import hashlib
import os
import re
import shutil
import subprocess
import tempfile
import urllib.request
import zipfile


class AutoUpdateService:
    @staticmethod
    def download_update_archive(download_url, destination_path):
        request = urllib.request.Request(
            download_url,
            headers={"User-Agent": "AnabasisManager-Updater"},
        )
        with urllib.request.urlopen(request, timeout=60) as response:
            with open(destination_path, "wb") as f:
                shutil.copyfileobj(response, f)

    @staticmethod
    def download_update_text(url):
        request = urllib.request.Request(
            url,
            headers={"User-Agent": "AnabasisManager-Updater"},
        )
        with urllib.request.urlopen(request, timeout=30) as response:
            return response.read().decode("utf-8", errors="replace")

    @staticmethod
    def sha256_file(path):
        digest = hashlib.sha256()
        with open(path, "rb") as f:
            for chunk in iter(lambda: f.read(1024 * 1024), b""):
                digest.update(chunk)
        return digest.hexdigest().lower()

    @staticmethod
    def extract_sha256_from_text(checksum_text, target_file_name):
        target = (target_file_name or "").strip().lower()
        for raw_line in checksum_text.splitlines():
            line = raw_line.strip()
            if not line:
                continue
            match = re.search(r"\b([A-Fa-f0-9]{64})\b", line)
            if not match:
                continue
            checksum = match.group(1).lower()
            if not target:
                return checksum
            line_lower = line.lower()
            if target in line_lower:
                return checksum
            if os.path.basename(target) in line_lower:
                return checksum
        return ""

    @classmethod
    def verify_update_checksum(cls, zip_path, checksum_url, download_name):
        if not checksum_url:
            raise RuntimeError("В релизе нет файла SHA256. Автообновление остановлено.")
        checksum_text = cls.download_update_text(checksum_url)
        expected_hash = cls.extract_sha256_from_text(checksum_text, download_name or os.path.basename(zip_path))
        if not expected_hash:
            raise RuntimeError("Не удалось найти SHA256 для архива обновления.")
        actual_hash = cls.sha256_file(zip_path)
        if actual_hash != expected_hash:
            raise RuntimeError("SHA256 не совпадает, обновление отменено.")

    @staticmethod
    def locate_extracted_root(extracted_dir):
        entries = []
        for name in os.listdir(extracted_dir):
            full_path = os.path.join(extracted_dir, name)
            if os.path.isdir(full_path):
                entries.append(full_path)
        if len(entries) == 1:
            candidate = entries[0]
            if os.path.exists(os.path.join(candidate, "AnabasisManager.exe")):
                return candidate
        return extracted_dir

