import { useState } from 'react'
import { Play, Brain, Plus, Trash2, Settings2, Loader2, Wrench } from 'lucide-react'
import { useAgentStore } from '../store/agentStore'
import { tools as builtinTools } from '../utils/tools'
import { agents } from '../utils/agents'

const EMPTY_PARAMS = '{"type":"object","properties":{}}'

function ToolChip({ call }) {
  return (
    <div className="mt-2 p-3 rounded-2xl bg-app border border-edge text-sm">
      <div className="flex items-center gap-2 text-amber-400 font-medium">
        <Wrench className="w-4 h-4" /> {call?.function?.name || '未知工具'}
      </div>
      <pre className="mt-1 text-xs text-muted whitespace-pre-wrap break-words">{call?.function?.arguments || ''}</pre>
    </div>
  )
}

function ToolModal({ toolsList, onChange, onClose }) {
  const [draft, setDraft] = useState({ name: '', description: '', parameters: EMPTY_PARAMS })
  const [err, setErr] = useState('')

  const addTool = () => {
    const name = draft.name.trim()
    if (!name) return setErr('請輸入工具名稱')
    if (!/^[a-zA-Z0-9_-]+$/.test(name)) return setErr('名稱只能用英數字、底線與連字號')
    if (toolsList.some((t) => t.name === name)) return setErr('名稱重複')
    let parameters
    try {
      parameters = JSON.parse(draft.parameters || '{}')
    } catch {
      return setErr('parameters 不是合法 JSON')
    }
    onChange([
      ...toolsList,
      { name, description: draft.description.trim() || '自訂工具', parameters },
    ])
    setDraft({ name: '', description: '', parameters: EMPTY_PARAMS })
    setErr('')
  }

  return (
    <div className="fixed inset-0 bg-black/80 flex items-center justify-center z-50">
      <div className="bg-panel p-8 rounded-3xl w-full max-w-lg border border-edge">
        <h3 className="text-2xl font-bold mb-6">管理工具</h3>

        <div className="space-y-3 mb-6">
          {toolsList.length === 0 && <p className="text-sm text-muted">目前沒有工具</p>}
          {toolsList.map((t) => (
            <div key={t.name} className="flex items-start justify-between gap-3 bg-field p-3 rounded-2xl">
              <div className="min-w-0">
                <div className="font-medium break-words">{t.name}</div>
                <div className="text-xs text-muted break-words">{t.description}</div>
              </div>
              <button
                onClick={() => onChange(toolsList.filter((x) => x.name !== t.name))}
                className="text-red-500 shrink-0"
                title="移除工具"
              >
                <Trash2 className="w-4 h-4" />
              </button>
            </div>
          ))}
        </div>

        <div className="space-y-3 p-4 bg-field rounded-2xl">
          <div className="text-sm font-medium">新增工具</div>
          <input
            type="text"
            value={draft.name}
            onChange={(e) => setDraft({ ...draft, name: e.target.value })}
            placeholder="name，例如 get_weather"
            className="w-full bg-app px-4 py-2 rounded-xl focus:outline-none"
          />
          <input
            type="text"
            value={draft.description}
            onChange={(e) => setDraft({ ...draft, description: e.target.value })}
            placeholder="description（模型靠它決定何時呼叫）"
            className="w-full bg-app px-4 py-2 rounded-xl focus:outline-none"
          />
          <textarea
            value={draft.parameters}
            onChange={(e) => setDraft({ ...draft, parameters: e.target.value })}
            placeholder='parameters，例如 {"type":"object","properties":{"city":{"type":"string"}}}'
            rows={3}
            className="w-full bg-app px-4 py-2 rounded-xl font-mono text-xs focus:outline-none"
          />
          {err && <p className="text-xs text-red-400">{err}</p>}
          <p className="text-xs text-muted">
            注意：自訂工具只送進 API 讓模型呼叫，本機沒有對應的執行器，會回傳「未實作」。
          </p>
          <button
            onClick={addTool}
            className="w-full flex items-center justify-center gap-2 bg-purple-600 py-3 rounded-2xl font-medium"
          >
            <Plus className="w-4 h-4" /> 新增工具
          </button>
        </div>

        <button onClick={onClose} className="mt-6 w-full py-3 bg-field rounded-2xl">關閉</button>
      </div>
    </div>
  )
}

export default function AgentInterface({ apiConfig, onOpenSettings }) {
  const [input, setInput] = useState('')
  const [toolsList, setToolsList] = useState(builtinTools)
  const [currentAgent, setCurrentAgent] = useState(agents[0])
  const [showToolModal, setShowToolModal] = useState(false)
  const [showAgentModal, setShowAgentModal] = useState(false)

  const { messages, running, step, error, runAgent, reset } = useAgentStore()

  const handleRun = async () => {
    const text = input.trim()
    if (!text || running) return
    setInput('')
    await runAgent(text, toolsList, apiConfig, currentAgent)
  }

  const clearAll = () => {
    reset()
    setInput('')
  }

  const ready = !!(apiConfig.apiKey?.trim() && apiConfig.supplier?.trim() && apiConfig.model?.trim())

  return (
    <div className="flex flex-col h-[80vh] border border-edge rounded-3xl overflow-hidden bg-panel">
      <div className="p-4 border-b border-edge flex items-center justify-between gap-3 flex-wrap bg-app">
        <div className="flex items-center gap-3">
          <Brain className="w-6 h-6 text-purple-500" />
          <div>
            <h2 className="text-xl font-semibold leading-tight">Agent Studio</h2>
            <p className="text-xs text-muted">
              自訂多步工具呼叫迴圈（最多 6 步）· 目前 Agent：{currentAgent.icon} {currentAgent.name}
            </p>
          </div>
        </div>

