/**
 * 标注维度选择器：在 `Dialog` 内挂载 Vant `Picker` / `PickerGroup` / `Cascader`。
 *
 * @remarks
 * - **分流**：对维度**原始** `children` 用 `depthRange(roots, n => n.leaf).max`（`@/tools/tree.tool`）：`max≤1` → Picker，`max=2` → PickerGroup，`max>2` → Cascader；`AnnotPickerOptions.component` 可与深度冲突时降级为推断。
 * - **`open(values)`**：Pick/Cascader 按数组顺序取首个可命中；PickerGroup 与 tab 下标无关，按 tab 消费候选池。
 * - **`withDefault`**：无维度 `standardValue` 时插「正常」；有维度 `standardValue` 时 Pick/Cascader 只填标准叶；**PickerGroup** 下各分类 tab 若**本分类**无标准叶，仍对该 tab 插「正常」。
 * - **resolve**：去掉占位 id；PickerGroup 为紧凑 id 数组。
 * - **`dynamicTabs`**（仅 PickerGroup）：为 `true` 时 tab 标题随选中变：非占位叶用其 `label`；选「正常」或空则恢复分类原 `label`。
 *
 * @module modules/monitor/composables/useAnnotatorPicker
 */

import { defineComponent, h, ref, shallowRef, toValue, watch, type MaybeRefOrGetter } from 'vue';
import {
  ANNOTATOR_PLACEHOLDER_PREFIX,
  ANNOTATOR_PLACEHOLDER_ID_CASCADE,
  ANNOTATOR_PLACEHOLDER_ID_PICK,
  annotatorDefaultOptionLeaf,
  annotatorPlaceholderIdGroupTab,
  type AnnotatorTreeNode,
  findAnnotatorSubtreeNode,
  getAnnotatorNodePath,
  isAnnotatorTreeBranchMeta,
  isAnnotatorTreeLeafMeta,
} from '@/request/model/annotator.model';
import { cloneChildren, depthRange, findPreorder } from '@/tools/tree.tool';

import { Dialog, Cascader, Picker, PickerGroup, showFailToast } from 'vant';
import { clamp } from 'es-toolkit';

import 'vant/es/dialog/style';
import 'vant/es/cascader/style';
import 'vant/es/picker/style';

// ---------------------------------------------------------------------------
// 导出
// ---------------------------------------------------------------------------

/** Picker / PickerGroup / Cascader 三种 UI，对应 {@link inferPickerKind}。 */
export type AnnotPickerKind = 'pick' | 'pickerGroup' | 'cascader';

/** `useAnnotatorPicker` 与 `open` 的配置。 */
export interface AnnotPickerOptions {
  title?: string;
  /** Cascader 选叶后是否不经 Dialog「确定」直接 resolve。 */
  autoComplete?: boolean;
  /** 是否插「正常」占位、空选中是否填标准项（默认 `true`）。 */
  withDefault?: boolean;
  /** 强制 UI；与树深度矛盾时内部降级。 */
  component?: AnnotPickerKind;
  /** 仅 PickerGroup：tab 标题是否随选中更新（非占位叶用叶名，占位/空用分类名）。 */
  dynamicTabs?: boolean;
}

function isPlaceholderId(id: string | undefined): boolean {
  return !!id && id.startsWith(ANNOTATOR_PLACEHOLDER_PREFIX);
}

/** 按子树最大深度 `max` 推断 UI；`override` 与深度不符时用推断值。 */
function inferPickerKind(max: number, override?: AnnotPickerKind): AnnotPickerKind {
  const d: AnnotPickerKind = max <= 1 ? 'pick' : max === 2 ? 'pickerGroup' : 'cascader';
  if (!override) return d;
  if (override === 'pick' && max > 1) return d;
  if (override === 'pickerGroup' && (max <= 1 || max > 2)) return d;
  if (override === 'cascader' && max <= 2) return d;
  return override;
}

function firstStandardLeaf(roots: readonly AnnotatorTreeNode[]): AnnotatorTreeNode | undefined {
  return findPreorder(roots, (n) => !!(n.leaf && isAnnotatorTreeLeafMeta(n.meta) && n.meta.standard));
}

