import bpy
from . import fn
from mathutils import Vector, Euler
from mathutils.geometry import intersect_line_plane

## step 2 : Auto animate the path (with feet selection) and modal to adjust speed

def get_bone_transform_at_frame(b, act, frame):
    '''Find every loc, rot, scale values at given frame'''
    transform = {}
    for channel in ('location', 'rotation_euler', 'scale'):
        chan_list = []
        for i in range(3):
            f = act.fcurves.find(f'pose.bones["{b.name}"].{channel}', index=i)
            if not f:
                print(frame, channel, 'Not animated ! Using current value') # Dbg
                chan_list.append(getattr(b, channel)[i]) # get current value since not animated
                continue
            chan_list.append(f.evaluate(frame))
        
        # print('chan_list: ', chan_list)
        # print(frame, b.name, channel, chan_list) # Dbg
        if channel == 'rotation_euler':
            transform[channel] = Euler(chan_list)
        else:
            transform[channel] = Vector(chan_list)

    return transform # loc, rot, scale


def has_extremes(b, act=None):
    '''tell if a bone has extreme marked '''
    if not act:
        act = fn.get_obj_action(b.id_data)
        if not act:
            return False

    for fcu in act.fcurves:
        if not '"' in fcu.data_path:
            continue
        if fcu.data_path.split('"')[1] == b.name: # name of the bone
            if [k for k in fcu.keyframe_points if k.type == 'EXTREME']:
                return True
    return False

def get_extreme_range(ob, act, b):
    b_fcurves = [fcu for fcu in act.fcurves if '"' in fcu.data_path and fcu.data_path.split('"')[1] == b.bone.name]
    # for f in b_fcurves:
    #     print('fc:', f.data_path, f.array_index)
    curves = []
    for fcu in b_fcurves:
        start_frame = end_frame = None
        e_ct = 0
        encountered_marks = False # flag to stop after last extreme of each fcu
        for k in fcu.keyframe_points:
            # if k.select_control_point: # based on selection ?
            if k.type == 'EXTREME':
                encountered_marks = True
                
                f = k.co.x
                if start_frame is None:
                    start_frame = f
                if start_frame > f:
                    start_frame = f

                if end_frame is None:
                    end_frame = f
                if end_frame < f:
                    end_frame = f
                
                e_ct += 1
                continue
            
            # it's a normal keyframe
            if encountered_marks:
                if e_ct == 1:
                    # reset (continue scan to next frame range)
                    e_ct = 0
                    start_frame = end_frame = None
                    encountered_marks = False
                
                else:
                    ## means back to other frame type after passed sufficient key
                    ## (stop for this fcu)
                    break

        print(fcu.data_path, fcu.array_index, start_frame, end_frame)
        if start_frame is None or end_frame is None:
            continue
        if end_frame - start_frame == 0: # same key
            continue

        print('ok')
        curves.append(end_frame - start_frame)

    if not curves:
        return
    print('curves: ', curves)
    curves.sort()
    return curves[-1]

def find_best_foot(ob):
    '''Get an armature object and do some wizardry to return best match for foot bone'''

    b = bpy.context.active_pose_bone

    act = fn.get_obj_action(ob)
    if not act:
        return ('ERROR', f'No action active on {ob.name}')
    
    # use original action as ref
    act = fn.get_origin_action(act)
            
    if 'foot' in b.name.lower():
        # if best is selected 
        return b

    ## auto detect reference foot
    ref = 'foot.R'
    target_bones = [pb for pb in ob.pose.bones if not b.name.lower().startswith(('mch', 'org', 'def'))\
        and has_extremes(pb, act=act)]

    if not target_bones:
        return ('ERROR', f'No keys in action "{act.name}" are marked as Extreme (red keys)')

    target_bones.sort(key=lambda x: fn.fuzzy_match_ratio(ref, x.name))
    # print('target_bones: ', [b.name for b in target_bones]) #Dbg
    
    # analyse best bone for contact length
    b = target_bones[0]
    
    print(f'auto-detected best bone as {b.name}')

