#!/usr/bin/env python
# coding=utf-8
#
# Copyright (C) 2015 ~suv <suv-sf@users.sf.net>
# Copyright (C) 2010 Alvin Penner
# Copyright (C) 2006 Georg Wiora
# Copyright (C) 2006 Nathan Hurst
# Copyright (C) 2005 Aaron Spike, aaron@ekips.org
#
# 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.
#
"""
This extension module can measure arbitrary path and object length
It adds text to the selected path containing the length in a given unit.
Area and Center of Mass calculated using Green's Theorem:
http://mathworld.wolfram.com/GreensTheorem.html
"""

import inkex

from inkex import TextElement, TextPath, Tspan
from inkex.bezier import csparea, cspcofm, csplength

class MeasureLength(inkex.EffectExtension):
    """Measure the length of selected paths"""
    def add_arguments(self, pars):
        pars.add_argument("--type", dest="mtype", default="length",\
            help="Type of measurement")
        pars.add_argument("--method", type=self.arg_method(), default=self.method_textonpath,\
            help="Text Orientation method")
        pars.add_argument("--presetFormat", default="TaP_start", help="Preset text layout")
        pars.add_argument("--startOffset", default="custom", help="Text Offset along Path")
        pars.add_argument("--startOffsetCustom", type=int, default=50,\
            help="Text Offset along Path")
        pars.add_argument("--anchor", default="start", help="Text Anchor")
        pars.add_argument("--position", default="start", help="Text Position")
        pars.add_argument("--angle", type=float, default=0, help="Angle")
        pars.add_argument("-f", "--fontsize", type=int, default=20,\
            help="Size of length label text in px")
        pars.add_argument("-o", "--offset", type=float, default=-6,\
            help="The distance above the curve")
        pars.add_argument("-u", "--unit", default="mm",\
            help="The unit of the measurement")
        pars.add_argument("-p", "--precision", type=int, default=2,\
            help="Number of significant digits after decimal point")
        pars.add_argument("-s", "--scale", type=float, default=1.1,\
            help="Scale Factor (Drawing:Real Length)")

    def effect(self):
        # get number of digits
        prec = int(self.options.precision)
        scale = self.svg.unittouu('1px')  # convert to document units
        self.options.offset *= scale
        factor = 1.0

        if self.svg.get('viewBox'):
            factor = self.svg.scale / self.svg.unittouu('1px')
            self.options.fontsize /= factor

        factor *= scale / self.svg.unittouu('1' + self.options.unit)

        # loop over all selected paths
        filtered = self.svg.selection.filter(inkex.PathElement)
        if not filtered:
            raise inkex.AbortExtension("Please select at least one path object.")
        for node in filtered:
            csp = node.path.transform(node.composed_transform()).to_superpath()
            inverse_parent_transform = - node.getparent().composed_transform()
            if self.options.mtype == "length":
                slengths, stotal = csplength(csp)
                self.group = node.getparent().add(TextElement())
            elif self.options.mtype == "area":
                stotal = abs(csparea(csp) * factor * self.options.scale)
                self.group = node.getparent().add(TextElement())
            else:
                try:
                    xc, yc = cspcofm(csp)
                except ValueError as err:
                    raise inkex.AbortExtension(str(err))
                self.group = node.getparent().add(inkex.PathElement())
                self.group.set('id', 'MassCenter_' + node.get('id'))
                self.add_cross(self.group, xc, yc, scale)
                self.group.transform = inverse_parent_transform
                continue
            # Format the length as string
            val = round(stotal * factor * self.options.scale, prec)
            # Transform the result back
            self.options.method(node, str(val))

    def method_textonpath(self, node, lenstr):
        startOffset = self.options.startOffset
        if startOffset == "custom":
            startOffset = str(self.options.startOffsetCustom) + '%'
        if self.options.mtype == "length":
            self.add_textonpath(self.group, 0, 0, lenstr + ' ' + self.options.unit, node, self.options.anchor, startOffset, self.options.offset)
        else:
            self.add_textonpath(self.group, 0, 0, lenstr + ' ' + self.options.unit + '^2', node, self.options.anchor, startOffset, self.options.offset)

