#
# DbTex base class handling the compilation of a DocBook file via
# XSL Transformation and some TeX engine compilation.
#
from __future__ import print_function

import sys
import os
import re
import shlex
import tempfile
import shutil
try:
    from urllib import pathname2url
except ImportError:
    from urllib.request import pathname2url
import glob
import importlib.machinery
import importlib.util
from optparse import OptionParser
from io import open

from dbtexmf.core.txtparser import texinputs_parse, texstyle_parse
from dbtexmf.core.confparser import DbtexConfig
from dbtexmf.xslt import xslt
import dbtexmf.core.logger as logger
from dbtexmf.core.error import signal_error, failed_exit, dump_stack


def suffix_replace(path, oldext, newext=""):
    (root, ext) = os.path.splitext(path)
    if ext == oldext:
        return (root+newext)
    else:
        return (path+newext)

def path_to_uri(path):
    if os.name == 'nt':
        return 'file:' + pathname2url(path).replace('|', ':', 1)
    else:
        return pathname2url(path)


class Document:
    """
    Wrapper structure of the files built during the compilation per document
    """
    def __init__(self, filename, binfmt="pdf"):
        self.inputname = filename
        self.basename = os.path.splitext(filename)[0]
        self.rawfile = self.basename + ".rtex"
        self.texfile = self.basename + ".tex"
        self.binfile = self.basename + "." + binfmt

    def has_subext(self, ext):
        return (os.path.splitext(self.basename)[1] == ext)

    def __eq__(self, other):
        if self.rawfile == other:
            return True
        if self.texfile == other:
            return True
        if self.binfile == other:
            return True
        return False

    def __ne__(self, other):
        return not self.__eq__(other)

    def __lt__(self, other):
        return self.__ne__(other)

    def __le__(self, other):
        return False

    def __gt__(self, other):
        return False

    def __ge__(self, other):
        return False


class DbTex:
    USE_MKLISTINGS = 1

    xsl_header = \
"""<?xml version="1.0"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:m="http://www.w3.org/1998/Math/MathML"
                version="1.0">
                \n"""

    def __init__(self, base=""):
        self.name = None
        self.debug = 0
        self.verbose = 0
        if base:
            self.set_base(base)
        self.xslopts = []
        self.xslparams = []
        self.xslusers = []
        self.flags = self.USE_MKLISTINGS
        self.stdindir = ""
        self.inputdir = ""
        self.input = ""
        self.input_format = "xml"
        self.outputdir = ""
        self.output = ""
        self.format = "pdf"
        self.tmpdir = ""
        self.tmpdir_user = None
        self.fig_paths = []
        self.bib_paths = []
        self.bst_paths = []
        self.texinputs = []
        self.texbatch = 1
        self.texpost = ""
        self.fig_format = ""
        self.backend = ""

        # Temporary files
        self.documents = []
        self.interms = []
        self.included = []
        self.basefile = ""
        self.rawfile = ""

        # Engines to use
        self.runtex = None
        self.rawtex = None
        self.xsltproc = None
        self.sgmlxml = None

    def set_base(self, topdir):
        self.topdir = os.path.realpath(topdir)
        self.xslmain = os.path.join(self.topdir, "xsl", "docbook.xsl")
        self.xsllist = os.path.join(self.topdir, "xsl", "common", "mklistings.xsl")
        self.xslset = os.path.join(self.topdir, "xsl", "common", "mkdoclist.xsl")
        self.texdir = os.path.join(self.topdir, "texstyle")
        self.texlocal = ""
        self.confdir = os.path.join(self.topdir, "confstyle")

    def update_texinputs(self):
        sep = os.pathsep
        # Get a uniform list of paths (not a list of lists)
        ti = []
        for t in self.texinputs:
            ti += t.split(sep)

        # Systematically put the package style in TEXINPUTS
        ti_opts = ti + [self.texdir + "//"]

        # The original environment variable 
        texinputs = os.getenv("TEXINPUTS") or ""
        ti_env = texinputs.split(sep)

