'use client'

import { useState, useEffect, useCallback } from 'react'
import { useLocale } from 'next-intl'
import { useWsSubscribe } from '@/lib/wsContext'

const API_BASE = '/api/proxy/api'

interface SignalAlert {
  type:      'funding_signal'
  symbol:    string
  time:      string
  close:     number
  tbr:       number
  vol_mult:  number
  bb_pct:    number
  bb_upper:  number
  btc_trend: string
  enabled:   boolean
}

function symbolLabel(s: string) {
  return s.replace('USDT', '')
}

function timeAgo(iso: string) {
  const diff = (Date.now() - new Date(iso).getTime()) / 1000
  if (diff < 60)   return `${Math.round(diff)}s ago`
  if (diff < 3600) return `${Math.round(diff / 60)}m ago`
  return `${Math.round(diff / 3600)}h ago`
}

// ── iOS-style toggle switch ───────────────────────────────────────────────────
function ToggleSwitch({ on, loading, onToggle }: {
  on: boolean
  loading: boolean
  onToggle: () => void
}) {
  return (
    <button
      onClick={onToggle}
      disabled={loading}
      title={on ? 'Click to disable' : 'Click to enable'}
      style={{
        display: 'flex',
        alignItems: 'center',
        gap: 8,
        background: 'none',
        border: 'none',
        cursor: loading ? 'not-allowed' : 'pointer',
        padding: 0,
        opacity: loading ? 0.5 : 1,
      }}
    >
      {/* Switch track */}
      <div style={{
        width: 44,
        height: 26,
        borderRadius: 13,
        background: on ? '#22c55e' : 'var(--ink-4)',
        position: 'relative',
        transition: 'background 0.2s',
        flexShrink: 0,
        opacity: on ? 1 : 0.5,
      }}>
        {/* Thumb */}
        <div style={{
          width: 18,
          height: 18,
          borderRadius: '50%',
          background: '#fff',
          position: 'absolute',
          top: 2,
          left: on ? 20 : 2,
          transition: 'left 0.2s',
          boxShadow: '0 1px 3px rgba(0,0,0,0.3)',
        }} />
      </div>
      <span style={{
        fontSize: 12,
        fontWeight: 600,
        color: on ? '#22c55e' : 'var(--ink-3)',
        letterSpacing: '0.05em',
        minWidth: 24,
      }}>
        {on ? 'ON' : 'OFF'}
      </span>
    </button>
  )
}

// ── Main component ────────────────────────────────────────────────────────────
export default function SignalMonitor() {
  const locale = useLocale()
  const isZh = false  // i18n shelved — Chinese branches kept as dead code for future revival; see messages/zh.json
  const [enabled, setEnabledState] = useState(false)
  const [loading, setLoading]       = useState(false)
  const [backendOk, setBackendOk]   = useState<boolean | null>(null)
  const [signals, setSignals]        = useState<SignalAlert[]>([])
  const [btcTrend, setBtcTrend]     = useState<string | null>(null)
  const [lastScan, setLastScan]     = useState<Date | null>(null)

  // ── Load initial state ───────────────────────────────────────────────────
  useEffect(() => {
    fetch(`${API_BASE}/signal/status`)
      .then(r => { if (!r.ok) throw new Error(); return r.json() })
      .then(d => { setEnabledState(d.enabled); setBackendOk(true) })
      .catch(() => setBackendOk(false))

    fetch(`${API_BASE}/signal/history?limit=20`)
      .then(r => r.json())
      .then((list: SignalAlert[]) => {
        if (!Array.isArray(list)) return
        setSignals(list)
        if (list.length > 0) {
          setBtcTrend(list[0].btc_trend)
          setLastScan(new Date(list[0].time))
        }
      })
      .catch(() => {})
  }, [])

  // ── WebSocket listener (shared singleton connection via WsProvider) ─────────
  useWsSubscribe('funding_signal', (msg) => {
    const alert = msg as SignalAlert
    setBtcTrend(alert.btc_trend)
    setLastScan(new Date(alert.time))
    setSignals(prev => [alert, ...prev].slice(0, 50))
  })

  // ── Toggle ───────────────────────────────────────────────────────────────
  const toggle = useCallback(async () => {
    setLoading(true)
    try {
      const next = !enabled
      const r = await fetch(`${API_BASE}/signal/toggle?enabled=${next}`, { method: 'POST' })
      if (!r.ok) throw new Error()
      const d = await r.json()
      setEnabledState(d.enabled)
      setBackendOk(true)
    } catch {
      setBackendOk(false)
    }
    setLoading(false)
  }, [enabled])

  // ── Render ───────────────────────────────────────────────────────────────
  const btcUp = btcTrend?.includes('↑')

  return (
    <div className="card" style={{ padding: 20, marginTop: 12 }}>

      {/* Header */}
      <div style={{ display: 'flex', alignItems: 'flex-start', justifyContent: 'space-between', marginBottom: 14 }}>
        <div>
          <div style={{ fontSize: 12, fontWeight: 700, letterSpacing: '0.06em', textTransform: 'uppercase', color: 'var(--ink-3)', marginBottom: 3 }}>
            {isZh ? '突破监控' : 'Breakout Monitor'}
          </div>
          <div style={{ fontSize: 11, color: 'var(--ink-3)' }}>
            {isZh ? 'ETH · LINK · 5 分钟扫描' : 'ETH · LINK · 5m scan'}
          </div>
        </div>
        <ToggleSwitch on={enabled} loading={loading} onToggle={toggle} />
      </div>

