import type { Disposable } from 'vscode'
import type { ClaudeProfile } from '../../cc/profiles'
import { getDefaultProfilePath, getProfilesDir, listClaudeProfiles } from '../../cc/profiles'

/** 下拉里的一项：id 是 profile 名；「默认」（不带 `--settings`，claude 用 ~/.claude 的登录）的 id 是 ''。 */
export interface ProfileOption {
  id: string
  label: string
}

export interface ProfileChoice {
  options: ProfileOption[]
  selected: string
}

export const DEFAULT_OPTION: ProfileOption = { id: '', label: '默认' }

/** 下拉显示临时选择或设置默认值，失效的选择明确标出，避免回答时偷偷换模型。 */
export function profileChoice(profiles: readonly ClaudeProfile[], defaultPath: string, temporaryPath: string | undefined, configuredPath = ''): ProfileChoice {
  const fallback = profiles.find(profile => profile.path === defaultPath)
  const requestedPath = temporaryPath ?? (configuredPath || fallback?.path)
  const selected = profiles.find(profile => profile.path === requestedPath)?.name ?? requestedPath ?? DEFAULT_OPTION.id
  const options = [...(!fallback || selected === '' ? [DEFAULT_OPTION] : []), ...profiles.map(({ name }) => ({ id: name, label: name }))]
  if (!options.some(option => option.id === selected))
    options.push({ id: selected, label: `不可用：${selected}` })
  return { options, selected }
}

export interface ProfileSource {
  list: () => Promise<ClaudeProfile[]>
  defaultPath: () => string
  directory: () => string
}

const PROFILE_SOURCE: ProfileSource = { list: listClaudeProfiles, defaultPath: getDefaultProfilePath, directory: getProfilesDir }

/**
 * 一套 profile 选择：临时切换所有预览共用、不写进设置，重新创建服务或这一套的默认配置改了以后回到设置里的默认值。
 *
 * @param purpose 这一套给什么用（「问答」「重写注释」）；报错时用它说是哪一套、该改设置里的哪一项
 * @param configuredPath 读设置里这一套的默认 profile 路径
 */
export class AskProfiles {
  private readonly listeners = new Set<(choice: ProfileChoice) => void>()
  private temporary: string | undefined
  private defaultKey: string | undefined

  constructor(readonly purpose: string, private readonly configuredPath: () => string, private readonly source: ProfileSource = PROFILE_SOURCE) {}

  async choice(): Promise<ProfileChoice> {
    return (await this.read()).choice
  }

  /** 下一个问题使用当前显示的模型，失效时直接报错而不换成其他模型。 */
  async current(): Promise<ClaudeProfile | undefined> {
    const { profiles, choice } = await this.read()
    this.publish(choice)
    const profile = profiles.find(profile => profile.name === choice.selected)
    if (choice.selected && !profile)
      throw new Error(`${this.purpose}模型不可用：${choice.selected}。请在设置的「${this.purpose}默认模型」里重新选择，或在输入框旁临时切换。`)
    return profile
  }

  /** 选择变化时通知所有打开的预览，让显示和实际发送使用同一个模型。 */
  subscribe(listener: (choice: ProfileChoice) => void): Disposable {
    this.listeners.add(listener)
    return { dispose: () => this.listeners.delete(listener) }
  }

  async select(id: string): Promise<void> {
    const { profiles, choice } = await this.read()
    const profile = profiles.find(profile => profile.name === id)
    if (id ? !profile : !choice.options.some(option => option.id === ''))
      throw new Error(`${this.purpose}模型不可用：${id}。请重新选择。`)
    this.temporary = profile?.path ?? ''
    await this.refresh()
  }

  async refresh(): Promise<void> {
    this.publish(await this.choice())
  }

  private publish(choice: ProfileChoice): void {
    for (const listener of [...this.listeners])
      listener(choice)
  }

  private async read(): Promise<{ profiles: ClaudeProfile[], choice: ProfileChoice }> {
    const profiles = await this.source.list()
    const configuredPath = this.configuredPath().trim()
    const defaultPath = this.source.defaultPath()
    const key = JSON.stringify([configuredPath, this.source.directory()])
    if (key !== this.defaultKey) {
      this.defaultKey = key
      this.temporary = undefined
    }
    return { profiles, choice: profileChoice(profiles, defaultPath, this.temporary, configuredPath) }
  }
}