from .Exporter import Exporter
from ..python2_3 import asUnicode
from ..parametertree import Parameter
from ..Qt import QtGui, QtCore, QtSvg
from .. import debug
from .. import functions as fn
import re
import xml.dom.minidom as xml
import numpy as np


__all__ = ['SVGExporter']

class SVGExporter(Exporter):
    Name = "Scalable Vector Graphics (SVG)"
    allowCopy=True
    
    def __init__(self, item):
        Exporter.__init__(self, item)
        #tr = self.getTargetRect()
        self.params = Parameter(name='params', type='group', children=[
            #{'name': 'width', 'type': 'float', 'value': tr.width(), 'limits': (0, None)},
            #{'name': 'height', 'type': 'float', 'value': tr.height(), 'limits': (0, None)},
            #{'name': 'viewbox clipping', 'type': 'bool', 'value': True},
            #{'name': 'normalize coordinates', 'type': 'bool', 'value': True},
            #{'name': 'normalize line width', 'type': 'bool', 'value': True},
        ])
        #self.params.param('width').sigValueChanged.connect(self.widthChanged)
        #self.params.param('height').sigValueChanged.connect(self.heightChanged)

    def widthChanged(self):
        sr = self.getSourceRect()
        ar = sr.height() / sr.width()
        self.params.param('height').setValue(self.params['width'] * ar, blockSignal=self.heightChanged)
        
    def heightChanged(self):
        sr = self.getSourceRect()
        ar = sr.width() / sr.height()
        self.params.param('width').setValue(self.params['height'] * ar, blockSignal=self.widthChanged)
        
    def parameters(self):
        return self.params
    
    def export(self, fileName=None, toBytes=False, copy=False):
        if toBytes is False and copy is False and fileName is None:
            self.fileSaveDialog(filter="Scalable Vector Graphics (*.svg)")
            return
        #self.svg = QtSvg.QSvgGenerator()
        #self.svg.setFileName(fileName)
        #dpi = QtGui.QDesktopWidget().physicalDpiX()
        ### not really sure why this works, but it seems to be important:
        #self.svg.setSize(QtCore.QSize(self.params['width']*dpi/90., self.params['height']*dpi/90.))
        #self.svg.setResolution(dpi)
        ##self.svg.setViewBox()
        #targetRect = QtCore.QRect(0, 0, self.params['width'], self.params['height'])
        #sourceRect = self.getSourceRect()
        
        #painter = QtGui.QPainter(self.svg)
        #try:
            #self.setExportMode(True)
            #self.render(painter, QtCore.QRectF(targetRect), sourceRect)
        #finally:
            #self.setExportMode(False)
        #painter.end()

        ## Workaround to set pen widths correctly
        #data = open(fileName).readlines()
        #for i in range(len(data)):
            #line = data[i]
            #m = re.match(r'(<g .*)stroke-width="1"(.*transform="matrix\(([^\)]+)\)".*)', line)
            #if m is not None:
                ##print "Matched group:", line
                #g = m.groups()
                #matrix = list(map(float, g[2].split(',')))
                ##print "matrix:", matrix
                #scale = max(abs(matrix[0]), abs(matrix[3]))
                #if scale == 0 or scale == 1.0:
                    #continue
                #data[i] = g[0] + ' stroke-width="%0.2g" ' % (1.0/scale) + g[1] + '\n'
                ##print "old line:", line
                ##print "new line:", data[i]
        #open(fileName, 'w').write(''.join(data))
        
        ## Qt's SVG generator is not complete. (notably, it lacks clipping)
        ## Instead, we will use Qt to generate SVG for each item independently,
        ## then manually reconstruct the entire document.
        xml = generateSvg(self.item)
        
        if toBytes:
            return xml.encode('UTF-8')
        elif copy:
            md = QtCore.QMimeData()
            md.setData('image/svg+xml', QtCore.QByteArray(xml.encode('UTF-8')))
            QtGui.QApplication.clipboard().setMimeData(md)
        else:
            with open(fileName, 'wb') as fh:
                fh.write(asUnicode(xml).encode('utf-8'))


xmlHeader = """\
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"  version="1.2" baseProfile="tiny">
<title>pyqtgraph SVG export</title>
<desc>Generated with Qt and pyqtgraph</desc>
<defs>
</defs>
"""