    # determine contact chain length
    
    flip_name = fn.get_flipped_name(b.name)
    flipped = next((b for b in target_bones if b.name == flip_name), None)

    if not flipped:
        print(f'No flipped name found (using "{flip_name}")')
        return b
    
    flipped_contact_range = get_extreme_range(ob, act, flipped)
    print('flipped_contact_range: ', flipped_contact_range)
    
    bone_contact_range = get_extreme_range(ob, act, b)
    print('bone_contact_range: ', bone_contact_range)
    
    if bone_contact_range:
        if flipped_contact_range and (bone_contact_range < flipped_contact_range):
            return flipped
        else:
            return b
    elif flipped_contact_range:
        return flipped

    return ('ERROR', f'No Extreme (red keys) on bone "{b.name}" for action "{act.name}"')


def anim_path_from_translate():
    '''Calculate step size from selected foot and forward axis and animate curve'''
    print(fn.helper())

    ob = bpy.context.object

    debug = fn.get_addon_prefs().debug
    settings = bpy.context.scene.anim_cycle_settings
    axis = settings.forward_axis
    
    curve = None
    if settings.path_to_follow:
        curve = settings.path_to_follow

    if curve and not bpy.context.scene.objects.get(curve.name):
        return 'ERROR', f'Curve {curve.name} is not in scene'

    # if curve is not defined try to track it from constraints on armature
    if not curve:
        curve, _const = fn.get_follow_curve_from_armature(ob)
        if isinstance(curve, str):
            return curve, _const

    act = fn.get_obj_action(ob)
    if not act:
        return ('ERROR', f'No action active on {ob.name}')

    base_act = None
    # use original action as ref
    if '_baked' in act.name:
        base_act_name = act.name.split('_baked')[0]
        base_act = bpy.data.actions.get(base_act_name)
        if base_act:
            act = base_act
            print(f'Using for action {base_act_name} as reference')
        else:
            print(f'No base action found (searching for {base_act_name})')
            
    # b = bpy.context.active_pose_bone
    b = find_best_foot(ob)
    if isinstance(b, tuple):
        return b # return error and message
    print('best: ', b.name)

    # if not 'foot' in b.bone.name:
    #     return ('ERROR', 'No "foot" in active bone name\n-> Select foot that has the most reliable contact')
    
    ## calculate offset from bones by evaluating distance at extremes
    # fcurve parsing:
    #   name : fcu.data_path.split('"')[1] (bone_name)
    #   properties: fcu.data_path.split('.')[-1] ('location', rotation_euler)
    #   axis : fcu.array_index (to get axis letter : {0:'X', 1:'Y', 2:'Z'}[fcu.array_index])

    ## get only fcurves relative to selected bone
    b_fcurves = [fcu for fcu in act.fcurves if '"' in fcu.data_path and fcu.data_path.split('"')[1] == b.bone.name]
    print('b_fcurves: ', len(b_fcurves))

    # find best fcurve

    for fcu in b_fcurves:
        start_frame = end_frame = None
        # skip problematic keys
        if not len(fcu.keyframe_points):
            if debug: print(fcu.data_path, fcu.array_index, '>> no keys !')
            continue

        if all(k.type == 'EXTREME' for k in fcu.keyframe_points):
            # True if all are extreme or no keyframe in fcu
            if debug: print(fcu.data_path, fcu.array_index, '>> all keys are marked as extremes !')
            continue

        encountered_marks = False # flag to stop after last extreme of each fcu
        e_ct = 0
        for k in fcu.keyframe_points:
            if k.type == 'EXTREME':
                encountered_marks = True
                
                f = k.co.x
                if start_frame is None:
                    start_frame = f
                if start_frame > f:
                    start_frame = f

                if end_frame is None:
                    end_frame = f
                if end_frame < f:
                    end_frame = f
                
                e_ct += 1
                continue
            
            # this is a normal keyframe 
            if encountered_marks:
                if e_ct == 1:
                    # mean only one extreme has been scanned
                    # reset and continue de keys scan
                    e_ct = 0
                    start_frame = end_frame = None
                    encountered_marks = False
                else:
                    ## means back to other frame type after passed breakdown we stop
                    ## (for this fcu)
                    break

        if start_frame is None or end_frame is None:
            continue
        if start_frame == end_frame:
            continue

        # we have a range and were probably happy with this one.
        break

    if start_frame is None or end_frame is None:
        return ('ERROR', f'No / All or not enough keyframe marked Extreme {ob.name} > {b.name}')
    if start_frame == end_frame:
       return ('ERROR', f'Only one key detected as extreme (at frame {start_frame}) !\nNeed at least two chained marked keys')

    print(f'Offset from key range. start: {start_frame} - end: {end_frame}')
    move_frame = end_frame - start_frame

    ## Find move_val from diff position at start and end frame wihtin character forward axis

    ## FIXME: problem when cycle axis is not Forward compare to character 
    ## apply rotations in real world ? quat_diff = b.matrix_basis.to_quaternion().rotation_difference(b.matrix.to_quaternion())

    start_transform = get_bone_transform_at_frame(b, act, start_frame)
    start_mat = fn.compose_matrix(start_transform['location'], start_transform['rotation_euler'], start_transform['scale'])

    end_transform = get_bone_transform_at_frame(b, act, end_frame)
    end_mat = fn.compose_matrix(end_transform['location'], end_transform['rotation_euler'], end_transform['scale'])


