# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See LICENSE in the project root
# for license information.

from __future__ import absolute_import, division, print_function, unicode_literals

import json
import os
import re
import runpy
import sys

# debugpy.__main__ should have preloaded pydevd properly before importing this module.
# Otherwise, some stdlib modules above might have had imported threading before pydevd
# could perform the necessary detours in it.
assert "pydevd" in sys.modules
import pydevd

import debugpy
from debugpy.common import compat, fmt, log
from debugpy.server import api


TARGET = "<filename> | -m <module> | -c <code> | --pid <pid>"

HELP = """debugpy {0}
See https://aka.ms/debugpy for documentation.

Usage: debugpy [--listen | --connect] [<address>:]<port>
               [--wait-for-client]
               [--configure-<name> <value>]...
               [--log-to <path>] [--log-to-stderr]
               {1}
               [<arg>]...
""".format(
    debugpy.__version__, TARGET
)


class Options(object):
    mode = None
    address = None
    log_to = None
    log_to_stderr = False
    target = None
    target_kind = None
    wait_for_client = False
    adapter_access_token = None


options = Options()
options.config = {"subProcess": True}


def in_range(parser, start, stop):
    def parse(s):
        n = parser(s)
        if start is not None and n < start:
            raise ValueError(fmt("must be >= {0}", start))
        if stop is not None and n >= stop:
            raise ValueError(fmt("must be < {0}", stop))
        return n

    return parse


pid = in_range(int, 0, None)


def print_help_and_exit(switch, it):
    print(HELP, file=sys.stderr)
    sys.exit(0)


def print_version_and_exit(switch, it):
    print(debugpy.__version__)
    sys.exit(0)


def set_arg(varname, parser=(lambda x: x)):
    def do(arg, it):
        value = parser(next(it))
        setattr(options, varname, value)

    return do


def set_const(varname, value):
    def do(arg, it):
        setattr(options, varname, value)

    return do


def set_address(mode):
    def do(arg, it):
        if options.address is not None:
            raise ValueError("--listen and --connect are mutually exclusive")

        # It's either host:port, or just port.
        value = next(it)
        host, sep, port = value.partition(":")
        if not sep:
            host = "127.0.0.1"
            port = value
        try:
            port = int(port)
        except Exception:
            port = -1
        if not (0 <= port < 2 ** 16):
            raise ValueError("invalid port number")

        options.mode = mode
        options.address = (host, port)

    return do


def set_config(arg, it):
    prefix = "--configure-"
    assert arg.startswith(prefix)
    name = arg[len(prefix) :]
    value = next(it)

    if name not in options.config:
        raise ValueError(fmt("unknown property {0!r}", name))

    expected_type = type(options.config[name])
    try:
        if expected_type is bool:
            value = {"true": True, "false": False}[value.lower()]
        else:
            value = expected_type(value)
    except Exception:
        raise ValueError(fmt("{0!r} must be a {1}", name, expected_type.__name__))

    options.config[name] = value


def set_target(kind, parser=(lambda x: x), positional=False):
    def do(arg, it):
        options.target_kind = kind
        options.target = parser(arg if positional else next(it))

    return do


# fmt: off
switches = [
    # Switch                    Placeholder         Action
    # ======                    ===========         ======

    # Switches that are documented for use by end users.
    ("-(\?|h|-help)",           None,               print_help_and_exit),
    ("-(V|-version)",           None,               print_version_and_exit),
    ("--log-to" ,               "<path>",           set_arg("log_to")),
    ("--log-to-stderr",         None,               set_const("log_to_stderr", True)),
    ("--listen",                "<address>",        set_address("listen")),
    ("--wait-for-client",       None,               set_const("wait_for_client", True)),
    ("--configure-.+",          "<value>",          set_config),

    # Switches that are used internally by the client or debugpy itself.
    ("--connect",               "<address>",        set_address("connect")),
    ("--adapter-access-token",   "<token>",         set_arg("adapter_access_token")),