        # Find where system default is in the paths
        try:
            syspos = ti_env.index('')
        except:
            # By default system has precedence (i.e. is the first one)
            ti_env = [''] + ti_env
            syspos = 0

        ti_before = ti_env[:syspos]
        ti_after = ti_env[syspos+1:]

        # Paths passed by options have no precedence over the system 
        ti_after = ti_opts + ti_after

        # Texlocal has precedence over the standard (and added) paths
        if self.texlocal:
            ti_before = [ self.texlocal + "//" ] + ti_before
        
        # Export the whole paths
        texinputs = sep.join(ti_before + [''] + ti_after)
        os.environ["TEXINPUTS"] = texinputs

    def set_xslt(self, xsltmod=None):
        # Set the XSLT to use. Set a default XSLT if none specified.
        # One can replace an already defined XSLT if explicitely required.
        if not(xsltmod):
            if self.xsltproc:
                return
            xsltmod = "xsltproc"
        self.xsltproc = xslt.load(xsltmod)

    def set_backend(self):
        # Set the backend to use or retrieve the default one
        if self.backend:
            self.runtex.set_backend(self.backend)
        else:
            self.backend = self.runtex.get_backend()

    def set_format(self, format):
        if not(format in ("rtex", "tex", "dvi", "ps", "pdf")):
            raise ValueError("unknown format '%s'" % format)
        else:
            self.format = format

    def unset_flags(self, what):
        self.flags &= ~what

    def get_version(self):
        f = open(os.path.join(self.topdir, "xsl", "version.xsl"), "rt", encoding="latin-1")
        versions = re.findall("<xsl:variable[^>]*>([^<]*)<", f.read())
        f.close()
        if versions:
            return versions[0].strip()
        else:
            return "unknown"

    def build_stylesheet(self, wrapper="custom.xsl"):
        if not(self.xslparams or self.xslusers):
            self.xslbuild = self.xslmain
            return

        f = open(wrapper, "wt", encoding="latin-1")
        f.write(self.xsl_header)
        f.write('<xsl:import href="%s"/>\n' % path_to_uri(self.xslmain))
        for xsluser in self.xslusers:
            f.write('<xsl:import href="%s"/>\n' % path_to_uri(xsluser))

        # Reverse to set the latest parameter first (case of overriding)
        self.xslparams.reverse()
        for param in self.xslparams:
            v = param.split("=", 1)
            f.write('<xsl:param name="%s">' % v[0])
            if len(v) == 2:
                f.write('%s' % v[1])
            f.write('</xsl:param>\n')

        f.write('</xsl:stylesheet>\n')
        f.close()
        self.xslbuild = os.path.realpath(wrapper)

    def make_xml(self):
        self.log.info("Build the XML file...")
        xmlfile = self.basefile + ".xml"
        self.sgmlxml.run(self.input, xmlfile)
        self.input = xmlfile

    def make_listings(self):
        self.listings = os.path.join(self.tmpdir, "listings.xml")
        if (self.flags & self.USE_MKLISTINGS):
            self.log.info("Build the listings...")
            param = {"current.dir": self.inputdir}
            self.xsltproc.use_catalogs = 0
            self.xsltproc.run(self.xsllist, self.input,
                              self.listings, opts=self.xslopts, params=param)
        else:
            self.log.info("No external file support")
            f = open(self.listings, "wt", encoding="latin-1")
            f.write("<listings/>\n")
            f.close()

    def _single_setup(self):
        # If not specified the output name can be deduced from the input one:
        # /path/to/input.{xml|sgml} -> /path/to/input.{tex|pdf|dvi|ps}
        if not(self.output):
            output = suffix_replace(self.input, "."+self.input_format,
                                    ".%s" % self.format)
            self.output = output

        self.documents.append(Document(self.basefile + \
                                       "." + self.input_format,
                                       binfmt=self.format))

    def _multiple_setup(self, doclist):
        # If not specified, output the chunked books in the working dir
        if not(self.outputdir):
            self.log.info("No specified output dir (-O). "\
                          "Use the working directory")
            self.outputdir = self.cwdir

