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# <pep8 compliant>

import bpy
from rigify import bone_class_instance, copy_bone_simple, add_pole_target_bone, add_stretch_to, blend_bone_list, get_side_name, get_base_name
from rna_prop_ui import rna_idprop_ui_prop_get
from Mathutils import Vector

METARIG_NAMES = "shoulder", "arm", "forearm", "hand"


def metarig_template():
    # generated by rigify.write_meta_rig
    bpy.ops.object.mode_set(mode='EDIT')
    obj = bpy.context.active_object
    arm = obj.data
    bone = arm.edit_bones.new('shoulder')
    bone.head[:] = 0.0000, -0.4515, 0.0000
    bone.tail[:] = 1.0000, -0.0794, 0.3540
    bone.roll = -0.2227
    bone.connected = False
    bone = arm.edit_bones.new('upper_arm')
    bone.head[:] = 1.1319, -0.0808, -0.0101
    bone.tail[:] = 3.0319, 0.2191, -0.1101
    bone.roll = 1.6152
    bone.connected = False
    bone.parent = arm.edit_bones['shoulder']
    bone = arm.edit_bones.new('forearm')
    bone.head[:] = 3.0319, 0.2191, -0.1101
    bone.tail[:] = 4.8319, -0.0809, -0.0242
    bone.roll = 1.5153
    bone.connected = True
    bone.parent = arm.edit_bones['upper_arm']
    bone = arm.edit_bones.new('hand')
    bone.head[:] = 4.8319, -0.0809, -0.0242
    bone.tail[:] = 5.7590, -0.1553, -0.1392
    bone.roll = -3.0083
    bone.connected = True
    bone.parent = arm.edit_bones['forearm']

    bpy.ops.object.mode_set(mode='OBJECT')
    pbone = obj.pose.bones['upper_arm']
    pbone['type'] = 'arm'


def metarig_definition(obj, orig_bone_name):
    mt = bone_class_instance(obj, METARIG_NAMES) # meta
    mt.arm = orig_bone_name
    mt.update()

    mt.shoulder_p = mt.arm_p.parent

    if not mt.shoulder_p:
        raise Exception("could not find '%s' parent, skipping:" % orig_bone_name)

    mt.shoulder = mt.shoulder_p.name

    # We could have some bones attached, find the bone that has this as its 2nd parent
    hands = []
    for pbone in obj.pose.bones:
        index = pbone.parent_index(mt.arm_p)
        if index == 2 and pbone.bone.connected and pbone.bone.parent.connected:
            hands.append(pbone)

    if len(hands) != 1:
        raise Exception("Found %s possible hands attached to this arm, expected 1 from bone: %s" % ([pbone.name for pbone in hands], orig_bone_name))

    # first add the 2 new bones
    mt.hand_p = hands[0]
    mt.hand = mt.hand_p.name

    mt.forearm_p = mt.hand_p.parent
    mt.forearm = mt.forearm_p.name

    return mt.names()


def ik(obj, definitions, base_names):
    mt = bone_class_instance(obj, METARIG_NAMES)
    mt.shoulder, mt.arm, mt.forearm, mt.hand = definitions
    mt.update()
    
    ik = bone_class_instance(obj, ["pole", "pole_vis", "hand_vis"])
    ik_chain = mt.copy(to_fmt="MCH-%s_ik", base_names=base_names, exclude_attrs=["shoulder"])
    
    # IK needs no parent_index
    ik_chain.hand_e.connected = False
    ik_chain.hand_e.parent = None
    ik_chain.hand_e.local_location = False
    ik_chain.rename("hand", get_base_name(base_names[mt.hand]) + "_ik" + get_side_name(mt.hand))

    ik_chain.arm_e.connected = False
    ik_chain.arm_e.parent = mt.shoulder_e
    
    # Add the bone used for the arms poll target
    #ik.pole = add_pole_target_bone(obj, mt.forearm, get_base_name(base_names[mt.forearm]) + "_target" + get_side_name(mt.forearm), mode='ZAVERAGE')
    ik.pole = add_pole_target_bone(obj, mt.forearm, "elbow_target" + get_side_name(mt.forearm), mode='ZAVERAGE')
 
    ik.update()
    ik.pole_e.local_location = False
    
    # update bones after this!
    ik.hand_vis = add_stretch_to(obj, mt.hand, ik_chain.hand, "VIS-%s_ik" % base_names[mt.hand])
    ik.pole_vis = add_stretch_to(obj, mt.forearm, ik.pole, "VIS-%s_ik" % base_names[mt.forearm])
    
    ik.update()
    ik.hand_vis_e.restrict_select = True
    ik.pole_vis_e.restrict_select = True
    
    bpy.ops.object.mode_set(mode='OBJECT')
    
    mt.update()
    ik.update()
    ik_chain.update()