    # Targets. The "" entry corresponds to positional command line arguments,
    # i.e. the ones not preceded by any switch name.
    ("",                        "<filename>",       set_target("file", positional=True)),
    ("-m",                      "<module>",         set_target("module")),
    ("-c",                      "<code>",           set_target("code")),
    ("--pid",                   "<pid>",            set_target("pid", pid)),
]
# fmt: on


def consume_argv():
    while len(sys.argv) >= 2:
        value = sys.argv[1]
        del sys.argv[1]
        yield value


def parse_argv():
    seen = set()
    it = consume_argv()

    while True:
        try:
            arg = next(it)
        except StopIteration:
            raise ValueError("missing target: " + TARGET)

        switch = compat.filename(arg)
        if not switch.startswith("-"):
            switch = ""
        for pattern, placeholder, action in switches:
            if re.match("^(" + pattern + ")$", switch):
                break
        else:
            raise ValueError("unrecognized switch " + switch)

        if switch in seen:
            raise ValueError("duplicate switch " + switch)
        else:
            seen.add(switch)

        try:
            action(arg, it)
        except StopIteration:
            assert placeholder is not None
            raise ValueError(fmt("{0}: missing {1}", switch, placeholder))
        except Exception as exc:
            raise ValueError(fmt("invalid {0} {1}: {2}", switch, placeholder, exc))

        if options.target is not None:
            break

    if options.mode is None:
        raise ValueError("either --listen or --connect is required")
    if options.adapter_access_token is not None and options.mode != "connect":
        raise ValueError("--adapter-access-token requires --connect")
    if options.target_kind == "pid" and options.wait_for_client:
        raise ValueError("--pid does not support --wait-for-client")

    assert options.target is not None
    assert options.target_kind is not None
    assert options.address is not None


def start_debugging(argv_0):
    # We need to set up sys.argv[0] before invoking either listen() or connect(),
    # because they use it to report the "process" event. Thus, we can't rely on
    # run_path() and run_module() doing that, even though they will eventually.
    sys.argv[0] = compat.filename_str(argv_0)
    log.debug("sys.argv after patching: {0!r}", sys.argv)

    debugpy.configure(options.config)

    if options.mode == "listen":
        debugpy.listen(options.address)
    elif options.mode == "connect":
        debugpy.connect(options.address, access_token=options.adapter_access_token)
    else:
        raise AssertionError(repr(options.mode))

    if options.wait_for_client:
        debugpy.wait_for_client()


def run_file():
    start_debugging(options.target)

    # run_path has one difference with invoking Python from command-line:
    # if the target is a file (rather than a directory), it does not add its
    # parent directory to sys.path. Thus, importing other modules from the
    # same directory is broken unless sys.path is patched here.
    if os.path.isfile(options.target):
        dir = os.path.dirname(options.target)
        sys.path.insert(0, dir)
    else:
        log.debug("Not a file: {0!r}", options.target)

    log.describe_environment("Pre-launch environment:")
    log.info("Running file {0!r}", options.target)

    runpy.run_path(options.target, run_name=compat.force_str("__main__"))


def run_module():
    # Add current directory to path, like Python itself does for -m. This must
    # be in place before trying to use find_spec below to resolve submodules.
    sys.path.insert(0, "")

    # We want to do the same thing that run_module() would do here, without
    # actually invoking it. On Python 3, it's exposed as a public API, but
    # on Python 2, we have to invoke a private function in runpy for this.
    # Either way, if it fails to resolve for any reason, just leave argv as is.
    argv_0 = sys.argv[0]
    try:
        if sys.version_info >= (3,):
            from importlib.util import find_spec

            spec = find_spec(options.target)
            if spec is not None:
                argv_0 = spec.origin
        else:
            _, _, _, argv_0 = runpy._get_module_details(options.target)
    except Exception:
        log.swallow_exception("Error determining module path for sys.argv")

    start_debugging(argv_0)

    # On Python 2, module name must be a non-Unicode string, because it ends up
    # a part of module's __package__, and Python will refuse to run the module
    # if __package__ is Unicode.
    target = (
        compat.filename_bytes(options.target)
        if sys.version_info < (3,)
        else options.target
    )

    log.describe_environment("Pre-launch environment:")
    log.info("Running module {0!r}", target)

