import { defineStore } from "pinia";
import { ref } from "vue";
import { api } from "../api/client";
import { useUiStore } from "./ui";
import type { NoteColor } from "../notes/colors";

export type NoteView = "active" | "archived" | "trash";
export type NoteKind = "text" | "list";

export interface NoteLabel {
  id: string;
  name: string;
  color: string;
  // True when this label is attached because of a #tag in the note body (kept in
  // sync with the text); false = added manually via the picker.
  via_tag: boolean;
}

export interface ChecklistItem {
  id: string;
  text: string;
  checked: boolean;
  position: number;
}

export interface Attachment {
  id: string;
  url: string;
  mime: string;
}

// A past version of a note's title+body (version history).
export interface NoteRevision {
  id: string;
  title: string | null;
  body: string;
  created_at: string | null;
}

export interface Note {
  id: string;
  title: string | null;
  // The note's display NAME: explicit title, else its first body line (server-derived).
  // Every note has one, so body-only notes are still nameable + [[link]]-able.
  display_title: string;
  body: string;
  color: NoteColor;
  kind: NoteKind;
  position: number;
  pinned: boolean;
  archived: boolean;
  trashed: boolean;
  remind_at: string | null;
  labels: NoteLabel[];
  items: ChecklistItem[];
  attachments: Attachment[];
  created_at: string | null;
  updated_at: string | null;
}

export const useNotesStore = defineStore("notes", () => {
  const items = ref<Note[]>([]);
  const loading = ref(false);
  const view = ref<NoteView>("active");
  const activeLabel = ref<string | null>(null);

  function sortItems(): void {
    items.value.sort((a, b) => {
      if (a.pinned !== b.pinned) return a.pinned ? -1 : 1;
      if (a.position !== b.position) return b.position - a.position;
      return (b.updated_at ?? "").localeCompare(a.updated_at ?? "");
    });
  }

  function belongsHere(n: Note): boolean {
    const v = view.value;
    const inView =
      v === "trash" ? n.trashed : v === "archived" ? !n.trashed && n.archived : !n.trashed && !n.archived;
    if (!inView) return false;
    if (activeLabel.value) return n.labels.some((lb) => lb.id === activeLabel.value);
    return true;
  }

  function reconcile(note: Note): void {
    const idx = items.value.findIndex((n) => n.id === note.id);
    if (belongsHere(note)) {
      if (idx >= 0) items.value[idx] = note;
      else items.value.push(note);
      sortItems();
    } else if (idx >= 0) {
      items.value.splice(idx, 1);
    }
  }

  async function load(v: NoteView, labelId: string | null = null): Promise<void> {
    view.value = v;
    activeLabel.value = labelId;
    loading.value = true;
    try {
      const query = labelId ? `/api/notes?filter=${v}&label=${labelId}` : `/api/notes?filter=${v}`;
      const res = await api.get<{ notes: Note[] }>(query);
      items.value = res.notes;
      sortItems();
    } finally {
      loading.value = false;
    }
  }

  async function create(input: {
    title: string;
    body: string;
    color: NoteColor;
    kind?: NoteKind;
    items?: string[];
  }): Promise<Note> {
    const note = await api.post<Note>("/api/notes", input);
    reconcile(note);
    return note;
  }

  async function mutate(
    id: string,
    changes: Partial<Pick<Note, "title" | "body" | "color" | "kind" | "pinned" | "archived" | "remind_at">>,
  ): Promise<void> {
    reconcile(await api.patch<Note>(`/api/notes/${id}`, changes));
  }

  const setPinned = (id: string, pinned: boolean) => mutate(id, { pinned });
  const setArchived = async (id: string, archived: boolean): Promise<void> => {
    await mutate(id, { archived });
    if (archived)
      useUiStore().showToast("Note archived", { label: "Undo", run: () => void setArchived(id, false) });
  };
  const setColor = (id: string, color: NoteColor) => mutate(id, { color });
  const setKind = (id: string, kind: NoteKind) => mutate(id, { kind });
  const setReminder = (id: string, remindAt: string | null) => mutate(id, { remind_at: remindAt });
  const saveEdit = (id: string, changes: { title: string; body: string; color: NoteColor }) => mutate(id, changes);

