import json
import os
from collections import defaultdict, OrderedDict
from six import iteritems

from .item import item_types, ManualTest, WebdriverSpecTest, Stub, RefTest, TestharnessTest
from .log import get_logger
from .sourcefile import SourceFile
from .utils import from_os_path, to_os_path


CURRENT_VERSION = 3


class ManifestError(Exception):
    pass


class ManifestVersionMismatch(ManifestError):
    pass

class Manifest(object):
    def __init__(self, git_rev=None, url_base="/"):
        # Dict of item_type: {path: set(manifest_items)}
        self._data = dict((item_type, defaultdict(set))
                          for item_type in item_types)
        self.rev = git_rev
        self.url_base = url_base
        self.local_changes = LocalChanges(self)
        # reftest nodes arranged as {path: set(manifest_items)}
        self.reftest_nodes = defaultdict(set)
        self.reftest_nodes_by_url = {}

    def _included_items(self, include_types=None):
        if include_types is None:
            include_types = item_types

        for item_type in include_types:
            paths = self._data[item_type].copy()
            for local_types, local_paths in self.local_changes.itertypes(item_type):
                for path, items in iteritems(local_paths):
                    paths[path] = items
                for path in self.local_changes.iterdeleted():
                    if path in paths:
                        del paths[path]
                if item_type == "reftest":
                    for path, items in self.local_changes.iterdeletedreftests():
                        paths[path] -= items
                        if len(paths[path]) == 0:
                            del paths[path]

            yield item_type, paths

    def contains_path(self, path):
        return any(path in paths for _, paths in self._included_items())

    def add(self, item):
        if item is None:
            return

        if isinstance(item, RefTest):
            self.reftest_nodes[item.path].add(item)
            self.reftest_nodes_by_url[item.url] = item
        else:
            self._add(item)

        item.manifest = self

    def _add(self, item):
        self._data[item.item_type][item.path].add(item)

    def extend(self, items):
        for item in items:
            self.add(item)

    def remove_path(self, path):
        for item_type in item_types:
            if path in self._data[item_type]:
                del self._data[item_type][path]

    def itertypes(self, *types):
        if not types:
            types = None
        for item_type, items in self._included_items(types):
            for item in sorted(iteritems(items)):
                yield item

    def __iter__(self):
        for item in self.itertypes():
            yield item

    def __getitem__(self, path):
        for _, paths in self._included_items():
            if path in paths:
                return paths[path]
        raise KeyError

    def get_reference(self, url):
        if url in self.local_changes.reftest_nodes_by_url:
            return self.local_changes.reftest_nodes_by_url[url]

        if url in self.reftest_nodes_by_url:
            return self.reftest_nodes_by_url[url]

        return None

    def _committed_with_path(self, rel_path):
        rv = set()

        for paths_items in self._data.itervalues():
            rv |= paths_items.get(rel_path, set())

        if rel_path in self.reftest_nodes:
            rv |= self.reftest_nodes[rel_path]

        return rv

    def _committed_paths(self):
        rv = set()
        for paths_items in self._data.itervalues():
            rv |= set(paths_items.keys())
        return rv

    def update(self,
               tests_root,
               url_base,
               new_rev,
               committed_changes=None,
               local_changes=None,
               remove_missing_local=False):

        if local_changes is None:
            local_changes = {}

        if committed_changes is not None:
            for rel_path, status in committed_changes:
                self.remove_path(rel_path)
                if status == "modified":
                    use_committed = rel_path in local_changes
                    source_file = SourceFile(tests_root,
                                             rel_path,
                                             url_base,
                                             use_committed=use_committed)
                    self.extend(source_file.manifest_items())

        self.local_changes = LocalChanges(self)

        local_paths = set()
        for rel_path, status in iteritems(local_changes):
            local_paths.add(rel_path)

            if status == "modified":
                existing_items = self._committed_with_path(rel_path)
                source_file = SourceFile(tests_root,
                                         rel_path,
                                         url_base,
                                         use_committed=False)
                local_items = set(source_file.manifest_items())