      {/* Backend offline warning */}
      {backendOk === false && (
        <div style={{
          fontSize: 11, color: '#f59e0b',
          padding: '6px 10px', borderRadius: 6,
          background: 'rgba(245,158,11,0.1)',
          marginBottom: 12,
        }}>
          ⚠️ {isZh ? '后端离线，开关暂时不可用' : "Backend offline — toggle won't work"}
        </div>
      )}

      {/* Status row: BTC trend + last scan */}
      <div style={{
        display: 'flex', alignItems: 'center', justifyContent: 'space-between',
        fontSize: 11, color: 'var(--ink-3)',
        padding: '6px 10px', borderRadius: 8,
        background: 'rgba(255,255,255,0.04)',
        marginBottom: 14,
      }}>
        <span>
          BTC &nbsp;
          {btcTrend ? (
            <strong style={{ color: btcUp ? '#22c55e' : '#ef4444' }}>{btcTrend}</strong>
          ) : (
            <span style={{ opacity: 0.5 }}>—</span>
          )}
        </span>
        <span>
          {lastScan
            ? (isZh ? `最近信号 ${timeAgo(lastScan.toISOString())}` : `Last signal ${timeAgo(lastScan.toISOString())}`)
            : enabled ? (isZh ? '扫描中…' : 'Scanning…') : (isZh ? '已暂停' : 'Paused')
          }
        </span>
      </div>

      {/* Signal list */}
      {signals.length === 0 ? (
        <div style={{
          fontSize: 13, color: 'var(--ink-3)',
          textAlign: 'center', padding: '20px 0',
          lineHeight: 1.5,
        }}>
          {enabled
            ? (isZh ? '· 正在等待信号…' : '· Watching for signals…')
            : (isZh ? '· 打开开关后开始监控' : '· Enable the toggle to start watching')}
        </div>
      ) : (
        <div style={{ display: 'flex', flexDirection: 'column', gap: 8 }}>
          {signals.map((s) => (
            <div key={`${s.symbol}-${s.time}`} style={{
              padding: '11px 13px',
              borderRadius: 10,
              background: 'rgba(255,255,255,0.04)',
              borderLeft: `3px solid ${s.enabled ? '#22c55e' : 'rgba(255,255,255,0.15)'}`,
            }}>
              {/* Top row */}
              <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginBottom: 8 }}>
                <div style={{ display: 'flex', alignItems: 'center', gap: 8 }}>
                  <span style={{
                    fontWeight: 700, fontSize: 14,
                    fontFamily: 'var(--mono)',
                    color: 'var(--ink)',
                  }}>
                    {symbolLabel(s.symbol)}
                  </span>
                  {!s.enabled && (
                    <span style={{
                      fontSize: 9, padding: '2px 6px', borderRadius: 4,
                      background: 'rgba(255,255,255,0.08)',
                      color: 'var(--ink-3)',
                      textTransform: 'uppercase', letterSpacing: '0.05em',
                    }}>
                      silent
                    </span>
                  )}
                </div>
                <span style={{ fontSize: 11, color: 'var(--ink-3)' }}>
                  {timeAgo(s.time)}
                </span>
              </div>

              {/* Metrics grid */}
              <div style={{ display: 'grid', gridTemplateColumns: 'repeat(3, 1fr)', gap: 6 }}>
                {[
                  { label: isZh ? '价格' : 'Price', value: `$${s.close.toLocaleString(undefined, { maximumFractionDigits: 2 })}`, color: 'var(--ink)' },
                  { label: isZh ? '主动买入' : 'Taker Buy', value: `${(s.tbr * 100).toFixed(1)}%`, color: '#22c55e' },
                  { label: isZh ? '成交量倍数' : 'Vol ×', value: `${s.vol_mult}×`, color: '#22c55e' },
                ].map(m => (
                  <div key={m.label} style={{
                    background: 'rgba(255,255,255,0.03)',
                    borderRadius: 6, padding: '5px 8px',
                  }}>
                    <div style={{ fontSize: 9, color: 'var(--ink-3)', marginBottom: 2, textTransform: 'uppercase', letterSpacing: '0.04em' }}>
                      {m.label}
                    </div>
                    <div style={{ fontSize: 13, fontFamily: 'var(--mono)', fontWeight: 600, color: m.color }}>
                      {m.value}
                    </div>
                  </div>
                ))}
              </div>

              {/* Footer */}
              <div style={{ fontSize: 10, color: 'var(--ink-3)', marginTop: 8 }}>
                {isZh ? `BB squeeze 处于第 ${s.bb_pct} 分位` : `BB squeeze ${s.bb_pct}th pct`} &nbsp;·&nbsp; {s.btc_trend}
              </div>
            </div>
          ))}
        </div>
      )}
    </div>
  )
}
