from bitarray import bitarray


class BZZCompressor:
    def decompress(self, input_file_path) -> bytes:
        data = bitarray(endian="big")
        output_buffer = []

        # read the input file
        try:
            with open(input_file_path, "rb") as input_file:
                data.fromfile(input_file)
        except IOError:
            print("Could not open input file ...")
            raise

        if len(data) > 9:
            # Getting our method, this is likely imprecise, since I'm one dealing with one method type, but it gets what I want
            method = data[0:8] | bitarray("00001010")
            # We move on to the next byte in data
            del data[0:8]

            # Gathering variables based on the method according to https://problemkaputt.de/psxspx-cdrom-file-compression-bzz.htm
            # Note: bin(int)[2:].zfill(8) converts a number to an 8-bit binary string

            # `>> 3` is the same as dividing by 8
            shifter = (method >> 3) & bitarray(bin(0x03)[2:].zfill(8))
            len_bits = (method & bitarray(bin(0x07)[2:].zfill(8))) ^ bitarray(
                bin(0x07)[2:].zfill(8)
            )

            # The bin() function only returns the second half of the byte, so we pad the byte
            len_mask = bitarray(bin((1 << int(len_bits.to01(), 2)) - 1)[2:].zfill(8))

            threshold = len_mask >> 1
            if int(threshold.to01(), 2) > 0x07:
                threshold = bitarray(bin(0x13).zfill(8))

            len_table = []

            for i in range(int(len_mask.to01(), 2)):
                if i > int(threshold.to01(), 2):
                    len_table.append(
                        (i - int(threshold.to01(), 2) << int(shifter.to01(), 2))
                        + int(threshold.to01(), 2)
                        + 3
                    )
                else:
                    len_table.append(i + 3)

            num_flags = bitarray(bin(int(data[0:24].to01(), 2) + 1)[2:].zfill(24))
            del data[0:24]

            print(f"Method: {method.tobytes()}")
            print(f"Shifter: {shifter.tobytes()}")
            print(f"Len Bits: {len_bits.tobytes()}")
            print(f"Len Mask: {len_mask.tobytes()}")
            print(f"Threshold: {threshold.tobytes()}")
            print(f"Len Table: {len_table}")
            print(f"Num Flags: {num_flags.tobytes()}")

            flag_bits = bitarray(bin(int(data[0:8].to01(), 2) + 0x100)[2:])
            del data[0:8]

            print(f"Starting flag_bits: {flag_bits.tobytes()}")
            hold_val = b""

            while int(num_flags.to01(), 2) > 0:
                # Any time we reset the flag_bits, it's length is 9 digits. So we shift right and trim.
                # Otherwise, we just shift right
                carry = flag_bits[-1]
                flag_bits = flag_bits >> 1

                if len(flag_bits) > 8 and flag_bits[0] == 0:
                    flag_bits = flag_bits[1:]

                print(f"Carry: {carry}")
                print(f"Flag Bits: {flag_bits}")

                if int(flag_bits.to01(), 2) == 0:
                    flag_bits = bitarray(bin(int(data[0:8].to01(), 2) + 0x100)[2:])
                    del data[0:8]
                    continue

                if carry:
                    if len(data) == 0:
                        print("Error processing file. Reached of data stream early.")
                        return

                    output_buffer.append(data[0:8])
                    del data[0:8]
                else:
                    if len(data) <= 8:
                        print("Error processing file. Reached of data stream early.")
                        return

                    distance_data = data[0:16]
                    del data[0:16]

                    length = len_table[
                        int(
                            (
                                distance_data
                                & bitarray(bin(int(len_mask.to01(), 2))[2:].zfill(16))
                            ).to01(),
                            2,
                        )
                    ]

                    displacement = distance_data >> int(len_bits.to01(), 2)

                    if displacement == 0:
                        print("Error processing file. Displacement was 0")
                        return

                    print(f"Output Buffer Size: {len(output_buffer)}")
                    print(f"Distance Data: {distance_data.tobytes()}")
                    print(f"Displacement: {int(displacement.to01(), 2)}")
                    print(f"Length: {length}")

                    for i in range(length):
                        output_buffer.append(
                            output_buffer[-int(displacement.to01(), 2)]
                        )

                num_flags = bitarray(bin(int(num_flags.to01(), 2) - 1)[2:].zfill(24))

            if len(data) > 0:
                output_buffer.append(
                    bitarray(
                        data.to01() + "0".join("" for i in range(8 - len(data)))
                    ).tobytes()
                )

        else:
            # If the file is less than 9 bits, it's just output
            for i in data.tobytes():
                output_buffer.append(i)

        out_data = b"".join(output_buffer)

        try:
            if "bin_extract" in input_file_path[0:11]:
                output_file_path = input_file_path[12:]
            else:
                output_file_path = input_file_path

            if "/" in output_file_path:
                output_file_name = output_file_path.split("/")[-1]
            else:
                output_file_name = output_file_path

            # TODO: Create file path, if it doesn't exist
            with open(
                f"decompressed_files/{output_file_name[:4]}.file", "wb"
            ) as outfile:
                outfile.write(out_data)
                print(f"File {output_file_name} saved successfully!")
        except IOError:
            print(f"Unable to write file for {input_file_path}")


compressor = BZZCompressor()

compressor.decompress("bin_extract/level/mc/mccave01.bzz")