import collections
import logging
import os

from galaxy.util import (
    asbool,
    plugin_config
)
from .container_classes import (
    CONTAINER_CLASSES,
    DOCKER_CONTAINER_TYPE,
    NULL_CONTAINER,
    SINGULARITY_CONTAINER_TYPE,
)
from .container_resolvers import ResolutionCache
from .container_resolvers.explicit import (
    ExplicitContainerResolver,
    ExplicitSingularityContainerResolver,
)
from .container_resolvers.mulled import (
    BuildMulledDockerContainerResolver,
    BuildMulledSingularityContainerResolver,
    CachedMulledDockerContainerResolver,
    CachedMulledSingularityContainerResolver,
    MulledDockerContainerResolver,
    MulledSingularityContainerResolver,
)
from .requirements import (
    ContainerDescription,
)

log = logging.getLogger(__name__)


DEFAULT_CONTAINER_TYPE = DOCKER_CONTAINER_TYPE
ALL_CONTAINER_TYPES = [DOCKER_CONTAINER_TYPE, SINGULARITY_CONTAINER_TYPE]

ResolvedContainerDescription = collections.namedtuple('ResolvedContainerDescription', ['container_resolver', 'container_description'])


class ContainerFinder(object):

    def __init__(self, app_info, mulled_resolution_cache=None):
        self.app_info = app_info
        self.container_registry = ContainerRegistry(app_info, mulled_resolution_cache=mulled_resolution_cache)

    def _enabled_container_types(self, destination_info):
        return [t for t in ALL_CONTAINER_TYPES if self.__container_type_enabled(t, destination_info)]

    def find_best_container_description(self, enabled_container_types, tool_info, **kwds):
        """Regardless of destination properties - find best container for tool.

        Given container types and container.ToolInfo description of the tool."""
        return self.container_registry.find_best_container_description(enabled_container_types, tool_info, **kwds)

    def resolve(self, enabled_container_types, tool_info, **kwds):
        """Regardless of destination properties - find ResolvedContainerDescription for tool."""
        return self.container_registry.resolve(enabled_container_types, tool_info, **kwds)

    def find_container(self, tool_info, destination_info, job_info):
        enabled_container_types = self._enabled_container_types(destination_info)

        # Short-cut everything else and just skip checks if no container type is enabled.
        if not enabled_container_types:
            return NULL_CONTAINER

        def __destination_container(container_description=None, container_id=None, container_type=None):
            if container_description:
                container_id = container_description.identifier
                container_type = container_description.type
            container = self.__destination_container(
                container_id,
                container_type,
                tool_info,
                destination_info,
                job_info,
                container_description,
            )
            return container

        def container_from_description_from_dicts(destination_container_dicts):
            for destination_container_dict in destination_container_dicts:
                container_description = ContainerDescription.from_dict(destination_container_dict)
                if container_description:
                    container = __destination_container(container_description)
                    if container:
                        return container

        if "container_override" in destination_info:
            container = container_from_description_from_dicts(destination_info["container_override"])
            if container:
                return container

        # If destination forcing Galaxy to use a particular container do it,
        # this is likely kind of a corner case. For instance if deployers
        # do not trust the containers annotated in tools.
        for container_type in CONTAINER_CLASSES.keys():
            container_id = self.__overridden_container_id(container_type, destination_info)
            if container_id:
                container = __destination_container(container_type=container_type, container_id=container_id)
                if container:
                    return container

        # Otherwise lets see if we can find container for the tool.
        container_description = self.find_best_container_description(enabled_container_types, tool_info)
        container = __destination_container(container_description)
        if container:
            return container

        # If we still don't have a container, check to see if any container
        # types define a default container id and use that.
        if "container" in destination_info:
            container = container_from_description_from_dicts(destination_info["container"])
            if container:
                return container

        for container_type in CONTAINER_CLASSES.keys():
            container_id = self.__default_container_id(container_type, destination_info)
            if container_id:
                container = __destination_container(container_type=container_type, container_id=container_id)
                if container:
                    return container

        return NULL_CONTAINER

    def resolution_cache(self):
        cache = ResolutionCache()
        if self.container_registry.mulled_resolution_cache is not None:
            cache.mulled_resolution_cache = self.container_registry.mulled_resolution_cache
        return cache

    def __overridden_container_id(self, container_type, destination_info):
        if not self.__container_type_enabled(container_type, destination_info):
            return None
        if "%s_container_id_override" % container_type in destination_info:
            return destination_info.get("%s_container_id_override" % container_type)
        if "%s_image_override" % container_type in destination_info:
            return self.__build_container_id_from_parts(container_type, destination_info, mode="override")

