import { Injectable, Logger } from '@nestjs/common';
import { AiGatewayService } from '../ai/gateway/ai-gateway.service';
import { QuizGenerationResultSchema } from '../ai/prompts/schemas/quiz-generation.schema';
import type { QuizGenerationSnapshot } from './quiz-generation-snapshot-builder';

/**
 * M-AI-07-03: Quiz Generation Executor
 *
 * 将 Quiz 生成输入快照适配到统一 Job Engine 的 EXECUTE 阶段。
 *
 * 职责：从 Snapshot 构造模型输入、通过 AiGateway 调用、返回结构化输出。
 * 不负责：写数据库、写 Job 状态、重试、Artifact、Credential。
 */

@Injectable()
export class QuizGenerationExecutor {
  private readonly logger = new Logger(QuizGenerationExecutor.name);

  constructor(private readonly aiGateway: AiGatewayService) {}

  async execute(snapshot: QuizGenerationSnapshot, timeoutMs: number) {
    const s = snapshot.snapshot;

    // 构造知识点列表文本
    const itemsText = s.knowledgeItems
      .map((item, i) =>
        `【知识点${i + 1}】${item.title}\n${item.content}`,
      )
      .join('\n\n');

    const typeDesc = s.questionTypes.join('、');
    const userMessage = [
      `【知识库】${s.knowledgeBaseTitle}`,
      s.knowledgeBaseDescription ? `描述：${s.knowledgeBaseDescription}` : '',
      '',
      itemsText,
      '',
      `请为以上知识点生成 ${s.questionCount} 道测验题目。`,
      `题型：${typeDesc}`,
      `难度：${s.difficultyLevel}`,
    ].filter(Boolean).join('\n');

    this.logger.log(
      `Quiz Generation Executor calling AI: userId=${s.userId} ` +
      `kb=${s.targetId} items=${s.knowledgeItems.length} ` +
      `questionCount=${s.questionCount} types=${s.questionTypes.join(',')} ` +
      `difficulty=${s.difficultyLevel} modelTier=${s.modelTier} timeoutMs=${timeoutMs}`,
    );

    const response = await this.aiGateway.generate(
      {
        feature: 'quiz-generation',
        userId: s.userId,
        tier: s.modelTier as any,
        promptKey: s.promptKey,
        promptVersion: s.promptVersion,
        messages: [{ role: 'user' as const, content: userMessage }],
        outputSchema: QuizGenerationResultSchema,
        maxTokens: 4096,
      },
      timeoutMs,
    );

    this.logger.log(
      `Quiz Generation Executor completed: userId=${s.userId} ` +
      `kb=${s.targetId} questions=${(response.parsed as any)?.questions?.length} ` +
      `tokens=${response.usage.inputTokens}/${response.usage.outputTokens}`,
    );

    return response;
  }
}