from utils.memory_array import MemoryArray
from utils.memory_cell import MemoryCell
from utils.literal import Literal
from utils.constants import MAX_VALUE
from utils.memory_range import mrange

# Impl of MemoryArray says we cant add our own Datatypes beside Literal and List
# BUUUUT we can just wrap our Datatype in a List :-)
# We store them in a MemoryArray internaly tho anyhow so we increment our Counters for the RAM
class HeapEntry:
    def __init__(self, item, priority=1):
        self.data = MemoryArray(Literal(2))
        # 0: Content, 1: Prio
        self.data[Literal(0)] = Literal(item)
        self.data[Literal(1)] = Literal(priority)
    
    def getItem(self):
        return self.data[Literal(0)]
    
    def getPriority(self):
        return self.data[Literal(1)]
    
    def setPriority(self, priority):
        self.data[Literal(1)] = Literal(priority)
    
    def __lt__(self, other):
        if other is None:
            return True 
        if isinstance(other, (int, float)):
            return self.getPriority().value > other
        return self.getPriority() > other.getPriority()
    
    def __gt__(self, other):
        if other is None:
            return False 
        if isinstance(other, (int, float)):
            return self.getPriority().value < other
        return self.getPriority() < other.getPriority()
    
    def __eq__(self, other):
        return self.getPriority() == other.getPriority()
    
    def __str__(self):
        return f"({self.getItem()}, prio={self.getPriority()})"

class PriorityQueue:
    def __init__(self, max_size : Literal = Literal(100)):
        self.heap = MemoryArray(max_size) 
        # Add uninitialized HeapEntry Values so the Adds/Compares do not fail on emtpy stack. 
        # Would have to switch to MIN_VALUE if we switch what is a "Higher" Prio
        for i in mrange(max_size.value):
            self.heap[i].set([HeapEntry(MAX_VALUE, MAX_VALUE)])
        self.size = MemoryCell(0)
    
    def parent(self, i: Literal) -> Literal:
        return MemoryCell(i.pred()) // Literal(2)
    
    def leftChild(self, i: Literal) -> Literal:
        return MemoryCell(MemoryCell(2) * i) + Literal(1)
    
    def rightChild(self, i: Literal) -> Literal:
        return MemoryCell(MemoryCell(2) * i) + Literal(2)
    
    # Swap the Lists -> Therefore get the value which is the List and then Set it again
    def swap(self, i: Literal, j: Literal):
        tmp_i = self.heap[i].value
        tmp_j = self.heap[j].value
        self.heap[i].set(tmp_j)
        self.heap[j].set(tmp_i)
    
    def maxHeapify(self, i: Literal):
        left = self.leftChild(i)
        right = self.rightChild(i)
        largest = i
        
        if left < Literal(self.size.value) and self.heap[left].value[0] > self.heap[largest].value[0]:
            largest = left
        
        if right < Literal(self.size.value) and self.heap[right].value[0] > self.heap[largest].value[0]:
            largest = right
        
        if largest != i:
            self.swap(i, largest)
            self.maxHeapify(largest)
    
    def insert(self, entry : HeapEntry):
        if self.size >= self.heap.length():
            raise IndexError("Heap full")
        
        i = self.size
        self.heap[i].set([entry])
        self.size += Literal(1)
        
        while i > Literal(0) and self.heap[self.parent(i)].value[0] < self.heap[i].value[0]:
            self.swap(i, self.parent(i))
            i = self.parent(i)
    
    def pop(self):
        if self.isEmpty():
            raise IndexError("Queue is empty!")
        
        max_item = self.heap[Literal(0)].value[0]
        
        self.heap[Literal(0)] = self.heap[self.size - Literal(1)]
        self.size -= Literal(1)
        
        self.maxHeapify(Literal(0))
        
        return max_item
    
    def peek(self):
        if self.isEmpty():
            raise IndexError("Queue is empty")
        return self.heap[Literal(0)].value[0]
    
    def isEmpty(self):
        return self.size == Literal(0)
    
    def __len__(self):
        return self.size


if __name__ == '__main__':
    # Proof of Concept
    testEntry = HeapEntry("A", 2)
    print(testEntry)
    testArray = MemoryArray([testEntry])
    print(testArray)
    print(testArray[Literal(0)])

    # Queue Testing
    pq = PriorityQueue()
    try:
        pq.pop()
        assert False, "Queue should be empty"
    except IndexError:
        pass  
    assert(pq.isEmpty() and pq.size == Literal(0))
    entry = HeapEntry("A", 1)
    pq.insert(entry)
    assert(not pq.isEmpty() and pq.size == Literal(1))
    pq.peek()
    assert(not pq.isEmpty())
    assert(pq.pop() == HeapEntry("A", 1))
    assert(pq.isEmpty())
    pq.insert(HeapEntry("A", 1))
    pq.insert(HeapEntry("C", 3))
    pq.insert(HeapEntry("B", 2))
    assert(pq.size == Literal(3))
    assert(pq.pop() == HeapEntry("A", 1))
    assert(pq.pop() == HeapEntry("B", 2))
    assert(pq.pop() == HeapEntry("C", 3))
    pq.insert(HeapEntry("A", 1))
    pq.insert(HeapEntry("C", 3))
    pq.insert(HeapEntry("B", 2))
    print(pq.pop())
    print(pq.pop())
    print(pq.pop())