#!/usr/bin/env python
# vim:ts=4:sw=4:softtabstop=4:smarttab:expandtab

import sys, re
from mobi_utils import fromBase32

_OPF_PARENT_TAGS = ['xml', 'package', 'metadata', 'dc-metadata', 'x-metadata', 'manifest', 'spine', 'tours', 'guide']

class K8RESCProcessor(object):

    def __init__(self, data, debug = False):
        self._debug = debug
        self.resc = None
        self.opos = 0
        self.extrameta = []
        self.cover_name = None
        self.spine_idrefs = {}
        self.spine_order = []
        self.spine_pageattributes = {}
        self.spine_ppd = None
        # need3 indicate the book has fields which require epub3.
        # but the estimation of the source epub version from the fields is difficult.
        self.need3 = False
        self.package_ver = None
        self.extra_metadata = []
        self.refines_metadata = []
        self.extra_attributes = []
        # get header
        start_pos = data.find('<')
        self.resc_header = data[:start_pos]
        # get resc data length
        start = self.resc_header.find('=') + 1
        end = self.resc_header.find('&', start)
        resc_size = 0
        if end > 0:
            resc_size = fromBase32(self.resc_header[start:end])
        resc_rawbytes = len(data) - start_pos
        if resc_rawbytes == resc_size:
            self.resc_length = resc_size
        else:
            # Most RESC has a nul string at its tail but some do not.
            end_pos = data.find('\x00', start_pos)
            if end_pos < 0:
                self.resc_length = resc_rawbytes
            else:
                self.resc_length = end_pos - start_pos
        if self.resc_length != resc_size:
            print "Warning: RESC section length({:d}bytes) does not match its size({:d}bytes).".format(self.resc_length, resc_size)
        # now handle RESC
        self.resc = data[start_pos:start_pos+self.resc_length]
        self.parseData()


    def prepend_to_spine(self, key, idref, linear, properties):
        self.spine_order = [key] + self.spine_order
        self.spine_idrefs[key] = idref
        attributes = {}
        if linear is not None:
            attributes["linear"] = linear
        if properties is not None:
            attributes["properties"] = properties
        self.spine_pageattributes[key] = attributes


    # RESC tag iterator
    def resc_tag_iter(self):
        tcontent = last_tattr = None
        prefix = ['']
        while True:
            text, tag = self.parseresc()
            if text is None and tag is None:
                break
            if text is not None:
                tcontent = text.rstrip(" \r\n")
            else: # we have a tag
                ttype, tname, tattr = self.parsetag(tag)
                if ttype == "begin":
                    tcontent = None
                    prefix.append(tname + '.')
                    if tname in _OPF_PARENT_TAGS:
                        yield "".join(prefix), tname, tattr, tcontent
                    else:
                        last_tattr = tattr
                else: # single or end
                    if ttype == "end":
                        prefix.pop()
                        tattr = last_tattr
                        last_tattr = None
                        if tname in _OPF_PARENT_TAGS:
                            tname += '-end'
                    yield "".join(prefix), tname, tattr, tcontent
                    tcontent = None


    # now parse the RESC to extract spine and extra metadata info
    def parseData(self):
        for prefix, tname, tattr, tcontent in self.resc_tag_iter():
            if self._debug:
                print "   Parsing RESC: ", prefix, tname, tattr, tcontent
            if tname == "package":
                self.package_ver = tattr.get("version", "2.0")
                package_prefix = tattr.get("prefix",'')
                if self.package_ver.startswith("3") or package_prefix.startswith("rendition"):
                    self.need3 = True
            if tname == "spine":
                self.spine_ppd = tattr.get("page-progession-direction", None)
                if self.spine_ppd is not None and self.spine_ppd == "rtl":
                    self.need3 = True
            if tname == "itemref":
                skelid = tattr.pop("skelid", None)
                if skelid is None and len(self.spine_order) == 0:
                    # assume it was removed initial coverpage
                    skelid = "coverpage"
                    tattr["linear"] = "no"
                self.spine_order.append(skelid)
                idref = tattr.pop("idref", None)
                if idref is not None:
                    idref = 'x_' + idref
                self.spine_idrefs[skelid] = idref
                if "id" in tattr.keys():
                    del tattr["id"]
                # tattr["id"] = 'x_' + tattr["id"]
                if "properties" in tattr.keys():
                    self.need3 = True
                self.spine_pageattributes[skelid] = tattr
            if tname == "meta" or tname.startswith("dc:"):
                if "refines" in tattr.keys() or "property" in tattr.keys():
                    self.need3 = True
                if tattr.get("name","") == "cover":
                    cover_name = tattr.get("content",None)
                    if cover_name is not None:
                        cover_name = 'x_' + cover_name
                    self.cover_name = cover_name
                else:
                    self.extrameta.append([tname, tattr, tcontent])


