import { ref, computed, watch, watchEffect, type ComputedRef } from "vue";
import { useQuery, useMutation } from "@vue/apollo-composable";
import { ContactsQueryDocument, MarkThreadReadDocument } from "~~/graphql/generated";

export type Contact = {
  id: string;
  name: string;
  avatar: string;
  channels: string[];
  lastContactAt: string;
  lastMessageText: string;
  lastMessageChannel: string;
  hasUnread: boolean;
  description: string;
};

export type CommItem = {
  id: string;
  at: string;
  contact: string;
  contactInboxId: string;
  sourceExternalId: string;
  sourceTitle: string;
  channel: "Telegram" | "WhatsApp" | "Instagram" | "Phone" | "Email";
  kind: "message" | "call";
  direction: "in" | "out";
  text: string;
  audioUrl?: string;
  duration?: string;
  waveform?: number[];
  transcript?: string[];
  deliveryStatus?: "PENDING" | "SENT" | "DELIVERED" | "READ" | "FAILED" | string | null;
};

export type SortMode = "name" | "lastContact";

export function useContacts(opts: { apolloAuthReady: ComputedRef<boolean> }) {
  const { result: contactsResult, refetch: refetchContacts } = useQuery(
    ContactsQueryDocument,
    null,
    { enabled: opts.apolloAuthReady },
  );

  const contacts = ref<Contact[]>([]);

  watch(
    () => contactsResult.value?.contacts,
    (rawContacts) => {
      if (!rawContacts) return;
      contacts.value = [...rawContacts] as Contact[];
    },
    { immediate: true },
  );

  const contactSearch = ref("");
  const selectedChannel = ref("All");
  const sortMode = ref<SortMode>("name");

  const channels = computed(() => ["All", ...new Set(contacts.value.flatMap((c) => c.channels))].sort());

  function resetContactFilters() {
    contactSearch.value = "";
    selectedChannel.value = "All";
    sortMode.value = "name";
  }

  const filteredContacts = computed(() => {
    const query = contactSearch.value.trim().toLowerCase();
    const data = contacts.value.filter((contact) => {
      if (selectedChannel.value !== "All" && !contact.channels.includes(selectedChannel.value)) return false;
      if (query) {
        const haystack = [contact.name, contact.description, contact.channels.join(" ")]
          .join(" ")
          .toLowerCase();
        if (!haystack.includes(query)) return false;
      }
      return true;
    });

    return data.sort((a, b) => {
      if (sortMode.value === "lastContact") {
        return b.lastContactAt.localeCompare(a.lastContactAt);
      }
      return a.name.localeCompare(b.name);
    });
  });

  const groupedContacts = computed(() => {
    if (sortMode.value === "lastContact") {
      return [["Recent", filteredContacts.value]] as [string, Contact[]][];
    }

    const map = new Map<string, Contact[]>();

    for (const contact of filteredContacts.value) {
      const key = (contact.name[0] ?? "#").toUpperCase();
      if (!map.has(key)) {
        map.set(key, []);
      }
      map.get(key)?.push(contact);
    }

    return [...map.entries()].sort((a, b) => a[0].localeCompare(b[0]));
  });

  const selectedContactId = ref(contacts.value[0]?.id ?? "");

  watchEffect(() => {
    if (!filteredContacts.value.length) {
      selectedContactId.value = "";
      return;
    }
    if (!filteredContacts.value.some((item) => item.id === selectedContactId.value)) {
      // Always pick the most recently active contact, regardless of current sort mode
      const mostRecent = [...filteredContacts.value].sort((a, b) =>
        b.lastContactAt.localeCompare(a.lastContactAt),
      )[0];
      if (mostRecent) selectedContactId.value = mostRecent.id;
    }
  });

  const selectedContact = computed(() => contacts.value.find((item) => item.id === selectedContactId.value));

  const { mutate: doMarkThreadRead } = useMutation(MarkThreadReadDocument);

  function markContactRead(contactId: string) {
    if (!contactId) return;
    // Optimistically update local state
    const idx = contacts.value.findIndex((c) => c.id === contactId);
    if (idx >= 0 && contacts.value[idx]!.hasUnread) {
      contacts.value[idx] = { ...contacts.value[idx]!, hasUnread: false };
    }
    // Fire-and-forget backend call
    void doMarkThreadRead({ contactId }).catch(() => undefined);
  }

  const brokenAvatarByContactId = ref<Record<string, boolean>>({});

  function contactInitials(name: string) {
    const words = String(name ?? "")
      .trim()
      .split(/\s+/)
      .filter(Boolean);
    if (!words.length) return "?";
    return words
      .slice(0, 2)
      .map((part) => part[0]?.toUpperCase() ?? "")
      .join("");
  }

  function avatarSrcForThread(thread: { id: string; avatar: string }) {
    if (brokenAvatarByContactId.value[thread.id]) return "";
    return String(thread.avatar ?? "").trim();
  }

  function markAvatarBroken(contactId: string) {
    if (!contactId) return;
    brokenAvatarByContactId.value = {
      ...brokenAvatarByContactId.value,
      [contactId]: true,
    };
  }

  return {
    contacts,
    contactSearch,
    selectedChannel,
    sortMode,
    selectedContactId,
    selectedContact,
    filteredContacts,
    groupedContacts,
    channels,
    resetContactFilters,
    brokenAvatarByContactId,
    avatarSrcForThread,
    markAvatarBroken,
    contactInitials,
    markContactRead,
    refetchContacts,
  };
}