"""Run in the existing Blender studies via MCP; preserve walking geometry and facilities.

Photo-estimated weathering, not photogrammetry. Existing scan maps are reused.
"""
import bpy, math, json
from pathlib import Path
from mathutils import Vector, noise

ROOT = Path('D:/project/sunrise')
OUT = ROOT/'assets/summit/near-route-refinement'
TILE = 1.8
rocks = bpy.data.collections['Photo rocks - export']
slab = bpy.data.objects['SLAB_SURFACE']
before_slab = [tuple(v.co) for v in slab.data.vertices]
report = []

def joint(p):
    # Uneven, slightly wandering vertical fractures; avoid horizontal stacked bands.
    warp = .16*math.sin(p.z*.43+p.y*.27)
    distance = min(abs(p.x+.16*p.y+.07*p.z+warp-k) for k in (-23.4,-19.1,-14.7,-11.2,-5.2,.8,6.5))
    return math.exp(-(distance/.30)**2)

for obj in rocks.objects:
    if obj.get('route_detail_pass'):
        raise RuntimeError('Refinement already applied: edit the existing result, do not accumulate.')
    mesh = obj.data
    maximum = 0
    for v in mesh.vertices:
        p = v.co.copy()
        fade = max(0,min(1,(p.z+28)/6))
        # Retain supporting tops and overall silhouette; recess the exposed side faces.
        side = max(0,1-abs(v.normal.z))
        amount = -.14*joint(p)*side*fade
        v.co += v.normal*amount
        maximum = max(maximum,abs(amount))
    mesh.update()
    uv = mesh.uv_layers.active
    colors = mesh.color_attributes.active_color
    for face in mesh.polygons:
        axis = max(range(3),key=lambda a:abs(face.normal[a]))
        for li in face.loop_indices:
            p = mesh.vertices[mesh.loops[li].vertex_index].co
            uv.data[li].uv = Vector((p.y,p.z) if axis==0 else (p.x,p.z) if axis==1 else (p.x,p.y))/TILE
            patch = noise.noise_vector(p*.26).x
            stain = max(0,noise.noise_vector(p*.61+Vector((3,9,2))).y)
            shade = .93+.055*patch-.10*joint(p)-.045*stain
            colors.data[li].color = (shade,shade*.985,shade*.95,1)
    obj['route_detail_pass'] = True
    obj['texture_tile_metres'] = TILE
    report.append({'object':obj.name,'vertices':len(mesh.vertices),'maxRecessMetres':maximum})

def setup_material(mat, vertex_colors=False):
    nodes,links = mat.node_tree.nodes,mat.node_tree.links
    bsdf = next(n for n in nodes if n.type=='BSDF_PRINCIPLED')
    color = next(n for n in nodes if n.type=='TEX_IMAGE' and n.image and 'rock-color' in n.image.name)
    # Use identical two-scale sampling in Blender and the application's ground shader.
    texcoord = nodes.new('ShaderNodeTexCoord')
    mapping = nodes.new('ShaderNodeVectorMath');mapping.operation = next(i.identifier for i in mapping.bl_rna.properties['operation'].enum_items if i.identifier=='MULTIPLY_ADD')
    mapping.inputs[1].default_value=(1.37,1.37,1.37)
    mapping.inputs[2].default_value=(.31,.73,0)
    links.new(texcoord.outputs['UV'],mapping.inputs[0])
    separate=nodes.new('ShaderNodeSeparateXYZ');links.new(texcoord.outputs['UV'],separate.inputs[0])
    def math_node(operation,a,b=0):
        node=nodes.new('ShaderNodeMath')
        node.operation=next(i.identifier for i in node.bl_rna.properties['operation'].enum_items if i.identifier==operation)
        for socket,value in zip(node.inputs,(a,b)):
            if isinstance(value,(int,float)):socket.default_value=value
            else:links.new(value,socket)
        return node.outputs[0]
    blend=math_node('ADD',.5,math_node('MULTIPLY',.3,math_node('SINE',math_node('ADD',math_node('MULTIPLY',separate.outputs['X'],.71),math_node('SINE',math_node('MULTIPLY',separate.outputs['Y'],.53))))))
    def mixed(image, original=None):
        a = original or nodes.new('ShaderNodeTexImage');a.image=image
        b = nodes.new('ShaderNodeTexImage');b.image=image
        links.new(mapping.outputs[0],b.inputs['Vector'])
        mix=nodes.new('ShaderNodeMixRGB');links.new(blend,mix.inputs[0])
        links.new(a.outputs['Color'],mix.inputs[1]);links.new(b.outputs['Color'],mix.inputs[2])
        return mix.outputs[0]
    base=mixed(color.image,color)
    if vertex_colors:
        attr=nodes.new('ShaderNodeVertexColor');attr.layer_name='Weathering'
        mul=nodes.new('ShaderNodeMixRGB');mul.blend_type=next(i.identifier for i in mul.bl_rna.properties['blend_type'].enum_items if i.identifier=='MULTIPLY');mul.inputs[0].default_value=1
        links.new(base,mul.inputs[1]);links.new(attr.outputs['Color'],mul.inputs[2]);base=mul.outputs[0]
    links.new(base,bsdf.inputs['Base Color'])
    for kind in ('normal','roughness'):
        img=bpy.data.images.load(str(ROOT/f'public/terrain/materials/rock-{kind}.jpg'),check_existing=True)
        img.colorspace_settings.name='Non-Color'
        signal=mixed(img)
        if kind=='normal':
            normal=nodes.new('ShaderNodeNormalMap');normal.inputs['Strength'].default_value=.55
            links.new(signal,normal.inputs['Color']);links.new(normal.outputs['Normal'],bsdf.inputs['Normal'])
        else:
            links.new(signal,bsdf.inputs['Roughness'])

setup_material(bpy.data.materials['Photo study / weathered granite'],True)
# Copy the material so the summit marker retains its existing authored finish.
surface=slab.data.materials[0].copy();surface.name='Route slab / weathered granite detail'
slab.data.materials[0]=surface
setup_material(surface)
for face in slab.data.polygons:
    for li in face.loop_indices:
        p=slab.data.vertices[slab.data.loops[li].vertex_index].co
        slab.data.uv_layers.active.data[li].uv=(p.x/TILE,p.y/TILE)
assert before_slab==[tuple(v.co) for v in slab.data.vertices]
(OUT/'refinement.json').write_text(json.dumps({'walkingVerticesUnchanged':True,'tileMetres':TILE,'normalStrength':.55,'rocks':report},indent=2))
print('Refined',len(report),'rock meshes; walking surface vertices unchanged.')