"""Ore hose rig for the UNRIGGED carousel (the one whose arms are plain objects turned by drivers).

One small armature per arm. Its bones are 'identity' bones (rest rotation = none), so a bone that copies an object's
world transform deforms the hose exactly as that object moves:
    Hub                         rigid with the turret (the armature object is a child of the ArmN empty): the port to the boom joint
    Boom, Upper, Lower, Head    copy the arm's four moving objects (the boom pitches on its joint since 2026-10-16)
    R1..R6 / S1..S8 / E1..E9 / W1..W4   fan bones at the boom joint / shoulder / elbow / wrist: each takes i/n of its joint's
                                rotation, so the hose bends in even steps round the joint instead of kinking
Used by build_dockarm.py; rig_dockarm.py makes the same fans as bones of DockArm_Rig.
"""
import bpy
from mathutils import Vector

FAN_STEPS = {"R": 7, "S": 9, "E": 10, "W": 5}          # steps over the bend; fan bones = steps - 1
HOSE_GROUPS = (["Hub", "Boom", "Upper", "Lower", "Head"] + ["R%d" % i for i in range(1, FAN_STEPS["R"])] + ["S%d" % i for i in range(1, FAN_STEPS["S"])]
               + ["E%d" % i for i in range(1, FAN_STEPS["E"])] + ["W%d" % i for i in range(1, FAN_STEPS["W"])])

def make_hose_armature(name, J, S, E, W):
    """Armature data in the boom frame (rest = stowed). J, S, E, W: boom joint, shoulder, elbow, wrist pivots."""
    ad = bpy.data.armatures.new(name)
    tmp = bpy.data.objects.new("_tmp_hose_rig", ad)
    bpy.context.scene.collection.objects.link(tmp)
    vl = bpy.context.view_layer
    for o in vl.objects:
        o.select_set(False)
    tmp.select_set(True)
    vl.objects.active = tmp
    bpy.ops.object.mode_set(mode='EDIT')
    eb = ad.edit_bones
    def ibone(n, head, parent=None, size=0.12):
        b = eb.new(n)
        b.head = Vector(head)
        b.tail = Vector(head) + Vector((0, size, 0))        # along +Y with Z up = identity rest rotation
        b.align_roll(Vector((0, 0, 1)))
        if parent:
            b.parent = eb[parent]
        return b
    ibone("Hub", (J[0] - 0.6, 0, J[2] - 0.3), size=0.2)
    ibone("Boom", J, size=0.2)
    ibone("Upper", S, size=0.2)
    ibone("Lower", E, size=0.2)
    ibone("Head", W, size=0.2)
    for i in range(1, FAN_STEPS["R"]):
        ibone("R%d" % i, J, "Hub")
    for i in range(1, FAN_STEPS["S"]):
        ibone("S%d" % i, S, "Boom")
    for i in range(1, FAN_STEPS["E"]):
        ibone("E%d" % i, E, "Upper")
    for i in range(1, FAN_STEPS["W"]):
        ibone("W%d" % i, W, "Lower")
    bpy.ops.object.mode_set(mode='OBJECT')
    for b in ad.bones:
        r = b.matrix_local.to_3x3()
        assert all(abs(r[i][j] - (1.0 if i == j else 0.0)) < 1e-5 for i in range(3) for j in range(3)), ("not an identity bone", b.name)
    bpy.data.objects.remove(tmp)
    ad.display_type = 'STICK'
    return ad

def setup_hose_rig(arm_empty, boom, upper, lower, head, armature_data, hose_mesh, collection, prefix):
    """Armature object + hose object for one arm. arm_empty: the boom frame; boom/upper/lower/head: its moving objects."""
    rig = bpy.data.objects.new(prefix + "_HoseRig", armature_data)
    collection.objects.link(rig)
    rig.parent = arm_empty
    rig.show_in_front = False
    rig.hide_render = True
    bpy.context.view_layer.update()                    # the pose of a new armature object exists only after this
    P = rig.pose.bones
    for bone, target in (("Boom", boom), ("Upper", upper), ("Lower", lower), ("Head", head)):
        c = P[bone].constraints.new('COPY_TRANSFORMS')
        c.name = "Follow " + target.name
        c.target = target
    for key, src in (("R", "Boom"), ("S", "Upper"), ("E", "Lower"), ("W", "Head")):
        n = FAN_STEPS[key]
        for i in range(1, n):
            c = P["%s%d" % (key, i)].constraints.new('COPY_ROTATION')
            c.name = "%d/%d of the joint" % (i, n)
            c.target = rig
            c.subtarget = src
            c.influence = i / n
    hose = bpy.data.objects.new(prefix + "_OreHose", hose_mesh)
    collection.objects.link(hose)
    hose.parent = rig
    for g in HOSE_GROUPS:
        if g not in hose.vertex_groups:
            hose.vertex_groups.new(name=g)
    hose.modifiers.new("Armature", 'ARMATURE').object = rig
    return rig, hose