    def method_fixedtext(self, node, lenstr):
        _id = node.get('id')
        csp = node.path.transform(node.composed_transform()).to_superpath()
        if self.options.position == "mass":
            tx, ty = cspcofm(csp)
            anchor = 'middle'
        elif self.options.position == "center":
            bbox = node.bounding_box(True)
            tx, ty = bbox.center
            anchor = 'middle'
        else:  # default
            tx = csp[0][0][1][0]
            ty = csp[0][0][1][1]
            anchor = 'start'
        if self.options.mtype == "length":
            self.add_fixedtext(self.group, tx, ty, lenstr + ' ' + self.options.unit, anchor, -int(self.options.angle), self.options.offset + self.options.fontsize / 2)
        else:
            self.add_fixedtext(self.group, tx, ty, lenstr + ' ' + self.options.unit + '^2', anchor, -int(self.options.angle), -self.options.offset + self.options.fontsize / 2)

    def method_presets(self, node, lenstr):
        """A preset option for alignments"""
        preset_dict = {
            'default_cofm':   [None, None, None, None, None],
            'default_length': [self.method_textonpath, "50%", "start", None, None],
            'TaP_start':      [self.method_textonpath, "0%", "start", None, None],
            'TaP_middle':     [self.method_textonpath, "50%", "middle", None, None],
            'TaP_end':        [self.method_textonpath, "100%", "end", None, None],
            'default_area':   [self.method_fixedtext, None, None, "start", 0.0],
            'FT_start':       [self.method_fixedtext, None, None, "start", 0.0],
            'FT_bbox':        [self.method_fixedtext, None, None, "center", 0.0],
            'FT_mass':        [self.method_fixedtext, None, None, "mass", 0.0],
        }

        if self.options.presetFormat == "default":
            current_preset = 'default_' + self.options.mtype
        else:
            current_preset = self.options.presetFormat

        self.options.startOffset = preset_dict[current_preset][1]
        self.options.anchor = preset_dict[current_preset][2]
        self.options.position = preset_dict[current_preset][3]
        self.options.angle = preset_dict[current_preset][4]
        method = preset_dict[current_preset][0]
        if method is not None:
            return method(node, lenstr)

    def add_cross(self, node, x, y, scale):
        l = 3 * scale  # 3 pixels in document units
        node.set('d', 'm %s,%s %s,0 %s,0 m %s,%s 0,%s 0,%s' % (str(x - l), str(y), str(l), str(l), str(-l), str(-l), str(l), str(l)))
        node.set('style', 'stroke:#000000;fill:none;stroke-width:%s' % str(0.5 * scale))

    def add_textonpath(self, node, x, y, text, _node, anchor, startOffset, dy=0):
        new = node.add(TextPath())
        s = {'text-align': 'center', 'vertical-align': 'bottom',
             'text-anchor': anchor, 'font-size': str(self.options.fontsize),
             'fill-opacity': '1.0', 'stroke': 'none',
             'font-weight': 'normal', 'font-style': 'normal', 'fill': '#000000'}
        new.style = s
        new.href = _node
        new.set('startOffset', startOffset)
        new.set('dy', str(dy))  # dubious merit
        # new.append(tp)
        if text[-2:] == "^2":
            new.append(Tspan.superscript("2"))
            new.text = str(text)[:-2]
        else:
            new.text = str(text)
        # node.set('transform','rotate(180,'+str(-x)+','+str(-y)+')')
        node.set('x', str(x))
        node.set('y', str(y))

    def add_fixedtext(self, node, x, y, text, anchor, angle, dy=0):
        new = node.add(Tspan())
        new.set('sodipodi:role', 'line')
        s = {'text-align': 'center', 'vertical-align': 'bottom',
             'text-anchor': anchor, 'font-size': str(self.options.fontsize),
             'fill-opacity': '1.0', 'stroke': 'none',
             'font-weight': 'normal', 'font-style': 'normal', 'fill': '#000000'}
        new.style = s
        new.set('dy', str(dy))
        if text[-2:] == "^2":
            new.append(Tspan.superscript("2"))
            new.text = str(text)[:-2]
        else:
            new.text = str(text)
        node.set('x', str(x))
        node.set('y', str(y))
        node.set('transform', 'rotate(%s, %s, %s)' % (angle, x, y))
        node.transform = - node.getparent().composed_transform() * node.transform

if __name__ == '__main__':
    MeasureLength().run()