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#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
#  of the License, or (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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# ##### END GPL LICENSE BLOCK #####

import bpy
import bmesh
from mathutils import Vector
from bpy_extras.io_utils import create_derived_objects, free_derived_objects

# https://developer.valvesoftware.com/wiki/MAP_file_format

def fmt3(vec3):
    return '%f %f %f'%(vec3.x, vec3.y, vec3.z)
    #return ' '.join(['%%.%df']*3)%tuple([precision]*3)%(vec3.x, vec3.y, vec3.z)
def fmt_plane(plane3dots):
    return '( %s ) ( %s ) ( %s )'%(fmt3(plane3dots[0]), fmt3(plane3dots[1]), fmt3(plane3dots[2]))
def fmt_tex(tev, toff):
    return '[ %s %.1f ]'%(fmt3(tev), toff)
def fmt_face(plane3dots, tename, tev1, teoff1, tev2, teoff2, rot, scaleX, scaleY):
    return '%s %s %s %s %s'%(
        fmt_plane(plane3dots), tename,
        fmt_tex(tev1, teoff1),
        fmt_tex(tev2, teoff2),
        fmt3(Vector([rot, scaleX, scaleY]))
    )

def output_entity_start(dict_props, fh):
    fh.write('{\n')
    for k,v in dict_props.items():
        fh.write('\t%-16s "%s"\n'%('"'+k+'"',v))

def output_brush_start(fh):
    fh.write('\t{\n')

def output_brush_face(plane3dots, tename, tev1, teoff1, tev2, teoff2, rot, scaleX, scaleY, fh):
    fh.write('\t\t%s\n'%fmt_face(plane3dots, tename, tev1, teoff1, tev2, teoff2, rot, scaleX, scaleY))

def output_brush_end(fh):
    fh.write('\t}\n')
    
def output_entity_end(fh):
    fh.write('}\n')

def normal(plane3dots):
    v01 = plane3dots[1] - plane3dots[0]
    v02 = plane3dots[2] - plane3dots[0]
    n = v01.cross(v02)
    n.normalize()
    return n

def flip(plane3dots):
    tmp = plane3dots[2]
    plane3dots[2] = plane3dots[1]
    plane3dots[1] = tmp

def debug1(o=''):
    #print(o)
    return None

def debug2(fano,plane3dots):
    fano.normalize()
    debug1(fano)
    v01 = plane3dots[1] - plane3dots[0]
    v02 = plane3dots[2] - plane3dots[0]
    n = v01.cross(v02)
    n.normalize()
    debug1(n)
    debug1(fano-n)
    debug1()


def save(operator, context, filepath, worldspawn_props, blender_to_map_scale_factor, use_selection=True):
    """Save the Blender scene to a map file."""
    
    # Make sure that data we want to access is not out of sync because edit mode is in use
    if bpy.ops.object.mode_set.poll():
        bpy.ops.object.mode_set(mode='OBJECT')

    sc = context.scene
    if use_selection:
        objects = list(ob for ob in sc.objects if ob.is_visible(sc) and ob.type == 'MESH' and ob.data and ob.select)
    else:
        objects = list(ob for ob in sc.objects if ob.is_visible(sc) and ob.type == 'MESH' and ob.data)

    # Simplify each mesh once (a mesh could be used by multiple objects)
    for mesh in set([ob.data for ob in objects]):
        bm = bmesh.new()
        bm.from_mesh(mesh)
        bmesh.ops.remove_doubles(bm, verts=bm.verts, dist=1/blender_to_map_scale_factor)
        bmesh.ops.holes_fill(bm, edges=bm.edges) #, sides=0
        bmesh.ops.connect_verts_concave(bm, faces=bm.faces)
        bmesh.ops.connect_verts_nonplanar(bm, faces=bm.faces) #, angle_limit=0.0
        bmesh.ops.planar_faces(bm, faces=bm.faces)
        bmesh.ops.recalc_face_normals(bm, faces=bm.faces)
        bm.to_mesh(mesh)
        bm.free()

    # Iterate over objects, make computations (set of cross planes) and print them as worldspawn entity brushes
    with open(filepath, 'w') as fh:
        output_entity_start(worldspawn_props, fh)
        for ob in objects:
            debug1(ob.name)
            mat_to_map = ob.matrix_world * blender_to_map_scale_factor
            mesh = ob.data
            mesh.update(calc_tessface=True)
            for fa in mesh.tessfaces:
                output_brush_start(fh)
                tename='AAATRIGGER'
                tev1 = Vector([1,0,0])
                teoff1 = 0
                tev2 = Vector([0,-1,0])
                teoff2 = 0
                rot = 0
                scaleX = 1
                scaleY = 1
                # Make a brush in .map for each face in blender
                # Brushes are (strangely) defined as a set of intersecting planes in .map
                # Planes are defined with 3 3D points belonging to it
                # "They must be in a clockwise order when facing the outside of the plane 
                #  that is, the side that points outwards from the brush"
                brfront = [None,None,None]
                brback  = [None,None,None]
                # For now this code take the 3 first vectices of the face
                # TODO This can cause troubles if they are colinear or if they have narrow angle
                for i in [0,1,2]:
                    vi = mesh.vertices[fa.vertices[i]].co
                    # front plane in brush will match face in blender (in global coords, with a scale factor)
                    brfront[i]  = mat_to_map * vi
                    # back plane will be 1 (map) unit inside (normal facing outside, so substract it)
                    brback[i] = mat_to_map * ( vi - fa.normal / blender_to_map_scale_factor )
                # Check if coords are in clockwise order, else flip them
                fano = mat_to_map.to_3x3() * fa.normal
                frno = normal(brfront)
                epsilon = 0.1
                if ( (fano - frno).length_squared > epsilon ):
                    flip(brfront)
                    debug1('Front Flipped')
                else:
                    flip(brback)
                    debug1('Back Flipped')
                debug2(mat_to_map.to_3x3() * fa.normal, brfront)
                debug2(mat_to_map.to_3x3() *-fa.normal, brback)
                output_brush_face(brfront, tename, tev1, teoff1, tev2, teoff2, rot, scaleX, scaleY, fh)
                output_brush_face(brback,  tename, tev1, teoff1, tev2, teoff2, rot, scaleX, scaleY, fh)
                # make 1 side face in brush per blender edge
                for i,j in fa.edge_keys:
                    brside = [None,None,None]
                    brside[0] = mat_to_map * ( mesh.vertices[i].co )
                    brside[1] = mat_to_map * ( mesh.vertices[j].co )
                    brside[2] = mat_to_map * ( mesh.vertices[j].co - fa.normal )
                    # Let have a plane define by a point A and a normal n
                    # Let M a point in space. M is on the plane if AM.n = 0 
                    # Now we want to know if the "side" face normal is poiting outwards of the brush (<0)
                    # Take A = side[0], M = fa.center (that is inside the brush), n = normal(side)
                    if ( (mat_to_map * fa.center - brside[0]).dot(normal(brside)) < 0):
                        flip(brside)
                        debug1('Side Flipped')
                    debug1(normal(brside))
                    output_brush_face(brside, tename, tev1, teoff1, tev2, teoff2, rot, scaleX, scaleY, fh)
                output_brush_end(fh)
            # endfor fa in mesh.tessfaces:
        output_entity_end(fh)
    return {'FINISHED'}