    # Docs say that runpy.run_module is equivalent to -m, but it's not actually
    # the case for packages - -m sets __name__ to "__main__", but run_module sets
    # it to "pkg.__main__". This breaks everything that uses the standard pattern
    # __name__ == "__main__" to detect being run as a CLI app. On the other hand,
    # runpy._run_module_as_main is a private function that actually implements -m.
    try:
        run_module_as_main = runpy._run_module_as_main
    except AttributeError:
        log.warning("runpy._run_module_as_main is missing, falling back to run_module.")
        runpy.run_module(target, alter_sys=True)
    else:
        run_module_as_main(target, alter_argv=True)


def run_code():
    # Add current directory to path, like Python itself does for -c.
    sys.path.insert(0, "")
    code = compile(options.target, "<string>", "exec")

    start_debugging("-c")

    log.describe_environment("Pre-launch environment:")
    log.info("Running code:\n\n{0}", options.target)

    eval(code, {})


def attach_to_pid():
    pid = options.target
    log.info("Attaching to process with PID={0}", pid)

    encode = lambda s: list(bytearray(s.encode("utf-8"))) if s is not None else None

    script_dir = os.path.dirname(debugpy.server.__file__)
    assert os.path.exists(script_dir)
    script_dir = encode(script_dir)

    setup = {
        "mode": options.mode,
        "address": options.address,
        "wait_for_client": options.wait_for_client,
        "log_to": options.log_to,
        "adapter_access_token": options.adapter_access_token,
    }
    setup = encode(json.dumps(setup))

    python_code = """
import codecs;
import json;
import sys;

decode = lambda s: codecs.utf_8_decode(bytearray(s))[0] if s is not None else None;

script_dir = decode({script_dir});
setup = json.loads(decode({setup}));

sys.path.insert(0, script_dir);
import attach_pid_injected;
del sys.path[0];

attach_pid_injected.attach(setup);
"""
    python_code = (
        python_code.replace("\r", "")
        .replace("\n", "")
        .format(script_dir=script_dir, setup=setup)
    )
    log.info("Code to be injected: \n{0}", python_code.replace(";", ";\n"))

    # pydevd restriction on characters in injected code.
    assert not (
        {'"', "'", "\r", "\n"} & set(python_code)
    ), "Injected code should not contain any single quotes, double quotes, or newlines."

    pydevd_attach_to_process_path = os.path.join(
        os.path.dirname(pydevd.__file__), "pydevd_attach_to_process"
    )

    assert os.path.exists(pydevd_attach_to_process_path)
    sys.path.append(pydevd_attach_to_process_path)

    try:
        import add_code_to_python_process  # noqa

        log.info("Injecting code into process with PID={0} ...", pid)
        add_code_to_python_process.run_python_code(
            pid,
            python_code,
            connect_debugger_tracing=True,
            show_debug_info=int(os.getenv("DEBUGPY_ATTACH_BY_PID_DEBUG_INFO", "0")),
        )
    except Exception:
        log.reraise_exception("Code injection into PID={0} failed:", pid)
    log.info("Code injection into PID={0} completed.", pid)


def main():
    original_argv = list(sys.argv)
    try:
        parse_argv()
    except Exception as exc:
        print(HELP + "\nError: " + str(exc), file=sys.stderr)
        sys.exit(2)

    if options.log_to is not None:
        debugpy.log_to(options.log_to)
    if options.log_to_stderr:
        debugpy.log_to(sys.stderr)

    api.ensure_logging()

    log.info(
        "sys.argv before parsing: {0!r}\n" "         after parsing:  {1!r}",
        original_argv,
        sys.argv,
    )

    try:
        run = {
            "file": run_file,
            "module": run_module,
            "code": run_code,
            "pid": attach_to_pid,
        }[options.target_kind]
        run()
    except SystemExit as exc:
        log.reraise_exception("Debuggee exited via SystemExit: {0!r}", exc.code, level="debug")
