import { memo, useCallback, useEffect, useRef, useState, type CSSProperties } from 'react'
import { Button, Card, Spinner } from '@heroui/react'
import { useLogs } from '../../logs'
import { fmtBytes } from '../../lib/format'

// ANSI SGR 颜色码 → 内联样式，用于还原 loguru 彩色日志
const ANSI_FG: Record<number, string> = {
  30: '#9ca3af', 31: '#f87171', 32: '#4ade80', 33: '#fbbf24', 34: '#60a5fa', 35: '#c084fc', 36: '#22d3ee', 37: '#e5e7eb',
  90: '#6b7280', 91: '#f87171', 92: '#4ade80', 93: '#fbbf24', 94: '#60a5fa', 95: '#c084fc', 96: '#22d3ee', 97: '#f9fafb',
}
const ANSI_BG: Record<number, string> = {
  40: '#1f2937', 41: '#7f1d1d', 42: '#14532d', 43: '#713f12', 44: '#1e3a8a', 45: '#581c87', 46: '#155e75', 47: '#111827',
  100: '#374151', 101: '#7f1d1d', 102: '#14532d', 103: '#713f12', 104: '#1e3a8a', 105: '#581c87', 106: '#155e75', 107: '#111827',
}
// 当日志行不含 ANSI 颜色码（例如历史日志/旧进程写入的非彩色文本）时，
// 按 loguru 等级标记降级上色，确保 Web 日志查看器始终有颜色。
const LEVEL_COLORS: Record<string, string> = {
  TRACE: '#c084fc',
  DEBUG: '#60a5fa',
  INFO: '#22d3ee',
  SUCCESS: '#4ade80',
  WARNING: '#fbbf24',
  ERROR: '#f87171',
  CRITICAL: '#f87171',
}

function parseAnsi(text: string): { text: string; style: CSSProperties }[] {
  const out: { text: string; style: CSSProperties }[] = []
  let fg: string | undefined
  let bg: string | undefined
  let bold = false
  let underline = false
  let run = ''
  const flush = () => {
    if (!run) return
    const style: CSSProperties = {}
    if (fg) style.color = fg
    if (bg) style.backgroundColor = bg
    if (bold) style.fontWeight = 'bold'
    if (underline) style.textDecoration = 'underline'
    out.push({ text: run, style })
    run = ''
  }
  for (let i = 0; i < text.length; i++) {
    const ch = text[i]
    if (ch === '\u001b' && text[i + 1] === '[') {
      const end = text.indexOf('m', i)
      if (end !== -1) {
        const codes = text.slice(i + 2, end).split(';').map(s => parseInt(s, 10))
        flush()
        for (const c of codes) {
          if (c === 0) { fg = undefined; bg = undefined; bold = false; underline = false }
          else if (c === 1) bold = true
          else if (c === 4) underline = true
          else if (c >= 30 && c <= 37 || c >= 90 && c <= 97) fg = ANSI_FG[c]
          else if (c >= 40 && c <= 47 || c >= 100 && c <= 107) bg = ANSI_BG[c]
          else if (c === 39) fg = undefined
          else if (c === 49) bg = undefined
        }
        i = end
        continue
      }
    }
    run += ch
  }
  flush()
  return out
}

// 记忆化：窗口内已渲染过的行必须能整体跳过，否则每次更新都要把整窗口的
// ANSI 解析 + DOM 协调重做一遍。
const AnsiLine = memo(function AnsiLine({ text }: { text: string }) {
  const parts = parseAnsi(text)
  const hasAnsi = parts.some((p) => Boolean(p.style.color || p.style.backgroundColor || p.style.fontWeight || p.style.textDecoration))
  if (hasAnsi) {
    return <>{parts.map((p, i) => <span key={i} style={p.style}>{p.text}</span>)}</>
  }
  // 无 ANSI 时按等级标记整体上色，保证非彩色日志文件也能在 Web 里看到颜色。
  const m = text.match(/\[(TRACE|DEBUG|INFO|SUCCESS|WARNING|ERROR|CRITICAL)\]/)
  const color = m && LEVEL_COLORS[m[1]]
  if (color) return <span style={{ color }}>{text}</span>
  return <>{text}</>
})

export default function LogsPage() {
  // 数据与日志流由全局 LogProvider 常驻管理：离开/回来不重建连接、不转圈
  const { lines, info, error, loading, hasMore, loadingEarlier, follow, setFollow, wrap, setWrap, loadEarlier } = useLogs()
  const scrollRef = useRef<HTMLDivElement>(null)
  // 一次「滚到顶」只翻一页，必须离开顶部后才会再次触发（避免连环翻页）
  const topLoadBlockRef = useRef(false)
  // 本次前置进来的行数：等 DOM 更新后据此把视图锚回原来的位置
  const pendingAnchorRef = useRef<number | null>(null)

  useEffect(() => {
    if (follow && scrollRef.current) {
      scrollRef.current.scrollTop = scrollRef.current.scrollHeight
    }
  }, [lines, follow])

