"""
    Qualoth scripts are written in MEL. 
    This module makes a python interface to them
    Notes:
        * this module is Python 2.7-friendly
        * Error checks are sparse to save coding time & lines. 
            This sould not be a problem during the normal workflow
    
"""
from __future__ import print_function
from __future__ import division
import time
import sys

from maya import mel
from maya import cmds


def load_plugin():
    """
        Forces loading Qualoth plugin into Maya. 
        Note that plugin should be installed and licensed to use it!
        Inquire here: http://www.fxgear.net/vfxpricing
    """
    maya_year = int(mel.eval('getApplicationVersionAsFloat'))
    plugin_name = 'qualoth_' + str(maya_year) + '_x64'
    print('Loading ', plugin_name)

    cmds.loadPlugin(plugin_name)


# -------- Wrappers -----------
# Make sure that Qualoth plugin is loaded before running any wrappers!

def qlCreatePattern(curves_group):
    """
        Converts given 2D closed curve to a flat geometry piece
    """
    objects_before = cmds.ls(assemblies=True)
    # run
    cmds.select(curves_group)
    mel.eval('qlCreatePattern()')
    
    # Identify newly created objects
    objects_after = cmds.ls(assemblies=True)
    # No need for symmetric difference because we don't care if some objects were deleted
    return list(set(objects_after) - set(objects_before))


def qlCreateSeam(curve1, curve2):
    """
        Create a seam between two selected curves
    """
    cmds.select([curve1, curve2])
    # Operates on selection
    seam_shape = mel.eval('qlCreateSeam()')
    return seam_shape


def qlCreateCollider(cloth, target):
    """
        Marks object as a collider object for cloth --
        eshures that cloth won't penetrate body when simulated
    """
    objects_before = cmds.ls(assemblies=True)

    cmds.select([cloth, target])
    # Operates on selection
    mel.eval('qlCreateCollider()')

    objects_after = cmds.ls(assemblies=True)
    return list(set(objects_after) - set(objects_before))


def qlCleanCache(cloth):
    """Clean layback cache for given cloth. Accepts qlCloth object"""
    cmds.select(cloth)
    mel.eval('qlClearCache()')


# ------- Higher-level functions --------

def start_maya_sim(garment, props):
    """Start simulation through Maya defalut playback without checks
        Gives Maya user default control over stopping & resuming sim
        Current qlCloth material properties from Maya are used (instead of garment config)
    """
    config = props['config']
    solver = _init_sim(config)

    # Allow to assemble without gravity
    print('Simulation::Assemble without gravity')
    _set_gravity(solver, 0)
    for frame in range(1, config['zero_gravity_steps']):
        cmds.currentTime(frame)  # step

    # resume normally
    print('Simulation::normal playback.. Use ESC key to stop simulation')
    _set_gravity(solver, -980)
    cmds.currentTime(frame - 1)  # one step back to start from simulated state
    cmds.play()


def run_sim(garment, props):
    """
        Setup and run cloth simulator untill static equlibrium is achieved.
        Note:
            * Assumes garment is already properly aligned!
            * All of the garments existing in Maya scene will be simulated
                because solver is shared!!
    """
    config = props['config']
    solver = _init_sim(config)

    start_time = time.time()
    # Allow to assemble without gravity + skip checks for first few frames
    print('Simulating {}'.format(garment.name))
    _set_gravity(solver, 0)
    for frame in range(1, config['zero_gravity_steps']):
        cmds.currentTime(frame)  # step
        garment.cache_if_enabled(frame)
        garment.update_verts_info()
        _update_progress(frame, config['max_sim_steps'])  # progress bar

    # resume normally
    _set_gravity(solver, -980)
    for frame in range(config['zero_gravity_steps'], config['max_sim_steps']):
        cmds.currentTime(frame)  # step
        garment.cache_if_enabled(frame)
        garment.update_verts_info()

