/types/completion-template";
import { queryKeys } from "@/infra/query-key/query-key";

interface UpdateCompletionTemplateVariables {
  template: CompletionTemplate;
  input: CompletionTemplateInput;
}

/** The server's blank-title rejection, which the form shows on the title field instead. */
export function isTitleRequiredError(error: Error): boolean {
  if (!isHTTPError(error) || error.response.status !== 422) return false;
  const body: unknown = error.data;
  return (
    typeof body === "object" && body !== null && "code" in body && body.code === "TitleRequired"
  );
}

function invalidateTemplates(queryClient: QueryClient) {
  void queryClient.invalidateQueries({ queryKey: queryKeys.completionTemplates.all });
  // The Services registry lists template names and clears links to a deleted template.
  void queryClient.invalidateQueries({ queryKey: queryKeys.services.all });
}

function toastFailure(error: Error, fallback: string) {
  if (isTitleRequiredError(error)) return;
  toast.error(error.message || fallback);
}

export function useCreateCompletionTemplate(): UseMutationResult<
  CompletionTemplate,
  Error,
  CompletionTemplateInput
> {
  const queryClient = useQueryClient();
  return useMutation({
    mutationFn: (input: CompletionTemplateInput) => completionTemplatesApi.create(input),
    onSuccess: () => {
      invalidateTemplates(queryClient);
      toast.success(COMPLETION_TEMPLATE_COPY.added);
    },
    onError: (error: Error) => toastFailure(error, "Failed to add template"),
  });
}

export function useUpdateCompletionTemplate(): UseMutationResult<
  CompletionTemplate,
  Error,
  UpdateCompletionTemplateVariables
> {
  const queryClient = useQueryClient();
  return useMutation({
    mutationFn: ({ template, input }: UpdateCompletionTemplateVariables) =>
      completionTemplatesApi.update(template, input),
    onSuccess: () => {
      invalidateTemplates(queryClient);
      toast.success(COMPLETION_TEMPLATE_COPY.updated);
    },
    onError: (error: Error) => toastFailure(error, "Failed to update template"),
  });
}

export function useDeleteCompletionTemplate(): UseMutationResult<void, Error, number> {
  const queryClient = useQueryClient();
  return useMutation({
    mutationFn: (id: number) => completionTemplatesApi.delete(id),
    onSuccess: () => {
      invalidateTemplates(queryClient);
      toast.success(COMPLETION_TEMPLATE_COPY.deleted);
    },
    onError: (error: Error) => toastFailure(error, "Failed to delete template"),
  });
}