        <div className="flex items-center gap-2">
          <button
            onClick={onOpenSettings}
            className="flex items-center gap-2 px-4 py-2 bg-field rounded-xl"
            title="API 連線設定"
          >
            <Settings2 className="w-4 h-4" />
            <span className={`text-xs ${ready ? 'text-emerald-400' : 'text-red-400'}`}>
              {ready ? `${apiConfig.model.slice(0, 24)}…` : '未設定金鑰'}
            </span>
          </button>
          <button
            onClick={clearAll}
            disabled={running || messages.length === 0}
            className="flex items-center gap-2 px-4 py-2 bg-field rounded-xl disabled:opacity-40"
            title="清空對話"
          >
            <Trash2 className="w-4 h-4" /> 清空
          </button>
          <button
            onClick={() => setShowToolModal(true)}
            className="flex items-center gap-2 px-4 py-2 bg-field rounded-xl"
          >
            <Plus className="w-4 h-4" /> 工具 ({toolsList.length})
          </button>
          <button
            onClick={() => setShowAgentModal(true)}
            className="flex items-center gap-2 px-4 py-2 bg-field rounded-xl"
          >
            <Brain className="w-4 h-4" /> 切換 Agent
          </button>
          <button
            onClick={handleRun}
            disabled={running || !input.trim()}
            className="flex items-center gap-2 bg-purple-600 hover:bg-purple-700 px-6 py-2 rounded-2xl disabled:opacity-50"
          >
            {running ? <Loader2 className="w-4 h-4 animate-spin" /> : <Play className="w-4 h-4" />}
            {running ? `執行中 ${step}/6` : 'Run'}
          </button>
        </div>
      </div>

      {error && !running && (
        <div className="px-4 py-2 bg-red-900/50 text-red-200 text-sm border-b border-red-900">{error}</div>
      )}

      <div className="flex-1 overflow-y-auto p-4 space-y-3">
        {messages.length === 0 && !running && (
          <div className="h-full flex flex-col items-center justify-center text-center text-muted gap-2">
            <span className="text-4xl">{currentAgent.icon}</span>
            <p className="text-sm">{currentAgent.description}</p>
            <p className="text-xs">輸入任務後按 Enter 執行</p>
          </div>
        )}
        {messages.map((msg, i) => {
          if (msg.role === 'user') {
            return (
              <div key={i} className="bg-blue-600 p-4 rounded-3xl mr-12 whitespace-pre-wrap break-words">
                {msg.content}
              </div>
            )
          }
          if (msg.role === 'tool') {
            return (
              <div key={i} className="p-4 rounded-3xl bg-field border-l-4 border-amber-500 ml-12 text-sm">
                <div className="flex items-center gap-2 text-amber-400 font-medium mb-1">
                  <Wrench className="w-4 h-4" /> {msg.name || msg.tool_call_id}
                </div>
                <div className="whitespace-pre-wrap break-words">{msg.content}</div>
              </div>
            )
          }
          const isError = typeof msg.content === 'string' && msg.content.startsWith('⚠️')
          return (
            <div key={i} className={`p-4 rounded-3xl ${isError ? 'bg-red-900/60 text-red-200' : 'bg-field'} ml-12`}>
              <div className="whitespace-pre-wrap break-words">
                {typeof msg.content === 'string' ? msg.content : JSON.stringify(msg.content)}
              </div>
              {(msg.tool_calls || []).map((call, j) => <ToolChip key={j} call={call} />)}
            </div>
          )
        })}
        {running && step === 0 && (
          <div className="p-4 rounded-3xl bg-field ml-12 flex items-center gap-2 text-muted text-sm">
            <Loader2 className="w-4 h-4 animate-spin" /> 等待模型回應...
          </div>
        )}
      </div>

      <div className="p-4 border-t border-edge">
        <input
          value={input}
          onChange={(e) => setInput(e.target.value)}
          onKeyDown={(e) => {
            if (e.key === 'Enter' && !e.shiftKey) {
              e.preventDefault()
              handleRun()
            }
          }}
          disabled={running}
          placeholder={`輸入任務（目前使用 ${currentAgent.name}）...`}
          className="w-full bg-field px-6 py-4 rounded-3xl focus:outline-none disabled:opacity-50"
        />
      </div>

      {showToolModal && (
        <ToolModal toolsList={toolsList} onChange={setToolsList} onClose={() => setShowToolModal(false)} />
      )}

      {showAgentModal && (
        <div className="fixed inset-0 bg-black/80 flex items-center justify-center z-50">
          <div className="bg-panel p-8 rounded-3xl w-full max-w-md border border-edge">
            <h3 className="text-2xl font-bold mb-6">選擇 Agent</h3>
            <div className="space-y-3">
              {agents.map((agent) => (
                <button
                  key={agent.id}
                  onClick={() => {
                    setCurrentAgent(agent)
                    setShowAgentModal(false)
                  }}
                  className={`w-full text-left px-5 py-4 rounded-2xl flex items-center gap-3 ${
                    currentAgent.id === agent.id ? 'bg-purple-600' : 'bg-field hover:bg-app'
                  }`}
                >
                  <div className="text-2xl">{agent.icon}</div>
                  <div className="min-w-0">
                    <div className="font-medium">{agent.name}</div>
                    <div className="text-xs text-muted break-words">{agent.description}</div>
                  </div>
                </button>
              ))}
            </div>
            <p className="text-xs text-muted mt-4">切換後會以該 Agent 的 system prompt 執行下一輪。</p>
            <button onClick={() => setShowAgentModal(false)} className="mt-6 w-full py-3 bg-field rounded-2xl">
              關閉
            </button>
          </div>
        </div>
      )}
    </div>
  )
}