/**
 * 文档 · /brain/documents
 * 用途：语言层数据库核心——人格体读写，人类只读（渲染）
 */

const { Router } = require('express');
const crypto = require('crypto');
const router = Router();

// GET /brain/documents — 列出文档（支持树形查询）
router.get('/', (req, res) => {
  try {
    let sql = 'SELECT document_id, persona_id, parent_id, path, title, content_type, source, version, created_at, updated_at FROM documents WHERE 1=1';
    const params = [];

    if (req.query.parent_id) {
      sql += ' AND parent_id = ?';
      params.push(req.query.parent_id);
    }
    if (req.query.persona_id) {
      sql += ' AND persona_id = ?';
      params.push(req.query.persona_id);
    }
    if (req.query.root) {
      sql += ' AND parent_id IS NULL';
    }

    sql += ' ORDER BY path ASC';
    const rows = req.db.prepare(sql).all(...params);
    res.json({ data: rows, total: rows.length });
  } catch (err) {
    res.status(500).json({ error: true, message: err.message });
  }
});

// GET /brain/documents/:id — 读取单个文档（含完整内容）
router.get('/:id', (req, res) => {
  try {
    const row = req.db.prepare('SELECT * FROM documents WHERE document_id = ?').get(req.params.id);
    if (!row) {
      return res.status(404).json({ error: true, message: 'Document not found' });
    }
    if (row.tags) {
      try { row.tags = JSON.parse(row.tags); } catch (_e) {}
    }
    res.json({ data: row });
  } catch (err) {
    res.status(500).json({ error: true, message: err.message });
  }
});

// POST /brain/documents — 创建新文档
router.post('/', (req, res) => {
  try {
    const { persona_id, parent_id, path, title, content, content_type, source, tags } = req.body;

    if (!title) {
      return res.status(400).json({ error: true, message: 'Missing required field: title' });
    }

    const document_id = `DOC-${Date.now()}-${crypto.randomBytes(4).toString('hex')}`;
    const docPath = path || (parent_id ? `${parent_id}/${title}` : `/root/${title}`);

    req.db.prepare(`
      INSERT INTO documents (document_id, persona_id, parent_id, path, title, content, content_type, source, tags)
      VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
    `).run(
      document_id,
      persona_id || 'SY-001',
      parent_id || null,
      docPath,
      title,
      content || '',
      content_type || 'markdown',
      source || 'api',
      tags ? JSON.stringify(tags) : null
    );

    const created = req.db.prepare('SELECT * FROM documents WHERE document_id = ?').get(document_id);
    res.status(201).json({ data: created, message: 'Document created' });
  } catch (err) {
    res.status(500).json({ error: true, message: err.message });
  }
});

// PUT /brain/documents/:id — 更新文档
router.put('/:id', (req, res) => {
  try {
    const existing = req.db.prepare('SELECT * FROM documents WHERE document_id = ?').get(req.params.id);
    if (!existing) {
      return res.status(404).json({ error: true, message: 'Document not found' });
    }

    const { title, content, parent_id, path, tags } = req.body;
    const updates = [];
    const params = [];

    if (title !== undefined) { updates.push('title = ?'); params.push(title); }
    if (content !== undefined) { updates.push('content = ?'); params.push(content); }
    if (parent_id !== undefined) { updates.push('parent_id = ?'); params.push(parent_id); }
    if (path !== undefined) { updates.push('path = ?'); params.push(path); }
    if (tags !== undefined) { updates.push('tags = ?'); params.push(JSON.stringify(tags)); }

    if (updates.length > 0) {
      params.push(req.params.id);
      req.db.prepare(`UPDATE documents SET ${updates.join(', ')}, updated_at = CURRENT_TIMESTAMP WHERE document_id = ?`).run(...params);
    }

    const updated = req.db.prepare('SELECT * FROM documents WHERE document_id = ?').get(req.params.id);
    res.json({ data: updated, message: 'Document updated' });
  } catch (err) {
    res.status(500).json({ error: true, message: err.message });
  }
});

// DELETE /brain/documents/:id — 软删除
router.delete('/:id', (req, res) => {
  try {
    const existing = req.db.prepare('SELECT * FROM documents WHERE document_id = ?').get(req.params.id);
    if (!existing) {
      return res.status(404).json({ error: true, message: 'Document not found' });
    }

    const deletedId = `deleted_${req.params.id}`;
    req.db.prepare('UPDATE documents SET document_id = ?, path = ? WHERE document_id = ?')
      .run(deletedId, `/trash/${req.params.id}`, req.params.id);

    res.json({ data: { document_id: deletedId }, message: 'Document moved to trash' });
  } catch (err) {
    res.status(500).json({ error: true, message: err.message });
  }
});

module.exports = router;