/** `open` 初始 `selected`：PickerGroup 按 tab 消费候选池；否则取首个可命中叶。 */
function initPickerSelection(kind: AnnotPickerKind, roots: readonly AnnotatorTreeNode[], values?: string[]): string[] {
  if (kind === 'pickerGroup') {
    const n = roots.length;
    const row: string[] = Array.from({ length: n }, () => '');
    if (!values?.length || n === 0) return row;

    const pool = values.map((v) => v?.trim() ?? '').filter(Boolean);
    for (let ti = 0; ti < n; ti++) {
      const cols = roots[ti]?.children ?? [];
      let j = -1;
      let id: string | undefined;
      for (let k = 0; k < pool.length; k++) {
        const hit = findAnnotatorSubtreeNode(cols, pool[k]!)?.id;
        if (hit) {
          j = k;
          id = hit;
          break;
        }
      }
      if (j >= 0 && id) {
        row[ti] = id;
        pool.splice(j, 1);
      }
    }
    return row;
  }

  if (!values?.length) return [];
  for (const raw of values) {
    const t = raw?.trim();
    if (!t) continue;
    const id = findAnnotatorSubtreeNode(roots, t)?.id;
    if (id) return [id];
  }
  return [];
}

/**
 * 弹窗用 options 副本（可插「正常」）；`withDefault` 且存在 `standardValue` 时写回 `selected`。
 * 不修改入参 `roots` 引用。
 */
function buildDisplayTree(kind: AnnotPickerKind, dim: AnnotatorTreeNode, roots: AnnotatorTreeNode[], withDefault: boolean, selected: { value: string[] }): AnnotatorTreeNode[] {
  const cloneAll = () => roots.map(cloneChildren);

  if (!withDefault || !dim.meta || !isAnnotatorTreeBranchMeta(dim.meta)) {
    return cloneAll();
  }

  const { meta } = dim;

  if (meta.standardValue === undefined) {
    if (kind === 'pick') return [annotatorDefaultOptionLeaf(ANNOTATOR_PLACEHOLDER_ID_PICK), ...cloneAll()];
    if (kind === 'cascader') return [annotatorDefaultOptionLeaf(ANNOTATOR_PLACEHOLDER_ID_CASCADE), ...cloneAll()];
    if (kind === 'pickerGroup') {
      return roots.map((branch, i) => ({
        ...branch,
        children: [annotatorDefaultOptionLeaf(annotatorPlaceholderIdGroupTab(i)), ...(branch.children ?? [])],
      }));
    }
  } else {
    if (kind === 'pick' || kind === 'cascader') {
      if (!lastPickSegment(selected.value)) {
        const leaf = firstStandardLeaf(roots);
        if (leaf) selected.value = [leaf.id];
      }
    } else if (kind === 'pickerGroup') {
      const next = [...selected.value];
      let dirty = false;
      for (let i = 0; i < roots.length; i++) {
        if (!next[i]) {
          const leaf = firstStandardLeaf(roots[i]?.children ?? []);
          if (leaf) {
            while (next.length <= i) next.push('');
            next[i] = leaf.id;
            dirty = true;
          }
        }
      }
      if (dirty) selected.value = next;

      return roots.map((branch, ti) =>
        firstStandardLeaf(branch.children ?? [])
          ? cloneChildren(branch)
          : {
              ...branch,
              children: [annotatorDefaultOptionLeaf(annotatorPlaceholderIdGroupTab(ti)), ...(branch.children ?? [])],
            }
      );
    }
  }

  return cloneAll();
}

/** Pick/Cascader：自右向左首个非空；PickerGroup：前 `nTabs` 项全非空。 */
function canConfirm(kind: AnnotPickerKind, selected: readonly string[], nTabs: number, isLeaf: boolean): boolean {
  if (kind === 'pick') return !!lastPickSegment(selected);
  if (kind === 'cascader') return isLeaf && !!lastPickSegment(selected);
  if (nTabs === 0) return false;
  if (selected.length < nTabs) return false;
  return selected.slice(0, nTabs).every(Boolean);
}

function lastPickSegment(sel: readonly string[]): string {
  for (let i = sel.length - 1; i >= 0; i--) {
    const id = sel[i]?.trim();
    if (id) return id;
  }
  return '';
}

export interface AnnotatorPickerApi {
  /**
   * @param key - 维度 key / id（{@link findAnnotatorSubtreeNode}）
   * @param seed - 初始候选（简写可匹配完整 id）
   * @param overrides - 覆盖本次会话配置
   */
  open(key: string, seed?: string[], overrides?: Partial<AnnotPickerOptions>): Promise<string[]>;
}

