import { ref, type Ref, type ComputedRef } from "vue";
import type { TabId, CalendarView, PeopleLeftMode, CalendarEvent, PilotChangeItem } from "~/composables/crm-types";
import { safeTrim, dayKey } from "~/composables/crm-types";

export function useWorkspaceRouting(opts: {
  selectedTab: Ref<TabId>;
  peopleLeftMode: Ref<PeopleLeftMode>;
  peopleListMode: Ref<"contacts" | "deals">;
  selectedContactId: Ref<string>;
  selectedCommThreadId: Ref<string>;
  selectedDealId: Ref<string>;
  selectedChatId: Ref<string>;
  calendarView: Ref<CalendarView>;
  calendarCursor: Ref<Date>;
  selectedDateKey: Ref<string>;
  selectedDocumentId: Ref<string>;
  focusedCalendarEventId: Ref<string>;
  activeChangeSetId: Ref<string>;
  activeChangeStep: Ref<number>;
  // computed refs
  sortedEvents: ComputedRef<CalendarEvent[]>;
  commThreads: ComputedRef<{ id: string; [key: string]: any }[]>;
  contacts: Ref<{ id: string; name: string; [key: string]: any }[]>;
  deals: Ref<{ id: string; contact: string; [key: string]: any }[]>;
  commItems: Ref<{ id: string; contact: string; [key: string]: any }[]>;
  activeChangeMessage: ComputedRef<{ changeSetId?: string | null; changeItems?: PilotChangeItem[] | null } | null>;
  activeChangeItem: ComputedRef<PilotChangeItem | null>;
  activeChangeItems: ComputedRef<PilotChangeItem[]>;
  activeChangeIndex: ComputedRef<number>;
  authMe: Ref<{ conversation: { id: string } } | null>;
  // functions from outside
  pickDate: (key: string) => void;
  openCommunicationThread: (contact: string) => void;
  completeTelegramBusinessConnectFromToken: (token: string) => void;
}) {
  const uiPathSyncLocked = ref(false);
  let popstateHandler: (() => void) | null = null;

  // ---------------------------------------------------------------------------
  // Calendar route helpers (internal)
  // ---------------------------------------------------------------------------
  function calendarCursorToken(date: Date) {
    const y = date.getFullYear();
    const m = String(date.getMonth() + 1).padStart(2, "0");
    return `${y}-${m}`;
  }

  function calendarRouteToken(view: CalendarView) {
    if (view === "day" || view === "week") {
      return opts.selectedDateKey.value;
    }
    if (view === "year") {
      return String(opts.calendarCursor.value.getFullYear());
    }
    return calendarCursorToken(opts.calendarCursor.value);
  }

  function parseCalendarCursorToken(token: string | null | undefined) {
    const text = String(token ?? "").trim();
    const m = text.match(/^(\d{4})-(\d{2})$/);
    if (!m) return null;
    const year = Number(m[1]);
    const month = Number(m[2]);
    if (!Number.isFinite(year) || !Number.isFinite(month) || month < 1 || month > 12) return null;
    return new Date(year, month - 1, 1);
  }

  function parseCalendarDateToken(token: string | null | undefined) {
    const text = String(token ?? "").trim();
    const m = text.match(/^(\d{4})-(\d{2})-(\d{2})$/);
    if (!m) return null;
    const year = Number(m[1]);
    const month = Number(m[2]);
    const day = Number(m[3]);
    if (!Number.isFinite(year) || !Number.isFinite(month) || !Number.isFinite(day)) return null;
    if (month < 1 || month > 12 || day < 1 || day > 31) return null;
    const parsed = new Date(year, month - 1, day);
    if (Number.isNaN(parsed.getTime())) return null;
    return parsed;
  }

  function parseCalendarYearToken(token: string | null | undefined) {
    const text = String(token ?? "").trim();
    const m = text.match(/^(\d{4})$/);
    if (!m) return null;
    const year = Number(m[1]);
    if (!Number.isFinite(year)) return null;
    return year;
  }