def generateSvg(item):
    global xmlHeader
    try:
        node = _generateItemSvg(item)
    finally:
        ## reset export mode for all items in the tree
        if isinstance(item, QtGui.QGraphicsScene):
            items = item.items()
        else:
            items = [item]
            for i in items:
                items.extend(i.childItems())
        for i in items:
            if hasattr(i, 'setExportMode'):
                i.setExportMode(False)
    
    cleanXml(node)
    
    return xmlHeader + node.toprettyxml(indent='    ') + "\n</svg>\n"


def _generateItemSvg(item, nodes=None, root=None):
    ## This function is intended to work around some issues with Qt's SVG generator
    ## and SVG in general.
    ## 1) Qt SVG does not implement clipping paths. This is absurd.
    ##    The solution is to let Qt generate SVG for each item independently,
    ##    then glue them together manually with clipping.
    ##    
    ##    The format Qt generates for all items looks like this:
    ##    
    ##    <g>
    ##        <g transform="matrix(...)">
    ##            one or more of: <path/> or <polyline/> or <text/>
    ##        </g>
    ##        <g transform="matrix(...)">
    ##            one or more of: <path/> or <polyline/> or <text/>
    ##        </g>
    ##        . . .
    ##    </g>
    ##    
    ## 2) There seems to be wide disagreement over whether path strokes
    ##    should be scaled anisotropically. 
    ##      see: http://web.mit.edu/jonas/www/anisotropy/
    ##    Given that both inkscape and illustrator seem to prefer isotropic
    ##    scaling, we will optimize for those cases.  
    ##    
    ## 3) Qt generates paths using non-scaling-stroke from SVG 1.2, but 
    ##    inkscape only supports 1.1. 
    ##    
    ##    Both 2 and 3 can be addressed by drawing all items in world coordinates.
    
    profiler = debug.Profiler()
    
    if nodes is None:  ## nodes maps all node IDs to their XML element. 
                       ## this allows us to ensure all elements receive unique names.
        nodes = {}
        
    if root is None:
        root = item
                
    ## Skip hidden items
    if hasattr(item, 'isVisible') and not item.isVisible():
        return None
        
    ## If this item defines its own SVG generator, use that.
    if hasattr(item, 'generateSvg'):
        return item.generateSvg(nodes)
    

    ## Generate SVG text for just this item (exclude its children; we'll handle them later)
    tr = QtGui.QTransform()
    if isinstance(item, QtGui.QGraphicsScene):
        xmlStr = "<g>\n</g>\n"
        doc = xml.parseString(xmlStr)
        childs = [i for i in item.items() if i.parentItem() is None]
    elif item.__class__.paint == QtGui.QGraphicsItem.paint:
        xmlStr = "<g>\n</g>\n"
        doc = xml.parseString(xmlStr)
        childs = item.childItems()
    else:
        childs = item.childItems()
        tr = itemTransform(item, item.scene())
        
        ## offset to corner of root item
        if isinstance(root, QtGui.QGraphicsScene):
            rootPos = QtCore.QPoint(0,0)
        else:
            rootPos = root.scenePos()
        tr2 = QtGui.QTransform()
        tr2.translate(-rootPos.x(), -rootPos.y())
        tr = tr * tr2

        arr = QtCore.QByteArray()
        buf = QtCore.QBuffer(arr)
        svg = QtSvg.QSvgGenerator()
        svg.setOutputDevice(buf)
        dpi = QtGui.QDesktopWidget().physicalDpiX()
        svg.setResolution(dpi)

        p = QtGui.QPainter()
        p.begin(svg)
        if hasattr(item, 'setExportMode'):
            item.setExportMode(True, {'painter': p})
        try:
            p.setTransform(tr)
            item.paint(p, QtGui.QStyleOptionGraphicsItem(), None)
        finally:
            p.end()
            ## Can't do this here--we need to wait until all children have painted as well.
            ## this is taken care of in generateSvg instead.
            #if hasattr(item, 'setExportMode'):
                #item.setExportMode(False)

        xmlStr = bytes(arr).decode('utf-8')
        doc = xml.parseString(xmlStr)
        
    try:
        ## Get top-level group for this item
        g1 = doc.getElementsByTagName('g')[0]
        ## get list of sub-groups
        g2 = [n for n in g1.childNodes if isinstance(n, xml.Element) and n.tagName == 'g']
    except:
        print(doc.toxml())
        raise

    profiler('render')