                updated_items = local_items - existing_items
                self.local_changes.extend(updated_items)
            else:
                self.local_changes.add_deleted(rel_path)

        if remove_missing_local:
            for path in self._committed_paths() - local_paths:
                self.local_changes.add_deleted(path)

        self.update_reftests()

        if new_rev is not None:
            self.rev = new_rev
        self.url_base = url_base

    def update_reftests(self):
        default_reftests = self.compute_reftests(self.reftest_nodes)
        all_reftest_nodes = self.reftest_nodes.copy()
        all_reftest_nodes.update(self.local_changes.reftest_nodes)

        for item in self.local_changes.iterdeleted():
            if item in all_reftest_nodes:
                del all_reftest_nodes[item]

        modified_reftests = self.compute_reftests(all_reftest_nodes)

        added_reftests = modified_reftests - default_reftests
        # The interesting case here is not when the file is deleted,
        # but when a reftest like A == B is changed to the form
        # C == A == B, so that A still exists but is now a ref rather than
        # a test.
        removed_reftests = default_reftests - modified_reftests

        dests = [(default_reftests, self._data["reftest"]),
                 (added_reftests, self.local_changes._data["reftest"]),
                 (removed_reftests, self.local_changes._deleted_reftests)]

        #TODO: Warn if there exist unreachable reftest nodes
        for source, target in dests:
            for item in source:
                target[item.path].add(item)

    def compute_reftests(self, reftest_nodes):
        """Given a set of reftest_nodes, return a set of all the nodes that are top-level
        tests i.e. don't have any incoming reference links."""

        reftests = set()

        has_inbound = set()
        for path, items in iteritems(reftest_nodes):
            for item in items:
                for ref_url, ref_type in item.references:
                    has_inbound.add(ref_url)

        for path, items in iteritems(reftest_nodes):
            for item in items:
                if item.url in has_inbound:
                    continue
                reftests.add(item)

        return reftests

    def to_json(self):
        out_items = {
            item_type: sorted(
                test.to_json()
                for _, tests in iteritems(items)
                for test in tests
            )
            for item_type, items in iteritems(self._data)
        }

        reftest_nodes = OrderedDict()
        for key, value in sorted(iteritems(self.reftest_nodes)):
            reftest_nodes[from_os_path(key)] = [v.to_json() for v in value]

        rv = {"url_base": self.url_base,
              "rev": self.rev,
              "local_changes": self.local_changes.to_json(),
              "items": out_items,
              "reftest_nodes": reftest_nodes,
              "version": CURRENT_VERSION}
        return rv

    @classmethod
    def from_json(cls, tests_root, obj):
        version = obj.get("version")
        if version != CURRENT_VERSION:
            raise ManifestVersionMismatch

        self = cls(git_rev=obj["rev"],
                   url_base=obj.get("url_base", "/"))
        if not hasattr(obj, "items"):
            raise ManifestError

        item_classes = {"testharness": TestharnessTest,
                        "reftest": RefTest,
                        "manual": ManualTest,
                        "stub": Stub,
                        "wdspec": WebdriverSpecTest}

        source_files = {}

        for k, values in iteritems(obj["items"]):
            if k not in item_types:
                raise ManifestError
            for v in values:
                manifest_item = item_classes[k].from_json(self, tests_root, v,
                                                          source_files=source_files)
                self._add(manifest_item)

        for path, values in iteritems(obj["reftest_nodes"]):
            path = to_os_path(path)
            for v in values:
                item = RefTest.from_json(self, tests_root, v,
                                         source_files=source_files)
                self.reftest_nodes[path].add(item)
                self.reftest_nodes_by_url[v["url"]] = item

        self.local_changes = LocalChanges.from_json(self,
                                                    tests_root,
                                                    obj["local_changes"],
                                                    source_files=source_files)
        self.update_reftests()
        return self


