1
// Based on edgeworker D1 mock implementation with chaos
2
const MOCK_USER_ROWS = {
3
  1: { user_id: 1, name: 'Albert Ross', home: 'sky', features: 'wingspan' },
4
  2: { user_id: 2, name: 'Al Dente', home: 'bowl', features: 'mouthfeel' },
5
};
6
 
7
function shouldChaos() {
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  return Math.random() < 0.15; // 15% chaos for D1
9
}
10
 
11
function getChaoticD1Response() {
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  const chaos = Math.random();
13
  if (chaos < 0.25) {
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    // Database locked
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    return Response.json(
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      { error: 'database is locked', success: false },
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      { status: 500 }
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    );
19
  } else if (chaos < 0.45) {
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    // Connection limit exceeded
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    return Response.json(
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      { error: 'too many connections', success: false },
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      { status: 503 }
24
    );
25
  } else if (chaos < 0.65) {
26
    // Malformed response (missing success field)
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    return Response.json({ results: [], meta: { served_by: 'chaos' } });
28
  } else if (chaos < 0.85) {
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    // SQL constraint violation
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    return Response.json(
31
      {
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        error: 'UNIQUE constraint failed: users.email',
33
        success: false,
34
      },
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      { status: 400 }
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    );
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  } else {
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    // Completely wrong JSON structure
39
    return Response.json({ chaos: true, random_field: 'unexpected' });
40
  }
41
}
42
 
43
function mockQuery({ sql, params = [] }) {
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  // Occasional chaos even in successful queries
45
  if (shouldChaos()) {
46
    if (Math.random() < 0.5) {
47
      throw new Error('Random SQL execution error');
48
    }
49
  }
50
 
51
  switch (sql.trim()) {
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    case 'select 1;':
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    case 'SELECT 1':
54
      return ok({ 1: 1 });
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    case 'select * from users;':
56
      return ok(...Object.values(MOCK_USER_ROWS));
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    case 'select * from users where user_id = ?;':
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      return ok(MOCK_USER_ROWS[params[0]]);
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    default:
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      return ok(); // Empty result for unknown queries
61
  }
62
}
63
 
64
function ok(...results) {
65
  return {
66
    success: true,
67
    results,
68
    meta: { duration: Math.random() * 0.1, served_by: 'd1-mock' }, // Random duration
69
  };
70
}
71
 
72
export default {
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  async fetch(request, env, ctx) {
74
    // Random top-level chaos
75
    if (shouldChaos()) {
76
      return getChaoticD1Response();
77
    }
78
 
79
    try {
80
      const { pathname } = new URL(request.url);
81
 
82
      if (
83
        request.method === 'POST' &&
84
        (pathname.startsWith('/query') || pathname.startsWith('/execute'))
85
      ) {
86
        const body = await request.json();
87
        return Response.json(
88
          Array.isArray(body)
89
            ? body.map((query) => mockQuery(query))
90
            : mockQuery(body)
91
        );
92
      }
93
 
94
      return new Response('D1 mock ready', { status: 200 });
95
    } catch (err) {
96
      return Response.json(
97
        { error: err.message, success: false },
98
        { status: 500 }
99
      );
100
    }
101
  },
102
};