  // ---------------------------------------------------------------------------
  // Core routing functions
  // ---------------------------------------------------------------------------
  function normalizedConversationId() {
    return safeTrim(opts.selectedChatId.value || opts.authMe.value?.conversation.id || "pilot");
  }

  function withReviewQuery(path: string) {
    const reviewSet = opts.activeChangeSetId.value.trim();
    if (!reviewSet) return path;
    const params = new URLSearchParams();
    params.set("reviewSet", reviewSet);
    params.set("reviewStep", String(Math.max(1, opts.activeChangeStep.value + 1)));
    return `${path}?${params.toString()}`;
  }

  function currentUiPath() {
    if (opts.selectedTab.value === "documents") {
      const docId = opts.selectedDocumentId.value.trim();
      if (docId) {
        return withReviewQuery(`/documents/${encodeURIComponent(docId)}`);
      }
      return withReviewQuery("/documents");
    }

    if (opts.peopleLeftMode.value === "calendar") {
      if (opts.focusedCalendarEventId.value.trim()) {
        return withReviewQuery(`/calendar/event/${encodeURIComponent(opts.focusedCalendarEventId.value.trim())}`);
      }
      return withReviewQuery(`/calendar/${encodeURIComponent(opts.calendarView.value)}/${encodeURIComponent(calendarRouteToken(opts.calendarView.value))}`);
    }

    if (opts.peopleListMode.value === "deals" && opts.selectedDealId.value.trim()) {
      return withReviewQuery(`/deal/${encodeURIComponent(opts.selectedDealId.value.trim())}`);
    }

    if (opts.selectedContactId.value.trim()) {
      return withReviewQuery(`/contact/${encodeURIComponent(opts.selectedContactId.value.trim())}`);
    }

    return withReviewQuery(`/chat/${encodeURIComponent(normalizedConversationId())}`);
  }

  function syncPathFromUi(push = false) {
    if (process.server) return;
    const nextPath = currentUiPath();
    const currentPath = `${window.location.pathname}${window.location.search}`;
    if (nextPath === currentPath) return;
    if (push) {
      window.history.pushState({}, "", nextPath);
    } else {
      window.history.replaceState({}, "", nextPath);
    }
  }

  function applyPathToUi(pathname: string, search = "") {
    const path = String(pathname || "/").trim() || "/";
    const params = new URLSearchParams(String(search || ""));
    const reviewSet = (params.get("reviewSet") ?? "").trim();
    const reviewStep = Number(params.get("reviewStep") ?? "1");

    if (reviewSet) {
      opts.activeChangeSetId.value = reviewSet;
      opts.activeChangeStep.value = Number.isFinite(reviewStep) && reviewStep > 0 ? reviewStep - 1 : 0;
    } else {
      opts.activeChangeSetId.value = "";
      opts.activeChangeStep.value = 0;
    }

    const calendarEventMatch = path.match(/^\/calendar\/event\/([^/]+)\/?$/i);
    if (calendarEventMatch) {
      const rawEventId = decodeURIComponent(calendarEventMatch[1] ?? "").trim();
      opts.selectedTab.value = "communications";
      opts.peopleLeftMode.value = "calendar";
      const event = opts.sortedEvents.value.find((x) => x.id === rawEventId);
      if (event) {
        opts.pickDate(event.start.slice(0, 10));
      }
      opts.focusedCalendarEventId.value = rawEventId;
      return;
    }

