/**
 * 评分权重设置 hook：拉取维度与预设模板，提供权重调整、模板应用与保存能力。
 * 业务规则（权重总和校验）放在 api 层，本层只负责本地编辑态与远端数据的合并。
 */
import { useCallback, useMemo, useState } from 'react';
import { fetchWeightSettings, saveWeightSettings } from '../api';
import type { WeightDimension, WeightSettings } from '../types';
import { useAsyncData } from './useAsyncData';

export interface WeightSettingsState {
  /** 远端原始设置（含预设模板） */
  settings: WeightSettings | null;
  /** 当前生效的维度列表（本地编辑态优先，未编辑时回退远端） */
  dimensions: WeightDimension[];
  /** 各维度权重总和，正常应为 100 */
  totalWeight: number;
  loading: boolean;
  error: Error | null;
  saving: boolean;
  refresh: () => void;
  /** 调整单个维度权重 */
  updateWeight: (id: string, weight: number) => void;
  /** 应用预设模板（按维度名称匹配权重） */
  applyTemplate: (templateId: string) => void;
  /** 保存当前维度列表 */
  save: () => Promise<void>;
}

export function useWeightSettings(): WeightSettingsState {
  const fetcher = useCallback(() => fetchWeightSettings(), []);
  const { data, loading, error, refresh } = useAsyncData<WeightSettings>(fetcher);

  const [localDimensions, setLocalDimensions] = useState<WeightDimension[] | null>(null);
  const [saving, setSaving] = useState(false);

  const remoteDimensions = data?.dimensions ?? [];
  const dimensions = localDimensions ?? remoteDimensions;

  const totalWeight = useMemo(
    () => dimensions.reduce((sum, item) => sum + item.weight, 0),
    [dimensions],
  );

  const updateWeight = useCallback(
    (id: string, weight: number) => {
      setLocalDimensions((prev) => {
        const base = prev ?? remoteDimensions;
        return base.map((item) => (item.id === id ? { ...item, weight } : item));
      });
    },
    [remoteDimensions],
  );

  const applyTemplate = useCallback(
    (templateId: string) => {
      const template = data?.templates.find((item) => item.id === templateId);
      if (!template) return;
      setLocalDimensions((prev) => {
        const base = prev ?? remoteDimensions;
        return base.map((item) => ({
          ...item,
          weight: template.weights[item.name] ?? item.weight,
        }));
      });
    },
    [data, remoteDimensions],
  );

  const save = useCallback(async () => {
    setSaving(true);
    try {
      const saved = await saveWeightSettings(dimensions);
      setLocalDimensions(saved);
    } finally {
      setSaving(false);
    }
  }, [dimensions]);

  return {
    settings: data ?? null,
    dimensions,
    totalWeight,
    loading,
    error,
    saving,
    refresh,
    updateWeight,
    applyTemplate,
    save,
  };
}