    ## Determine direction vector of the charater (root)
    root = ob.pose.bones.get(fn.get_root_name())
    if not root:
        print('No root found')
        return {"CANCELLED"}

    root_axis_vec = fn.get_direction_vector_from_enum(axis) # world space
    root_axis_vec = root.bone.matrix_local @ root_axis_vec # aligned with object
    # bpy.context.scene.cursor.location = root_axis_vec # Dbg root direction

    ## Get difference between start_loc and ends loc on forward axis
    start_loc = (b.bone.matrix_local @ start_mat).to_translation()
    end_loc = (b.bone.matrix_local @ end_mat).to_translation()
    # bpy.context.scene.cursor.location = start_loc # Dbg foot start position
   
    if debug:
        print('root vec : ', root_axis_vec)
        print('start loc: ', start_loc)
        print('end loc: ', end_loc)

    ##  get distance on forward axis
    move_val = (intersect_line_plane(start_loc, start_loc + root_axis_vec, end_loc, root_axis_vec) - start_loc).length
    print('Detected move value: ', move_val)

    length = fn.get_curve_length(curve)    
    
    ## steps: number of repetitions (how many times the move distance fit in the lenght of the curve)
    steps = length / move_val

    ## frame_duration: number of frame for the move multiplied by the step
    frame_duration = int(steps * move_frame)

    const = root.constraints.get("Follow Path")
    if not const:
        return 'ERROR', f'No "Follow Path" constraint on bone "{root.name}"'

    offset_data_path = f'pose.bones["{root.name}"].constraints["{const.name}"].offset'

    fcu = ob.animation_data.action.fcurves.find(offset_data_path)
    if fcu:
        ob.animation_data.action.fcurves.remove(fcu)
    
    anim_frame = settings.start_frame
    # curve.data.path_duration = frame_duration # set only 100
    curve.data.path_duration = 100
    
    const.offset = 0
    const.keyframe_insert('offset', frame=anim_frame) # , options={'INSERTKEY_AVAILABLE'}

    ## negative (offset time rewinding so character move forward)

    # const.offset = -frame_duration # Valid when duration is set same as curve's path_duration
    # const.offset = -(((move_frame * 100) / frame_duration) * steps) # works and slightly more precise but super convoluted
    const.offset = -100
    const.keyframe_insert('offset', frame=anim_frame + frame_duration)

    ## All to linear (will be set to CONSTANT at the moment of sampling)
    fcu = ob.animation_data.action.fcurves.find(offset_data_path)
    if fcu:
        for k in fcu.keyframe_points:
            k.interpolation = 'LINEAR'
    
    # Set extrapolation to linear to avoid a stop # TODO: maybe expose choice ?
    fcu.extrapolation = 'LINEAR' # default is 'CONSTANT'
    # defaut to linear (avoid mothion blur problem if start is set exactly on scene.frame_start)

    ## set all to constant
    # for k in t_fcu.keyframe_points:
    #     k.interpolation = 'CONSTANT'

    # speed indicator if animator wants to adapt the cycle
    ## Show a marker to determine cycle range if needed to reach a
 
    ''' # Does not work yet
    if settings.end_frame > settings.start_frame:
        all_keys_list = [k.co.x for fc in act.fcurves if 'foot' in fc.data_path for k in fc.keyframe_points]
        base_start = int(min(all_keys_list))
        base_end = int(max(all_keys_list))
        base_range = base_end - base_start
        
        wanted_duration = settings.end_frame - settings.start_frame # defined in "autowalk > motion" interface
        range_needed_to_go_full_curve = base_range * (wanted_duration / frame_duration)

        # create marker
        mark_name = 'range to fill path'
        speed_mark = bpy.context.scene.timeline_markers.get(mark_name)
        if not speed_mark:
            speed_mark = bpy.context.scene.timeline_markers.new(mark_name)
        speed_mark.frame = int(base_start + range_needed_to_go_full_curve)
    '''
        

    if debug: print('end of set_follow_path_anim')

class AW_OT_animate_path(bpy.types.Operator):
    bl_idname = "autowalk.animate_path"
    bl_label = "Animate Path"
    bl_description = "Use most representative 'in contact' feet of the cycle\
        \nSelect foot bone to use as reference\
        \nSelected bone should have two keyframe marked as type extreme (red):\
        \nSelect keyframe and use R > Extreme)"
    bl_options = {"REGISTER", "UNDO"}