        f = open(doclist, "rt", encoding="latin-1")
        books = f.readlines()
        f.close()

        for b in books:
            d = Document(b.strip() + ".tex", binfmt=self.format)
            self.documents.append(d)

    def build_doclist(self):
        # The stylesheet must include the building stylesheets to have the
        # actual parameter values (e.g. set.book.num) needed to give the book
        # set list
        self.log.info("Build the book set list...")
        xslset = "doclist.xsl"
        f = open(xslset, "wt", encoding="latin-1")
        f.write(self.xsl_header)
        f.write('<xsl:import href="%s"/>\n' % path_to_uri(self.xslbuild))
        f.write('<xsl:import href="%s"/>\n' % path_to_uri(self.xslset))
        f.write('</xsl:stylesheet>\n')
        f.close()

        doclist = os.path.join(self.tmpdir, "doclist.txt")
        self.xsltproc.use_catalogs = 0
        self.xsltproc.run(xslset, self.input, doclist, opts=self.xslopts)

        # If <doclist> is missing or is empty, there's no set, or only one
        # book from the set is compiled
        if os.path.isfile(doclist) and os.path.getsize(doclist) > 0:
            self._multiple_setup(doclist)
        else:
            self._single_setup()

    def make_rawtex(self):
        if len(self.documents) == 1:
            self.rawfile = self.documents[0].rawfile
        else:
            self.rawfile = "output.rtex"

        param = {"listings.xml": self.listings,
                 "current.dir": self.inputdir}
        self.xsltproc.use_catalogs = 1
        self.xsltproc.run(self.xslbuild, self.input,
                          self.rawfile, opts=self.xslopts, params=param)

        # Now, find the intermediate raw files
        rawfiles = glob.glob("*.rtex")
        for rawfile in rawfiles:
            if not(rawfile in self.documents):
                d = Document(rawfile, binfmt=self.format)
                if d.has_subext(".input"):
                    self.included.append(d)
                else:
                    self.interms.append(d)

    def make_tex(self):
        self.rawtex.set_format(self.format, self.backend)
        if self.fig_format:
            self.rawtex.fig_format(self.fig_format)

        # By default figures are relative to the source file directory
        self.rawtex.set_fig_paths([self.inputdir] + self.fig_paths)

        for d in self.documents + self.interms + self.included:
            self.rawtex.parse(d.rawfile, d.texfile)

    def make_bin(self):
        self.runtex.texpost = self.texpost
        self.runtex.set_fig_paths([self.inputdir] + self.fig_paths)
        self.runtex.set_bib_paths([self.inputdir] + self.bib_paths,
                                  [self.inputdir] + self.bst_paths)

        # Build the intermediate files and (after) the main documents
        for d in self.interms + self.documents:
            self.log.info("Build %s" % d.binfile)
            self.runtex.compile(d.texfile, d.binfile, self.format,
                                batch=self.texbatch)
            # Only reinit, to not lose the produced working files
            # used to track the dependencies on other documents
            self.runtex.reinit()

    def compile(self):
        self.set_xslt()
        self.set_backend()
        self.cwdir = os.getcwd()
        self.tmpdir = self.tmpdir_user or tempfile.mkdtemp()
        if self.input:
            self.inputdir = os.path.dirname(self.input)
        else:
            self._stdin_write()
        os.chdir(self.tmpdir)
        try:
            donefiles = self._compile()
            if len(donefiles) == 1:
                shutil.move(donefiles[0], self.output)
                self.log.info("'%s' successfully built" % \
                              os.path.basename(self.output))
            else:
                for d in donefiles:
                    shutil.move(d, self.outputdir)
                donefiles.sort()
                self.log.info("Files successfully built in '%s':\n%s" % \
                              (self.outputdir, "\n".join(donefiles)))
        finally:
            os.chdir(self.cwdir)
            if not(self.debug):
                shutil.rmtree(self.tmpdir)
            else:
                self.log.info("%s not removed" % self.tmpdir)

    def _stdin_write(self):
        # Find out the stdin working directory
        self.inputdir = self.stdindir or self.cwdir

