import bpy
import bmesh
import operator
from mathutils import Vector
from collections import defaultdict
from math import pi
import sys
import time
from math import radians, hypot

from . import utilities_uv


class op(bpy.types.Operator):
    bl_idname = "uv.textools_rectify"
    bl_label = "Rectify"
    bl_description = "Align selected faces or verts to rectangular distribution."
    bl_options = {'REGISTER', 'UNDO'}

    @classmethod
    def poll(cls, context):
        if not bpy.context.active_object:
            return False

        if bpy.context.active_object.type != 'MESH':
            return False

        if bpy.context.active_object.mode != 'EDIT':
            return False

        # No Sync mode
        if context.scene.tool_settings.use_uv_select_sync:
            return False

        return True

    def execute(self, context):
        rectify(self, context)
        return {'FINISHED'}

def time_clock():
        if sys.version_info >= (3, 3):
                return time.process_time()
        else:
                return time.clock()

precision = 3


def rectify(self, context):
    obj = bpy.context.active_object

    bm = bmesh.from_edit_mesh(obj.data)
    uv_layers = bm.loops.layers.uv.verify()

    # Store selection
    utilities_uv.selection_store()

    main(False)

    # Restore selection
    utilities_uv.selection_restore()


def main(square=False, snapToClosest=False):

    startTime = time_clock()
    obj = bpy.context.active_object
    me = obj.data
    bm = bmesh.from_edit_mesh(me)
    uv_layers = bm.loops.layers.uv.verify()
    # bm.faces.layers.tex.verify()  # currently blender needs both layers.

    face_act = bm.faces.active
    targetFace = face_act

    # if len(bm.faces) > allowedFaces:
    #    operator.report({'ERROR'}, "selected more than " +str(allowedFaces) +" allowed faces.")
    #   return

    edgeVerts, filteredVerts, selFaces, nonQuadFaces, vertsDict, noEdge = ListsOfVerts(
        uv_layers, bm)

    if len(filteredVerts) is 0:
        return
    if len(filteredVerts) is 1:
        SnapCursorToClosestSelected(filteredVerts)
        return

    cursorClosestTo = CursorClosestTo(filteredVerts)
    #line is selected

    if len(selFaces) is 0:
        if snapToClosest is True:
            SnapCursorToClosestSelected(filteredVerts)
            return

        VertsDictForLine(uv_layers, bm, filteredVerts, vertsDict)

        if AreVectsLinedOnAxis(filteredVerts) is False:
            ScaleTo0OnAxisAndCursor(filteredVerts, vertsDict, cursorClosestTo)
            return SuccessFinished(me, startTime)

        MakeEqualDistanceBetweenVertsInLine(
            filteredVerts, vertsDict, cursorClosestTo)
        return SuccessFinished(me, startTime)

    # else:

    # active face checks
    if targetFace is None or targetFace.select is False or len(targetFace.verts) is not 4:
        targetFace = selFaces[0]
    else:
        for l in targetFace.loops:
            if l[uv_layers].select is False:
                targetFace = selFaces[0]
                break

    ShapeFace(uv_layers, operator, targetFace, vertsDict, square)

    for nf in nonQuadFaces:
        for l in nf.loops:
            luv = l[uv_layers]
            luv.select = False

    if square:
        FollowActiveUV(operator, me, targetFace, selFaces, 'EVEN')
    else:
        FollowActiveUV(operator, me, targetFace, selFaces)

    if noEdge is False:
        # edge has ripped so we connect it back
        for ev in edgeVerts:
            key = (round(ev.uv.x, precision), round(ev.uv.y, precision))
            if key in vertsDict:
                ev.uv = vertsDict[key][0].uv
                ev.select = True

    return SuccessFinished(me, startTime)


def ListsOfVerts(uv_layers, bm):
    edgeVerts = []
    allEdgeVerts = []
    filteredVerts = []
    selFaces = []
    nonQuadFaces = []
    vertsDict = defaultdict(list)  # dict

    for f in bm.faces:
        isFaceSel = True
        facesEdgeVerts = []
        if (f.select == False):
            continue

