# Utility functions for manipulating ThML

from xml.dom import minidom
from swordutils.xml import utils

    
def isScripCom(node):
    return node.nodeName == u'scripCom'

def findParentDiv(node):
    pnode = node.parentNode
    if pnode is None:
        raise Exception("Cannot find parent div for node %r" % node)
    if pnode.nodeType == minidom.Document.ELEMENT_NODE \
        and pnode.nodeName.startswith(u'div'):
        return pnode
    else:
        return findParentDiv(pnode)    

def moveToParent(node, destParent):
    if node.parentNode is destParent:
        return
    else:
        pnode = node.parentNode
        pnode.removeChild(node)
        pnode.parentNode.insertBefore(node, pnode)
        return moveToParent(node, destParent)

def _findNextScripComNode(node, return_parent):
    if node is None:
        return None
    if isScripCom(node):
        if return_parent:
            return node.parentNode
        else:
            return node
        
    else:
        # Search deeper, but return node that is on the
        # same level as our original node
        descendent = _findNextScripComNode(node.firstChild, True)
        if descendent is not None:
            if return_parent:
                return descendent.parentNode
            else:
                return descendent
        else:
            return _findNextScripComNode(node.nextSibling, False)

def _expandScripComNode(scNode):
    nextSCN = _findNextScripComNode(scNode.nextSibling, False)
    collection = []
    n = scNode.nextSibling
    while (n is not None and n is not nextSCN):
        collection.append(n)
        n = n.nextSibling
    for n in collection:
        n.parentNode.removeChild(n)
        scNode.appendChild(n)        

def expandScripComNodes(node):
    """Expands all empty <scripCom> nodes so that they contain
       the nodes that they refer to, using neighboring <scripCom>
       nodes and the structure of the XML as a guide,
       starting at the supplied node"""

    if isScripCom(node):
        # Often placed as markers instead of enclosing
        # the nodes to which they apply.
        if node.nodeValue is None or node.nodeValue == "":
            # Try to find scope over which the <scripCom> element
            # should actually be placed.
            # Rules:
            #  - move the scripCom element 'up' the tree until is
            #    a descendent of a `divX' node, placing it before
            #    any of its parent nodes along the way
            #  - make all its sibling nodes that are below it
            #    into child nodes, up to the point where there
            #    is another <scripCom> element
            div = findParentDiv(node)
            moveToParent(node, div)
            _expandScripComNode(node)
            
    if node.childNodes.length > 0:
        for n in node.childNodes:
            expandScripComNodes(n)