        _update_progress(frame, config['max_sim_steps'])  # progress bar
        static, non_st_count = garment.is_static(config['static_threshold'], config['non_static_percent'])
        if static:  # Success!
            print('\nAchieved static equilibrium for {}'.format(garment.name))
            break

    # stats
    props['stats']['sim_time'][garment.name] = time.time() - start_time
    props['stats']['spf'][garment.name] = props['stats']['sim_time'][garment.name] / frame
    props['stats']['fin_frame'][garment.name] = frame

    # Fail checks
    # static equilibrium never detected -- might have false negs!
    if frame == config['max_sim_steps'] - 1:
        print('\nFailed to achieve static equilibrium for {} with {} non-static vertices out of {}'.format(
            garment.name, non_st_count, len(garment.current_verts)))
        _record_fail(props, 'static_equilibrium', garment.name)
    # 3D penetrations 
    if garment.intersect_colliders_3D():
        _record_fail(props, 'intersect_colliders', garment.name)
    if garment.self_intersect_3D():
        _record_fail(props, 'intersect_self', garment.name)
    # Finished too fast 
    if props['stats']['sim_time'][garment.name] < 2:  # 2 sec
        _record_fail(props, 'fast_finish', garment.name)


def findSolver():
    """
        Returns the name of the qlSover existing in the scene
        (usully solver is created once per scene)
    """
    solver = cmds.ls('*qlSolver*Shape*')
    return solver[0]


def deleteSolver():
    """deletes all solver objects from the scene"""
    cmds.delete(cmds.ls('*qlSolver*'))


def flipPanelNormal(panel_geom):
    """Set flippling normals to True for a given panel geom objects
        at least one of the provided objects should a qlPattern object"""

    ql_pattern = [obj for obj in panel_geom if 'Pattern' in obj]
    ql_pattern = ql_pattern[0]
    shape = cmds.listRelatives(ql_pattern, shapes=True, path=True)

    cmds.setAttr(shape[0] + '.flipNormal', 1)


def getVertsOnCurve(panel_node, curve, curve_group=None):
    """
        Return the list of mesh vertices located on the curve 
        * panel_node is qlPattern object to which the curve belongs
        * curve is a main name of a curve object to get vertex info for
            OR any substring of it's full Maya name that would uniquely identify it
        * (optional) curve_group is a name of parent group of given curve to uni quely distinguish the curve 
    """
    # find qlDiscretizer node
    if 'Shape' not in panel_node:
        shapes = cmds.listRelatives(panel_node, shapes=True)
        panel_node = panel_node + '|' + shapes[0]

    connections = cmds.listConnections(panel_node)

    discretizer = [node for node in connections if 'qlDiscretizer' in node]
    discretizer = discretizer[0]
    info_array = discretizer + '.curveVeritcesInfoArray'

    # iterate over curveVeritcesInfoArray 
    num_curves = cmds.getAttr(info_array, size=True)
    # avoid matching 'curve1' with 'Acurve10' by adding a starting and ending caharacter
    if curve[0] != '|':
        curve = '|' + curve
    if curve[-1] != '|':
        curve = curve + '|'
    for idx in range(num_curves):
        curve_name = cmds.getAttr(info_array + '[%d].curveName' % idx)

        if curve in curve_name:
            if curve_group is not None and curve_group not in curve_name:
                # erroneous match
                continue
            # found!
            vertices = cmds.getAttr(info_array + '[%d].curveVertices' % idx)
            return vertices

    return None


# ------ Working with props ------
def setColliderFriction(collider_objects, friction_value):
    """Sets the level of friction of the given collider to friction_value"""

    main_collider = [obj for obj in collider_objects if 'Offset' not in obj]
    collider_shape = cmds.listRelatives(main_collider[0], shapes=True)

    cmds.setAttr(collider_shape[0] + '.friction', friction_value)


