import { Check, Copy, Moon, Plug, Sun } from 'lucide-react'
import { Component, createContext, useCallback, useContext, useEffect, useRef, useState, type ErrorInfo, type ReactNode } from 'react'
import { ApiError } from '../api/client'
import { getBase, getToken, normalizeBase, setSource } from '../api/source'
import { useTheme } from '../hooks'
import { translateCode, translateField, translateMessage } from '../i18n'

/** 连接式分组（单选）：组内小圆角、外角大圆角，选中段变胶囊。 */
export function Segmented<T extends string>({ options, value, onChange }: { options: { value: T; label: ReactNode; disabled?: boolean; title?: string }[]; value: T; onChange: (v: T) => void }) {
  return (
    <div className="group" role="tablist">
      {options.map((o) => (
        <button key={o.value} type="button" role="tab" aria-selected={o.value === value} className={o.value === value ? 'on' : ''} disabled={o.disabled} title={o.title} onClick={() => onChange(o.value)}>
          {o.label}
        </button>
      ))}
    </div>
  )
}

export function Chip({ tone = '', children }: { tone?: 'ok' | 'warn' | 'bad' | 'accent' | ''; children: ReactNode }) {
  return <span className={`chip ${tone}`}>{children}</span>
}

export function Dot({ tone = '' }: { tone?: 'ok' | 'warn' | 'bad' | '' }) {
  return <span className={`dot ${tone}`} />
}

export function Spinner() {
  return <span className="spinner" role="status" aria-label="加载中" />
}

export function Empty({ children }: { children: ReactNode }) {
  return <div className="empty">{children}</div>
}

export function Stat({ label, value, unit, tone = '' }: { label: string; value: ReactNode; unit?: string; tone?: 'ok' | 'warn' | 'bad' | '' }) {
  return (
    <div className="stat">
      <span className="k">{label}</span>
      <span className={`v ${tone}`}>
        {value}
        {unit ? <small>{unit}</small> : null}
      </span>
    </div>
  )
}

export function Field({ label, hint, children }: { label: string; hint?: string; children: ReactNode }) {
  return (
    <div className="field">
      <span className="label">{label}</span>
      {children}
      {hint ? <span className="hint">{hint}</span> : null}
    </div>
  )
}

export function Dialog({ title, onClose, children, actions }: { title: string; onClose: () => void; children: ReactNode; actions?: ReactNode }) {
  useEffect(() => {
    const onKey = (e: KeyboardEvent) => {
      if (e.key === 'Escape') onClose()
    }
    window.addEventListener('keydown', onKey)
    return () => window.removeEventListener('keydown', onKey)
  }, [onClose])
  return (
    <div className="scrim" onMouseDown={(e) => e.target === e.currentTarget && onClose()}>
      <div className="dialog" role="dialog" aria-modal="true" aria-label={title}>
        <h2>{title}</h2>
        {children}
        {actions ? <div className="actions">{actions}</div> : null}
      </div>
    </div>
  )
}

/** 错误提示：把常见的错误码、字段名和校验信息翻成中文；没有收录的信息原样显示。 */
export function describeError(e: unknown): string {
  if (e instanceof ApiError) {
    const fields = Object.entries(e.errors).flatMap(([field, messages]) => messages.map((m) => `${translateField(field)}：${translateMessage(m)}`))
    if (fields.length > 0) return fields.join('；')
    const byCode = translateCode(e.code)
    // 有具体说明的（例如“要覆盖的模板不存在”）优先给说明，翻不出来就用错误码对应的话
    const detail = e.detail ? translateMessage(e.detail) : ''
    if (detail && detail !== e.detail) return detail
    return byCode ?? (detail || e.code)
  }
  return e instanceof Error ? e.message : String(e)
}

export function ErrorNotice({ error }: { error: unknown }) {
  if (!error) return null
  const privateSite = error instanceof ApiError && error.code === 'site_private'
  return <div className={`notice ${privateSite ? '' : 'bad'}`}>{describeError(error)}</div>
}

/* ── 提示 ── */
interface ToastItem {
  id: number
  text: string
  bad: boolean
}

const ToastContext = createContext<(text: string, bad?: boolean) => void>(() => undefined)

export function ToastProvider({ children }: { children: ReactNode }) {
  const [items, setItems] = useState<ToastItem[]>([])
  const nextId = useRef(1)
  const push = useCallback((text: string, bad = false) => {
    const id = nextId.current++
    setItems((list) => [...list, { id, text, bad }])
    window.setTimeout(() => setItems((list) => list.filter((t) => t.id !== id)), bad ? 6000 : 3000)
  }, [])
  return (
    <ToastContext.Provider value={push}>
      {children}
      <div className="toasts" aria-live="polite">
        {items.map((t) => (
          <div key={t.id} className={`toast ${t.bad ? 'bad' : ''}`}>
            {t.text}
          </div>
        ))}
      </div>
    </ToastContext.Provider>
  )
}

export const useToast = () => useContext(ToastContext)