        # collect edge verts if any
        for l in f.loops:
            luv = l[uv_layers]
            if luv.select is True:
                facesEdgeVerts.append(luv)
            else:
                isFaceSel = False

        allEdgeVerts.extend(facesEdgeVerts)
        if isFaceSel:
            if len(f.verts) is not 4:
                nonQuadFaces.append(f)
                edgeVerts.extend(facesEdgeVerts)
            else:
                selFaces.append(f)

                for l in f.loops:
                    luv = l[uv_layers]
                    x = round(luv.uv.x, precision)
                    y = round(luv.uv.y, precision)
                    vertsDict[(x, y)].append(luv)

        else:
            edgeVerts.extend(facesEdgeVerts)

    noEdge = False
    if len(edgeVerts) is 0:
        noEdge = True
        edgeVerts.extend(allEdgeVerts)

    if len(selFaces) is 0:
        for ev in edgeVerts:
            if ListQuasiContainsVect(filteredVerts, ev) is False:
                filteredVerts.append(ev)
    else:
        filteredVerts = edgeVerts

    return edgeVerts, filteredVerts, selFaces, nonQuadFaces, vertsDict, noEdge


def ListQuasiContainsVect(list, vect):
    for v in list:
        if AreVertsQuasiEqual(v, vect):
            return True
    return False


def SnapCursorToClosestSelected(filteredVerts):
    # TODO: snap to closest selected
    if len(filteredVerts) is 1:
        SetAll2dCursorsTo(filteredVerts[0].uv.x, filteredVerts[0].uv.y)

    return


def VertsDictForLine(uv_layers, bm, selVerts, vertsDict):
    for f in bm.faces:
        for l in f.loops:
            luv = l[uv_layers]
            if luv.select is True:
                x = round(luv.uv.x, precision)
                y = round(luv.uv.y, precision)

                vertsDict[(x, y)].append(luv)


def AreVectsLinedOnAxis(verts):
    areLinedX = True
    areLinedY = True
    allowedError = 0.0009
    valX = verts[0].uv.x
    valY = verts[0].uv.y
    for v in verts:
        if abs(valX - v.uv.x) > allowedError:
            areLinedX = False
        if abs(valY - v.uv.y) > allowedError:
            areLinedY = False
    return areLinedX or areLinedY


def ScaleTo0OnAxisAndCursor(filteredVerts, vertsDict, startv=None, horizontal=None):

    verts = filteredVerts
    verts.sort(key=lambda x: x.uv[0])  # sort by .x

    first = verts[0]
    last = verts[len(verts)-1]

    if horizontal is None:
        horizontal = True
        if ((last.uv.x - first.uv.x) > 0.0009):
            slope = (last.uv.y - first.uv.y)/(last.uv.x - first.uv.x)
            if (slope > 1) or (slope < -1):
                horizontal = False
        else:
            horizontal = False

    if horizontal is True:
        if startv is None:
            startv = first

        SetAll2dCursorsTo(startv.uv.x, startv.uv.y)
        # scale to 0 on Y
        ScaleTo0('Y')
        return

    else:
        verts.sort(key=lambda x: x.uv[1])  # sort by .y
        verts.reverse()  # reverse because y values drop from up to down
        first = verts[0]
        last = verts[len(verts)-1]
        if startv is None:
            startv = first

        SetAll2dCursorsTo(startv.uv.x, startv.uv.y)
        # scale to 0 on X
        ScaleTo0('X')
        return


def SetAll2dCursorsTo(x, y):
    last_area = bpy.context.area.type
    bpy.context.area.type = 'IMAGE_EDITOR'

    bpy.ops.uv.cursor_set(location=(x, y))

    bpy.context.area.type = last_area
    return


def CursorClosestTo(verts, allowedError=0.025):
    ratioX, ratioY = ImageRatio()

    # any length that is certantly not smaller than distance of the closest
    min = 1000
    minV = verts[0]
    for v in verts:
        if v is None:
            continue
        for area in bpy.context.screen.areas:
            if area.type == 'IMAGE_EDITOR':
                loc = area.spaces[0].cursor_location
                hyp = hypot(loc.x/ratioX - v.uv.x, loc.y/ratioY - v.uv.y)
                if (hyp < min):
                    min = hyp
                    minV = v

    if min is not 1000:
        return minV
    return None


def SuccessFinished(me, startTime):
    # use for backtrack of steps
    # bpy.ops.ed.undo_push()
    bmesh.update_edit_mesh(me)
    #elapsed = round(time_clock()-startTime, 2)
    #if (elapsed >= 0.05): operator.report({'INFO'}, "UvSquares finished, elapsed:", elapsed, "s.")
    return


def ShapeFace(uv_layers, operator, targetFace, vertsDict, square):
    corners = []
    for l in targetFace.loops:
        luv = l[uv_layers]
        corners.append(luv)

    if len(corners) is not 4:
        #operator.report({'ERROR'}, "bla")
        return

    lucv, ldcv, rucv, rdcv = Corners(corners)

    cct = CursorClosestTo([lucv, ldcv, rdcv, rucv])
    if cct is None:
        cct = lucv

