import { NextRequest, NextResponse } from 'next/server';
import { isPathSafe } from '@/app/lib/novel-server-utils';
import { promises as fs } from 'fs';
import path from 'path';

export async function POST(request: NextRequest) {
  const body = await request.json().catch(() => null);
  if (!body) return NextResponse.json({ success: false, error: '无效请求' }, { status: 400 });

  const { projectPath, chapterIndex, chapterContent, apiSettings } = body;
  if (!projectPath || !isPathSafe(projectPath) || !apiSettings || !chapterContent) {
    return NextResponse.json({ success: false, error: '缺少必要参数' }, { status: 400 });
  }

  // Only trigger every 5 chapters, but allow override
  if (chapterIndex % 5 !== 0 && !body.force) {
    return NextResponse.json({ success: true, skipped: true });
  }

  // Get recent chapters for context
  let recentContext = '';
  const startChapter = Math.max(1, chapterIndex - 4);
  const chaptersDir = path.join(projectPath, 'chapters');
  try {
    const files = await fs.readdir(chaptersDir);
    for (const file of files) {
      const match = file.match(/^chapter_(\d+)_/);
      if (match) {
        const idx = parseInt(match[1]);
        if (idx >= startChapter && idx <= chapterIndex) {
          const content = await fs.readFile(path.join(chaptersDir, file), 'utf-8');
          recentContext += `\n### 第${idx}章\n${content.slice(0, 800)}\n`;
        }
      }
    }
  } catch { /* continue without context */ }

  const prompt = `你是一位付费阅读的资深读者。请对以下小说章节给出读者反馈。

## 最近章节（摘要）
${recentContext.slice(0, 3000)}

## 当前章节
${chapterContent.slice(0, 3000)}

## 评分维度（1-10分）
1. 节奏感：情节推进是否紧凑？是否拖沓或过赶？
2. 爽点密度：情绪释放是否到位？是否有满足感的峰值？
3. 情感共鸣：是否关心角色的命运？是否有打动人的时刻？
4. 阅读困惑：哪些地方可能需要回看才能理解？是否有逻辑断层？

## 输出格式
只返回 JSON：
{
  "pace": 7,
  "excitementDensity": 6,
  "emotionalEngagement": 8,
  "confusion": 3,
  "suggestions": "具体的读者感受和建议，2-3句话"
}`;

  try {
    const response = await fetch(apiSettings.apiUrl, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json', Authorization: `Bearer ${apiSettings.apiKey}` },
      body: JSON.stringify({ model: apiSettings.model, messages: [{ role: 'user', content: prompt }], max_tokens: 500 }),
      signal: AbortSignal.timeout(55000),
    });

    if (!response.ok) {
      return NextResponse.json({ success: false, error: `AI 请求失败: ${response.status}` }, { status: 502 });
    }

    const data = await response.json();
    const text = data.choices?.[0]?.message?.content || '';
    const jsonMatch = text.match(/\{[\s\S]*\}/);
    let feedback;
    try {
      feedback = jsonMatch ? JSON.parse(jsonMatch[0]) : null;
    } catch {
      return NextResponse.json({ success: false, error: 'AI 返回了无效的 JSON 响应' }, { status: 502 });
    }

    // Save feedback to file
    const feedbackDir = path.join(projectPath, 'logs', 'reader-feedback');
    await fs.mkdir(feedbackDir, { recursive: true });
    const range = `${startChapter}-${chapterIndex}`;
    await fs.writeFile(
      path.join(feedbackDir, `chapters-${range}.json`),
      JSON.stringify({ ...feedback, chapterRange: range }, null, 2),
      'utf-8'
    );

    return NextResponse.json({ success: true, feedback });
  } catch (error) {
    return NextResponse.json({ success: false, error: (error as Error).message }, { status: 500 });
  }
}