/**
 * 标注字典维度选择。
 *
 * @param dict - 完整标注树；`ref` / getter 均可。
 * @param defaults - 默认选项；`open` 第三参可覆盖。
 * @returns `[Wrapper, api]` — Wrapper 须挂模板；`api.open` → `Promise<string[]>`。
 */
export function useAnnotatorPicker(dict: MaybeRefOrGetter<AnnotatorTreeNode[]>, defaults?: AnnotPickerOptions) {
  let pending: PromiseWithResolvers<string[]> | undefined;

  const show = ref(false);
  const title = ref<string>();
  const selected = ref<string[]>([]);
  const displayRoots = shallowRef<AnnotatorTreeNode[]>([]);
  const session = shallowRef<AnnotPickerOptions>(defaults ?? {});
  const uiKind = shallowRef<AnnotPickerKind>('pick');
  const nTabs = ref(0);
  const isLeaf = ref(false);
  const groupActiveTab = ref(0);

  watch(show, (v) => {
    if (v && uiKind.value === 'pickerGroup') groupActiveTab.value = 0;
  });

  const settle = (raw: string[]) => {
    if (!pending) return;
    const kind = uiKind.value;
    const nt = nTabs.value;
    pending.resolve(
      kind === 'pickerGroup'
        ? raw
            .slice(0, Math.max(0, nt))
            .map((id) => (id && !isPlaceholderId(id) ? id : ''))
            .filter(Boolean)
        : raw.filter((id) => id && !isPlaceholderId(id))
    );
    pending = undefined;
    show.value = false;
  };

  const abortOpen = () => {
    if (!pending) {
      show.value = false;
      return;
    }
    const p = pending;
    pending = undefined;
    show.value = false;
    p.reject(new Error('cancelled'));
  };

  const api: AnnotatorPickerApi = {
    open(key: string, seed?: string[], overrides?: Partial<AnnotPickerOptions>) {
      pending?.reject(new Error('cancelled'));

      session.value = Object.assign({ autoComplete: false, withDefault: true }, defaults, overrides);

      let disabled: string[] = [];
      if (key === 'faceImg') key = 'face';
      else if (key === 'downImg') key = 'tongue';
      else if (key === 'upImg') {
        key = 'tongue';
        disabled = ['sublingualVein'];
      }

      const tree = toValue(dict);
      const dim = findAnnotatorSubtreeNode(tree, key);
      if (!dim) return Promise.reject(new Error('未找到该维度'));

      const roots = dim.children ?? [];
      if (!roots.length) return Promise.reject(new Error('暂无选项'));

      const { max } = depthRange(roots, (n) => n.leaf);
      const kind = inferPickerKind(max, session.value.component);
      uiKind.value = kind;
      nTabs.value = roots.length;

      selected.value = initPickerSelection(kind, roots, seed);

      displayRoots.value = buildDisplayTree(kind, dim, roots, session.value.withDefault !== false, selected);
      for (const key of disabled) {
        const node = findAnnotatorSubtreeNode(displayRoots.value, key);
        if (node) node.disabled = true;
      }

      title.value = overrides?.title ?? dim.label;

      pending = Promise.withResolvers<string[]>();
      show.value = true;
      return pending.promise;
    },
  };

  const Wrapper = defineComponent({
    name: 'WrapperAnnotatorPicker',
    setup() {
      const fieldNames = { text: 'label', value: 'id', children: 'children' };

      const applyPickerModel = (v: string[] | undefined) => {
        selected.value = v?.length ? [...v] : [];
      };

      type PickerVm = {
        columns: AnnotatorTreeNode[];
        modelValue: string[];
        title?: string;
        onChange: (v: string[] | undefined) => void;
      };

      const hPicker = (p: PickerVm) =>
        h(Picker, {
          confirmButtonText: '',
          cancelButtonText: '',
          columnsFieldNames: fieldNames,
          title: p.title ?? title.value,
          columns: p.columns,
          modelValue: p.modelValue,
          'onUpdate:modelValue'(v: string[]) {
            p.onChange(v);
          },
        });

