import os

from conan.api.output import ConanOutput
from conan.internal.cache.home_paths import HomePaths

from conans.client.loader import load_python_file
from conans.client.profile_loader import ProfileLoader
from conans.errors import ConanException, scoped_traceback
from conans.model.profile import Profile

DEFAULT_PROFILE_NAME = "default"


class ProfilesAPI:

    def __init__(self, conan_api):
        self._conan_api = conan_api
        self._home_paths = HomePaths(conan_api.cache_folder)

    def get_default_host(self):
        """
        :return: the path to the default "host" profile, either in the cache or as defined
            by the user in configuration
        """
        default_profile = os.environ.get("CONAN_DEFAULT_PROFILE")
        if default_profile is None:
            global_conf = self._conan_api.config.global_conf
            default_profile = global_conf.get("core:default_profile", default=DEFAULT_PROFILE_NAME)

        default_profile = os.path.join(self._home_paths.profiles_path, default_profile)
        if not os.path.exists(default_profile):
            msg = ("The default host profile '{}' doesn't exist.\n"
                   "You need to create a default profile (type 'conan profile detect' command)\n"
                   "or specify your own profile with '--profile:host=<myprofile>'")
            # TODO: Add detailed instructions when cli is improved
            raise ConanException(msg.format(default_profile))
        return default_profile

    def get_default_build(self):
        """
        :return: the path to the default "build" profile, either in the cache or as
            defined by the user in configuration
        """
        global_conf = self._conan_api.config.global_conf
        default_profile = global_conf.get("core:default_build_profile", default=DEFAULT_PROFILE_NAME)
        default_profile = os.path.join(self._home_paths.profiles_path, default_profile)
        if not os.path.exists(default_profile):
            msg = ("The default build profile '{}' doesn't exist.\n"
                   "You need to create a default profile (type 'conan profile detect' command)\n"
                   "or specify your own profile with '--profile:build=<myprofile>'")
            # TODO: Add detailed instructions when cli is improved
            raise ConanException(msg.format(default_profile))
        return default_profile

    def get_profiles_from_args(self, args):
        build_profiles = args.profile_build or [self.get_default_build()]
        host_profiles = args.profile_host or [self.get_default_host()]

        global_conf = self._conan_api.config.global_conf
        global_conf.validate()  # TODO: Remove this from here
        cache_settings = self._conan_api.config.settings_yml
        profile_plugin = self._load_profile_plugin()
        cwd = os.getcwd()
        profile_build = self._get_profile(build_profiles, args.settings_build, args.options_build,
                                          args.conf_build, cwd, cache_settings,
                                          profile_plugin, global_conf)
        profile_host = self._get_profile(host_profiles, args.settings_host, args.options_host, args.conf_host,
                                         cwd, cache_settings, profile_plugin, global_conf)
        return profile_host, profile_build

    def get_profile(self, profiles, settings=None, options=None, conf=None, cwd=None):
        """ Computes a Profile as the result of aggregating all the user arguments, first it
        loads the "profiles", composing them in order (last profile has priority), and
        finally adding the individual settings, options (priority over the profiles)
        """
        assert isinstance(profiles, list), "Please provide a list of profiles"
        global_conf = self._conan_api.config.global_conf
        global_conf.validate()  # TODO: Remove this from here
        cache_settings = self._conan_api.config.settings_yml
        profile_plugin = self._load_profile_plugin()

        profile = self._get_profile(profiles, settings, options, conf, cwd, cache_settings,
                                    profile_plugin, global_conf)
        return profile

    def _get_profile(self, profiles, settings, options, conf, cwd, cache_settings,
                     profile_plugin, global_conf):
        loader = ProfileLoader(self._conan_api.cache_folder)
        profile = loader.from_cli_args(profiles, settings, options, conf, cwd)
        if profile_plugin is not None:
            try:
                profile_plugin(profile)
            except Exception as e:
                msg = f"Error while processing 'profile.py' plugin"
                msg = scoped_traceback(msg, e, scope="/extensions/plugins")
                raise ConanException(msg)
        profile.process_settings(cache_settings)
        profile.conf.validate()
        # Apply the new_config to the profiles the global one, so recipes get it too
        profile.conf.rebase_conf_definition(global_conf)
        for k, v in sorted(profile.options._package_options.items()):
            ConanOutput().warning("Unscoped option definition is ambiguous.\n"
                                  f"Use '&:{k}={v}' to refer to the current package.\n"
                                  f"Use '*:{k}={v}' or other pattern if the intent was to apply to "
                                  f"dependencies", warn_tag="legacy")
        return profile

    def get_path(self, profile, cwd=None, exists=True):
        """
        :return: the resolved path of the given profile name, that could be in the cache,
            or local, depending on the "cwd"
        """
        cwd = cwd or os.getcwd()
        profiles_folder = self._home_paths.profiles_path
        profile_path = ProfileLoader.get_profile_path(profiles_folder, profile, cwd, exists=exists)
        return profile_path

    def list(self):
        """
        List all the profiles file sin the cache
        :return: an alphabetically ordered list of profile files in the default cache location
        """
        # List is to be extended (directories should not have a trailing slash)
        paths_to_ignore = ['.DS_Store']

        profiles = []
        profiles_path = self._home_paths.profiles_path
        if os.path.exists(profiles_path):
            for current_directory, _, files in os.walk(profiles_path, followlinks=True):
                files = filter(lambda file: os.path.relpath(
                    os.path.join(current_directory, file), profiles_path) not in paths_to_ignore, files)

                for filename in files:
                    rel_path = os.path.relpath(os.path.join(current_directory, filename),
                                               profiles_path)
                    profiles.append(rel_path)

        profiles.sort()
        return profiles

    @staticmethod
    def detect():
        """
        :return: an automatically detected Profile, with a "best guess" of the system settings
        """
        profile = Profile()
        from conans.client.conf.detect import detect_defaults_settings
        settings = detect_defaults_settings()
        for name, value in settings:
            profile.settings[name] = value
        # TODO: This profile is very incomplete, it doesn't have the processed_settings
        #  good enough at the moment for designing the API interface, but to improve
        return profile

    def _load_profile_plugin(self):
        profile_plugin = self._home_paths.profile_plugin_path
        if not os.path.exists(profile_plugin):
            raise ConanException("The 'profile.py' plugin file doesn't exist. If you want "
                                 "to disable it, edit its contents instead of removing it")

        mod, _ = load_python_file(profile_plugin)
        if hasattr(mod, "profile_plugin"):
            return mod.profile_plugin
