import React, { useState, useEffect, useCallback } from 'react'
import axios from 'axios'
import {
  Wifi, WifiOff, Server, FileText, GitBranch,
  Table2, Activity, TerminalSquare, Box, Settings, RefreshCw,
} from 'lucide-react'

import ConnectionPanel  from './components/ConnectionPanel'
import DocumentManager  from './components/DocumentManager'
import PipelineRunner   from './components/PipelineRunner'
import QAPairViewer     from './components/QAPairViewer'
import TrainingMonitor  from './components/TrainingMonitor'
import Terminal         from './components/Terminal'
import ModelManager     from './components/ModelManager'
import ConfigEditor     from './components/ConfigEditor'

const API = ''   // vite proxy forwards /api → :8080

const NAV = [
  { id: 'connection', label: 'Connection',  icon: Server      },
  { id: 'documents',  label: 'Documents',   icon: FileText    },
  { id: 'pipeline',   label: 'Pipeline',    icon: GitBranch   },
  { id: 'pairs',      label: 'QA Pairs',    icon: Table2      },
  { id: 'training',   label: 'Training',    icon: Activity    },
  { id: 'terminal',   label: 'Terminal',    icon: TerminalSquare },
  { id: 'models',     label: 'Models',      icon: Box         },
  { id: 'config',     label: 'Config',      icon: Settings    },
]

export default function App() {
  const [active, setActive]       = useState('connection')
  const [connected, setConnected] = useState(false)
  const [gpuInfo, setGpuInfo]     = useState(null)
  const [statusMsg, setStatusMsg] = useState('')

  const fetchStatus = useCallback(async () => {
    try {
      const { data } = await axios.get(`${API}/api/status`)
      setConnected(data.connected)
      if (data.gpu?.gpus?.length) setGpuInfo(data.gpu.gpus[0])
    } catch {
      setConnected(false)
    }
  }, [])

  useEffect(() => {
    fetchStatus()
    const id = setInterval(fetchStatus, 10000)
    return () => clearInterval(id)
  }, [fetchStatus])

  const panels = {
    connection: <ConnectionPanel onConnect={fetchStatus} setStatus={setStatusMsg} />,
    documents:  <DocumentManager connected={connected} />,
    pipeline:   <PipelineRunner  connected={connected} />,
    pairs:      <QAPairViewer    connected={connected} />,
    training:   <TrainingMonitor connected={connected} gpuInfo={gpuInfo} />,
    terminal:   <Terminal        connected={connected} />,
    models:     <ModelManager    connected={connected} />,
    config:     <ConfigEditor    connected={connected} />,
  }

  return (
    <div className="flex h-screen overflow-hidden bg-[#0f1117] text-slate-200">

      {/* ── Sidebar ── */}
      <aside className="w-52 flex-shrink-0 flex flex-col bg-[#161b27] border-r border-slate-700/50">
        {/* Logo */}
        <div className="px-4 py-5 border-b border-slate-700/50">
          <h1 className="text-sm font-semibold tracking-widest text-blue-400 uppercase">
            LLM Trainer
          </h1>
          <p className="text-xs text-slate-500 mt-0.5">Dashboard v1.0</p>
        </div>

        {/* Nav items */}
        <nav className="flex-1 py-3 overflow-y-auto">
          {NAV.map(({ id, label, icon: Icon }) => (
            <button
              key={id}
              onClick={() => setActive(id)}
              className={`w-full flex items-center gap-3 px-4 py-2.5 text-sm transition-colors
                ${active === id
                  ? 'bg-blue-600/20 text-blue-400 border-r-2 border-blue-500'
                  : 'text-slate-400 hover:text-slate-200 hover:bg-slate-700/30'}`}
            >
              <Icon size={16} />
              {label}
            </button>
          ))}
        </nav>

        {/* Status bar */}
        <div className="px-4 py-3 border-t border-slate-700/50 space-y-2">
          <div className={`flex items-center gap-2 text-xs font-medium
            ${connected ? 'text-green-400' : 'text-red-400'}`}>
            {connected
              ? <><Wifi size={12}/> Connected</>
              : <><WifiOff size={12}/> Disconnected</>
            }
          </div>
          {gpuInfo && connected && (
            <div className="text-xs text-slate-500 space-y-0.5">
              <div className="truncate">{gpuInfo.name}</div>
              <div className="flex gap-2">
                <span className="text-purple-400">{gpuInfo.utilization}%</span>
                <span className="text-blue-400">
                  {gpuInfo.memory_used}/{gpuInfo.memory_total}MB
                </span>
                <span className="text-orange-400">{gpuInfo.temperature}°C</span>
              </div>
            </div>
          )}
          <button
            onClick={fetchStatus}
            className="flex items-center gap-1.5 text-xs text-slate-500 hover:text-slate-300 transition-colors"
          >
            <RefreshCw size={11}/> Refresh
          </button>
        </div>
      </aside>

      {/* ── Main content ── */}
      <main className="flex-1 flex flex-col overflow-hidden">
        {/* Top bar */}
        <header className="flex items-center justify-between px-6 py-3 border-b border-slate-700/50 bg-[#161b27]">
          <h2 className="text-sm font-semibold text-slate-300 capitalize">
            {NAV.find(n => n.id === active)?.label}
          </h2>
          {statusMsg && (
            <span className="text-xs text-slate-500 italic">{statusMsg}</span>
          )}
        </header>

        <div className="flex-1 overflow-auto p-6">
          {panels[active]}
        </div>
      </main>
    </div>
  )
}