        # Need to dump the stdin input, because of the two passes
        self.input = os.path.join(self.tmpdir, "stdin.xml")
        if sys.stdin.encoding is None:
            f = open(self.input, "wb")
        else:
            f = open(self.input, "wt", encoding=sys.stdin.encoding)
        for line in sys.stdin:
            f.write(line)
        f.close()

    def _compile(self):
        # The temporary output file
        tmpout = os.path.basename(self.input)
        for s in (" ", "\t"):
            tmpout = tmpout.replace(s, "_")
        self.basefile = suffix_replace(tmpout, "." + self.input_format)

        # Convert SGML to XML if needed
        if self.input_format == "sgml":
            self.make_xml()

        # Build the user XSL stylesheet if needed
        self.build_stylesheet()

        # List the documents to build
        self.build_doclist()

        # Refresh the TEXINPUTS
        self.update_texinputs()

        # For easy debug
        if self.debug and "TEXINPUTS" in os.environ:
            if os.name != "nt":
                f = open("env_tex", "wt")
                f.write("TEXINPUTS=%s\nexport TEXINPUTS\n" % \
                        os.environ["TEXINPUTS"])
                f.close()
            else:
                f = open("env_tex.bat", "wt")
                f.write("set TEXINPUTS=%s\n" % os.environ["TEXINPUTS"])
                f.close()

        # Build the tex file(s), and compile it(them)
        self.make_listings()
        self.make_rawtex()
        if self.format == "rtex":
            return [ d.rawfile for d in self.documents ]

        self.make_tex()
        if self.format == "tex":
            return [ d.texfile for d in self.documents ]

        self.make_bin()
        return [ d.binfile for d in self.documents ]


#
# Command entry point
#
class DbTexCommand:
    def __init__(self, base):
        prog = os.path.splitext(os.path.basename(sys.argv[0]))[0]
        usage = "%s [options] file" % prog
        parser = OptionParser(usage=usage)
        parser.add_option("-b", "--backend",
                          help="Backend driver to use. The available drivers"
                               " are 'pdftex' (default), 'dvips' and 'xetex'.")
        parser.add_option("-B", "--no-batch", action="store_true",
                          help="All the tex output is printed")
        parser.add_option("-c", "-S", "--config", action="append",
                          help="Configuration file")
        parser.add_option("-C", "--changedir",
                          help="Standard input working directory")
        parser.add_option("-d", "--debug", action="store_true",
                          help="Debug mode. Keep the temporary directory in "
                               "which %s actually works" % prog)
        parser.add_option("-D", "--dump", action="store_true",
                          help="Dump error stack (debug purpose)")
        parser.add_option("-e", "--indexstyle",
                          help="Index Style file to pass to makeindex")
        parser.add_option("-f", "--fig-format",
                          help="Input figure format, used when not deduced "
                               "from figure extension")
        parser.add_option("-F", "--input-format",
                          help="Input file format: sgml, xml. (default=xml)")
        parser.add_option("-i", "--texinputs", action="append",
                          help="Path added to TEXINPUTS")
        parser.add_option("-I", "--fig-path", action="append",
                          dest="fig_paths", metavar="FIG_PATH",
                          help="Additional lookup path of the figures")
        parser.add_option("-l", "--bst-path", action="append",
                          dest="bst_paths", metavar="BST_PATH",
                          help="Bibliography style file path")
        parser.add_option("-L", "--bib-path", action="append",
                          dest="bib_paths", metavar="BIB_PATH",
                          help="BibTeX database path")
        parser.add_option("-m", "--xslt",
                          help="XSLT engine to use. (default=xsltproc)")
        parser.add_option("-o", "--output", dest="output",
                          help="Output filename. "
                               "When not used, the input filename "
                               "is used, with the suffix of the output format")
        parser.add_option("-O", "--output-dir",
                          help="Output directory for the built books."
                               " When not defined, the current working "
                               "directory is used. Option used only for "
                               "a document having a <set>")
        parser.add_option("-p", "--xsl-user", action="append",
                          help="XSL user configuration file to use")
        parser.add_option("-P", "--param", dest="xslparams",
                          action="append", metavar="PARAM=VALUE",
                          help="Set an XSL parameter value from command line")
        parser.add_option("-q", "--quiet", action="store_true",
                          help="Less verbose, showing only error messages")
        parser.add_option("-r", "--texpost", metavar="SCRIPT",
                          help="Script called at the very end of the tex "
                               "compilation. Its role is to modify the tex file "
                               "or one of the compilation file before the last "
                               "round.")
        parser.add_option("-s", "--texstyle", metavar="STYFILE",
                          help="Latex style to apply. It can be a package name, or "
                               "directly a package path that must ends with "
                               "'.sty'")
        parser.add_option("-t", "--type", dest="format",
                          help="Output format. Available formats:\n"
                               "tex, dvi, ps, pdf (default=pdf)")
        parser.add_option("--dvi", action="store_true", dest="format_dvi",
                          help="DVI output. Equivalent to -tdvi")
        parser.add_option("--pdf", action="store_true", dest="format_pdf",
                          help="PDF output. Equivalent to -tpdf")
        parser.add_option("--ps", action="store_true", dest="format_ps",
                          help="PostScript output. Equivalent to -tps")
        parser.add_option("-T", "--style",
                          help="Predefined output style")
        parser.add_option("--tmpdir",
                          help="Temporary working directory to use (for debug only)")
        parser.add_option("-v", "--version", action="store_true",
                          help="Print the %s version" % prog)
        parser.add_option("-V", "--verbose", action="store_true",
                          help="Verbose mode, showing the running commands")
        parser.add_option("-x", "--xslt-opts", dest="xslopts",
                          action="append", metavar="XSLT_OPTIONS",
                          help="Arguments directly passed to the XSLT engine")
        parser.add_option("-X", "--no-external", action="store_true",
                          help="Disable the external text file support used for "
                               "some callout processing")