    const calendarMatch = path.match(/^\/calendar\/([^/]+)\/([^/]+)\/?$/i);
    if (calendarMatch) {
      const rawView = decodeURIComponent(calendarMatch[1] ?? "").trim();
      const rawCursor = decodeURIComponent(calendarMatch[2] ?? "").trim();
      const view = (["day", "week", "month", "year", "agenda"] as CalendarView[]).includes(rawView as CalendarView)
        ? (rawView as CalendarView)
        : "month";
      const cursorByMonth = parseCalendarCursorToken(rawCursor);
      const cursorByDate = parseCalendarDateToken(rawCursor);
      const cursorByYear = parseCalendarYearToken(rawCursor);
      opts.selectedTab.value = "communications";
      opts.peopleLeftMode.value = "calendar";
      opts.focusedCalendarEventId.value = "";
      opts.calendarView.value = view;
      if (view === "day" || view === "week") {
        const parsed = cursorByDate;
        if (parsed) {
          opts.selectedDateKey.value = dayKey(parsed);
          opts.calendarCursor.value = new Date(parsed.getFullYear(), parsed.getMonth(), 1);
        }
      } else if (view === "year") {
        if (cursorByYear) {
          opts.calendarCursor.value = new Date(cursorByYear, 0, 1);
          opts.selectedDateKey.value = dayKey(new Date(cursorByYear, 0, 1));
        }
      } else if (cursorByMonth) {
        opts.calendarCursor.value = cursorByMonth;
        opts.selectedDateKey.value = dayKey(cursorByMonth);
      }
      return;
    }

    const documentsMatch = path.match(/^\/documents(?:\/([^/]+))?\/?$/i);
    if (documentsMatch) {
      const rawDocumentId = decodeURIComponent(documentsMatch[1] ?? "").trim();
      opts.selectedTab.value = "documents";
      opts.focusedCalendarEventId.value = "";
      if (rawDocumentId) opts.selectedDocumentId.value = rawDocumentId;
      return;
    }

    const contactMatch = path.match(/^\/contact\/([^/]+)\/?$/i);
    if (contactMatch) {
      const rawContactId = decodeURIComponent(contactMatch[1] ?? "").trim();
      opts.selectedTab.value = "communications";
      opts.peopleLeftMode.value = "contacts";
      opts.peopleListMode.value = "contacts";
      if (rawContactId) {
        opts.selectedContactId.value = rawContactId;
        const linkedThread = opts.commThreads.value.find((thread) => thread.id === rawContactId);
        if (linkedThread) opts.selectedCommThreadId.value = linkedThread.id;
      }
      opts.focusedCalendarEventId.value = "";
      return;
    }

    const dealMatch = path.match(/^\/deal\/([^/]+)\/?$/i);
    if (dealMatch) {
      const rawDealId = decodeURIComponent(dealMatch[1] ?? "").trim();
      opts.selectedTab.value = "communications";
      opts.peopleLeftMode.value = "contacts";
      opts.peopleListMode.value = "deals";
      if (rawDealId) {
        opts.selectedDealId.value = rawDealId;
        const linkedDeal = opts.deals.value.find((deal) => deal.id === rawDealId);
        const linkedContact = linkedDeal
          ? opts.contacts.value.find((contact) => contact.name === linkedDeal.contact)
          : null;
        if (linkedContact) {
          opts.selectedContactId.value = linkedContact.id;
          opts.selectedCommThreadId.value = linkedContact.id;
        }
      }
      opts.focusedCalendarEventId.value = "";
      return;
    }

    const chatMatch = path.match(/^\/chat\/([^/]+)\/?$/i);
    if (chatMatch) {
      const rawChatId = decodeURIComponent(chatMatch[1] ?? "").trim();
      opts.selectedTab.value = "communications";
      opts.peopleLeftMode.value = "contacts";
      opts.peopleListMode.value = "contacts";
      opts.focusedCalendarEventId.value = "";
      if (rawChatId) opts.selectedChatId.value = rawChatId;
      return;
    }

    const changesMatch = path.match(/^\/changes\/([^/]+)(?:\/step\/(\d+))?\/?$/i);
    if (changesMatch) {
      const rawId = decodeURIComponent(changesMatch[1] ?? "").trim();
      const rawStep = Number(changesMatch[2] ?? "1");
      if (rawId) {
        opts.activeChangeSetId.value = rawId;
        opts.activeChangeStep.value = Number.isFinite(rawStep) && rawStep > 0 ? rawStep - 1 : 0;
      }
      opts.selectedTab.value = "communications";
      opts.peopleLeftMode.value = "contacts";
      opts.peopleListMode.value = "contacts";
      opts.focusedCalendarEventId.value = "";
      return;
    }

    opts.selectedTab.value = "communications";
    opts.peopleLeftMode.value = "contacts";
    opts.peopleListMode.value = "contacts";
    opts.focusedCalendarEventId.value = "";
  }