    ## Get rid of group transformation matrices by applying
    ## transformation to inner coordinates
    correctCoordinates(g1, item)
    profiler('correct')
    ## make sure g1 has the transformation matrix
    #m = (tr.m11(), tr.m12(), tr.m21(), tr.m22(), tr.m31(), tr.m32())
    #g1.setAttribute('transform', "matrix(%f,%f,%f,%f,%f,%f)" % m)
    
    #print "=================",item,"====================="
    #print g1.toprettyxml(indent="  ", newl='')
    
    ## Inkscape does not support non-scaling-stroke (this is SVG 1.2, inkscape supports 1.1)
    ## So we need to correct anything attempting to use this.
    #correctStroke(g1, item, root)
    
    ## decide on a name for this item
    baseName = item.__class__.__name__
    i = 1
    while True:
        name = baseName + "_%d" % i
        if name not in nodes:
            break
        i += 1
    nodes[name] = g1
    g1.setAttribute('id', name)
    
    ## If this item clips its children, we need to take care of that.
    childGroup = g1  ## add children directly to this node unless we are clipping
    if not isinstance(item, QtGui.QGraphicsScene):
        ## See if this item clips its children
        if int(item.flags() & item.ItemClipsChildrenToShape) > 0:
            ## Generate svg for just the path
            #if isinstance(root, QtGui.QGraphicsScene):
                #path = QtGui.QGraphicsPathItem(item.mapToScene(item.shape()))
            #else:
                #path = QtGui.QGraphicsPathItem(root.mapToParent(item.mapToItem(root, item.shape())))
            path = QtGui.QGraphicsPathItem(item.mapToScene(item.shape()))
            item.scene().addItem(path)
            try:
                pathNode = _generateItemSvg(path, root=root).getElementsByTagName('path')[0]
            finally:
                item.scene().removeItem(path)
            
            ## and for the clipPath element
            clip = name + '_clip'
            clipNode = g1.ownerDocument.createElement('clipPath')
            clipNode.setAttribute('id', clip)
            clipNode.appendChild(pathNode)
            g1.appendChild(clipNode)
            
            childGroup = g1.ownerDocument.createElement('g')
            childGroup.setAttribute('clip-path', 'url(#%s)' % clip)
            g1.appendChild(childGroup)
    profiler('clipping')
            
    ## Add all child items as sub-elements.
    childs.sort(key=lambda c: c.zValue())
    for ch in childs:
        cg = _generateItemSvg(ch, nodes, root)
        if cg is None:
            continue
        childGroup.appendChild(cg)  ### this isn't quite right--some items draw below their parent (good enough for now)
    profiler('children')
    return g1

def correctCoordinates(node, item):
    ## Remove transformation matrices from <g> tags by applying matrix to coordinates inside.
    ## Each item is represented by a single top-level group with one or more groups inside.
    ## Each inner group contains one or more drawing primitives, possibly of different types.
    groups = node.getElementsByTagName('g')
    
    ## Since we leave text unchanged, groups which combine text and non-text primitives must be split apart.
    ## (if at some point we start correcting text transforms as well, then it should be safe to remove this)
    groups2 = []
    for grp in groups:
        subGroups = [grp.cloneNode(deep=False)]
        textGroup = None
        for ch in grp.childNodes[:]:
            if isinstance(ch, xml.Element):
                if textGroup is None:
                    textGroup = ch.tagName == 'text'
                if ch.tagName == 'text':
                    if textGroup is False:
                        subGroups.append(grp.cloneNode(deep=False))
                        textGroup = True
                else:
                    if textGroup is True:
                        subGroups.append(grp.cloneNode(deep=False))
                        textGroup = False
            subGroups[-1].appendChild(ch)
        groups2.extend(subGroups)
        for sg in subGroups:
            node.insertBefore(sg, grp)
        node.removeChild(grp)
    groups = groups2
        
    
    for grp in groups:
        matrix = grp.getAttribute('transform')
        match = re.match(r'matrix\((.*)\)', matrix)
        if match is None:
            vals = [1,0,0,1,0,0]
        else:
            vals = [float(a) for a in match.groups()[0].split(',')]
        tr = np.array([[vals[0], vals[2], vals[4]], [vals[1], vals[3], vals[5]]])
        