    def __build_container_id_from_parts(self, container_type, destination_info, mode):
        repo = ""
        owner = ""
        repo_key = "%s_repo_%s" % (container_type, mode)
        owner_key = "%s_owner_%s" % (container_type, mode)
        if repo_key in destination_info:
            repo = destination_info[repo_key] + "/"
        if owner_key in destination_info:
            owner = destination_info[owner_key] + "/"
        cont_id = repo + owner + destination_info["%s_image_%s" % (container_type, mode)]
        tag_key = "%s_tag_%s" % (container_type, mode)
        if tag_key in destination_info:
            cont_id += ":" + destination_info[tag_key]
        return cont_id

    def __default_container_id(self, container_type, destination_info):
        if not self.__container_type_enabled(container_type, destination_info):
            return None
        key = "%s_default_container_id" % container_type
        # Also allow docker_image...
        if key not in destination_info:
            key = "%s_image" % container_type
        if key in destination_info:
            return destination_info.get(key)
        elif "%s_image_default" % container_type in destination_info:
            return self.__build_container_id_from_parts(container_type, destination_info, mode="default")
        return None

    def __destination_container(self, container_id, container_type, tool_info, destination_info, job_info, container_description=None):
        # TODO: ensure destination_info is dict-like
        if not self.__container_type_enabled(container_type, destination_info):
            return NULL_CONTAINER

        # TODO: Right now this assumes all containers available when a
        # container type is - there should be more thought put into this.
        # Checking which are available - settings policies for what can be
        # auto-fetched, etc....
        return CONTAINER_CLASSES[container_type](container_id, self.app_info, tool_info, destination_info, job_info, container_description)

    def __container_type_enabled(self, container_type, destination_info):
        return asbool(destination_info.get("%s_enabled" % container_type, False))


class NullContainerFinder(object):

    def find_container(self, tool_info, destination_info, job_info):
        return []


class ContainerRegistry(object):
    """Loop through enabled ContainerResolver plugins and find first match."""

    def __init__(self, app_info, mulled_resolution_cache=None):
        self.resolver_classes = self.__resolvers_dict()
        self.enable_mulled_containers = app_info.enable_mulled_containers
        self.app_info = app_info
        self.container_resolvers = self.__build_container_resolvers(app_info)
        self.mulled_resolution_cache = mulled_resolution_cache

    def __build_container_resolvers(self, app_info):
        conf_file = getattr(app_info, 'containers_resolvers_config_file', None)
        if not conf_file:
            return self.__default_containers_resolvers()
        if not os.path.exists(conf_file):
            log.debug("Unable to find config file '%s'", conf_file)
            return self.__default_containers_resolvers()
        plugin_source = plugin_config.plugin_source_from_path(conf_file)
        return self.__parse_resolver_conf_xml(plugin_source)

    def __parse_resolver_conf_xml(self, plugin_source):
        extra_kwds = {
            'app_info': self.app_info
        }
        return plugin_config.load_plugins(self.resolver_classes, plugin_source, extra_kwds)

    def __default_containers_resolvers(self):
        default_resolvers = [
            ExplicitContainerResolver(self.app_info),
            ExplicitSingularityContainerResolver(self.app_info),
        ]
        if self.enable_mulled_containers:
            default_resolvers.extend([
                CachedMulledDockerContainerResolver(self.app_info, namespace="biocontainers"),
                CachedMulledDockerContainerResolver(self.app_info, namespace="local"),
                CachedMulledSingularityContainerResolver(self.app_info, namespace="biocontainers"),
                CachedMulledSingularityContainerResolver(self.app_info, namespace="local"),
                MulledDockerContainerResolver(self.app_info, namespace="biocontainers"),
                MulledSingularityContainerResolver(self.app_info, namespace="biocontainers"),
                BuildMulledDockerContainerResolver(self.app_info),
                BuildMulledSingularityContainerResolver(self.app_info),
            ])
        return default_resolvers

    def __resolvers_dict(self):
        import galaxy.tool_util.deps.container_resolvers
        return plugin_config.plugins_dict(galaxy.tool_util.deps.container_resolvers, 'resolver_type')

    def find_best_container_description(self, enabled_container_types, tool_info, **kwds):
        """Yield best container description of supplied types matching tool info."""
        resolved_container_description = self.resolve(enabled_container_types, tool_info, **kwds)
        return None if resolved_container_description is None else resolved_container_description.container_description

    def resolve(self, enabled_container_types, tool_info, index=None, resolver_type=None, install=True, resolution_cache=None):
        for i, container_resolver in enumerate(self.container_resolvers):
            if index is not None and i != index:
                continue

            if resolver_type is not None and resolver_type != container_resolver.resolver_type:
                continue

            if hasattr(container_resolver, "container_type"):
                if container_resolver.container_type not in enabled_container_types:
                    continue

            if not install and container_resolver.builds_on_resolution:
                continue

            container_description = container_resolver.resolve(enabled_container_types, tool_info, resolution_cache=resolution_cache)
            log.info("Checking with container resolver [%s] found description [%s]" % (container_resolver, container_description))
            if container_description:
                assert container_description.type in enabled_container_types
                return ResolvedContainerDescription(container_resolver, container_description)

        return None
