"""Shared primitive helpers. Blender coordinates: +Z up, -Y forward.

Every helper creates one named, flat-shaded part. No joining, textures, scene
deletion or export here. Angles are radians; sizes are metres.
"""
from math import pi
import re
import bpy
from mathutils import Vector


def _finish(obj, name, mat=None):
    name = re.sub(r'[^A-Za-z0-9_]', '_', name)
    obj.name = name
    obj['part_name'] = name
    if obj.type == 'MESH':
        obj.data.name = name + '_Mesh'
        for face in obj.data.polygons:
            face.use_smooth = False
        if mat is not None:
            obj.data.materials.append(mat)
    return obj


def box(name, loc, size, mat, rotation=None):
    bpy.ops.mesh.primitive_cube_add(size=1, location=loc)
    obj = bpy.context.object
    obj.scale = size
    if rotation is not None:
        obj.rotation_euler = rotation
    return _finish(obj, name, mat)


def ellipsoid(name, loc, scale, mat, subdivisions=1):
    bpy.ops.mesh.primitive_ico_sphere_add(subdivisions=subdivisions, radius=1, location=loc)
    obj = bpy.context.object
    obj.scale = scale
    return _finish(obj, name, mat)


def cylinder(name, loc, radius, depth, mat, vertices=10, rotation=None):
    return cone(name, loc, radius, radius, depth, mat, vertices, rotation)


def cone(name, loc, radius1, radius2, depth, mat, vertices=10, rotation=None):
    bpy.ops.mesh.primitive_cone_add(vertices=vertices, radius1=radius1,
                                  radius2=radius2, depth=depth, location=loc)
    obj = bpy.context.object
    if rotation is not None:
        obj.rotation_euler = rotation
    return _finish(obj, name, mat)


def beam(name, start, end, radius, mat, vertices=8):
    start, end = Vector(start), Vector(end)
    direction = end - start
    if direction.length < 1e-6:
        raise ValueError(name + ': beam endpoints must differ')
    obj = cylinder(name, (start + end) * 0.5, radius, direction.length, mat, vertices)
    obj.rotation_euler = direction.to_track_quat('Z', 'Y').to_euler()
    return obj


def ring(name, loc, major_radius, minor_radius, mat, rotation=None, segments=12):
    bpy.ops.mesh.primitive_torus_add(major_segments=segments, minor_segments=4,
                                   location=loc, major_radius=major_radius,
                                   minor_radius=minor_radius)
    obj = bpy.context.object
    if rotation is not None:
        obj.rotation_euler = rotation
    return _finish(obj, name, mat)


def mesh_object(name, vertices, faces, mat):
    mesh = bpy.data.meshes.new(name + '_Mesh')
    mesh.from_pydata(vertices, [], faces)
    mesh.update()
    obj = bpy.data.objects.new(name, mesh)
    bpy.context.scene.collection.objects.link(obj)
    return _finish(obj, name, mat)


def empty(name, loc=(0, 0, 0)):
    name = re.sub(r'[^A-Za-z0-9_]', '_', name)
    obj = bpy.data.objects.new(name, None)
    obj['part_name'] = name
    obj.location = loc
    obj.empty_display_type = 'PLAIN_AXES'
    obj.empty_display_size = 0.12
    bpy.context.scene.collection.objects.link(obj)
    return obj


PALETTES = {
    'glutpakt': ['292B35', 'EF6B3B', 'D9A441', 'D8CEC0'],
    'nietenkonvent': ['247A80', 'C79A48', '657481', 'E6DCCA'],
    'nebelchor': ['45456F', '9578CF', '82DBCE', 'C4D6E5'],
    'wurzelbund': ['685441', '56845A', 'A7BA6C', 'D996AF'],
    'neutral': ['536375', 'A8654D', '9578CF', 'D8D2BF'],
    'worker': ['A8654D', '536375', 'D9A441', '82DBCE'],
    'terrain': ['657481', '292B35', 'D9A441', '56845A'],
    'team0': ['292B35', 'D9A441', '82DBCE', 'D8CEC0'],
    'team1': ['292B35', 'D9A441', 'E9967C', 'D8CEC0'],
}


def srgb_to_linear(value):
    return value / 12.92 if value <= 0.04045 else ((value + 0.055) / 1.055) ** 2.4


def make_materials(palette_name, overrides=None):
    """Hex colours match Phase 3; shader inputs use linear RGB for glTF export.

    Override individual keys with RGB hex strings in an entry script, e.g.
    PALETTE_OVERRIDES = {'accent': 'FFAA55'}. All materials stay opaque and matte.
    """
    colours = dict(zip(('primary', 'secondary', 'accent', 'light'), PALETTES[palette_name]))
    if palette_name == 'wurzelbund':
        colours['water'] = '82DBCE'  # Dew/spring accent from the Phase 3 healer icons.
        colours['wood'] = '9B805C'
        colours['bark_dark'] = '483A2F'
    if palette_name in ('neutral', 'worker'):
        colours['shadow'] = '202832'
    if palette_name == 'neutral':
        colours['rift'] = '82DBCE'
    colours.update(overrides or {})
    result = {}
    for key, hex_colour in colours.items():
        value = hex_colour.lstrip('#')
        rgb = [srgb_to_linear(int(value[i:i + 2], 16) / 255) for i in (0, 2, 4)]
        name = 'SW_' + palette_name + '_' + key + '_' + value
        # A previous user-edited material must never be reset by another run.
        mat = bpy.data.materials.new(name)
        mat['material_name'] = name
        mat.diffuse_color = (*rgb, 1)
        mat.use_nodes = True
        shader = mat.node_tree.nodes.get('Principled BSDF')
        shader.inputs['Base Color'].default_value = (*rgb, 1)
        shader.inputs['Metallic'].default_value = 0.08 if palette_name in ('nietenkonvent', 'team0', 'team1') else 0.0
        shader.inputs['Roughness'].default_value = 0.82
        if palette_name == 'glutpakt' and key == 'secondary':
            shader.inputs['Emission Color'].default_value = (*rgb, 1)
            shader.inputs['Emission Strength'].default_value = 0.18
        if palette_name == 'glutpakt' and key == 'accent':
            shader.inputs['Metallic'].default_value = 0.5
            shader.inputs['Roughness'].default_value = 0.62
        result[key] = mat
    return result