import { ref, computed } from "vue";
import { useAuthSession } from "./useAuthSession";

export interface CharacterSessionItem {
  id: string;
  userId: number | null;
  tempToken: string | null;
  cardId: number | null;
  title: string;
  modelId: number | null;
  lastActiveAt: string;
  expiresAt: string | null;
  deletedAt: string | null;
  createdAt: string;
  updatedAt: string;
}

export function useCharacterSessions(cardSlug: string) {
  const auth = useAuthSession();
  const sessions = ref<CharacterSessionItem[]>([]);
  const currentSessionId = ref<string | null>(null);
  const loading = ref(false);
  const initialized = ref(false);

  const currentSession = computed(() =>
    sessions.value.find((s) => s.id === currentSessionId.value) ?? null,
  );

  async function fetchSessions() {
    loading.value = true;
    try {
      const res = await $fetch<{ code: number; data: { list: CharacterSessionItem[] } }>(
        `/api/characters/${cardSlug}/sessions`,
      );
      sessions.value = res.data?.list ?? [];
    } catch {
      sessions.value = [];
    } finally {
      loading.value = false;
    }
  }

  async function createSession(): Promise<CharacterSessionItem | null> {
    try {
      const res = await $fetch<{ code: number; data: { session: CharacterSessionItem } }>(
        `/api/characters/${cardSlug}/sessions`,
        { method: "POST" },
      );
      const session = res.data?.session;
      if (session) {
        sessions.value.unshift(session);
      }
      return session ?? null;
    } catch {
      return null;
    }
  }

  async function newSession(): Promise<CharacterSessionItem | null> {
    const latest = sessions.value[0];
    if (latest && latest.lastActiveAt === latest.createdAt) {
      currentSessionId.value = latest.id;
      return latest;
    }
    const session = await createSession();
    if (session) {
      currentSessionId.value = session.id;
    }
    return session;
  }

  async function selectSession(id: string) {
    currentSessionId.value = id;
  }

  async function renameSession(id: string, title: string) {
    try {
      await $fetch(`/api/characters/${cardSlug}/sessions/${id}`, {
        method: "PUT",
        body: { title },
      });
      const s = sessions.value.find((x) => x.id === id);
      if (s) s.title = title;
    } catch {
    }
  }

  async function deleteSession(id: string) {
    try {
      await $fetch(`/api/characters/${cardSlug}/sessions/${id}`, { method: "DELETE" });
      sessions.value = sessions.value.filter((s) => s.id !== id);
      if (currentSessionId.value === id) {
        if (sessions.value.length > 0) {
          currentSessionId.value = sessions.value[0]?.id ?? null;
        } else {
          const session = await createSession();
          if (session) currentSessionId.value = session.id;
          else currentSessionId.value = null;
        }
      }
    } catch {
    }
  }

  async function updateModelConfig(id: string, modelId: number | null) {
    try {
      await $fetch(`/api/characters/${cardSlug}/sessions/${id}/config`, {
        method: "PUT",
        body: { modelId },
      });
      const s = sessions.value.find((x) => x.id === id);
      if (s) s.modelId = modelId;
    } catch {
    }
  }

  function touchSessionOrder(id: string) {
    const idx = sessions.value.findIndex((s) => s.id === id);
    if (idx > 0) {
      const [s] = sessions.value.splice(idx, 1);
      if (s) {
        s.lastActiveAt = new Date().toISOString();
        sessions.value.unshift(s);
      }
    } else if (idx === 0 && sessions.value[0]) {
      sessions.value[0].lastActiveAt = new Date().toISOString();
    }
  }

  async function init() {
    if (initialized.value) return;
    await auth.refresh();
    await fetchSessions();
    if (sessions.value.length === 0) {
      await newSession();
    } else {
      currentSessionId.value = sessions.value[0]?.id ?? null;
    }
    initialized.value = true;
  }

  return {
    sessions,
    currentSessionId,
    currentSession,
    loading,
    initialized,
    fetchSessions,
    createSession,
    newSession,
    selectSession,
    renameSession,
    deleteSession,
    updateModelConfig,
    touchSessionOrder,
    init,
  };
}