/** 执行一个操作，成功提示、失败显示错误。 */
export function useAction() {
  const toast = useToast()
  const [busy, setBusy] = useState(false)
  const run = useCallback(
    async (action: () => Promise<unknown>, done?: string) => {
      setBusy(true)
      try {
        await action()
        if (done) toast(done)
        return true
      } catch (e) {
        toast(describeError(e), true)
        return false
      } finally {
        setBusy(false)
      }
    },
    [toast],
  )
  return { busy, run }
}

/** 确认对话框。 */
export function Confirm({ title, children, confirmText = '确定', danger, onConfirm, onClose }: { title: string; children: ReactNode; confirmText?: string; danger?: boolean; onConfirm: () => void | Promise<void>; onClose: () => void }) {
  const [busy, setBusy] = useState(false)
  return (
    <Dialog
      title={title}
      onClose={onClose}
      actions={
        <>
          <button type="button" className="btn text" onClick={onClose}>
            取消
          </button>
          <button
            type="button"
            className={`btn ${danger ? 'danger' : 'primary'}`}
            disabled={busy}
            onClick={async () => {
              setBusy(true)
              try {
                await onConfirm()
              } finally {
                setBusy(false)
                onClose()
              }
            }}
          >
            {confirmText}
          </button>
        </>
      }
    >
      <div className="muted">{children}</div>
    </Dialog>
  )
}

export function CopyButton({ text, label = '复制' }: { text: string; label?: string }) {
  const [done, setDone] = useState(false)
  return (
    <button
      type="button"
      className="btn small"
      onClick={async () => {
        try {
          await navigator.clipboard.writeText(text)
          setDone(true)
          window.setTimeout(() => setDone(false), 1500)
        } catch {
          // 没有剪贴板权限时用户可以手动选中
        }
      }}
    >
      {done ? <Check size={14} /> : <Copy size={14} />}
      {done ? '已复制' : label}
    </button>
  )
}

export function ThemeToggle() {
  const [theme, toggle] = useTheme()
  return (
    <button type="button" className="btn icon" onClick={toggle} aria-label="切换明暗主题" title="切换明暗主题">
      {theme === 'dark' ? <Sun size={18} /> : <Moon size={18} />}
    </button>
  )
}

/**
 * 组件上的加载进度条：放在卡片（`position: relative`）里，贴着上边缘。
 * 数据在加载时流动，不加载时不占地方。
 */
export function LoadingBar({ active }: { active: boolean }) {
  return active ? (
    <div className="loading-bar" role="progressbar" aria-label="加载中">
      <i />
    </div>
  ) : null
}

export interface CommandTab {
  id: string
  label: string
  command: string
}

/** 按浏览器所在的系统挑一个默认的标签（Windows / macOS / 其他当 Linux）。 */
export function guessPlatform(): 'windows' | 'macos' | 'linux' {
  const text = `${navigator.platform} ${navigator.userAgent}`.toLowerCase()
  return text.includes('win') ? 'windows' : text.includes('mac') ? 'macos' : 'linux'
}

/**
 * 带标签切换的命令框（curl / npm / bun 那样）：上面一排下划线标签，下面是等宽的命令，右侧一个复制图标。
 * 记住上次选的标签（只是浏览器里的小方便）。
 */
export function CommandTabs({ tabs, initial, storageKey }: { tabs: CommandTab[]; initial?: string; storageKey?: string }) {
  const [active, setActive] = useState(() => {
    let saved: string | null = null
    try {
      saved = storageKey ? localStorage.getItem(storageKey) : null
    } catch {
      // 浏览器禁用存储时只是不记住
    }
    return [saved, initial].find((id) => id && tabs.some((t) => t.id === id)) ?? tabs[0]?.id ?? ''
  })
  const [done, setDone] = useState(false)
  const tab = tabs.find((t) => t.id === active) ?? tabs[0]
  if (!tab) return null
  const pick = (id: string) => {
    setActive(id)
    try {
      if (storageKey) localStorage.setItem(storageKey, id)
    } catch {
      // 同上
    }
  }
  return (
    <div className="cmd-tabs">
      <div className="cmd-tablist" role="tablist">
        {tabs.map((t) => (
          <button key={t.id} type="button" role="tab" aria-selected={t.id === tab.id} className={t.id === tab.id ? 'on' : ''} onClick={() => pick(t.id)}>
            {t.label}
          </button>
        ))}
      </div>
      <div className="cmd-body">
        <code>{tab.command}</code>
        <button
          type="button"
          className="cmd-copy"
          aria-label="复制命令"
          title="复制命令"
          onClick={async () => {
            try {
              await navigator.clipboard.writeText(tab.command)
              setDone(true)
              window.setTimeout(() => setDone(false), 1500)
            } catch {
              // 没有剪贴板权限时用户可以手动选中
            }
          }}
        >
          {done ? <Check size={16} /> : <Copy size={16} />}
        </button>
      </div>
    </div>
  )
}