    # Set IK dof
    ik_chain.forearm_p.ik_dof_x = True
    ik_chain.forearm_p.ik_dof_y = False
    ik_chain.forearm_p.ik_dof_z = False

    con = ik_chain.forearm_p.constraints.new('IK')
    con.target = obj
    con.subtarget = ik_chain.hand
    con.pole_target = obj
    con.pole_subtarget = ik.pole

    con.use_tail = True
    con.use_stretch = True
    con.use_target = True
    con.use_rotation = False
    con.chain_length = 2
    con.pole_angle = -90.0 # XXX, RAD2DEG

    # ID Propery on the hand for IK/FK switch

    prop = rna_idprop_ui_prop_get(ik_chain.hand_p, "ik", create=True)
    ik_chain.hand_p["ik"] = 0.5
    prop["soft_min"] = 0.0
    prop["soft_max"] = 1.0

    bpy.ops.object.mode_set(mode='EDIT')
    
    # don't blend the shoulder
    return [None] + ik_chain.names()


def fk(obj, definitions, base_names):
    
    arm = obj.data
    
    mt = bone_class_instance(obj, METARIG_NAMES)
    mt.shoulder, mt.arm, mt.forearm, mt.hand = definitions
    mt.update()

    ex = bone_class_instance(obj, ["socket", "arm_hinge", "hand_delta"])
    fk_chain = mt.copy(base_names=base_names)

    # shoulder is used as a hinge
    fk_chain.rename("shoulder", "MCH-%s_hinge" % base_names[mt.arm])
    fk_chain.shoulder_e.translate(Vector(0.0, fk_chain.shoulder_e.length / 2, 0.0))

    # upper arm constrains to this.
    ex.socket_e = copy_bone_simple(arm, mt.arm, "MCH-%s_socket" % base_names[mt.arm])
    ex.socket = ex.socket_e.name
    ex.socket_e.connected = False
    ex.socket_e.parent = mt.shoulder_e
    ex.socket_e.length *= 0.5
    
    # insert the 'DLT-hand', between the forearm and the hand
    # copies forarm rotation
    ex.hand_delta_e = copy_bone_simple(arm, fk_chain.hand, "DLT-%s" % base_names[mt.hand], parent=True)
    ex.hand_delta = ex.hand_delta_e.name
    ex.hand_delta_e.length *= 0.5
    ex.hand_delta_e.connected = False
    
    fk_chain.hand_e.connected = False
    fk_chain.hand_e.parent = ex.hand_delta_e

    bpy.ops.object.mode_set(mode='OBJECT')
    
    mt.update()
    ex.update()
    fk_chain.update()

    # Set rotation modes and axis locks
    fk_chain.forearm_p.rotation_mode = 'XYZ'
    fk_chain.forearm_p.lock_rotation = (False, True, True)
    fk_chain.hand_p.rotation_mode = 'ZXY'

    con = fk_chain.arm_p.constraints.new('COPY_LOCATION')
    con.target = obj
    con.subtarget = ex.socket
    
    fk_chain.hand_p.lock_location = True, True, True
    con = ex.hand_delta_p.constraints.new('COPY_ROTATION')
    con.target = obj
    con.subtarget = fk_chain.forearm

    def hinge_setup():
        # Hinge constraint & driver
        con = fk_chain.shoulder_p.constraints.new('COPY_ROTATION')
        con.name = "hinge"
        con.target = obj
        con.subtarget = mt.shoulder
        driver_fcurve = con.driver_add("influence", 0)
        driver = driver_fcurve.driver


        controller_path = fk_chain.arm_p.path_to_id()
        # add custom prop
        fk_chain.arm_p["hinge"] = 0.0
        prop = rna_idprop_ui_prop_get(fk_chain.arm_p, "hinge", create=True)
        prop["soft_min"] = 0.0
        prop["soft_max"] = 1.0


        # *****
        driver = driver_fcurve.driver
        driver.type = 'AVERAGE'

        tar = driver.targets.new()
        tar.name = "hinge"
        tar.id_type = 'OBJECT'
        tar.id = obj
        tar.rna_path = controller_path + '["hinge"]'

        mod = driver_fcurve.modifiers[0]
        mod.poly_order = 1
        mod.coefficients[0] = 1.0
        mod.coefficients[1] = -1.0

    hinge_setup()
    
    bpy.ops.object.mode_set(mode='EDIT')

    return None, fk_chain.arm, fk_chain.forearm, fk_chain.hand


def main(obj, bone_definition, base_names):    
    bones_ik = ik(obj, bone_definition, base_names)
    bones_fk = fk(obj, bone_definition, base_names)

    bpy.ops.object.mode_set(mode='OBJECT')
    blend_bone_list(obj, bone_definition, bones_ik, bones_fk, target_bone=bone_definition[1])