    # parse and return either leading text or the next tag
    def parseresc(self):
        p = self.opos
        if p >= len(self.resc):
            return None, None
        if self.resc[p] != '<':
            res = self.resc.find('<',p)
            if res == -1 :
                res = len(self.resc)
            self.opos = res
            return self.resc[p:res], None
        # handle comment as a special case
        if self.resc[p:p+4] == '<!--':
            te = self.resc.find('-->',p+1)
            if te != -1:
                te = te+2
        else:
            te = self.resc.find('>',p+1)
            ntb = self.resc.find('<',p+1)
            if ntb != -1 and ntb < te:
                self.opos = ntb
                return self.resc[p:ntb], None
        self.opos = te + 1
        return None, self.resc[p:te+1]


    # parses tag to identify:  [tname, ttype, tattr]
    #    tname: tag name
    #    ttype: tag type ('begin', 'end' or 'single');
    #    tattr: dictionary of tag atributes
    def parsetag(self, s):
        p = 1
        tname = None
        ttype = None
        tattr = {}
        while s[p:p+1] == ' ' : p += 1
        if s[p:p+1] == '/':
            ttype = 'end'
            p += 1
            while s[p:p+1] == ' ' : p += 1
        b = p
        while s[p:p+1] not in ('>', '/', ' ', '"', "'","\r","\n") : p += 1
        tname=s[b:p].lower()
        # some special cases
        if tname == "?xml":
            tname = "xml"
        if tname == "!--":
            ttype = 'single'
            comment = s[p:-3].strip()
            tattr['comment'] = comment
        if ttype is None:
            # parse any attributes of begin or single tags
            while s.find('=',p) != -1 :
                while s[p:p+1] == ' ' : p += 1
                b = p
                while s[p:p+1] != '=' : p += 1
                aname = s[b:p].lower()
                aname = aname.rstrip(' ')
                p += 1
                while s[p:p+1] == ' ' : p += 1
                if s[p:p+1] in ('"', "'") :
                    p = p + 1
                    b = p
                    while s[p:p+1] not in ('"', "'"): p += 1
                    val = s[b:p]
                    p += 1
                else :
                    b = p
                    while s[p:p+1] not in ('>', '/', ' ') : p += 1
                    val = s[b:p]
                tattr[aname] = val
        if ttype is None:
            ttype = 'begin'
            if s.find('/',p) >= 0:
                ttype = 'single'
        return ttype, tname, tattr


    def taginfo_toxml(self, taginfo):
        res = []
        tname, tattr, tcontent = taginfo
        res.append('<' + tname)
        if tattr is not None:
            for key in tattr.keys():
                res.append(' ' + key + '="'+tattr[key]+'"' )
        if tcontent is not None:
            res.append('>' + tcontent + '</' + tname + '>\n')
        else:
            res.append('/>\n')
        return "".join(res)


    def hasSpine(self):
        return len(self.spine_order) > 0

    def needEPUB3(self):
        return self.need3

    def hasRefines(self):
        for [tname, tattr, tcontent] in self.extrameta:
            if 'refines' in tattr.keys():
                return True
        return False


    def createMetadata(self, epubver):
        for taginfo in self.extrameta:
            tname, tattr, tcontent = taginfo
            if 'refines' in tattr.keys():
                if epubver == 'F' and 'property' in tattr:
                    attr = ' id="%s" opf:%s="%s"\n' % (tattr['refines'], tattr['property'], tcontent)
                    self.extra_attributes.append(attr)
                else:
                    tag = self.taginfo_toxml(taginfo)
                    self.refines_metadata.append(tag)
            else:
                tag = self.taginfo_toxml(taginfo)
                self.extra_metadata.append(tag)