  // 向前翻页后把新行（它们被插在顶部）往上推出视野，让原本正在看的那一行留在原处。
  // 窗口行数固定，翻页前后总高度几乎不变，浏览器自带的滚动锚定在 scrollTop=0 时也不生效，
  // 所以这里手动按元素位置锚定。
  useEffect(() => {
    const n = pendingAnchorRef.current
    if (n == null) return
    const el = scrollRef.current
    if (!el) { pendingAnchorRef.current = null; return }
    const first = el.firstElementChild as HTMLElement | null
    const target = el.children[n] as HTMLElement | undefined
    if (!first || !target) return // DOM 还没更新，等下一次 lines 变化再试
    el.scrollTop = target.offsetTop - first.offsetTop
    pendingAnchorRef.current = null
  }, [lines])

  const handleLoadEarlier = useCallback(async () => {
    const n = await loadEarlier()
    if (n > 0) pendingAnchorRef.current = n
  }, [loadEarlier])

  const onScroll = useCallback(() => {
    const el = scrollRef.current
    if (!el) return
    const atBottom = el.scrollHeight - el.scrollTop - el.clientHeight < 24
    if (atBottom) {
      // 回到底部即恢复跟随（否则新日志会把视图拽走，永远看不了历史）
      if (!follow) setFollow(true)
      return
    }
    if (follow) setFollow(false)
    if (el.scrollTop > 8) {
      topLoadBlockRef.current = false
      return
    }
    if (!topLoadBlockRef.current && hasMore && !loadingEarlier) {
      topLoadBlockRef.current = true
      handleLoadEarlier()
    }
  }, [follow, hasMore, loadingEarlier, handleLoadEarlier, setFollow])

  return (
    <div className="space-y-6">
      <div className="flex flex-col gap-3 md:flex-row md:items-center md:justify-between">
        <div className="min-w-0">
          <h2 className="text-xl font-semibold text-slate-800">查看日志</h2>
          <p className="text-sm text-slate-400">实时读取 bot 运行日志（SSE 推送，固定窗口滚动，向上滚动自动加载更早）</p>
        </div>
        <div className="flex shrink-0 flex-wrap items-center gap-2 md:justify-end">
          <Button size="sm" variant="tertiary" onPress={() => setFollow(!follow)}>{follow ? '停止跟随' : '跟随最新'}</Button>
          <Button size="sm" variant="tertiary" onPress={() => setWrap(!wrap)}>{wrap ? '关闭换行' : '自动换行'}</Button>
        </div>
      </div>

      {error && <Card className="border border-red-200 bg-red-50"><Card.Content><p className="text-sm text-red-600">{error}</p></Card.Content></Card>}

      <Card className="border border-slate-200 bg-white">
        <Card.Header>
          <div className="flex w-full items-center justify-between">
            <Card.Title>
              日志流
              {loadingEarlier && <span className="ml-2 text-xs font-normal text-slate-400">加载更早…</span>}
            </Card.Title>
            {info.file && <span className="text-xs text-slate-400">{info.file} · {fmtBytes(info.size)} · 共 {info.total} 行</span>}
          </div>
        </Card.Header>
        <Card.Content>
          <div
            ref={scrollRef}
            onScroll={onScroll}
            // white-space / word-break 都是可继承属性，放在容器上：切换「自动换行」只改一个 class，
            // 不必逐行改 1000 个元素（那会导致整列表重排，实测一次卡 100ms+）
            className={`h-[60vh] min-h-[320px] overflow-auto rounded-lg bg-slate-900 p-3 font-mono text-xs leading-relaxed text-slate-100 md:h-[calc(100vh-320px)] ${wrap ? 'whitespace-pre-wrap break-all' : 'whitespace-pre'}`}
          >
            {loading && !lines.length ? (
              <div className="flex h-full items-center justify-center"><Spinner /></div>
            ) : lines.length ? lines.map(ln => (
              <div key={ln.id}><AnsiLine text={ln.text} /></div>
            )) : (
              <div className="text-slate-500">暂无日志…</div>
            )}
          </div>
        </Card.Content>
      </Card>
    </div>
  )
}