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__bpydoc__ = """\
InnerWeld.  This addon welds parallel connected selected edges together. 

Documentation

First go to User Preferences->Addons and enable the InnerWeld addon in the Mesh category.
Go to EditMode, select some parallel edge(loop)(slices).  Handles ALL edges parallel next to each other.
These edges will be welded together when invoking addon (button in Mesh Tools panel).
Innerweld will only work when in Edge select component mode!

If you wish to hotkey InnerWeld:
In the Input section of User Preferences at the bottom of the 3D View > Mesh section click 'Add New' button.
In the Operator Identifier box put 'mesh.innerweld'.
Assign a hotkey.
Save as Default (Optional).
"""


bl_info = {
	"name": "InnerWeld",
	"author": "Gert De Roost",
	"version": (0, 2, 0),
	"blender": (2, 6, 3),
	"location": "View3D > Tools",
	"description": "Welding parallel edges together.",
	"warning": "",
	"wiki_url": "",
	"tracker_url": "",
	"category": "Mesh"}



import bpy
import bmesh




class InnerWeld(bpy.types.Operator):
	bl_idname = "mesh.innerweld"
	bl_label = "InnerWeld"
	bl_description = "Welding parallel edges together"
	bl_options = {'REGISTER', 'UNDO'}

	
	@classmethod
	def poll(cls, context):
		obj = context.active_object
		return (obj and obj.type == 'MESH' and context.mode == 'EDIT_MESH' and list(context.tool_settings.mesh_select_mode) == [False, True, False])

	def invoke(self, context, event):
		
		bpy.ops.object.editmode_toggle()
		bpy.ops.object.editmode_toggle()
		
		self.do_innerweld(context)
		
		bpy.ops.object.editmode_toggle()
		bpy.ops.object.editmode_toggle()
		
		return {'FINISHED'}


	def do_innerweld(self, context):
	
		selobj = context.active_object
		mesh = selobj.data
		bm = bmesh.from_edit_mesh(mesh)
	
		self.sellist = []
		for edge in bm.edges:
			if edge.select:
				self.sellist.append(edge)
	
	
		def addstart(vert, posn):
			
			# recursive: adds to initial edgelist at start
			for e in vert.link_edges:
				if e in self.sellist:
					self.sellist.pop(self.sellist.index(e))
					v = e.other_vert(vert)
					self.vertlist[posn].insert(0, v)
					addstart(v, posn)
		
		def addend(vert, posn):
			
			# recursive: adds to initial edgelist at end
			for e in vert.link_edges:
				if e in self.sellist:
					self.sellist.pop(self.sellist.index(e))
					v = e.other_vert(vert)
					self.vertlist[posn].append(v)
					addend(v, posn)
	
		posn = 0
		self.vertlist = []
		while len(self.sellist) > 0:
			# initialize next edgesnake		
			self.vertlist.append([])
			vert = self.sellist[0].verts[0]
			self.vertlist[posn].append(vert)
			# add to start and end of arbitrary start vert
			addstart(vert, posn)
			addend(vert, posn)
			posn += 1
			
			
		found = True
		posn = 0
		mergesets = []
		while found:
			found = False
			for idx in range(len(self.vertlist)):
				if len(self.vertlist[idx]) > 0:
					found = True
					vset = set([])
					vset.add(self.vertlist[idx].pop())
					mergesets.append(vset.copy())
					while len(vset) > 0:
						vert = vset.pop()
						for edge in vert.link_edges:
							if edge.select:
								continue
							v1 = edge.other_vert(vert)
							for vlist in self.vertlist:
								if v1 in vlist and not(v1 in mergesets[posn]):
									mergesets[posn].add(v1)
									vset.add(v1)
									self.vertlist[self.vertlist.index(vlist)].pop(vlist.index(v1))
					posn +=1
	
		mergeverts = []
		for st in mergesets:
			bpy.ops.mesh.select_all(action = 'DESELECT')
			for vert in st:
				vert.select = True
				mergeverts.append(vert)
			bpy.ops.mesh.merge(type='CENTER', uvs=True)
		
		for v in mergeverts:
			try:
				v.select = True
			except:
				pass
		
		bm.select_flush(1)
		bm.free()
		
		
		
	

def panel_func(self, context):
	self.layout.label(text="InnerWeld:")
	self.layout.operator("mesh.innerweld", text="Weld Edges")


def register():
	bpy.utils.register_module(__name__)
	bpy.types.VIEW3D_PT_tools_meshedit.append(panel_func)

def unregister():
	bpy.utils.unregister_module(__name__)
	bpy.types.VIEW3D_PT_tools_meshedit.remove(panel_func)

if __name__ == "__main__":
	register()