import unittest

# ############################################################
# Layer Collection Crawler
# ############################################################

def listbase_iter(data, struct, listbase):
    element = data.get_pointer((struct, listbase, b'first'))
    while element is not None:
        yield element
        element = element.get_pointer(b'next')


def linkdata_iter(collection, data):
    element = collection.get_pointer((data, b'first'))
    while element is not None:
        yield element
        element = element.get_pointer(b'next')


def get_layer_collection(layer_collection):
    data = {}
    flag = layer_collection.get(b'flag')

    data['is_visible']    = (flag & (1 << 0)) != 0;
    data['is_selectable'] = (flag & (1 << 1)) != 0;
    data['is_folded']     = (flag & (1 << 2)) != 0;

    scene_collection = layer_collection.get_pointer(b'scene_collection')
    if scene_collection is None:
        name = 'Fail!'
    else:
        name = scene_collection.get(b'name')
    data['name'] = name

    objects = []
    for link in linkdata_iter(layer_collection, b'object_bases'):
        ob_base = link.get_pointer(b'data')
        ob = ob_base.get_pointer(b'object')
        objects.append(ob.get((b'id', b'name'))[2:])
    data['objects'] = objects

    collections = {}
    for nested_layer_collection in linkdata_iter(layer_collection, b'layer_collections'):
        subname, subdata = get_layer_collection(nested_layer_collection)
        collections[subname] = subdata
    data['collections'] = collections

    return name, data


def get_layer(layer):
    data = {}
    name = layer.get(b'name')

    data['name'] = name
    data['active_object'] = layer.get((b'basact', b'object', b'id', b'name'))[2:]
    data['engine'] = layer.get(b'engine')

    objects = []
    for link in linkdata_iter(layer, b'object_bases'):
        ob = link.get_pointer(b'object')
        objects.append(ob.get((b'id', b'name'))[2:])
    data['objects'] = objects

    collections = {}
    for layer_collection in linkdata_iter(layer, b'layer_collections'):
        subname, subdata = get_layer_collection(layer_collection)
        collections[subname] = subdata
    data['collections'] = collections

    return name, data


def get_layers(scene):
    """Return all the render layers and their data"""
    layers = {}
    for layer in linkdata_iter(scene, b'render_layers'):
        name, data = get_layer(layer)
        layers[name] = data
    return layers


def get_scene_collection_objects(collection, listbase):
    objects = []
    for link in linkdata_iter(collection, listbase):
        ob = link.get_pointer(b'data')
        if ob is None:
            name  = 'Fail!'
        else:
            name = ob.get((b'id', b'name'))[2:]
        objects.append(name)
    return objects


def get_scene_collection(collection):
    """"""
    data = {}
    name = collection.get(b'name')

    data['name'] = name
    data['filter'] = collection.get(b'filter')

    data['objects'] = get_scene_collection_objects(collection, b'objects')
    data['filter_objects'] = get_scene_collection_objects(collection, b'filter_objects')

    collections = {}
    for nested_collection in linkdata_iter(collection, b'scene_collections'):
        subname, subdata = get_scene_collection(nested_collection)
        collections[subname] = subdata
    data['collections'] = collections

    return name, data


def get_scene_collections(scene):
    """Return all the scene collections ahd their data"""
    master_collection = scene.get_pointer(b'collection')
    return get_scene_collection(master_collection)


def query_scene(filepath, name, callbacks):
    """Return the equivalent to bpy.context.scene"""
    import blendfile
    with blendfile.open_blend(filepath) as blend:
        scenes = [block for block in blend.blocks if block.code == b'SC']
        for scene in scenes:
            if scene.get((b'id', b'name'))[2:] == name:
                output = []
                for callback in callbacks:
                    output.append(callback(scene))
                return output


# ############################################################
# Utils
# ############################################################

def import_blendfile():
    import bpy
    import os, sys
    path = os.path.join(
            bpy.utils.resource_path('LOCAL'),
            'scripts',
            'addons',
            'io_blend_utils',
            'blend',
            )

    if path not in sys.path:
        sys.path.append(path)


def dump(data):
    import json
    return json.dumps(
            data,
            sort_keys=True,
            indent=4,
            separators=(',', ': '),
            )


# ############################################################
# Tests
# ############################################################

PDB = False
DUMP_DIFF = True

def compare_files(file_a, file_b):
    import filecmp

    if not filecmp.cmp(
        file_a,
        file_b):

        if DUMP_DIFF:
            import subprocess
            subprocess.call(["diff", "-u", file_a, file_b])

        if PDB:
            import pdb
            print("Files differ:", file_a, file_b)
            pdb.set_trace()

        return False

    return True


class RenderLayerTesting(unittest.TestCase):
    _test_simple = False
    _extra_arguments = []

    @classmethod
    def setUpClass(cls):
        """Runs once"""
        cls.pretest_import_blendfile()
        cls.pretest_parsing()

    @classmethod
    def setUp(cls):
        """Runs once per test"""
        import bpy
        bpy.ops.wm.read_factory_settings()

    def path_exists(self, filepath):
        import os
        self.assertTrue(
                os.path.exists(filepath),
                "Test file \"{0}\" not found".format(filepath))

    @classmethod
    def get_root(cls):
        """
        return the folder with the test files
        """
        arguments = {}
        for argument in cls._extra_arguments:
            name, value = argument.split('=')
            cls.assertTrue(name and name.startswith("--"), "Invalid argument \"{0}\"".format(argument))
            cls.assertTrue(value, "Invalid argument \"{0}\"".format(argument))
            arguments[name[2:]] = value.strip('"')

        return arguments.get('testdir')

    @classmethod
    def pretest_parsing(cls):
        """
        Test if the arguments are properly set, and store ROOT
        name has extra _ because we need this test to run first
        """
        root = cls.get_root()
        cls.assertTrue(root, "Testdir not set")

    @staticmethod
    def pretest_import_blendfile():
        """
        Make sure blendfile imports with no problems
        name has extra _ because we need this test to run first
        """
        import_blendfile()
        import blendfile