#!/usr/bin/env python3
#
# InspIRCd -- Internet Relay Chat Daemon
#
#   Copyright (C) 2024 Val Lorentz <progval+git@progval.net>
#   Copyright (C) 2024 Sadie Powell <sadie@witchery.services>
#
# This file is part of InspIRCd.  InspIRCd is free software: you can
# redistribute it and/or modify it under the terms of the GNU General Public
# License as published by the Free Software Foundation, version 2.
#
# 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 General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#


import io
import os
import sys


class UnrealDB:
    def __init__(self, path):
        self.error = None
        try:
            with open(sys.argv[1], mode="rb") as fh:
                data = fh.read()
                if data.startswith(b"UnrealIRCd-DB-v1"):
                    self.data = io.BytesIO(data[40:])
                elif data.startswith(b"UnrealIRCd-DB"):
                    self.error = f"Unsupported database version: {data[0:32]}"
                else:
                    self.data = io.BytesIO(data)
        except OSError as e:
            self.error = f"Read error: {e}"

    def read_i16(self):
        return int.from_bytes(self.data.read(2), byteorder="little")

    def read_i32(self):
        return int.from_bytes(self.data.read(4), byteorder="little")

    def read_i64(self):
        return int.from_bytes(self.data.read(8), byteorder="little")

    def read_str(self):
        len = self.read_i16()
        if len == 0 or len == 0xFFFF:
            return ""
        return self.data.read(len).decode("utf-8")


def error(msg):
    print(msg, file=sys.stderr)
    sys.exit(1)


if len(sys.argv) < 3:
    program = os.path.basename(__file__)
    error(f"Usage: {program} <input-file> <output-file>")

db = UnrealDB(sys.argv[1])
if db.error:
    error(db.error)

version = db.read_i32()
if version != 100:
    error(f"Unrecognised channel database version: {version}")

count = db.read_i64()
print(f"Converting {count} channels ...")

try:
    with open(sys.argv[2], mode="w") as fh:
        for i in range(count):
            magic = db.read_i32()
            if magic != 0x11111111:
                error(f"Unrecognised database start magic: {magic}")

            channel = db.read_str()
            print(f'<permchannels name="{channel}"', file=fh)

            created = db.read_i64()
            print(f'              ts="{created}"', file=fh)

            topic = db.read_str()
            print(f'              topic="{topic}"', file=fh)

            topic_set_by = db.read_str()
            print(f'              topicsetby="{topic_set_by}"', file=fh)

            topic_set_at = db.read_i64()
            print(f'              topicts="{topic_set_at}"', file=fh)

            modes = db.read_str()
            mode_params = db.read_str()
            print(f'              modes="{modes} {mode_params}"', file=fh)

            mode_lock = db.read_str()  # unused
            for mode in ["ban", "banexception", "invex"]:
                mode_count = db.read_i32()
                if mode_count == 0:
                    continue

                print(f'              {mode}list="', end="", file=fh)
                for j in range(mode_count):
                    mode_str = db.read_str()
                    mode_set_by = db.read_str()
                    mode_set_at = db.read_i64()
                    print(f"{mode_str} {mode_set_by} {mode_set_at} ", end="", file=fh)
                print('"', file=fh)

            magic = db.read_i32()
            if magic != 0x22222222:
                error(f"Unrecognised database end magic: {magic}")

            print(">", file=fh)


except OSError as e:
    error(f"Write error: {e}")