    MakeUvFaceEqualRectangle(vertsDict, lucv, rucv, rdcv, ldcv, cct, square)
    return


def MakeUvFaceEqualRectangle(vertsDict, lucv, rucv, rdcv, ldcv, startv, square=False):
    ratioX, ratioY = ImageRatio()
    ratio = ratioX/ratioY

    if startv is None:
        startv = lucv.uv
    elif AreVertsQuasiEqual(startv, rucv):
        startv = rucv.uv
    elif AreVertsQuasiEqual(startv, rdcv):
        startv = rdcv.uv
    elif AreVertsQuasiEqual(startv, ldcv):
        startv = ldcv.uv
    else:
        startv = lucv.uv

    lucv = lucv.uv
    rucv = rucv.uv
    rdcv = rdcv.uv
    ldcv = ldcv.uv

    if (startv == lucv):
        finalScaleX = hypotVert(lucv, rucv)
        finalScaleY = hypotVert(lucv, ldcv)
        currRowX = lucv.x
        currRowY = lucv.y

    elif (startv == rucv):
        finalScaleX = hypotVert(rucv, lucv)
        finalScaleY = hypotVert(rucv, rdcv)
        currRowX = rucv.x - finalScaleX
        currRowY = rucv.y

    elif (startv == rdcv):
        finalScaleX = hypotVert(rdcv, ldcv)
        finalScaleY = hypotVert(rdcv, rucv)
        currRowX = rdcv.x - finalScaleX
        currRowY = rdcv.y + finalScaleY

    else:
        finalScaleX = hypotVert(ldcv, rdcv)
        finalScaleY = hypotVert(ldcv, lucv)
        currRowX = ldcv.x
        currRowY = ldcv.y + finalScaleY

    if square:
        finalScaleY = finalScaleX*ratio
    #lucv, rucv
    x = round(lucv.x, precision)
    y = round(lucv.y, precision)
    for v in vertsDict[(x, y)]:
        v.uv.x = currRowX
        v.uv.y = currRowY

    x = round(rucv.x, precision)
    y = round(rucv.y, precision)
    for v in vertsDict[(x, y)]:
        v.uv.x = currRowX + finalScaleX
        v.uv.y = currRowY

    #rdcv, ldcv
    x = round(rdcv.x, precision)
    y = round(rdcv.y, precision)
    for v in vertsDict[(x, y)]:
        v.uv.x = currRowX + finalScaleX
        v.uv.y = currRowY - finalScaleY

    x = round(ldcv.x, precision)
    y = round(ldcv.y, precision)
    for v in vertsDict[(x, y)]:
        v.uv.x = currRowX
        v.uv.y = currRowY - finalScaleY

    return


def FollowActiveUV(operator, me, f_act, faces, EXTEND_MODE='LENGTH_AVERAGE'):
    bm = bmesh.from_edit_mesh(me)
    uv_act = bm.loops.layers.uv.active

    # our own local walker
    def walk_face_init(faces, f_act):
        # first tag all faces True (so we dont uvmap them)
        for f in bm.faces:
            f.tag = True
        # then tag faces arg False
        for f in faces:
            f.tag = False
        # tag the active face True since we begin there
        f_act.tag = True

    def walk_face(f):
        # all faces in this list must be tagged
        f.tag = True
        faces_a = [f]
        faces_b = []

        while faces_a:
            for f in faces_a:
                for l in f.loops:
                    l_edge = l.edge
                    if (l_edge.is_manifold is True) and (l_edge.seam is False):
                        l_other = l.link_loop_radial_next
                        f_other = l_other.face
                        if not f_other.tag:
                            yield (f, l, f_other)
                            f_other.tag = True
                            faces_b.append(f_other)
            # swap
            faces_a, faces_b = faces_b, faces_a
            faces_b.clear()

    def walk_edgeloop(l):
        """
        Could make this a generic function
        """
        e_first = l.edge
        e = None
        while True:
            e = l.edge
            yield e

            # don't step past non-manifold edges
            if e.is_manifold:
                # welk around the quad and then onto the next face
                l = l.link_loop_radial_next
                if len(l.face.verts) == 4:
                    l = l.link_loop_next.link_loop_next
                    if l.edge is e_first:
                        break
                else:
                    break
            else:
                break

    def extrapolate_uv(fac,
                       l_a_outer, l_a_inner,
                       l_b_outer, l_b_inner):
        l_b_inner[:] = l_a_inner
        l_b_outer[:] = l_a_inner + ((l_a_inner - l_a_outer) * fac)

    def apply_uv(f_prev, l_prev, f_next):
        l_a = [None, None, None, None]
        l_b = [None, None, None, None]

        l_a[0] = l_prev
        l_a[1] = l_a[0].link_loop_next
        l_a[2] = l_a[1].link_loop_next
        l_a[3] = l_a[2].link_loop_next

        #  l_b
        #  +-----------+
        #  |(3)        |(2)
        #  |           |
        #  |l_next(0)  |(1)
        #  +-----------+
        #        ^
        #  l_a   |
        #  +-----------+
        #  |l_prev(0)  |(1)
        #  |    (f)    |
        #  |(3)        |(2)
        #  +-----------+
        #  copy from this face to the one above.