        removeTransform = False
        for ch in grp.childNodes:
            if not isinstance(ch, xml.Element):
                continue
            if ch.tagName == 'polyline':
                removeTransform = True
                coords = np.array([[float(a) for a in c.split(',')] for c in ch.getAttribute('points').strip().split(' ')])
                coords = fn.transformCoordinates(tr, coords, transpose=True)
                ch.setAttribute('points', ' '.join([','.join([str(a) for a in c]) for c in coords]))
            elif ch.tagName == 'path':
                removeTransform = True
                newCoords = ''
                oldCoords = ch.getAttribute('d').strip()
                if oldCoords == '':
                    continue
                for c in oldCoords.split(' '):
                    x,y = c.split(',')
                    if x[0].isalpha():
                        t = x[0]
                        x = x[1:]
                    else:
                        t = ''
                    nc = fn.transformCoordinates(tr, np.array([[float(x),float(y)]]), transpose=True)
                    newCoords += t+str(nc[0,0])+','+str(nc[0,1])+' '
                ch.setAttribute('d', newCoords)
            elif ch.tagName == 'text':
                removeTransform = False
                ## leave text alone for now. Might need this later to correctly render text with outline.
                #c = np.array([
                    #[float(ch.getAttribute('x')), float(ch.getAttribute('y'))], 
                    #[float(ch.getAttribute('font-size')), 0], 
                    #[0,0]])
                #c = fn.transformCoordinates(tr, c, transpose=True)
                #ch.setAttribute('x', str(c[0,0]))
                #ch.setAttribute('y', str(c[0,1]))
                #fs = c[1]-c[2]
                #fs = (fs**2).sum()**0.5
                #ch.setAttribute('font-size', str(fs))
                
                ## Correct some font information
                families = ch.getAttribute('font-family').split(',')
                if len(families) == 1:
                    font = QtGui.QFont(families[0].strip('" '))
                    if font.style() == font.SansSerif:
                        families.append('sans-serif')
                    elif font.style() == font.Serif:
                        families.append('serif')
                    elif font.style() == font.Courier:
                        families.append('monospace')
                    ch.setAttribute('font-family', ', '.join([f if ' ' not in f else '"%s"'%f for f in families]))
                
            ## correct line widths if needed
            if removeTransform and ch.getAttribute('vector-effect') != 'non-scaling-stroke':
                w = float(grp.getAttribute('stroke-width'))
                s = fn.transformCoordinates(tr, np.array([[w,0], [0,0]]), transpose=True)
                w = ((s[0]-s[1])**2).sum()**0.5
                ch.setAttribute('stroke-width', str(w))
            
        if removeTransform:
            grp.removeAttribute('transform')


SVGExporter.register()        


def itemTransform(item, root):
    ## Return the transformation mapping item to root
    ## (actually to parent coordinate system of root)
    
    if item is root:
        tr = QtGui.QTransform()
        tr.translate(*item.pos())
        tr = tr * item.transform()
        return tr
        
    
    if int(item.flags() & item.ItemIgnoresTransformations) > 0:
        pos = item.pos()
        parent = item.parentItem()
        if parent is not None:
            pos = itemTransform(parent, root).map(pos)
        tr = QtGui.QTransform()
        tr.translate(pos.x(), pos.y())
        tr = item.transform() * tr
    else:
        ## find next parent that is either the root item or 
        ## an item that ignores its transformation
        nextRoot = item
        while True:
            nextRoot = nextRoot.parentItem()
            if nextRoot is None:
                nextRoot = root
                break
            if nextRoot is root or int(nextRoot.flags() & nextRoot.ItemIgnoresTransformations) > 0:
                break
        
        if isinstance(nextRoot, QtGui.QGraphicsScene):
            tr = item.sceneTransform()
        else:
            tr = itemTransform(nextRoot, root) * item.itemTransform(nextRoot)[0]
    
    return tr

            
def cleanXml(node):
    ## remove extraneous text; let the xml library do the formatting.
    hasElement = False
    nonElement = []
    for ch in node.childNodes:
        if isinstance(ch, xml.Element):
            hasElement = True
            cleanXml(ch)
        else:
            nonElement.append(ch)
    
    if hasElement:
        for ch in nonElement:
            node.removeChild(ch)
    elif node.tagName == 'g':  ## remove childless groups
        node.parentNode.removeChild(node)