def setFabricProps(cloth, props):
    """Set given material propertied to qlClothObject"""
    if not props:
        return
    # Simple ones
    cmds.setAttr(cloth + '.density', props['density'], clamp=True)  
    cmds.setAttr(cloth + '.stretch', props['stretch_resistance'], clamp=True)
    cmds.setAttr(cloth + '.shear', props['shear_resistance'], clamp=True)
    cmds.setAttr(cloth + '.stretchDamp', props['stretch_damp'], clamp=True)
    cmds.setAttr(cloth + '.bend', props['bend_resistance'], clamp=True)
    cmds.setAttr(cloth + '.bendAngleDropOff', props['bend_angle_dropoff'], clamp=True)
    cmds.setAttr(cloth + '.bendDamp', props['bend_damp'], clamp=True)
    cmds.setAttr(cloth + '.bendDampDropOff', props['bend_damp_dropoff'], clamp=True)
    cmds.setAttr(cloth + '.bendYield', props['bend_yield'], clamp=True)
    cmds.setAttr(cloth + '.bendPlasticity', props['bend_plasticity'], clamp=True)
    cmds.setAttr(cloth + '.viscousDamp', props['viscous_damp'], clamp=True)
    cmds.setAttr(cloth + '.friction', props['friction'], clamp=True)
    cmds.setAttr(cloth + '.pressure', props['pressure'], clamp=True)
    cmds.setAttr(cloth + '.lengthScale', props['length_scale'], clamp=True)
    cmds.setAttr(cloth + '.airDrag', props['air_drag'], clamp=True)
    cmds.setAttr(cloth + '.rubber', props['rubber'], clamp=True)

    # need setting flags
    cmds.setAttr(cloth + '.overrideCompression', 1)
    cmds.setAttr(cloth + '.compression', props['compression_resistance'], clamp=True)

    cmds.setAttr(cloth + '.anisotropicControl', 1)
    cmds.setAttr(cloth + '.uStretchScale', props['weft_resistance_scale'], clamp=True)
    cmds.setAttr(cloth + '.vStretchScale', props['warp_resistance_scale'], clamp=True)
    cmds.setAttr(cloth + '.rubberU', props['weft_rubber_scale'], clamp=True)
    cmds.setAttr(cloth + '.rubberV', props['warp_rubber_scale'], clamp=True)


def setPanelsResolution(scaling):
    """Set resoluiton conroller of all qlPatterns in the scene"""
    all_panels = cmds.ls('*qlPattern*', shapes=True)
    for panel in all_panels:
        cmds.setAttr(panel + '.resolutionScale', scaling)


def fetchFabricProps(cloth):
    """Returns current material properties of the cloth's objects
        Requires qlCloth object
    """
    props = {}
    # Mass density per unit area. (Kg/cm2)
    props['density'] = cmds.getAttr(cloth + '.density')  
    # Resisting force to planar stretching and compression
    props['stretch_resistance'] = cmds.getAttr(cloth + '.stretch') 
    # Resisting force to shearing. (See Figure.) This parameter is 
    # interpreted as a scale factor to the stretch resistance. 
    props['shear_resistance'] = cmds.getAttr(cloth + '.shear')
    # Damping factor for stretching motion.
    props['stretch_damp'] = cmds.getAttr(cloth + '.stretchDamp')
    # Resisting force to bending.
    props['bend_resistance'] = cmds.getAttr(cloth + '.bend')
    props['bend_angle_dropoff'] = cmds.getAttr(cloth + '.bendAngleDropOff')
    # Damping factor for bending motion
    props['bend_damp'] = cmds.getAttr(cloth + '.bendDamp')
    props['bend_damp_dropoff'] = cmds.getAttr(cloth + '.bendDampDropOff')

    # creases: elasticity vs plasticity
    props['bend_yield'] = cmds.getAttr(cloth + '.bendYield')
    props['bend_plasticity'] = cmds.getAttr(cloth + '.bendPlasticity')

