# This file is part of the Trezor project.
#
# Copyright (C) 2012-2022 SatoshiLabs and contributors
#
# This library is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License version 3
# as published by the Free Software Foundation.
#
# This library 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 Lesser General Public License for more details.
#
# You should have received a copy of the License along with this library.
# If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.

import logging
import os
import subprocess
import time
from pathlib import Path
from typing import Any, Dict, Iterable, List, Optional, Sequence, TextIO, Union, cast

from ..debuglink import TrezorClientDebugLink
from ..transport.udp import UdpTransport

LOG = logging.getLogger(__name__)

EMULATOR_WAIT_TIME = 60


def _rm_f(path: Path) -> None:
    try:
        path.unlink()
    except FileNotFoundError:
        pass


class Emulator:
    STORAGE_FILENAME: str

    def __init__(
        self,
        executable: Path,
        profile_dir: str,
        *,
        logfile: Union[TextIO, str, Path, None] = None,
        storage: Optional[bytes] = None,
        headless: bool = False,
        debug: bool = True,
        auto_interact: bool = True,
        extra_args: Iterable[str] = (),
    ) -> None:
        self.executable = Path(executable).resolve()
        if not executable.exists():
            raise ValueError(f"emulator executable not found: {self.executable}")

        self.profile_dir = Path(profile_dir).resolve()
        if not self.profile_dir.exists():
            self.profile_dir.mkdir(parents=True)
        elif not self.profile_dir.is_dir():
            raise ValueError("profile_dir is not a directory")

        self.workdir = self.profile_dir

        self.storage = self.profile_dir / self.STORAGE_FILENAME
        if storage:
            self.storage.write_bytes(storage)

        if logfile:
            self.logfile = logfile
        else:
            self.logfile = self.profile_dir / "trezor.log"

        # Using `client` property instead to assert `not None`
        self._client: Optional[TrezorClientDebugLink] = None
        self.process: Optional[subprocess.Popen] = None

        self.port = 21324
        self.headless = headless
        self.debug = debug
        self.auto_interact = auto_interact
        self.extra_args = list(extra_args)

    @property
    def client(self) -> TrezorClientDebugLink:
        """So that type-checkers do not see `client` as `Optional`.

        (it is not None between `start()` and `stop()` calls)
        """
        if self._client is None:
            raise RuntimeError
        return self._client

    def make_args(self) -> List[str]:
        return []

    def make_env(self) -> Dict[str, str]:
        return os.environ.copy()

    def _get_transport(self) -> UdpTransport:
        return UdpTransport(f"127.0.0.1:{self.port}")

    def wait_until_ready(self, timeout: float = EMULATOR_WAIT_TIME) -> None:
        assert self.process is not None, "Emulator not started"
        transport = self._get_transport()
        transport.open()
        LOG.info("Waiting for emulator to come up...")
        start = time.monotonic()
        try:
            while True:
                if transport._ping():
                    break
                if self.process.poll() is not None:
                    raise RuntimeError("Emulator proces died")

                elapsed = time.monotonic() - start
                if elapsed >= timeout:
                    raise TimeoutError("Can't connect to emulator")

                time.sleep(0.1)
        finally:
            transport.close()

        LOG.info(f"Emulator ready after {time.monotonic() - start:.3f} seconds")

    def wait(self, timeout: Optional[float] = None) -> int:
        assert self.process is not None, "Emulator not started"
        ret = self.process.wait(timeout=timeout)
        self.process = None
        self.stop()
        return ret

    def launch_process(self) -> subprocess.Popen:
        args = self.make_args()
        env = self.make_env()

        # Opening the file if it is not already opened
        if hasattr(self.logfile, "write"):
            output = self.logfile
        else:
            assert isinstance(self.logfile, (str, Path))
            output = open(self.logfile, "w")

        return subprocess.Popen(
            [str(self.executable)] + args + self.extra_args,
            cwd=self.workdir,
            stdout=cast(TextIO, output),
            stderr=subprocess.STDOUT,
            env=env,
        )

    def start(self) -> None:
        if self.process:
            if self.process.poll() is not None:
                # process has died, stop and start again
                LOG.info("Starting from a stopped process.")
                self.stop()
            else:
                # process is running, no need to start again
                return

        self.process = self.launch_process()
        try:
            self.wait_until_ready()
        except TimeoutError:
            # Assuming that after the default 60-second timeout, the process is stuck
            LOG.warning(f"Emulator did not come up after {EMULATOR_WAIT_TIME} seconds")
            self.process.kill()
            raise

        (self.profile_dir / "trezor.pid").write_text(str(self.process.pid) + "\n")
        (self.profile_dir / "trezor.port").write_text(str(self.port) + "\n")

        transport = self._get_transport()
        self._client = TrezorClientDebugLink(
            transport, auto_interact=self.auto_interact
        )
        self._client.open()

    def stop(self) -> None:
        if self._client:
            self._client.close()
        self._client = None

        if self.process:
            LOG.info("Terminating emulator...")
            start = time.monotonic()
            self.process.terminate()
            try:
                self.process.wait(EMULATOR_WAIT_TIME)
                end = time.monotonic()
                LOG.info(f"Emulator shut down after {end - start:.3f} seconds")
            except subprocess.TimeoutExpired:
                LOG.info("Emulator seems stuck. Sending kill signal.")
                self.process.kill()

        _rm_f(self.profile_dir / "trezor.pid")
        _rm_f(self.profile_dir / "trezor.port")
        self.process = None

    def restart(self) -> None:
        self.stop()
        self.start()

    def __enter__(self) -> "Emulator":
        return self

    def __exit__(self, exc_type: Any, exc_value: Any, traceback: Any) -> None:
        self.stop()

    def get_storage(self) -> bytes:
        return self.storage.read_bytes()


class CoreEmulator(Emulator):
    STORAGE_FILENAME = "trezor.flash"

    def __init__(
        self,
        *args: Any,
        port: Optional[int] = None,
        main_args: Sequence[str] = ("-m", "main"),
        workdir: Optional[Path] = None,
        sdcard: Optional[bytes] = None,
        disable_animation: bool = True,
        heap_size: str = "20M",
        **kwargs: Any,
    ) -> None:
        super().__init__(*args, **kwargs)
        if workdir is not None:
            self.workdir = Path(workdir).resolve()

        self.sdcard = self.profile_dir / "trezor.sdcard"
        if sdcard is not None:
            self.sdcard.write_bytes(sdcard)

        if port:
            self.port = port
        self.disable_animation = disable_animation
        self.main_args = list(main_args)
        self.heap_size = heap_size

    def make_env(self) -> Dict[str, str]:
        env = super().make_env()
        env.update(
            TREZOR_PROFILE_DIR=str(self.profile_dir),
            TREZOR_PROFILE=str(self.profile_dir),
            TREZOR_UDP_PORT=str(self.port),
        )
        if self.headless:
            env["SDL_VIDEODRIVER"] = "dummy"
        if self.headless or self.disable_animation:
            env["TREZOR_DISABLE_FADE"] = "1"
            env["TREZOR_DISABLE_ANIMATION"] = "1"

        return env

    def make_args(self) -> List[str]:
        pyopt = "-O0" if self.debug else "-O1"
        return (
            [pyopt, "-X", f"heapsize={self.heap_size}"]
            + self.main_args
            + self.extra_args
        )


class LegacyEmulator(Emulator):
    STORAGE_FILENAME = "emulator.img"

    def make_env(self) -> Dict[str, str]:
        env = super().make_env()
        if self.headless:
            env["SDL_VIDEODRIVER"] = "dummy"
        return env