  function applyReviewStepToUi(push = false) {
    const item = opts.activeChangeItem.value;
    if (!item) {
      syncPathFromUi(push);
      return;
    }

    opts.selectedTab.value = "communications";

    if (item.entity === "calendar_event" && item.entityId) {
      opts.peopleLeftMode.value = "calendar";
      opts.calendarView.value = "month";
      const event = opts.sortedEvents.value.find((x) => x.id === item.entityId);
      if (event) {
        opts.pickDate(event.start.slice(0, 10));
      }
      opts.focusedCalendarEventId.value = item.entityId;
      syncPathFromUi(push);
      return;
    }

    if (item.entity === "contact_note" && item.entityId) {
      opts.peopleLeftMode.value = "contacts";
      opts.peopleListMode.value = "contacts";
      opts.selectedContactId.value = item.entityId;
      const thread = opts.commThreads.value.find((entry) => entry.id === item.entityId);
      if (thread) opts.selectedCommThreadId.value = thread.id;
      opts.focusedCalendarEventId.value = "";
      syncPathFromUi(push);
      return;
    }

    if (item.entity === "deal" && item.entityId) {
      opts.peopleLeftMode.value = "contacts";
      opts.peopleListMode.value = "deals";
      opts.selectedDealId.value = item.entityId;
      const deal = opts.deals.value.find((entry) => entry.id === item.entityId);
      if (deal) {
        const contact = opts.contacts.value.find((entry) => entry.name === deal.contact);
        if (contact) {
          opts.selectedContactId.value = contact.id;
          opts.selectedCommThreadId.value = contact.id;
        }
      }
      opts.focusedCalendarEventId.value = "";
      syncPathFromUi(push);
      return;
    }

    if (item.entity === "message" && item.entityId) {
      opts.peopleLeftMode.value = "contacts";
      opts.peopleListMode.value = "contacts";
      const message = opts.commItems.value.find((entry) => entry.id === item.entityId);
      if (message?.contact) {
        opts.openCommunicationThread(message.contact);
      }
      opts.focusedCalendarEventId.value = "";
      syncPathFromUi(push);
      return;
    }

    if (item.entity === "workspace_document" && item.entityId) {
      opts.selectedTab.value = "documents";
      opts.selectedDocumentId.value = item.entityId;
      opts.focusedCalendarEventId.value = "";
      syncPathFromUi(push);
      return;
    }

    opts.peopleLeftMode.value = "contacts";
    opts.focusedCalendarEventId.value = "";
    syncPathFromUi(push);
  }

  // ---------------------------------------------------------------------------
  // Lifecycle init / cleanup
  // ---------------------------------------------------------------------------
  function initRouting() {
    uiPathSyncLocked.value = true;
    try {
      const params = new URLSearchParams(window.location.search);
      const tgLinkToken = String(params.get("tg_link_token") ?? "").trim();
      if (tgLinkToken) {
        void opts.completeTelegramBusinessConnectFromToken(tgLinkToken);
        params.delete("tg_link_token");
        const nextSearch = params.toString();
        window.history.replaceState({}, "", `${window.location.pathname}${nextSearch ? `?${nextSearch}` : ""}`);
      }
      applyPathToUi(window.location.pathname, window.location.search);
    } finally {
      uiPathSyncLocked.value = false;
    }
    syncPathFromUi(false);

    popstateHandler = () => {
      uiPathSyncLocked.value = true;
      try {
        applyPathToUi(window.location.pathname, window.location.search);
      } finally {
        uiPathSyncLocked.value = false;
      }
    };
    window.addEventListener("popstate", popstateHandler);
  }

  function cleanupRouting() {
    if (popstateHandler) {
      window.removeEventListener("popstate", popstateHandler);
      popstateHandler = null;
    }
  }

  return {
    uiPathSyncLocked,
    currentUiPath,
    applyPathToUi,
    syncPathFromUi,
    applyReviewStepToUi,
    withReviewQuery,
    initRouting,
    cleanupRouting,
  };
}