import Anthropic from '@anthropic-ai/sdk';
import type { Tool, ToolResult, Message, AgentConfig } from '../types/index.js';

export class Agent {
  private client: Anthropic;
  private config: AgentConfig;
  private tools: Map<string, Tool> = new Map();
  private conversationHistory: Message[] = [];

  constructor(config: AgentConfig) {
    this.config = config;
    this.client = new Anthropic({
      apiKey: config.apiKey,
    });
  }

  // 注册工具
  registerTool(tool: Tool): void {
    this.tools.set(tool.name, tool);
  }

  // 获取所有工具定义（用于 Claude API）
  private getToolDefinitions(): Anthropic.Tool[] {
    return Array.from(this.tools.values()).map((tool) => ({
      name: tool.name,
      description: tool.description,
      input_schema: {
        type: 'object' as const,
        properties: Object.fromEntries(
          Object.entries(tool.parameters).map(([key, param]) => [
            key,
            {
              type: param.type,
              description: param.description,
            },
          ])
        ),
        required: Object.entries(tool.parameters)
          .filter(([, param]) => param.required)
          .map(([key]) => key),
      },
    }));
  }

  // 执行工具
  private async executeTool(
    toolName: string,
    input: Record<string, unknown>
  ): Promise<ToolResult> {
    const tool = this.tools.get(toolName);
    if (!tool) {
      return {
        success: false,
        output: '',
        error: `Tool "${toolName}" not found`,
      };
    }

    try {
      return await tool.execute(input);
    } catch (error) {
      return {
        success: false,
        output: '',
        error: error instanceof Error ? error.message : String(error),
      };
    }
  }

  // 发送消息并处理响应
  async chat(
    userMessage: string,
    onStream?: (text: string) => void
  ): Promise<string> {
    // 添加用户消息到历史
    this.conversationHistory.push({
      role: 'user',
      content: userMessage,
    });

    const messages: Anthropic.MessageParam[] = this.conversationHistory.map(
      (msg) => ({
        role: msg.role,
        content: msg.content,
      })
    );

    let fullResponse = '';

    // 循环处理，直到没有工具调用
    while (true) {
      const response = await this.client.messages.create({
        model: this.config.model,
        max_tokens: this.config.maxTokens,
        system: this.config.systemPrompt,
        tools: this.getToolDefinitions(),
        messages,
      });

      // 处理响应内容
      const textBlocks: string[] = [];
      const toolUseBlocks: Anthropic.ToolUseBlock[] = [];

      for (const block of response.content) {
        if (block.type === 'text') {
          textBlocks.push(block.text);
          if (onStream) {
            onStream(block.text);
          }
        } else if (block.type === 'tool_use') {
          toolUseBlocks.push(block);
        }
      }

      fullResponse += textBlocks.join('');

      // 如果没有工具调用，结束循环
      if (toolUseBlocks.length === 0) {
        break;
      }

      // 添加 assistant 消息
      messages.push({
        role: 'assistant',
        content: response.content,
      });

      // 处理工具调用
      const toolResults: Anthropic.ToolResultBlockParam[] = [];

      for (const toolUse of toolUseBlocks) {
        if (onStream) {
          onStream(`\n[调用工具: ${toolUse.name}]\n`);
        }

        const result = await this.executeTool(
          toolUse.name,
          toolUse.input as Record<string, unknown>
        );

        if (onStream) {
          onStream(
            result.success ? `[结果: ${result.output}]\n` : `[错误: ${result.error}]\n`
          );
        }

        toolResults.push({
          type: 'tool_result',
          tool_use_id: toolUse.id,
          content: result.success ? result.output : `Error: ${result.error}`,
        });
      }

      // 添加工具结果
      messages.push({
        role: 'user',
        content: toolResults,
      });
    }

    // 保存助手响应到历史
    this.conversationHistory.push({
      role: 'assistant',
      content: fullResponse,
    });

    return fullResponse;
  }

  // 清空对话历史
  clearHistory(): void {
    this.conversationHistory = [];
  }

  // 获取对话历史
  getHistory(): Message[] {
    return [...this.conversationHistory];
  }
}