/**
 * 页面出错时显示提示，而不是整页白屏：说明出了什么错，可以重试（重新渲染这一块）或刷新整个页面。
 * 常见原因是前端和后端版本对不上（后端还没升级到新接口）。
 */
export class ErrorBoundary extends Component<{ children: ReactNode }, { error: Error | null }> {
  state: { error: Error | null } = { error: null }

  static getDerivedStateFromError(error: Error) {
    return { error }
  }

  componentDidCatch(error: Error, info: ErrorInfo) {
    console.error(error, info.componentStack)
  }

  render() {
    const { error } = this.state
    if (!error) return this.props.children
    return (
      <div className="login">
        <div className="card stack" style={{ maxWidth: 520 }}>
          <div>
            <h1>页面出错了</h1>
            <p className="muted">这一页没能显示出来。如果刚升级过，多半是前端和后端的版本对不上：先把后端升级到对应的版本，再刷新。</p>
          </div>
          <pre className="code">{error.message}</pre>
          <div className="row" style={{ gap: 8 }}>
            <button type="button" className="btn primary" onClick={() => this.setState({ error: null })}>
              重试
            </button>
            <button type="button" className="btn" onClick={() => location.reload()}>
              刷新页面
            </button>
          </div>
        </div>
      </div>
    )
  }
}

/** 数据源设置：默认连同源的后端；填了地址就连别的后端（跨域用 API 令牌，后端要放行这个前端的来源）。 */
export function SourceButton({ tokenLabel = '只读令牌（站点私有时才需要）' }: { tokenLabel?: string }) {
  const [open, setOpen] = useState(false)
  const [base, setBase] = useState('')
  const [token, setToken] = useState('')
  const remote = getBase() !== ''
  const show = () => {
    setBase(getBase())
    setToken(getToken())
    setOpen(true)
  }
  const apply = (nextBase: string, nextToken: string) => {
    setSource(nextBase, nextToken)
    location.reload()
  }
  return (
    <>
      <button type="button" className={`btn icon${remote ? ' primary' : ''}`} onClick={show} aria-label="数据源" title={remote ? `数据源：${getBase()}` : '数据源：同源'}>
        <Plug size={18} />
      </button>
      {open ? (
        <Dialog
          title="数据源"
          onClose={() => setOpen(false)}
          actions={
            <>
              <button type="button" className="btn" onClick={() => apply('', '')}>
                恢复同源
              </button>
              <button type="button" className="btn primary" onClick={() => apply(base, token)}>
                保存并刷新
              </button>
            </>
          }
        >
          <div className="stack">
            <p className="muted">默认连这个页面所在的后端。填了地址就连另一个后端（比如本机跑前端、连线上的）；此时不用 Cookie，改用 API 令牌，后端需要放行这个页面的来源（<code>Monitor__CorsOrigins</code>）。</p>
            <Field label="后端地址" hint={base && normalizeBase(base) !== base.trim() ? `将使用 ${normalizeBase(base)}` : '例如 https://mo.oeo.one；留空 = 同源'}>
              <input className="input" value={base} onChange={(e) => setBase(e.target.value)} placeholder="https://mo.oeo.one" autoFocus />
            </Field>
            <Field label={tokenLabel}>
              <input className="input" type="password" value={token} onChange={(e) => setToken(e.target.value)} autoComplete="off" />
            </Field>
          </div>
        </Dialog>
      ) : null}
    </>
  )
}

/** 下载文本文件（probe.json 只给一次）。 */
export function downloadText(filename: string, text: string) {
  const url = URL.createObjectURL(new Blob([text], { type: 'application/json' }))
  const a = document.createElement('a')
  a.href = url
  a.download = filename
  a.click()
  URL.revokeObjectURL(url)
}