import json
import sys

def resolve_ref(spec, ref):
    """
    Resolves a $ref reference in the OpenAPI spec.
    """
    parts = ref.strip('#/').split('/')
    current = spec
    for part in parts:
        if part in current:
            current = current[part]
        else:
            return None
    return current

def format_schema(spec, schema, indent=0):
    """
    Formats a schema definition into a readable string.
    """
    indent_str = '    ' * indent
    output = []

    if 'type' in schema:
        if schema['type'] == 'object' and 'properties' in schema:
            output.append(f'{indent_str}Object with properties:\n')
            for prop_name, prop_details in schema['properties'].items():
                prop_type = prop_details.get('type', 'any')
                prop_desc = prop_details.get('description', 'No description')
                output.append(f'{indent_str}    - `{prop_name}` ({prop_type}): {prop_desc}\n')
        elif schema['type'] == 'array' and 'items' in schema:
            output.append(f'{indent_str}Array of:\n')
            item_schema = schema['items']
            if '$ref' in item_schema:
                ref_schema = resolve_ref(spec, item_schema['$ref'])
                if ref_schema:
                    output.append(format_schema(spec, ref_schema, indent + 1))
                else:
                    output.append(f'{indent_str}    Unresolved reference: {item_schema["$ref"]}\n')
            else:
                output.append(format_schema(spec, item_schema, indent + 1))
        else:
            output.append(f'{indent_str}{schema["type"]}\n')
    elif '$ref' in schema:
        ref_schema = resolve_ref(spec, schema['$ref'])
        if ref_schema:
            output.append(format_schema(spec, ref_schema, indent))
        else:
            output.append(f'{indent_str}Unresolved reference: {schema["$ref"]}\n')

    return ''.join(output)


def main(input_file, output_file):
    """
    Main function to process the OpenAPI spec.
    """
    try:
        with open(input_file, 'r', encoding='utf-8') as f:
            spec = json.load(f)
    except FileNotFoundError:
        print(f"Error: Input file not found at {input_file}")
        return
    except json.JSONDecodeError:
        print(f"Error: Could not decode JSON from {input_file}")
        return

    with open(output_file, 'w', encoding='utf-8') as f:
        f.write("<API_SUMMARY>\n\n")
        f.write(f"# API Summary: {spec.get('info', {}).get('title', 'Untitled API')}\n\n")

        for path, path_item in spec.get('paths', {}).items():
            for method, operation in path_item.items():
                f.write(f"<{method.upper()} {path}>\n")

                summary = operation.get('summary', '')
                if summary:
                    f.write(f"**Summary:** {summary}\n\n")

                description = operation.get('description', '')
                if description:
                    f.write(f"**Description:** {description}\n\n")

                # Parameters
                if 'parameters' in operation:
                    f.write("<PARAMETERS>\n")
                    f.write("| Name | In | Required | Type | Description |\n")
                    f.write("|------|----|----------|------|-------------|\n")
                    for param in operation['parameters']:
                        param_name = param.get('name')
                        param_in = param.get('in')
                        param_req = param.get('required', False)
                        param_type = param.get('type', 'N/A')
                        param_desc = param.get('description', '').replace('\n', ' ')
                        if 'schema' in param:
                            param_type = 'object'
                        f.write(f"| `{param_name}` | {param_in} | {param_req} | {param_type} | {param_desc} |\n")
                    f.write("\n")
                    f.write("</PARAMETERS>\n")

                # Request Body (for 'body' parameters)
                if 'parameters' in operation:
                    for param in operation['parameters']:
                        if param.get('in') == 'body' and 'schema' in param:
                            f.write("<REQUEST_BODY>\n")
                            schema_str = format_schema(spec, param['schema'])
                            f.write(schema_str)
                            f.write("```\n\n")
                            f.write("</REQUEST_BODY>\n")

                # Form Data (for 'formData' parameters)
                form_data_params = [p for p in operation.get('parameters', []) if p.get('in') == 'formData']
                if form_data_params:
                    f.write("<FORM_DATA>")
                    f.write("| Name | Type | Description |\n")
                    f.write("|------|------|-------------|\n")
                    for param in form_data_params:
                        param_name = param.get('name')
                        param_type = param.get('type', 'N/A')
                        param_desc = param.get('description', '').replace('\n', ' ')
                        f.write(f"| `{param_name}` | {param_type} | {param_desc} |\n")
                    f.write("\n")
                    f.write("</FORM_DATA>")


                # Responses
                if 'responses' in operation:
                    f.write("<RESPONSES>\n")
                    for status_code, response in operation['responses'].items():
                        f.write(f"- **{status_code}**: {response.get('description', '')}\n")
                        if 'schema' in response:
                            schema_str = format_schema(spec, response['schema'], indent=1)
                            if schema_str.strip():
                                f.write(f"    **Schema:**\n{schema_str}\n")
                    f.write("</RESPONSES>\n")
                
                f.write("---\n\n")
                f.write(f"</{method.upper()} {path}>")

        f.write("</API_SUMMARY>\n")

if __name__ == "__main__":
    if len(sys.argv) != 3:
        print("Usage: python process_openapi.py <input_file.json> <output_file.md>")
    else:
        main(sys.argv[1], sys.argv[2])