import { ref, computed, watch, type ComputedRef, type Ref } from "vue";
import { useQuery } from "@vue/apollo-composable";
import { DealsQueryDocument } from "~~/graphql/generated";
import type { Deal, DealStep, CalendarEvent, Contact } from "~/composables/crm-types";
import { safeTrim, formatDay } from "~/composables/crm-types";

export function useDeals(opts: {
  apolloAuthReady: ComputedRef<boolean>;
  contacts: Ref<Contact[]>;
  calendarEvents: Ref<CalendarEvent[]>;
}) {
  const { result: dealsResult, refetch: refetchDeals } = useQuery(
    DealsQueryDocument,
    null,
    { enabled: opts.apolloAuthReady },
  );

  const deals = ref<Deal[]>([]);
  const selectedDealId = ref(deals.value[0]?.id ?? "");
  const selectedDealStepsExpanded = ref(false);

  watch(() => dealsResult.value?.deals, (v) => {
    if (v) deals.value = v as Deal[];
  }, { immediate: true });

  const sortedEvents = computed(() => [...opts.calendarEvents.value].sort((a, b) => a.start.localeCompare(b.start)));

  const selectedWorkspaceDeal = computed(() => {
    const explicit = deals.value.find((deal) => deal.id === selectedDealId.value);
    if (explicit) return explicit;

    const contactName = opts.contacts.value[0]?.name;
    if (contactName) {
      const linked = deals.value.find((deal) => deal.contact === contactName);
      if (linked) return linked;
    }
    return null;
  });

  function formatDealHeadline(deal: Deal) {
    const title = safeTrim(deal.title);
    const amountRaw = safeTrim(deal.amount);
    if (!amountRaw) return title;

    const normalized = amountRaw.replace(/\s+/g, "").replace(",", ".");
    if (/^\d+(\.\d+)?$/.test(normalized)) {
      return `${title} за ${new Intl.NumberFormat("ru-RU").format(Number(normalized))} $`;
    }

    return `${title} за ${amountRaw}`;
  }

  function getDealCurrentStep(deal: Deal) {
    if (!deal.steps?.length) return null;
    if (deal.currentStepId) {
      const explicit = deal.steps.find((step) => step.id === deal.currentStepId);
      if (explicit) return explicit;
    }
    const inProgress = deal.steps.find((step) => step.status === "in_progress");
    if (inProgress) return inProgress;
    const nextTodo = deal.steps.find((step) => step.status !== "done");
    return nextTodo ?? deal.steps[deal.steps.length - 1];
  }

  function getDealCurrentStepLabel(deal: Deal) {
    return safeTrim(getDealCurrentStep(deal)?.title) || safeTrim(deal.nextStep) || safeTrim(deal.stage) || "Без шага";
  }

  function parseDateFromText(input: string) {
    const text = input.trim();
    if (!text) return null;

    const isoMatch = text.match(/\b(\d{4})-(\d{2})-(\d{2})\b/);
    if (isoMatch) {
      const [, y, m, d] = isoMatch;
      const parsed = new Date(Number(y), Number(m) - 1, Number(d));
      if (!Number.isNaN(parsed.getTime())) return parsed;
    }

    const ruMatch = text.match(/\b(\d{1,2})[./](\d{1,2})[./](\d{4})\b/);
    if (ruMatch) {
      const [, d, m, y] = ruMatch;
      const parsed = new Date(Number(y), Number(m) - 1, Number(d));
      if (!Number.isNaN(parsed.getTime())) return parsed;
    }

    return null;
  }

  function pluralizeRuDays(days: number) {
    const mod10 = days % 10;
    const mod100 = days % 100;
    if (mod10 === 1 && mod100 !== 11) return "день";
    if (mod10 >= 2 && mod10 <= 4 && (mod100 < 12 || mod100 > 14)) return "дня";
    return "дней";
  }

  function formatDealDeadline(dueDate: Date) {
    const today = new Date();
    const startOfToday = new Date(today.getFullYear(), today.getMonth(), today.getDate());
    const startOfDue = new Date(dueDate.getFullYear(), dueDate.getMonth(), dueDate.getDate());
    const dayDiff = Math.round((startOfDue.getTime() - startOfToday.getTime()) / 86_400_000);

    if (dayDiff < 0) {
      const overdue = Math.abs(dayDiff);
      return `просрочено на ${overdue} ${pluralizeRuDays(overdue)}`;
    }
    if (dayDiff === 0) return "сегодня";
    if (dayDiff === 1) return "завтра";
    return `через ${dayDiff} ${pluralizeRuDays(dayDiff)}`;
  }

  function isDealStepDone(step: DealStep) {
    return step.status === "done";
  }

  function formatDealStepMeta(step: DealStep) {
    if (step.status === "done") return "выполнено";
    if (step.status === "blocked") return "заблокировано";
    if (!step.dueAt) {
      if (step.status === "in_progress") return "в работе";
      return "без дедлайна";
    }
    const parsed = new Date(step.dueAt);
    if (Number.isNaN(parsed.getTime())) return "без дедлайна";
    return formatDealDeadline(parsed);
  }

  function getDealCurrentStepMeta(deal: Deal) {
    const step = getDealCurrentStep(deal);
    if (!step) return "";
    return formatDealStepMeta(step);
  }

  const selectedWorkspaceDealDueDate = computed(() => {
    const deal = selectedWorkspaceDeal.value;
    if (!deal) return null;

    const currentStep = getDealCurrentStep(deal);
    if (currentStep?.dueAt) {
      const parsed = new Date(currentStep.dueAt);
      if (!Number.isNaN(parsed.getTime())) return parsed;
    }

    const fromNextStep = parseDateFromText(currentStep?.title || deal.nextStep);
    if (fromNextStep) return fromNextStep;

    const now = Date.now();
    const contactEvents = sortedEvents.value
      .filter((event) => event.contact === deal.contact)
      .map((event) => new Date(event.start))
      .filter((date) => !Number.isNaN(date.getTime()))
      .sort((a, b) => a.getTime() - b.getTime());

    const nextUpcoming = contactEvents.find((date) => date.getTime() >= now);
    if (nextUpcoming) return nextUpcoming;

    return contactEvents.length ? contactEvents[contactEvents.length - 1] : null;
  });

  const selectedWorkspaceDealSubtitle = computed(() => {
    const deal = selectedWorkspaceDeal.value;
    if (!deal) return "";
    const stepLabel = getDealCurrentStepLabel(deal);
    const dueDate = selectedWorkspaceDealDueDate.value;
    if (!dueDate) return `${stepLabel} · без дедлайна`;
    return `${stepLabel} · ${formatDealDeadline(dueDate)}`;
  });

  const selectedWorkspaceDealSteps = computed(() => {
    const deal = selectedWorkspaceDeal.value;
    if (!deal?.steps?.length) return [];
    return [...deal.steps].sort((a, b) => a.order - b.order);
  });

  watch(
    () => selectedWorkspaceDeal.value?.id ?? "",
    () => {
      selectedDealStepsExpanded.value = false;
    },
  );

  return {
    deals,
    selectedDealId,
    selectedDealStepsExpanded,
    selectedWorkspaceDeal,
    selectedWorkspaceDealDueDate,
    selectedWorkspaceDealSubtitle,
    selectedWorkspaceDealSteps,
    formatDealHeadline,
    getDealCurrentStep,
    getDealCurrentStepLabel,
    getDealCurrentStepMeta,
    formatDealDeadline,
    isDealStepDone,
    formatDealStepMeta,
    refetchDeals,
  };
}