from collections.abc import Callable
from utils.literal import Literal
from utils.memory_array import MemoryArray
from utils.memory_cell import MemoryCell
from utils.memory_range import mrange


UNUSED_MARK = "UNUSED"
DELETED_MARK = "DELETED"

class HashTableOpenAddressing:
    def __init__(self, m: Literal, f: Callable[[MemoryCell, Literal, Literal], Literal]):
        if not isinstance(m, Literal):
            m = Literal(m)
        self.m = m
        self.f = f
        self.table = MemoryArray(m)
        for i in mrange(m):
            self.table[i].value = UNUSED_MARK

    def insert(self, x: MemoryCell):
        with MemoryCell(0) as i:
            while i < self.m:
                j = self.f(x, i, self.m)
                if self.is_free(j):
                    self.table[j].set(x)
                    return True
                i.set(i.succ())
        return False

    def search(self, x: MemoryCell):
        with MemoryCell(0) as i:
            while i < self.m:
                j = self.f(x, i, self.m)
                if self.is_unused(j):
                    return False
                if self.table[j] == x:
                    return True
                i.set(i.succ())
        return False

    def delete(self, x: MemoryCell):
        with MemoryCell(0) as i:
            while i < self.m:
                j = self.f(x, i, self.m)
                if self.is_unused(j):
                    return False
                if self.table[j] == x:
                    self.table[j].value = DELETED_MARK
                    return True
                i.set(i.succ())
        return False

    def __str__(self):
        return str(self.table)

    def alpha(self):
        with MemoryCell(0) as i:
            used = 0
            while i < self.m:
                used += 0 if self.is_free(i) else 1
                i.set(i.succ())
        return used / int(self.m)

    def is_unused(self, i: Literal):
        if self.table[i].value == UNUSED_MARK:
            return True
        return False

    def is_deleted(self, i: Literal):
        if self.table[i].value == DELETED_MARK:
            return True
        return False

    def is_free(self, i: Literal):
        return self.is_unused(i) or self.is_deleted(i)