        # get the other loops
        l_next = l_prev.link_loop_radial_next
        if l_next.vert != l_prev.vert:
            l_b[1] = l_next
            l_b[0] = l_b[1].link_loop_next
            l_b[3] = l_b[0].link_loop_next
            l_b[2] = l_b[3].link_loop_next
        else:
            l_b[0] = l_next
            l_b[1] = l_b[0].link_loop_next
            l_b[2] = l_b[1].link_loop_next
            l_b[3] = l_b[2].link_loop_next

        l_a_uv = [l[uv_act].uv for l in l_a]
        l_b_uv = [l[uv_act].uv for l in l_b]

        if EXTEND_MODE == 'LENGTH_AVERAGE':
            fac = edge_lengths[l_b[2].edge.index][0] / \
                edge_lengths[l_a[1].edge.index][0]
        elif EXTEND_MODE == 'LENGTH':
            a0, b0, c0 = l_a[3].vert.co, l_a[0].vert.co, l_b[3].vert.co
            a1, b1, c1 = l_a[2].vert.co, l_a[1].vert.co, l_b[2].vert.co

            d1 = (a0 - b0).length + (a1 - b1).length
            d2 = (b0 - c0).length + (b1 - c1).length
            try:
                fac = d2 / d1
            except ZeroDivisionError:
                fac = 1.0
        else:
            fac = 1.0

        extrapolate_uv(fac,
                       l_a_uv[3], l_a_uv[0],
                       l_b_uv[3], l_b_uv[0])

        extrapolate_uv(fac,
                       l_a_uv[2], l_a_uv[1],
                       l_b_uv[2], l_b_uv[1])

    # -------------------------------------------
    # Calculate average length per loop if needed

    if EXTEND_MODE == 'LENGTH_AVERAGE':
        bm.edges.index_update()
        # NoneType times the length of edges list
        edge_lengths = [None] * len(bm.edges)

        for f in faces:
            # we know its a quad
            l_quad = f.loops[:]
            l_pair_a = (l_quad[0], l_quad[2])
            l_pair_b = (l_quad[1], l_quad[3])

            for l_pair in (l_pair_a, l_pair_b):
                if edge_lengths[l_pair[0].edge.index] is None:

                    edge_length_store = [-1.0]
                    edge_length_accum = 0.0
                    edge_length_total = 0

                    for l in l_pair:
                        if edge_lengths[l.edge.index] is None:
                            for e in walk_edgeloop(l):
                                if edge_lengths[e.index] is None:
                                    edge_lengths[e.index] = edge_length_store
                                    edge_length_accum += e.calc_length()
                                    edge_length_total += 1

                    edge_length_store[0] = edge_length_accum / \
                        edge_length_total

    # done with average length
    # ------------------------

    walk_face_init(faces, f_act)
    for f_triple in walk_face(f_act):
        apply_uv(*f_triple)

    bmesh.update_edit_mesh(me, False)


def ImageRatio():
    ratioX, ratioY = 256, 256
    for a in bpy.context.screen.areas:
        if a.type == 'IMAGE_EDITOR':
            img = a.spaces[0].image
            if img is not None and img.size[0] is not 0:
                ratioX, ratioY = img.size[0], img.size[1]
            break
    return ratioX, ratioY


def Corners(corners):
    firstHighest = corners[0]
    for c in corners:
        if c.uv.y > firstHighest.uv.y:
            firstHighest = c
    corners.remove(firstHighest)

    secondHighest = corners[0]
    for c in corners:
        if (c.uv.y > secondHighest.uv.y):
            secondHighest = c

    if firstHighest.uv.x < secondHighest.uv.x:
        leftUp = firstHighest
        rightUp = secondHighest
    else:
        leftUp = secondHighest
        rightUp = firstHighest
    corners.remove(secondHighest)

    firstLowest = corners[0]
    secondLowest = corners[1]

    if firstLowest.uv.x < secondLowest.uv.x:
        leftDown = firstLowest
        rightDown = secondLowest
    else:
        leftDown = secondLowest
        rightDown = firstLowest

    return leftUp, leftDown, rightUp, rightDown


def AreVertsQuasiEqual(v1, v2, allowedError=0.0009):
    if abs(v1.uv.x - v2.uv.x) < allowedError and abs(v1.uv.y - v2.uv.y) < allowedError:
        return True
    return False


def hypotVert(v1, v2):
    hyp = hypot(v1.x - v2.x, v1.y - v2.y)
    return hyp


bpy.utils.register_class(op)