import json
import re
import sys

def read_mapping(mapping_file):
    """
    Read device-to-IP mapping from a text file.
    Format: <device_name> <IP_address>
    Returns a dictionary with DPM{number}_DEVICE and DPM{number}_TEXT mappings.
    """
    mapping = {}
    try:
        with open(mapping_file, 'r') as f:
            for i, line in enumerate(f, 1):
                line = line.strip()
                if not line or line.startswith('#'):
                    continue
                try:
                    device, ip = line.split()
                    mapping[f"DPM{i}_DEVICE"] = device
                    mapping[f"DPM{i}_TEXT"] = f"{device} {ip}"
                except ValueError:
                    print(f"Warning: Skipping invalid line {i} in {mapping_file}: '{line}'")
        return mapping
    except FileNotFoundError:
        print(f"Error: Mapping file {mapping_file} not found.")
        sys.exit(1)
    except Exception as e:
        print(f"Error reading mapping file: {str(e)}")
        sys.exit(1)

def replace_placeholders(data, mapping):
    """
    Recursively replace placeholders in the data structure with values from mapping.
    """
    if isinstance(data, dict):
        return {k: replace_placeholders(v, mapping) for k, v in data.items()}
    elif isinstance(data, list):
        return [replace_placeholders(item, mapping) for item in data]
    elif isinstance(data, str):
        for placeholder, value in mapping.items():
            data = re.sub(r'\b' + re.escape(placeholder) + r'\b', value, data)
        return data
    else:
        return data

def process_view_json(input_file, output_file, mapping):
    """
    Process view.json, replace placeholders, and save to output_file.
    """
    try:
        with open(input_file, 'r') as f:
            data = json.load(f)

        modified_data = replace_placeholders(data, mapping)

        with open(output_file, 'w') as f:
            json.dump(modified_data, f, indent=4)

        print(f"Successfully processed {input_file} and saved to {output_file}")

    except FileNotFoundError:
        print(f"Error: The file {input_file} was not found.")
        sys.exit(1)
    except json.JSONDecodeError:
        print(f"Error: The file {input_file} is not a valid JSON file.")
        sys.exit(1)
    except Exception as e:
        print(f"An error occurred: {str(e)}")
        sys.exit(1)

def main():
    if len(sys.argv) != 3:
        print("Usage: python replace_placeholders.py <mapping_file> <view_json_file>")
        sys.exit(1)

    mapping_file = sys.argv[1]
    input_json_file = sys.argv[2]
    output_json_file = "view.json"

    mapping = read_mapping(mapping_file)
    process_view_json(input_json_file, output_json_file, mapping)

if __name__ == "__main__":
    main()