    @staticmethod
    def build_update_script(app_dir, source_dir, exe_name, target_pid):
        script_path = os.path.join(tempfile.gettempdir(), "anabasis_apply_update.cmd")
        script_lines = [
            "@echo off",
            "setlocal EnableExtensions",
            f"set \"APP_DIR={app_dir}\"",
            f"set \"SRC_DIR={source_dir}\"",
            f"set \"EXE_NAME={exe_name}\"",
            f"set \"TARGET_PID={target_pid}\"",
            "set \"BACKUP_DIR=%TEMP%\\anabasis_backup_%RANDOM%%RANDOM%\"",
            "set \"UPDATE_LOG=%APP_DIR%\\update_error.log\"",
            "echo [%DATE% %TIME%] Update start > \"%UPDATE_LOG%\"",
            "if not exist \"%SRC_DIR%\\%EXE_NAME%\" (",
            "  echo Source executable not found: \"%SRC_DIR%\\%EXE_NAME%\" >> \"%UPDATE_LOG%\"",
            "  exit /b 3",
            ")",
            "set /a WAIT_LOOPS=0",
            ":wait_for_exit",
            "tasklist /FI \"PID eq %TARGET_PID%\" | find \"%TARGET_PID%\" >nul",
            "if %ERRORLEVEL% EQU 0 (",
            "  set /a WAIT_LOOPS+=1",
            "  if %WAIT_LOOPS% GEQ 180 (",
            "    echo Timeout waiting for process %TARGET_PID%, attempting force stop >> \"%UPDATE_LOG%\"",
            "    taskkill /PID %TARGET_PID% /T /F >nul 2>&1",
            "    timeout /t 2 /nobreak >nul",
            "    tasklist /FI \"PID eq %TARGET_PID%\" | find \"%TARGET_PID%\" >nul",
            "    if %ERRORLEVEL% EQU 0 goto :pid_still_running",
            "    goto :wait_image_unlock",
            "  )",
            "  timeout /t 1 /nobreak >nul",
            "  goto :wait_for_exit",
            ")",
            ":wait_image_unlock",
            "set /a IMG_LOOPS=0",
            ":check_image",
            "tasklist /FI \"IMAGENAME eq %EXE_NAME%\" | find /I \"%EXE_NAME%\" >nul",
            "if %ERRORLEVEL% EQU 0 (",
            "  set /a IMG_LOOPS+=1",
            "  if %IMG_LOOPS% GEQ 60 goto :image_still_running",
            "  timeout /t 1 /nobreak >nul",
            "  goto :check_image",
            ")",
            ":backup",
            "timeout /t 1 /nobreak >nul",
            "mkdir \"%BACKUP_DIR%\" >nul 2>&1",
            "robocopy \"%APP_DIR%\" \"%BACKUP_DIR%\" /E /NFL /NDL /NJH /NJS /NP /R:6 /W:2 >nul",
            "set \"RC=%ERRORLEVEL%\"",
            "if %RC% GEQ 8 goto :backup_error",
            "robocopy \"%SRC_DIR%\" \"%APP_DIR%\" /E /NFL /NDL /NJH /NJS /NP /R:12 /W:2 >nul",
            "set \"RC=%ERRORLEVEL%\"",
            "if %RC% GEQ 8 goto :rollback",
            "start \"\" \"%APP_DIR%\\%EXE_NAME%\"",
            "timeout /t 2 /nobreak >nul",
            "tasklist /FI \"IMAGENAME eq %EXE_NAME%\" | find /I \"%EXE_NAME%\" >nul",
            "if %ERRORLEVEL% NEQ 0 goto :rollback",
            "echo Update success >> \"%UPDATE_LOG%\"",
            "rmdir /S /Q \"%BACKUP_DIR%\" >nul 2>&1",
            "exit /b 0",
            ":rollback",
            "robocopy \"%BACKUP_DIR%\" \"%APP_DIR%\" /E /NFL /NDL /NJH /NJS /NP /R:6 /W:2 >nul",
            "start \"\" \"%APP_DIR%\\%EXE_NAME%\"",
            "echo Auto-update failed. Rollback executed. >> \"%UPDATE_LOG%\"",
            "exit /b 2",
            ":backup_error",
            "echo Auto-update failed during backup. Code %RC% >> \"%UPDATE_LOG%\"",
            "exit /b %RC%",
            ":pid_still_running",
            "echo Auto-update aborted: process %TARGET_PID% is still running after force stop. >> \"%UPDATE_LOG%\"",
            "exit /b 4",
            ":image_still_running",
            "echo Auto-update aborted: %EXE_NAME% still running and file lock may remain. >> \"%UPDATE_LOG%\"",
            "exit /b 5",
        ]
        with open(script_path, "w", encoding="utf-8", newline="\r\n") as f:
            f.write("\r\n".join(script_lines) + "\r\n")
        return script_path

    @staticmethod
    def launch_update_script(script_path, work_dir):
        creation_flags = 0
        if hasattr(subprocess, "CREATE_NEW_PROCESS_GROUP"):
            creation_flags |= subprocess.CREATE_NEW_PROCESS_GROUP
        if hasattr(subprocess, "DETACHED_PROCESS"):
            creation_flags |= subprocess.DETACHED_PROCESS
        subprocess.Popen(
            ["cmd.exe", "/c", script_path],
            cwd=work_dir,
            creationflags=creation_flags,
        )

    @staticmethod
    def launch_gui_updater(app_exe, source_dir, work_dir, target_pid, version=""):
        app_dir = os.path.dirname(app_exe)
        exe_name = os.path.basename(app_exe)
        updater_exe = os.path.join(app_dir, "AnabasisUpdater.exe")
        if not os.path.exists(updater_exe):
            raise RuntimeError("Файл AnabasisUpdater.exe не найден в папке приложения.")

        creation_flags = 0
        if hasattr(subprocess, "CREATE_NEW_PROCESS_GROUP"):
            creation_flags |= subprocess.CREATE_NEW_PROCESS_GROUP
        if hasattr(subprocess, "DETACHED_PROCESS"):
            creation_flags |= subprocess.DETACHED_PROCESS

        subprocess.Popen(
            [
                updater_exe,
                "--app-dir",
                app_dir,
                "--source-dir",
                source_dir,
                "--exe-name",
                exe_name,
                "--target-pid",
                str(target_pid),
                "--version",
                str(version or ""),
                "--work-dir",
                str(work_dir or ""),
            ],
            cwd=work_dir,
            creationflags=creation_flags,
        )

    @classmethod
    def prepare_update(cls, download_url, checksum_url, download_name):
        work_dir = tempfile.mkdtemp(prefix="anabasis_update_")
        zip_path = os.path.join(work_dir, "update.zip")
        unpack_dir = os.path.join(work_dir, "extracted")
        cls.download_update_archive(download_url, zip_path)
        cls.verify_update_checksum(zip_path, checksum_url, download_name)
        os.makedirs(unpack_dir, exist_ok=True)
        with zipfile.ZipFile(zip_path, "r") as archive:
            archive.extractall(unpack_dir)
        source_dir = cls.locate_extracted_root(unpack_dir)
        return work_dir, source_dir