    # external
    # This damping force drags the motion of each cloth vertex in all directions uniformly 
    # regardless of the directions of normals of each vertex.
    props['viscous_damp'] = cmds.getAttr(cloth + '.viscousDamp')
    # Controls the friction among cloth objects or colliders. Also self-friction
    props['friction'] = cmds.getAttr(cloth + '.friction')
    # The amount of pressure force which are applied to the vertex normal directions of each cloth vertex.
    props['pressure'] = cmds.getAttr(cloth + '.pressure')

    # need setting flags
    # need to turn on .overrideCompression
    props['compression_resistance'] = cmds.getAttr(cloth + '.compression')

    # ------ unlikely to be used ---------
    # Scale factor for length unit. 
    props['length_scale'] = cmds.getAttr(cloth + '.lengthScale') 
    # value controls the amount of influence from those air fields. In case 
    # here is no attached field to this cloth, 'Air Drag' simply drags the 
    # cloth motion in the direction of face normals of each triangle. 
    props['air_drag'] = cmds.getAttr(cloth + '.airDrag')
    # This value scales the area of the cloth in rest state. 
    props['rubber'] = cmds.getAttr(cloth + '.rubber')
    # fine-grained
    # The scale factor to the planar stretching/compression resistance in weft (U) direction.
    props['weft_resistance_scale'] = cmds.getAttr(cloth + '.uStretchScale')
    # The scale factor to the planar stretching/compression resistance in warp (V) direction.
    props['warp_resistance_scale'] = cmds.getAttr(cloth + '.vStretchScale')
    # The scale factor to the rubber value (rest length scale) in weft (U) direction.
    props['weft_rubber_scale'] = cmds.getAttr(cloth + '.rubberU')
    # The scale factor to the rubber value (rest length scale) in warp (V) direction.
    props['warp_rubber_scale'] = cmds.getAttr(cloth + '.rubberV')

    return props


def fetchColliderFriction(collider_objects):
    """Retrieve collider friction info from given collider"""

    try:
        main_collider = [obj for obj in collider_objects if 'Offset' not in obj]
        collider_shape = cmds.listRelatives(main_collider[0], shapes=True)

        return cmds.getAttr(collider_shape[0] + '.friction')
    except ValueError as e:
        # collider doesn't exist any more
        return None


def fetchPanelResolution():
    some_panels = cmds.ls('*qlPattern*')

    shape = cmds.listRelatives(some_panels[0], shapes=True, path=True)

    return cmds.getAttr(shape[0] + '.resolutionScale')


# ------- Self-Utils ---------
def _init_sim(config):
    """
        Basic simulation settings before starting simulation
    """
    solver = findSolver()

    cmds.setAttr(solver + '.selfCollision', 1)
    cmds.setAttr(solver + '.startTime', 1)
    cmds.setAttr(solver + '.solverStatistics', 0)  # for easy reading of console output
    cmds.playbackOptions(ps=0, max=config['max_sim_steps'])  # 0 playback speed = play every frame

    return solver


def _set_gravity(solver, gravity):
    """Set a given value of gravity to sim solver"""
    cmds.setAttr(solver + '.gravity1', gravity)


def _update_progress(progress, total):
    """Progress bar in console"""
    # https://stackoverflow.com/questions/3173320/text-progress-bar-in-the-console
    amtDone = progress / total
    num_dash = int(amtDone * 50)
    sys.stdout.write('\rProgress: [{0:50s}] {1:.1f}%'.format('#' * num_dash + '-' * (50 - num_dash), amtDone * 100))
    sys.stdout.flush()


def _record_fail(props, fail_type, garment_name):
    """add a failure recording to props. Creates nodes if don't exist"""
    if 'fails' not in props['stats']:
        props['stats']['fails'] = {}
    try:
        props['stats']['fails'][fail_type].append(garment_name)
    except KeyError:
        props['stats']['fails'][fail_type] = [garment_name]
