gochat/backend/scripts/align_error_codes.py

#!/usr/bin/env python3
"""Batch align error responses in GoChat handlers to Chatwoot's error code convention.

Chatwoot conventions:
- Record not found → 404
- Validation/create/update/delete failures → 422 UnprocessableEntity
- Auth failures → 401 Unauthorized
- Permission failures → 403 Forbidden
- Request format/bind errors → 400 BadRequest
- Conflict/duplicate → 409 Conflict
- Internal server errors should be rare (only for unexpected DB/infra failures)

Current GoChat pattern: most errors use 500 InternalServerError for business logic failures.
Target: replace 500 with appropriate 422/404/401/403 based on error message content.
"""

import re
import os
import sys

# Error message → target HTTP status mapping
# Pattern: if the gin.H{"error": "..."} message matches a keyword, use the mapped status
MESSAGE_STATUS_MAP = {
    # 404 patterns
    'not found': 'http.StatusNotFound',
    'does not exist': 'http.StatusNotFound',
    
    # 401 patterns
    'unauthorized': 'http.StatusUnauthorized',
    'authentication': 'http.StatusUnauthorized',
    'invalid token': 'http.StatusUnauthorized',
    
    # 403 patterns
    'forbidden': 'http.StatusForbidden',
    'not allowed': 'http.StatusForbidden',
    'permission': 'http.StatusForbidden',
    'access denied': 'http.StatusForbidden',
    'does not belong': 'http.StatusForbidden',  # "does not belong to this account"
    
    # 409 patterns
    'already exists': 'http.StatusConflict',
    'duplicate': 'http.StatusConflict',
    
    # 422 patterns (default for business logic failures)
    'failed to': 'http.StatusUnprocessableEntity',  # "failed to create/update/delete/list"
    'invalid': 'http.StatusUnprocessableEntity',
    'cannot': 'http.StatusUnprocessableEntity',
    'must': 'http.StatusUnprocessableEntity',
    'required': 'http.StatusUnprocessableEntity',
    'missing': 'http.StatusUnprocessableEntity',
}

def classify_error_status(error_msg: str) -> str:
    """Classify an error message into the appropriate HTTP status code constant."""
    lower_msg = error_msg.lower()
    
    # Check in priority order — specific patterns first
    for pattern, status in MESSAGE_STATUS_MAP.items():
        if pattern in lower_msg:
            return status
    
    # Default: 422 for business logic failures that were previously 500
    return 'http.StatusUnprocessableEntity'

def process_file(filepath: str) -> dict:
    """Process a single Go file, replacing 500 errors with appropriate status codes."""
    with open(filepath, 'r') as f:
        content = f.read()
    
    original_content = content
    changes = []
    
    # Pattern: c.JSON(http.StatusInternalServerError, gin.H{"error": "..."})
    # Replace with appropriate status code based on error message
    pattern = re.compile(
        r'c\.JSON\(http\.StatusInternalServerError,\s*gin\.H\{'
        r'"error":\s*"([^"]+)"'
        r'\}\)'
    )
    
    def replacer(match):
        error_msg = match.group(1)
        new_status = classify_error_status(error_msg)
        old = match.group(0)
        new = f'c.JSON({new_status}, gin.H{{"error": "{error_msg}"}})'
        changes.append({
            'line': content[:match.start()].count('\n') + 1,
            'old': old,
            'new': new,
            'status': new_status.replace('http.Status', ''),
        })
        return new
    
    content = pattern.sub(replacer, content)
    
    # Also handle: c.JSON(http.StatusInternalServerError, response.APIResponse{...})
    pattern2 = re.compile(
        r'c\.JSON\(http\.StatusInternalServerError,\s*response\.APIResponse\{[^}]+\}\)'
    )
    # For these, just replace status code — can't easily classify the message
    content2 = re.sub(
        r'c\.JSON\(http\.StatusInternalServerError,\s*response\.APIResponse',
        'c.JSON(http.StatusUnprocessableEntity, response.APIResponse',
        content
    )
    if content2 != content:
        changes.append({'line': 0, 'old': '500 APIResponse', 'new': '422 APIResponse', 'status': 'UnprocessableEntity'})
        content = content2
    
    if content != original_content:
        with open(filepath, 'w') as f:
            f.write(content)
    
    return {'file': filepath, 'changes': changes, 'total_changes': len(changes)}

def main():
    handler_dir = '/home/yanghao05/Workspace/gochat/internal/handler'
    
    # Find all handler Go files (exclude tests)
    go_files = []
    for root, dirs, files in os.walk(handler_dir):
        for f in files:
            if f.endswith('.go') and not f.endswith('_test.go'):
                go_files.append(os.path.join(root, f))
    
    total_changes = 0
    status_distribution = {}
    
    for filepath in go_files:
        result = process_file(filepath)
        if result['total_changes'] > 0:
            total_changes += result['total_changes']
            for change in result['changes']:
                status = change['status']
                status_distribution[status] = status_distribution.get(status, 0) + 1
                print(f"  {filepath}:{change['line']} → {status}: {change['new']}")
    
    print(f"\n=== Summary ===")
    print(f"Files processed: {len(go_files)}")
    print(f"Total changes: {total_changes}")
    print(f"Status distribution:")
    for status, count in sorted(status_distribution.items()):
        print(f"  {status}: {count}")
    
    # Also handle 400 → 422 for "failed to" business logic errors
    # Pattern: c.JSON(http.StatusBadRequest, gin.H{"error": "failed to..."})
    print(f"\n=== Phase 2: 400 → 422 for business logic errors ===")
    
    for filepath in go_files:
        with open(filepath, 'r') as f:
            content = f.read()
        original = content
        
        # Replace 400 with 422 for "failed to" errors (business logic, not request format)
        pattern = re.compile(
            r'c\.JSON\(http\.StatusBadRequest,\s*gin\.H\{'
            r'"error":\s*"([^"]+)"'
            r'\}\)'
        )
        
        changes_400 = []
        def replacer400(match):
            error_msg = match.group(1)
            lower = error_msg.lower()
            # Only replace if it's a business logic failure, not a request format error
            if 'failed to' in lower or 'cannot' in lower or 'must' in lower:
                new = f'c.JSON(http.StatusUnprocessableEntity, gin.H{{"error": "{error_msg}"}})'
                changes_400.append({'msg': error_msg, 'status': 'UnprocessableEntity'})
                return new
            return match.group(0)
        
        content = pattern.sub(replacer400, content)
        
        if content != original:
            with open(filepath, 'w') as f:
                f.write(content)
            for c in changes_400:
                print(f"  {filepath}: 400→422: {c['msg']}")
            total_changes += len(changes_400)

if __name__ == '__main__':
    main()