#!/usr/bin/python
# -*- coding: utf-8 -*-

#####################################
# Copyright (c) 2026
# Licensed under LGPL v2
#
# This macro resets the origin of selected Mesh objects to the world
# origin, WITHOUT moving the geometry. The current placement transform
# is baked into the mesh vertex coordinates, then the Placement property
# is reset to identity (0,0,0 / 0 deg). The mesh stays exactly where it
# seats in the world, but its origin now coincides with the world origin.
#
# Useful after using alignment tools (e.g. Mesh Alignment) to
# consolidate transformations without relying on a parent container.
# Take a look at the example given on my GitHub page for a common use case:
# https://github.com/de-seingalt/MeshResetOrigin/tree/main#example-common-use-case
#
# Only Mesh::Feature objects are processed. Non-mesh objects and meshes
# that live inside a parent container (App::Part) are skipped with a
# console warning. A single undo transaction wraps all changes.
#
# Version history:
# *0.2 : added multiple mesh selection support and tested on FreeCAD 1.1.1
# *0.1 : initial draft
#
#####################################

__Name__          = 'MeshResetOrigin'
__Comment__       = 'Reset selected mesh origins to global document origin without moving geometry'
__Author__        = 'de-seingalt'
__Version__       = '0.2'
__Date__          = '2026-06-09'
__License__       = 'LGPL v2'
__Web__           = 'https://github.com/de-seingalt/MeshResetOrigin'
__Wiki__          = 'https://wiki.freecad.org/Macro_MeshResetOrigin'
__Icon__          = 'https://wiki.freecad.org/images/3/3f/Macro_MeshResetOrigin.svg'
__Xpm__           = ''
__Help__          = ('Select one or more Mesh objects, then run the macro. '
                     'The origin of each mesh is set to global document origin'
                     'while the geometry stays in place.')
__Status__        = 'Beta'
__Requires__      = 'FreeCAD >= 1.1.1'
__Communication__ = 'https://github.com/de-seingalt/MeshResetOrigin/issues'
__Files__         = ''


import FreeCAD
import FreeCADGui


def reset_mesh_origin(obj):
    """
    Bake the placement of a Mesh::Feature into its vertex coordinates so
    that its local origin coincides with the world origin, WITHOUT moving
    the geometry visually.

    How it works:
    - We read the current Placement matrix.
    - We apply that matrix to a copy of the mesh: every vertex is moved
      into the position it currently occupies in world space.
    - We reassign the transformed mesh and reset Placement to identity.

    Net effect: the mesh stays exactly where it was on screen, but its
    Placement now reads (0,0,0) / 0 deg, because the transform lives in
    the geometry instead of the Placement property.

    Note: this only handles meshes with no parent container. A parented
    mesh is filtered out earlier in run(), because baking the LOCAL
    placement would leave the parent transform still composed on top.
    """
    placement = obj.Placement
    if placement.isIdentity():
        return False  # nothing to do, already at origin

    # Work on a copy so the operation is atomic and undoable
    mesh = obj.Mesh.copy()
    mesh.transform(placement.toMatrix())

    obj.Mesh = mesh
    obj.Placement = FreeCAD.Placement()  # identity: (0,0,0) / 0 deg
    return True


def run():
    doc = FreeCAD.ActiveDocument

    if doc is None:
        FreeCAD.Console.PrintError(
            'MeshResetOrigin: no active document.\n'
        )
        return

    selection = FreeCADGui.Selection.getSelection()

    if not selection:
        FreeCAD.Console.PrintWarning(
            'MeshResetOrigin: no object selected. '
            'Please select one or more Mesh objects first.\n'
        )
        return

    # Filter: keep only Mesh::Feature objects
    meshes = [obj for obj in selection
              if obj.isDerivedFrom('Mesh::Feature')]
    skipped = len(selection) - len(meshes)

    if not meshes:
        FreeCAD.Console.PrintWarning(
            'MeshResetOrigin: no Mesh object in the selection '
            '({} non-mesh object(s) ignored).\n'.format(len(selection))
        )
        return

    # Exclude meshes that have a parent GeoFeature container (e.g. App::Part).
    # Reassigning the global placement while the mesh is still parented would
    # cause FreeCAD to compose the parent transform on top of it, moving the
    # geometry to an unintended position.
    safe_meshes = []
    parented = []
    for obj in meshes:
        if obj.getParentGeoFeatureGroup() is not None:
            parented.append(obj)
        else:
            safe_meshes.append(obj)

    for obj in parented:
        FreeCAD.Console.PrintWarning(
            "MeshResetOrigin: '{}' has a parent container — skipped. "
            "Remove it from its container before running this macro.\n"
            .format(obj.Label)
        )

    if not safe_meshes:
        FreeCAD.Console.PrintWarning(
            'MeshResetOrigin: no eligible mesh to process '
            '(all selected meshes have a parent container).\n'
        )
        return

    doc.openTransaction('Reset Mesh Origin')

    try:
        processed = 0
        already_ok = 0
        for obj in safe_meshes:
            changed = reset_mesh_origin(obj)
            if changed:
                processed += 1
                FreeCAD.Console.PrintMessage(
                    "MeshResetOrigin: '{}' origin reset to world origin.\n"
                    .format(obj.Label)
                )
            else:
                already_ok += 1
                FreeCAD.Console.PrintMessage(
                    "MeshResetOrigin: '{}' already at origin — unchanged.\n"
                    .format(obj.Label)
                )

        doc.commitTransaction()
        doc.recompute()

        summary = '{} mesh(es) reset'.format(processed)
        if already_ok:
            summary += ', {} already at origin'.format(already_ok)
        if skipped:
            summary += ', {} non-mesh object(s) skipped'.format(skipped)
        if parented:
            summary += ', {} parented mesh(es) skipped'.format(len(parented))
        FreeCAD.Console.PrintMessage(
            'MeshResetOrigin: done — {}.\n'.format(summary)
        )

    except Exception as e:
        doc.abortTransaction()
        FreeCAD.Console.PrintError(
            'MeshResetOrigin: error — {}. Transaction aborted.\n'.format(e)
        )


run()