""" Contains functions for extracting a scene from a .msh file"""

from itertools import islice
from typing import Dict
from .msh_scene import Scene
from .msh_model import *
from .msh_material import *
from .msh_reader import Reader
from .msh_utilities import *

from .crc import *

def read_scene(input_file) -> Scene:

    scene = Scene()
    scene.models = []
    scene.materials = {}

    with Reader(file=input_file) as hedr:

        while hedr.could_have_child():

            next_header = hedr.peak_next_header()

            if "MSH2" in next_header:

                with hedr.read_child() as msh2:

                    materials_list = []

                    while (msh2.could_have_child()):

                        next_header = msh2.peak_next_header()

                        if "SINF" in next_header:
                            with msh2.read_child() as sinf:
                                pass

                        elif "MATL" in next_header:
                            with msh2.read_child() as matl:
                                materials_list += _read_matl_and_get_materials_list(matl)
                                for i,mat in enumerate(materials_list):
                                    scene.materials[mat.name] = mat

                        elif "MODL" in next_header:
                            while ("MODL" in msh2.peak_next_header()):
                                with msh2.read_child() as modl:
                                    scene.models.append(_read_modl(modl, materials_list))

                        else:
                            with hedr.read_child() as unknown:
                                pass

            elif "SKL2" in next_header:
            	with hedr.read_child() as skl2:
            		num_bones = skl2.read_u32()
            		scene.skeleton = [skl2.read_u32(5)[0] for i in range(num_bones)]
            	print("Skeleton models: ")
            	for crc_hash in scene.skeleton:
            		for model in scene.models:
            			if crc_hash == crc(model.name):
            				print("\t" + model.name + " with type: " + str(model.model_type))


            else:
                with hedr.read_child() as unknown:
                    pass

    return scene


def _read_matl_and_get_materials_list(matl: Reader) -> List[Material]:
    materials_list: List[Material] = []

    num_mats = matl.read_u32()

    for _ in range(num_mats):
        with matl.read_child() as matd:
            materials_list.append(_read_matd(matd))

    return materials_list



def _read_matd(matd: Reader) -> Material:

    mat = Material()

    while matd.could_have_child():

        next_header = matd.peak_next_header()

        if "NAME" in next_header:
            with matd.read_child() as name:
                mat.name = name.read_string()

        elif "DATA" in next_header:
            with matd.read_child() as data:
                data.read_f32(4) # Diffuse Color (Seams to get ignored by modelmunge)
                mat.specular_color = data.read_f32(4)
                data.read_f32(4) # Ambient Color (Seams to get ignored by modelmunge and Zero(?))
                data.read_f32()  # Specular Exponent/Decay (Gets ignored by RedEngine in SWBFII for all known materials)    
    
        elif "ATRB" in next_header:
            with matd.read_child() as atrb:
                mat.flags = atrb.read_u8()
                mat.rendertype = atrb.read_u8()
                mat.data = atrb.read_u8(2)

        elif "TX0D" in next_header:
            with matd.read_child() as tx0d:
                mat.texture0 = tx0d.read_string()

        elif "TX1D" in next_header:
            with matd.read_child() as tx1d:
                mat.texture1 = tx1d.read_string()

        elif "TX2D" in next_header:
            with matd.read_child() as tx2d:
                mat.texture2 = tx2d.read_string()

        elif "TX3D" in next_header:
            with matd.read_child() as tx3d:
                mat.texture3 = tx3d.read_string()

        else:
            matd.skip_bytes(4)

    return mat


def _read_modl(modl: Reader, materials_list: List[Material]) -> Model:

    model = Model()

    while modl.could_have_child():

        next_header = modl.peak_next_header()

        if "MTYP" in next_header:
            with modl.read_child() as mtyp:
                model.model_type = ModelType(mtyp.read_u32())

        elif "MNDX" in next_header:
            with modl.read_child() as mndx:
                pass

        elif "NAME" in next_header:
            with modl.read_child() as name:
                model.name = name.read_string()

        elif "PRNT" in next_header:
            with modl.read_child() as prnt:
                model.parent = prnt.read_string()

        elif "FLGS" in next_header:
            with modl.read_child() as flgs:
                model.hidden = flgs.read_u32()

        elif "TRAN" in next_header:
            with modl.read_child() as tran:
                model.transform = _read_tran(tran)

        elif "GEOM" in next_header:
            model.geometry = []
            with modl.read_child() as geom:

                next_header_modl = geom.peak_next_header()

                if "SEGM" in next_header_modl:
                    with geom.read_child() as segm:
                       model.geometry.append(_read_segm(segm, materials_list))

        elif "SWCI" in next_header:
            prim = CollisionPrimitive()
            with modl.read_child() as swci:
                prim.shape = CollisionPrimitiveShape(swci.read_u32())
                prim.radius = swci.read_f32()
                prim.height = swci.read_f32()
                prim.length = swci.read_f32()
            model.collisionprimitive = prim

        else:
            with modl.read_child() as unknown:
                pass

    return model


def _read_tran(tran: Reader) -> ModelTransform:

    xform = ModelTransform()

    tran.skip_bytes(4 * 3) #ignore scale

    rot = tran.read_f32(4)
    xform.rotation = Quaternion((rot[3], rot[0], rot[1], rot[2]))
    xform.translation = Vector(tran.read_f32(3))

    return xform


def _read_segm(segm: Reader, materials_list: List[Material]) -> GeometrySegment:

    geometry_seg = GeometrySegment()

    while segm.could_have_child():

        next_header = segm.peak_next_header()

        if "MATI" in next_header:
            with segm.read_child() as mati:
                geometry_seg.material_name = materials_list[mati.read_u32()].name

        elif "POSL" in next_header:
            with segm.read_child() as posl:
                num_positions = posl.read_u32()

                for _ in range(num_positions):
                    geometry_seg.positions.append(Vector(posl.read_f32(3)))

        elif "NRML" in next_header:
            with segm.read_child() as nrml:
                num_normals = nrml.read_u32()
                
                for _ in range(num_positions):
                    geometry_seg.normals.append(Vector(nrml.read_f32(3))) 

        elif "CLRL" in next_header:
            geometry_seg.colors = []

            with segm.read_child() as clrl:
                num_colors = clrl.read_u32()

                for _ in range(num_colors):
                    geometry_seg.colors += unpack_color(clrl.read_u32())

        elif "UV0L" in next_header:
            with segm.read_child() as uv0l:
                num_texcoords = uv0l.read_u32()

                for _ in range(num_texcoords):
                    geometry_seg.texcoords.append(Vector(uv0l.read_f32(2))) 

        elif "NDXL" in next_header:
            with segm.read_child() as ndxl:
                num_polygons = ndxl.read_u32()

                for _ in range(num_polygons):
                    polygon = ndxl.read_u16(ndxl.read_u16())
                    geometry_seg.polygons.append(polygon)

        elif "NDXT" in next_header:
            with segm.read_child() as ndxt:
                num_tris = ndxt.read_u32()

                for _ in range(num_tris):
                    geometry_seg.triangles.append(ndxt.read_u16(3))

        elif "STRP" in next_header:
            with segm.read_child() as strp:
                pass

            if segm.read_u16 != 0: #trailing 0 bug https://schlechtwetterfront.github.io/ze_filetypes/msh.html#STRP
                segm.skip_bytes(-2)

        else:
            with segm.read_child() as unknown:
                pass

    return geometry_seg