Structures.py

class Block:
    def __init__(self, mining_time: float = 0):
        self.mining_time: float = mining_time
        # timestamp is calculated when a block is added to the chain
        self.timestamp: float = 0

    def __str__(self):
        return "\n".join(["mining time: {}".format(self.mining_time), "timestamp: {}".format(self.timestamp)])


class Blockchain:
    def __init__(self):
        self.chain: list[Block] = []

    def add_block(self, block: Block):
        if len(self.chain) != 0:
            block.timestamp = self.get_global_time_of_chain() + block.mining_time
        # edge case if we are adding genesis block
        else:
            block.timestamp = block.mining_time
        self.chain.append(block)

    def pop(self) -> Block:
        return self.chain.pop()

    def remove_blocks_from_end(self, num_blocks: int) -> None:
        for i in range(num_blocks):
            self.chain.pop()

    def get_global_time_of_chain(self) -> float:
        # check that chain is non-empty
        if len(self.chain) == 0:
            return 0.0
        else:
            return self.chain[-1].timestamp

    def get_block_at_index(self, index: int) -> Block:
        return self.chain[index]

    def __len__(self):
        return len(self.chain)

    def __str__(self):
        output = []
        for i in range(len(self.chain)):
            output.append("Block: {}".format(i+1))
            output.append("*" * 40)
            output.append(self.chain[i].__str__())
            output.append("-" * 40)
        return "\n".join(output)