        self.parser = parser
        self.base = base
        self.prog = prog
        # The actual engine to use is unknown
        self.run = None

    def load_plugin(self, pathname):
        moddir, modname = os.path.split(pathname)
        spec = importlib.machinery.PathFinder.find_spec(modname, [moddir])
        if not spec:
            spec = importlib.machinery.PathFinder.find_spec(modname)
        if not spec:
            failed_exit("Error: '%s' module not found" % modname)
        mod = importlib.util.module_from_spec(spec)
        spec.loader.exec_module(mod)
        sys.modules[modname] = mod
        return mod

    def run_setup(self, options):
        run = self.run

        if not(options.format):
            if options.format_pdf:
                options.format = "pdf"
            elif options.format_ps:
                options.format = "ps"
            elif options.format_dvi:
                options.format = "dvi"

        if options.format:
            try:
                run.set_format(options.format)
            except Exception as e:
                failed_exit("Error: %s" % e)

        # Always set the XSLT (default or not)
        try:
            run.set_xslt(options.xslt)
        except Exception as e:
            failed_exit("Error: %s" % e)

        if options.xslopts:
            for o in options.xslopts:
                run.xslopts += shlex.split(o)

        if options.xslparams:
            run.xslparams += options.xslparams

        if options.debug:
            run.debug = options.debug

        if options.fig_paths:
            run.fig_paths += [os.path.realpath(p) for p in options.fig_paths]

        if options.bib_paths:
            run.bib_paths += [os.path.realpath(p) for p in options.bib_paths]

        if options.bst_paths:
            run.bst_paths += [os.path.realpath(p) for p in options.bst_paths]

        if options.texstyle:
            try:
                xslparam, texpath = texstyle_parse(options.texstyle)
            except Exception as e:
                failed_exit("Error: %s" % e)
            run.xslparams.append(xslparam)
            if texpath: run.texinputs.append(texpath)

        if options.indexstyle:
            run.runtex.index_style = os.path.abspath(options.indexstyle)

        if options.texinputs:
            for texinputs in options.texinputs:
                run.texinputs += texinputs_parse(texinputs)