      const hPickerGroup = () => {
        const roots = displayRoots.value ?? [];
        const reflect = session.value.dynamicTabs === true;
        const tabs = reflect
          ? roots.map((branch, ti) => {
              const id = selected.value[ti]?.trim();
              const def = branch.label ?? '';
              if (!id || isPlaceholderId(id)) return def;
              const path = getAnnotatorNodePath(branch.children ?? [], id);
              return path[path.length - 1]?.label ?? def;
            })
          : roots.map((r) => r.label);
        const k = roots.length;
        const at = Number(groupActiveTab.value);
        const prevDisabled = at <= 0;
        const nextDisabled = k === 0 || at >= k - 1;

        const children = roots.map((branch, ti) => {
          const cols = branch.children ?? [];
          const leaf = selected.value[ti] ?? '';
          const path = leaf ? getAnnotatorNodePath(cols, leaf).map((n) => n.id) : [];
          return hPicker({
            columns: cols,
            modelValue: path,
            onChange: (mv) => {
              const row = [...selected.value];
              while (row.length < k) row.push('');
              row[ti] = mv?.length ? mv[mv.length - 1]! : '';
              selected.value = row;
            },
          });
        });
        return h(
          PickerGroup,
          {
            style: {
              '--van-picker-cancel-action-color': prevDisabled ? 'var(--van-text-color-2)' : 'var(--van-primary-color)',
              '--van-picker-confirm-action-color': nextDisabled ? 'var(--van-text-color-2)' : 'var(--van-primary-color)',
            },
            title: title.value ?? '',
            tabs,
            activeTab: groupActiveTab.value,
            cancelButtonText: '上一项',
            confirmButtonText: '下一项',
            onCancel() {
              if (!prevDisabled) groupActiveTab.value = at - 1;
            },
            onConfirm() {
              if (!nextDisabled) groupActiveTab.value = at + 1;
            },
            'onUpdate:activeTab'(v: number | string) {
              groupActiveTab.value = Number(v);
            },
          },
          {
            default: () => children,
          }
        );
      };

      const hCascader = () => {
        const roots = displayRoots.value ?? [];
        return h(Cascader, {
          title: title.value,
          closeable: false,
          showHeader: true,
          fieldNames: fieldNames,
          options: roots,
          modelValue: lastPickSegment(selected.value) || undefined,
          'onUpdate:modelValue'(v: string) {
            selected.value = [v];
            isLeaf.value = false;
          },
          onFinish({ value }: { value: string }) {
            if (session.value.autoComplete) settle([value]);
            isLeaf.value = true;
          },
        });
      };

      const hBody = () => {
        const kind = uiKind.value;
        const roots = displayRoots.value ?? [];

        if (kind === 'pick') {
          const leaf = lastPickSegment(selected.value);
          const path = leaf ? getAnnotatorNodePath(roots, leaf) : [];
          return hPicker({
            columns: roots,
            modelValue: path.map((n) => n.id),
            onChange: applyPickerModel,
          });
        }
        if (kind === 'pickerGroup') return hPickerGroup();
        if (kind === 'cascader') return hCascader();

        return h('div', { class: 'p-4 text-center text-gray-500' }, '暂无选项');
      };

      return () =>
        h(
          Dialog,
          {
            show: show.value,
            'onUpdate:show'(v: boolean) {
              show.value = v;
            },
            showCancelButton: true,
            width: typeof window === 'undefined' ? 480 : clamp(480, window.innerWidth * 0.9),
            beforeClose(action: string) {
              if (action !== 'confirm') return true;
              if (!canConfirm(uiKind.value, selected.value, nTabs.value, isLeaf.value)) {
                showFailToast('请选择一项');
                return false;
              }
              return true;
            },
            onClosed() {
              abortOpen();
            },
            onCancel: () => abortOpen(),
            onConfirm() {
              if (canConfirm(uiKind.value, selected.value, nTabs.value, isLeaf.value)) settle([...selected.value]);
            },
          },
          { default: () => hBody() }
        );
    },
  });

  return [Wrapper, api] as const;
}