import html.parser

from django.utils.encoding import smart_str

from compressor.exceptions import ParserError
from compressor.parser import ParserBase


# The HTMLParser constructor takes a 'convert_charrefs'
# argument which raises a warning if we don't pass it.
HTML_PARSER_ARGS = {
    "convert_charrefs": False,
}


class DefaultHtmlParser(ParserBase, html.parser.HTMLParser):
    def __init__(self, content):
        html.parser.HTMLParser.__init__(self, **HTML_PARSER_ARGS)
        self.content = content
        self._css_elems = []
        self._js_elems = []
        self._current_tag = None
        try:
            self.feed(self.content)
            self.close()
        except Exception as err:
            lineno = err.lineno
            line = self.content.splitlines()[lineno]
            raise ParserError(
                "Error while initializing HtmlParser: %s (line: %s)" % (err, repr(line))
            )

    def handle_starttag(self, tag, attrs):
        tag = tag.lower()
        if tag in ("style", "script"):
            if tag == "style":
                tags = self._css_elems
            elif tag == "script":
                tags = self._js_elems
            tags.append(
                {"tag": tag, "attrs": attrs, "attrs_dict": dict(attrs), "text": ""}
            )
            self._current_tag = tag
        elif tag == "link":
            self._css_elems.append(
                {"tag": tag, "attrs": attrs, "attrs_dict": dict(attrs), "text": None}
            )

    def handle_endtag(self, tag):
        if self._current_tag and self._current_tag == tag.lower():
            self._current_tag = None

    def handle_data(self, data):
        if self._current_tag == "style":
            self._css_elems[-1]["text"] = data
        elif self._current_tag == "script":
            self._js_elems[-1]["text"] = data

    def css_elems(self):
        return self._css_elems

    def js_elems(self):
        return self._js_elems

    def elem_name(self, elem):
        return elem["tag"]

    def elem_attribs(self, elem):
        return elem["attrs_dict"]

    def elem_content(self, elem):
        return smart_str(elem["text"])

    def elem_str(self, elem):
        tag = {}
        tag.update(elem)
        tag["attrs"] = ""
        if len(elem["attrs"]):
            tag["attrs"] = " %s" % " ".join(
                ['%s="%s"' % (name, value) for name, value in elem["attrs"]]
            )
        if elem["tag"] == "link":
            return "<%(tag)s%(attrs)s>" % tag
        else:
            return "<%(tag)s%(attrs)s>%(text)s</%(tag)s>" % tag