#ProjectEuler/Python/Problem2.py
#Matthew Ellison
# Created: 01-26-19
#Modified: 10-30-20
#The sum of the even Fibonacci numbers less than 4,000,000
#Unless otherwise listed, all of my non-standard imports can be gotten from my pyClasses repository at https://bitbucket.org/Mattrixwv/pyClasses
"""
	Copyright (C) 2020  Matthew Ellison

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Lesser General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with this program.  If not, see <https://www.gnu.org/licenses/>.
"""


from Problems.Problem import Problem
from Algorithms import getAllFib
from Unsolved import Unsolved


class Problem2(Problem):
	#Variables
	__topNumber = 4000000 - 1

	#Functions
	#Constructor
	def __init__(self):
		super().__init__("What is the sum of the even Fibonacci numbers less than 4,000,000?")
		self.fullSum = 0

	#Operational functions
	#Solve the problem
	def solve(self):
		#If the problem has already been solved do nothing and end the function
		if(self.solved):
			return

		#Start the timer
		self.timer.start()

		#Get a list of all fibonacci numbers < 4,000,000
		fibNums = getAllFib(self.__topNumber)	#Send it - 1 because it is < __topNumber
		#Step through every element in the list checking if it is even
		for num in fibNums:
			#If the number is even add it to the running tally
			if((num % 2) == 0):
				self.fullSum += num

		#Stop the timer
		self.timer.stop()

		#Throw a flag to show the problem is solved
		self.solved = True

	#Reset the problem
	def reset(self):
		super().reset()
		self.fullSum = 0

	#Gets
	#Returns the result of solving the problem
	def getResult(self):
		#If the problem hasn't been solved throw an exception
		if(not self.solved):
			raise Unsolved("You must solve the problem before you can see the result")
		return f"The sum of all even Fibonacci numbers less than {self.__topNumber + 1} is {self.fullSum}"
	#Returns the requested sum
	def getSum(self) -> int:
		#If the problem hasn't been solved throw an exception
		if(not self.solved):
			raise Unsolved("You must solve the problem before can you see the sum")
		return self.fullSum


"""Results:
The sum of all even Fibonacci numbers less than 4000000 is 4613732
It took an average of 10.286 microseconds to run this problem through 100 iterations
"""