    @classmethod
    def poll(cls, context):
        return context.object and context.object.type == 'ARMATURE'

    # def invoke(self, context, event):
    #     self.shift = event.shift
    #     return self.execute(context)

    def execute(self, context):
        # TODO clear previous animation (keys) if there is any
        if context.mode == 'OBJECT':
            # Go in pose mode
            bpy.ops.object.mode_set(mode='POSE')

        err = anim_path_from_translate()
        if err:
            self.report({err[0]}, err[1])
            if err[0] == 'ERROR':
                return {"CANCELLED"}
        return {"FINISHED"}


class AW_OT_adjust_animation_length(bpy.types.Operator):
    bl_idname = "autowalk.adjust_animation_length"
    bl_label = "Adjust Anim speed"
    bl_description = "Adjust speed\nOnce pressed, move up/down to move animation path last key value"
    bl_options = {"REGISTER"} # , "UNDO"

    @classmethod
    def poll(cls, context):
        return context.object and context.object.type == 'ARMATURE' #  in ('ARMATURE', 'CURVE')

    val : bpy.props.FloatProperty(name='End key value')

    def invoke(self, context, event):
        # check animation data of curve
        # self.pref = fn.get_addon_prefs()

        ob = context.object
        root_name = fn.get_root_name()
        root = ob.pose.bones.get(root_name)
        if not root:
            self.report({'ERROR'}, f'no bone {root_name} found in {ob.name}')
            return {"CANCELLED"}
        
        # TODO replace fcurve getter by fn.get_offset_fcu(root)
        # self.fcu = fn.get_offset_fcu(root)
        # if isinstance(self.fcu, str):
        #     self.report({'ERROR'}, self.fcu)
        #     return {"CANCELLED"}


        self.act = fn.get_obj_action(ob)
        if not self.act:
            self.report({'ERROR'}, f'No action on {ob.name} data')
            return {"CANCELLED"}

        # if '_baked' in self.act.name:
        #     self.report({'WARNING'}, f'Action is expanded')

        const = root.constraints.get("Follow Path")
        if not const:
            self.report({'ERROR'}, f'No "Follow Path" constraint on bone "{root.name}"')
            return {"CANCELLED"}
        offset_data_path = f'pose.bones["{root.name}"].constraints["{const.name}"].offset'

        self.fcu = self.act.fcurves.find(offset_data_path)
        if not self.fcu:
            self.report({'ERROR'}, f'No fcurve at datapath: {offset_data_path}')
            return {"CANCELLED"}

        if not len(self.fcu.keyframe_points):
            self.report({'ERROR'}, f'No keys on fcurve {self.fcu.data_path}')
            return {"CANCELLED"}

        if len(self.fcu.keyframe_points) > 2:
            self.report({'WARNING'}, f'{ob.name} offset anim has {len(self.fcu.keyframe_points)} keyframe (should just have 2 to redefine speed)')
        
        self.k = self.fcu.keyframe_points[-1]
        self.val = self.init_ky = self.k.co.y
        self.init_my = event.mouse_y
        
        context.window_manager.modal_handler_add(self)
        return {'RUNNING_MODAL'}


    def modal(self, context, event):
        # added reduction factor
        self.val = self.init_ky + ((event.mouse_y - self.init_my) * 0.1)
        offset = self.val - self.init_ky
        display_text = f"Path animation end key value {self.val:.3f}, offset {offset:.3f}"
        context.area.header_text_set(display_text)
        self.k.co.y = self.val
        if event.type == 'LEFTMOUSE' and event.value == "PRESS":
            context.area.header_text_set(None)
            self.execute(context)
            return {"FINISHED"}
        
        if event.type in ('RIGHTMOUSE', 'ESC') and event.value == "PRESS":
            self.k.co.y = self.init_ky
            context.area.header_text_set(None)
            return {"CANCELLED"}
        if event.type in ('MIDDLEMOUSE', 'SPACE'): # Mmaybe not mid mouse ?
            return {'PASS_THROUGH'}
        return {"RUNNING_MODAL"}

    def execute(self, context):
        self.k.co.y = self.val
        return {"FINISHED"}

    # def draw(self, context):
    #     layout = self.layout
    #     layout.prop(self, "val")

classes=(
AW_OT_animate_path,
AW_OT_adjust_animation_length,
)

def register():
    for cls in classes:
        bpy.utils.register_class(cls)

def unregister():
    for cls in reversed(classes):
        bpy.utils.unregister_class(cls)