Python Datetime Manipulation Challenge

This challenge focuses on testing your ability to work with Python's built-in datetime module. You will be tasked with parsing, manipulating, and formatting date and time information, a fundamental skill for many applications including data analysis, scheduling, and logging.

Problem Description

You are to create a Python function that takes a string representing a date and time, along with a target timezone, and performs several operations:

1. Parse the input string: Convert the input string into a Python datetime object. Assume the input string will always be in the YYYY-MM-DD HH:MM:SS format.
2. Convert to target timezone: Adjust the parsed datetime object to the specified target timezone.
3. Calculate time difference: Determine the difference between the converted datetime object and a specific reference time (e.g., the current time or a fixed past date).
4. Format the output: Present the results in a structured string, including the original parsed time, the converted time, and the calculated time difference.

Key Requirements:

• Your function must handle timezones correctly. You will need to use a library like pytz for robust timezone support.
• The output format should be consistent and clearly present all requested information.
• The function should be able to handle different input timezones implicitly if the input string doesn't specify it, assuming a default (e.g., UTC) or raise an error if it's ambiguous and not provided. For this challenge, assume the input string is not timezone-aware and represents a time in UTC.

Expected Behavior:

The function should accept a date-time string and a target timezone string. It should return a formatted string containing:

• The original parsed datetime.
• The datetime converted to the target timezone.
• The difference in days between the converted datetime and the current UTC time.

Edge Cases to Consider:

• Dates around daylight saving time changes (though for this problem, pytz will handle this).
• Invalid input string formats (though the constraints will limit this).

Examples

Example 1:

Input: datetime_str = "2023-10-27 10:30:00" target_timezone = "America/New_York"

Output:

Original Datetime (UTC): 2023-10-27 10:30:00
Converted Datetime (America/New_York): 2023-10-27 06:30:00-04:00
Difference in days from current UTC time: [A number representing days, e.g., X days]

Explanation: The input string "2023-10-27 10:30:00" is interpreted as UTC. It is then converted to the "America/New_York" timezone, which is UTC-4 at this date. The difference in days is calculated between this converted time and the current UTC time.

Example 2:

Input: datetime_str = "2024-01-15 22:00:00" target_timezone = "Europe/London"

Output:

Original Datetime (UTC): 2024-01-15 22:00:00
Converted Datetime (Europe/London): 2024-01-15 22:00:00+00:00
Difference in days from current UTC time: [A number representing days, e.g., Y days]

Explanation: The input string is UTC. "Europe/London" is UTC+0 during January. The difference is calculated accordingly.

Constraints

• The input datetime_str will always be a valid string in the YYYY-MM-DD HH:MM:SS format.
• The input target_timezone will always be a valid timezone string recognized by the pytz library.
• The function should be efficient enough to run within typical competitive programming time limits.

Notes

• You will need to install the pytz library: pip install pytz.
• Remember to make your datetime objects timezone-aware before performing timezone conversions.
• When calculating the difference in days, be mindful of how timedelta objects represent differences. You can access the .days attribute for the whole number of days.
• The "current UTC time" should be determined at the moment your function is called.