        if options.fig_format:
            run.fig_format = options.fig_format

        if options.input_format:
            run.input_format = options.input_format

        if options.no_batch:
            run.texbatch = 0

        if options.backend:
            run.backend = options.backend

        if options.xsl_user:
            for xfile in options.xsl_user:
                xsluser = os.path.realpath(xfile)
                if not(os.path.isfile(xsluser)):
                    failed_exit("Error: '%s' does not exist" % options.xsl_user)
                run.xslusers.append(xsluser)

        if options.texpost:
            is_plugin = options.texpost.startswith("plugin:")
            if is_plugin:
                path = self.load_plugin(options.texpost[len("plugin:"):])
            else:
                path = os.path.realpath(options.texpost)
                if not(os.path.isfile(path)):
                    failed_exit("Error: '%s' does not exist" % options.texpost)
            run.texpost = path

        if options.no_external:
            run.unset_flags(run.USE_MKLISTINGS)

        if options.verbose:
            run.verbose = options.verbose

        if options.quiet:
            run.verbose = logger.QUIET
            run.xslparams.append("output.quietly=1")

        if options.tmpdir:
            if not(os.path.exists(options.tmpdir)):
                try:
                    os.mkdir(options.tmpdir)
                except Exception as e:
                    failed_exit("Error: %s" % e)
            run.tmpdir_user = os.path.abspath(options.tmpdir)

        if options.dump:
            dump_stack()

    def get_config_paths(self):
        # Allows user directories where to look for configuration files
        paths = [os.getcwd()]
        paths.append(os.path.expanduser(os.path.join("~", "."+self.prog)))

        # Unix specific system-wide config files
        if "posix" in sys.builtin_module_names:
            paths.append(os.path.join("/etc", self.prog))

        # Last but not least, the tool config dir
        paths.append(self.run.confdir)

        # Optionally the paths from an environment variable
        conf_paths = os.getenv("DBLATEX_CONFIG_FILES")
        if not(conf_paths):
            return paths

        paths += conf_paths.split(os.pathsep)
        return paths

    def main(self):
        (options, args) = self.parser.parse_args()

        run = self.run
        parser = self.parser

        if options.version:
            version = run.get_version()
            print("%s version %s" % (self.prog, version))
            if not(args):
                sys.exit(0)

        # At least the input file is expected
        if not(args):
            parser.parse_args(args=["-h"])

        # Load the specified configurations
        conf = DbtexConfig()
        if options.dump:
            dump_stack()

        if options.style:
            try:
                conf.paths = self.get_config_paths()
                conf.fromstyle(options.style)
            except Exception as e:
                failed_exit("Error: %s" % e)
            
        if options.config:
            try:
                for config in options.config:
                    conf.fromfile(config)
            except Exception as e:
                failed_exit("Error: %s" % e)

        if conf.options:
            options2, args2 = parser.parse_args(conf.options)
            self.run_setup(options2)
         
        # Now apply the command line setup
        self.run_setup(options)

        # Verbose mode
        run.log = logger.logger(self.prog, run.verbose)

        # Data from standard input?
        if args[0] == "-":
            if not(options.output):
                failed_exit("Error: -o expected when input from stdin")
            input = ""
            if options.changedir:
                run.stdindir = os.path.realpath(options.changedir)
        else:
            input = os.path.realpath(args[0])

        # Output file in case of single document (main case)
        if not(options.output):
            output = None
        else:
            output = os.path.realpath(options.output)

        # Output directory in case of chunked books (from a set)
        if not(options.output_dir):
            outputdir = None
        else:
            # Check the output dir is OK
            outputdir = os.path.realpath(options.output_dir)
            if not(os.path.isdir(outputdir)):
                failed_exit("Error: '%s' is not a directory" %\
                            options.output_dir)

        run.input = input
        run.output = output
        run.outputdir = outputdir

        # Try to buid the file
        try:
            run.compile()
        except Exception as e:
            signal_error(self, e)
            failed_exit("Error: %s" % e)