class LocalChanges(object):
    def __init__(self, manifest):
        self.manifest = manifest
        self._data = dict((item_type, defaultdict(set)) for item_type in item_types)
        self._deleted = set()
        self.reftest_nodes = defaultdict(set)
        self.reftest_nodes_by_url = {}
        self._deleted_reftests = defaultdict(set)

    def add(self, item):
        if item is None:
            return

        if isinstance(item, RefTest):
            self.reftest_nodes[item.path].add(item)
            self.reftest_nodes_by_url[item.url] = item
        else:
            self._add(item)

        item.manifest = self.manifest

    def _add(self, item):
        self._data[item.item_type][item.path].add(item)

    def extend(self, items):
        for item in items:
            self.add(item)

    def add_deleted(self, path):
        self._deleted.add(path)

    def is_deleted(self, path):
        return path in self._deleted

    def itertypes(self, *types):
        for item_type in types:
            yield item_type, self._data[item_type]

    def iterdeleted(self):
        for item in self._deleted:
            yield item

    def iterdeletedreftests(self):
        for item in iteritems(self._deleted_reftests):
            yield item

    def __getitem__(self, item_type):
        return self._data[item_type]

    def to_json(self):
        reftest_nodes = {from_os_path(key): [v.to_json() for v in value]
                         for key, value in iteritems(self.reftest_nodes)}

        deleted_reftests = {from_os_path(key): [v.to_json() for v in value]
                            for key, value in iteritems(self._deleted_reftests)}

        rv = {"items": defaultdict(dict),
              "reftest_nodes": reftest_nodes,
              "deleted": [from_os_path(path) for path in self._deleted],
              "deleted_reftests": deleted_reftests}

        for test_type, paths in iteritems(self._data):
            for path, tests in iteritems(paths):
                path = from_os_path(path)
                rv["items"][test_type][path] = [test.to_json() for test in tests]

        return rv

    @classmethod
    def from_json(cls, manifest, tests_root, obj, source_files=None):
        self = cls(manifest)
        if not hasattr(obj, "items"):
            raise ManifestError

        item_classes = {"testharness": TestharnessTest,
                        "reftest": RefTest,
                        "manual": ManualTest,
                        "stub": Stub,
                        "wdspec": WebdriverSpecTest}

        for test_type, paths in iteritems(obj["items"]):
            for path, tests in iteritems(paths):
                for test in tests:
                    manifest_item = item_classes[test_type].from_json(manifest,
                                                                      tests_root,
                                                                      test,
                                                                      source_files=source_files)
                    self.add(manifest_item)

        for path, values in iteritems(obj["reftest_nodes"]):
            path = to_os_path(path)
            for v in values:
                item = RefTest.from_json(self.manifest, tests_root, v,
                                         source_files=source_files)
                self.reftest_nodes[path].add(item)
                self.reftest_nodes_by_url[item.url] = item

        for item in obj["deleted"]:
            self.add_deleted(to_os_path(item))

        for path, values in iteritems(obj.get("deleted_reftests", {})):
            path = to_os_path(path)
            for v in values:
                item = RefTest.from_json(self.manifest, tests_root, v,
                                         source_files=source_files)
                self._deleted_reftests[path].add(item)

        return self

def load(tests_root, manifest):
    logger = get_logger()

    # "manifest" is a path or file-like object.
    if isinstance(manifest, basestring):
        if os.path.exists(manifest):
            logger.debug("Opening manifest at %s" % manifest)
        else:
            logger.debug("Creating new manifest at %s" % manifest)
        try:
            with open(manifest) as f:
                rv = Manifest.from_json(tests_root, json.load(f))
        except IOError:
            rv = Manifest(None)
        return rv

    return Manifest.from_json(tests_root, json.load(manifest))


def write(manifest, manifest_path):
    with open(manifest_path, "wb") as f:
        json.dump(manifest.to_json(), f, sort_keys=True, indent=2, separators=(',', ': '))
        f.write("\n")