import { reactive } from 'vue'

/** 组件默认配置存储：组件名 -> 默认 props/配置 */
const componentSettings = reactive<Record<string, Record<string, unknown>>>({})

/**
 * 深度合并两个对象
 * - source 的值会覆盖 target 的值
 * - 对于嵌套对象，会递归合并
 * - 数组直接替换，不合并
 */
function deepMerge(target: Record<string, unknown>, source?: Record<string, unknown>): Record<string, unknown> {
  if (!source) return target

  for (const key in source) {
    if (Object.prototype.hasOwnProperty.call(source, key)) {
      const targetValue = target[key]
      const sourceValue = source[key]
      if (key === 'components') {
        target[key] = { ...(targetValue as Record<string, unknown>), ...(sourceValue as Record<string, unknown>) }
      } else if (isPlainObject(sourceValue)) {
        if (!isPlainObject(targetValue)) {
          target[key] = { ...(sourceValue as Record<string, unknown>) }
        } else {
          target[key] = deepMerge(
            targetValue as Record<string, unknown>,
            sourceValue as Record<string, unknown>
          )
        }
      } else {
        target[key] = sourceValue
      }
    }
  }

  return target
}

/** 判断是否为普通对象（非数组、非 null） */
function isPlainObject(value: unknown): value is Record<string, unknown> {
  if (!value || typeof value !== 'object') return false
  const proto = Object.getPrototypeOf(value)
  return proto === Object.prototype || proto === null
}

export interface UseComponentSettingReturn {
  /** 获取组件默认配置；不传参时返回全部组件的配置 */
  getSetting: <T extends Record<string, unknown> = Record<string, unknown>>(componentName?: string) => T
  /** 设置组件默认配置（与已有配置深度合并） */
  setSetting: (componentName: string, config: Record<string, unknown>) => void
  /** 合并组件配置：全局配置与组件 props 合并，返回合并后的结果 */
  mergeSettings: <T extends Record<string, unknown> = Record<string, unknown>>(componentName: string, props: Record<string, unknown>) => T
}

/**
 * 组件默认配置：供所有组件统一获取/设置默认配置
 * - getSetting：获取组件默认配置
 * - setSetting：设置组件默认配置（深度合并），可在应用入口或按需调用
 * - mergeSettings：合并全局配置与组件 props，props 优先级更高
 *
 * 合并优先级：组件默认值 < 全局配置 < 组件 props
 */
export function useComponentSetting(): UseComponentSettingReturn {
  /** 返回浅拷贝（仅外层解包），内部保持对 reactive 存储的直接引用，保证响应式追踪 */
  const getSetting = <T extends Record<string, unknown> = Record<string, unknown>>(componentName?: string): T => {
    if (componentName === undefined) {
      return { ...componentSettings } as T
    }
    return { ...(componentSettings[componentName] ?? {}) } as T
  }

  const setSetting = (componentName: string, config: Record<string, unknown>): void => {
    const current = componentSettings[componentName]
    if (current) {
      componentSettings[componentName] = deepMerge({ ...current }, config)
    } else {
      componentSettings[componentName] = { ...config }
    }
  }

  /** 合并全局配置与组件 props，props 优先级更高 */
  const mergeSettings = <T extends Record<string, unknown> = Record<string, unknown>>(componentName: string, props: Record<string, unknown>): T => {
    const globalSetting = componentSettings[componentName] ?? {}
    return deepMerge({ ...globalSetting }, props) as T
  }

  return {
    getSetting,
    setSetting,
    mergeSettings,
  }
}