Given a date, return the number of days remaining from that date until the last day of the same year (December 31). The count includes December 31 itself. Return -1 for null input. If the date is already December 31, return 0.
Examples:
Input: inputDate = Date.newInstance(2025, 1, 1)
Output: 364
Explanation: January 1st to December 31st of 2025 (not a leap year) is 364 days
Input: inputDate = Date.newInstance(2025, 12, 31)
Output: 0
Explanation: Already the last day of the year
Input: inputDate = Date.newInstance(2025, 12, 1)
Output: 30
Explanation: 30 days from December 1 to December 31
Input: inputDate = null
Output: -1
Explanation: Null input returns -1
Input: inputDate = Date.newInstance(2024, 1, 1)
Output: 365
Explanation: January 1st to December 31st of 2024 (a leap year) is 365 days
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