import SCons.Util
import xml.dom.minidom, os, os.path

################################################################################
# XSLT processor
################################################################################

def generate(env) :
    def generate_actions(source, target, env, for_signature) :
        if not env.has_key("XSLTSTYLESHEET") :
            raise SCons.Errors.UserError("The XSLTSTYLESHEET construction variable must be defined")

        # Process the XML catalog files
        # FIXME: It's probably not clean to do an ENV assignment globally
        env["ENV"]["XML_CATALOG_FILES"] = " ".join(env.get("XMLCATALOGS", ""))

        # Build the XMLLint command
        xmllintcmd = ["$XMLLINT", "--nonet", "--xinclude", "--postvalid", "--noout", "$SOURCE"]

        # Build the XSLT command
        xsltcmd = ["$XSLT", "--nonet", "--xinclude"]
        for (param, value) in env["XSLTPARAMS"] :
            xsltcmd += ["--stringparam", param, value]
        xsltcmd += ["-o", "$TARGET", "$XSLTSTYLESHEET", "$SOURCE"]

        return [
            SCons.Action.Action([xmllintcmd], cmdstr = "$XMLLINTCOMSTR"),
            SCons.Action.Action([xsltcmd], cmdstr = "$XSLTCOMSTR")]

    def modify_sources(target, source, env) :
        if len(env["FOCFG"]) > 0 :
            source.append(env["FOCFG"])
        source.append(env.get("XMLCATALOGS", []))
        return target, source

    def scan_xml(node, env, path) :
        dependencies = set()
        nodes = [node]
        while len(nodes) > 0 :
            node = nodes.pop()
            try :
                document = xml.dom.minidom.parseString(node.get_contents())
            except xml.parsers.expat.ExpatError:
                continue
            for include in document.getElementsByTagNameNS("http://www.w3.org/2001/XInclude", "include") :
                include_file = include.getAttribute("href")
                dependencies.add(include_file)
                if include.getAttribute("parse") != "text" :
                    nodes.append(env.File(include_file))
        return list(dependencies)

    env["XMLLINT"] = "xmllint"
    env["XSLT"] = "xsltproc"
    env["XSLTPARAMS"] = []
    env["BUILDERS"]["XSLT"] = SCons.Builder.Builder(
                generator = generate_actions,
                emitter = modify_sources,
                source_scanner = SCons.Scanner.Scanner(function = scan_xml),
                src_suffix = ".xml"
            )

def exists(env) :
    return True