  async function setLabels(id: string, labelIds: string[]): Promise<void> {
    reconcile(await api.put<Note>(`/api/notes/${id}/labels`, { label_ids: labelIds }));
  }

  async function addItem(id: string, text: string): Promise<void> {
    reconcile(await api.post<Note>(`/api/notes/${id}/items`, { text }));
  }

  async function updateItem(id: string, itemId: string, changes: { text?: string; checked?: boolean }): Promise<void> {
    reconcile(await api.patch<Note>(`/api/notes/${id}/items/${itemId}`, changes));
  }

  async function deleteItem(id: string, itemId: string): Promise<void> {
    reconcile(await api.del<Note>(`/api/notes/${id}/items/${itemId}`));
  }

  async function uploadAttachment(id: string, file: File): Promise<void> {
    const form = new FormData();
    form.append("file", file);
    const resp = await fetch(`/api/notes/${id}/attachments`, { method: "POST", credentials: "include", body: form });
    const data: unknown = await resp.json().catch(() => ({}));
    if (!resp.ok) {
      const message =
        typeof data === "object" && data !== null && "error" in data
          ? String((data as { error: unknown }).error)
          : "Upload failed.";
      throw { error: message, status: resp.status };
    }
    reconcile(data as Note);
  }

  async function deleteAttachment(id: string, attId: string): Promise<void> {
    reconcile(await api.del<Note>(`/api/notes/${id}/attachments/${attId}`));
  }

  async function importNotes(file: File): Promise<{ source: string; imported: number; skipped: number }> {
    const form = new FormData();
    form.append("file", file);
    const resp = await fetch("/api/notes/import", { method: "POST", credentials: "include", body: form });
    const data: unknown = await resp.json().catch(() => ({}));
    if (!resp.ok) {
      const message =
        typeof data === "object" && data !== null && "error" in data
          ? String((data as { error: unknown }).error)
          : "Import failed.";
      throw { error: message, status: resp.status };
    }
    // Refresh the current lens so imported notes appear (labels reloaded by caller).
    await load(view.value, activeLabel.value);
    return data as { source: string; imported: number; skipped: number };
  }

  async function fetchOne(id: string): Promise<Note | null> {
    try {
      return await api.get<Note>(`/api/notes/${id}`);
    } catch {
      return null;
    }
  }

  async function createTitled(title: string): Promise<Note> {
    const created = await api.post<Note>("/api/notes", { title, body: "" });
    reconcile(created);
    return created;
  }

  async function reorder(orderedIds: string[]): Promise<void> {
    // Optimistically assign positions matching the backend (total - index), sort,
    // then persist.
    const total = orderedIds.length;
    orderedIds.forEach((id, index) => {
      const n = items.value.find((x) => x.id === id);
      if (n) n.position = total - index;
    });
    sortItems();
    await api.post("/api/notes/reorder", { ids: orderedIds });
  }

  async function trash(id: string): Promise<void> {
    reconcile(await api.post<Note>(`/api/notes/${id}/trash`));
    useUiStore().showToast("Note moved to trash", { label: "Undo", run: () => void restore(id) });
  }

  async function restore(id: string): Promise<void> {
    reconcile(await api.post<Note>(`/api/notes/${id}/restore`));
  }

  async function deleteForever(id: string): Promise<void> {
    await api.del(`/api/notes/${id}`);
    const idx = items.value.findIndex((n) => n.id === id);
    if (idx >= 0) items.value.splice(idx, 1);
  }

  async function fetchRevisions(id: string): Promise<NoteRevision[]> {
    const res = await api.get<{ revisions: NoteRevision[] }>(`/api/notes/${id}/revisions`);
    return res.revisions;
  }

  async function restoreRevision(id: string, revId: string): Promise<Note> {
    const note = await api.post<Note>(`/api/notes/${id}/revisions/${revId}/restore`);
    reconcile(note);
    return note;
  }

  return {
    items,
    loading,
    view,
    activeLabel,
    load,
    create,
    setPinned,
    setArchived,
    setColor,
    setKind,
    setReminder,
    saveEdit,
    setLabels,
    addItem,
    updateItem,
    deleteItem,
    uploadAttachment,
    deleteAttachment,
    importNotes,
    fetchOne,
    createTitled,
    reorder,
    trash,
    restore,
    deleteForever,
    fetchRevisions,
    restoreRevision,
  };
});