""" Context-sensitive help API for Adobe RoboHelp projects.

    :Copyright: 2004, Enthought, Inc.
    :License: BSD Style

    This file corresponds to the RoboHelp_CSH.* files provided with Adobe
    RoboHelp X5 for C++, VB, Java, and Javascript. However, this file is a less
    robust subset of those files. It supports HMTL Help on Win32, and WebHelp
    on other platforms. It does not support WinHelp, FlashHelp, WebHelp
    Enterprise, or "airplane" help.
"""

# Standard library imports
import logging
import os
import atexit
import webbrowser


# Setup a logger for this module.
logger = logging.getLogger(__name__)


# Help constants
HH_DISPLAY_TOPIC = 0x0000
HH_DISPLAY_TOC = 0x0001
HH_DISPLAY_INDEX = 0x0002
HH_DISPLAY_SEARCH = 0x0003
HH_HELP_CONTEXT = 0x000f


def rh_showhelp( hparent, help_file, command, data):
    """ Displays a help project.

        For HTML Help on Win32, it uses the HTML Help Viewer. Otherwise, it
        assumes WebHelp format and uses the default platform browser.

        Parameters
        ----------
        hparent : integer
            Handle to the parent window. This is reserved for future versions
            of the API. Can be a window handle or 0.
        help_file : string
            For standard WebHelp, this is the path to the help project start
            page, which can be local or on a web server:
            "http://www.myurl.com/help/help.htm" or "/help/help.htm".
            For custom windows (defined in the help project), add ">" followed
            by the window name: "/help/help.htm>mywin".
        command
            Command for what to display. One of the following:
                - HH_HELP_CONTEXT : Displays the topic associated with the map
                  number sent in `data`.
                - HH_DISPLAY_SEARCH : Displays the search pane and default
                  topic.
                - HH_DISPLAY_INDEX : Displays the index pane and default topic.
                - HH_DISPLAY_TOC : Displays the table of contents pane and
                  default topic.
        data : integer
            Map number associated with the topic to open (if using
            HH_HELP_CONTEXT).

    """
    #logger.debug("HELP: rh_showhelp(hparent=%s, help_file=%s, command=%s, data=%s)" % (hparent, help_file, command, data))
    if is_html_help(help_file):
        show_html_help_csh(hparent, help_file, command, data)
    else:
        show_web_help_csh(hparent, help_file, command, data)

def show_html_help_csh(hparent, help_file, command, data):
    #logger.debug("\tHELP: show_html_help(hparent=%s, help_file=%s, command=%s, data=%s)" % (hparent, help_file, command, data))
    import sys
    if sys.platform=='win32':
        from ctypes import windll
    else:
        return
    libc = windll.LoadLibrary("HHCTRL.OCX")
    if help_file:
        libc.HtmlHelpA(hparent, help_file, command, data)


def show_web_help_csh(hparent, help_file, command, data):
    """ Displays WebHelp.
    """
    #logger.debug("\tHELP: show_web_help(hparent=%s, help_file=%s, command=%s, data=%s)" % (hparent, help_file, command, data))
    help_path = help_file

    pos = help_file.find('>')
    if pos != -1:
        help_path = help_file[:pos]
        window = help_file[pos+1:]
    else:
        window = ""

    if help_path:
        if command == HH_DISPLAY_TOPIC:
            help_path = help_path + '#<id=0'
        elif command == HH_HELP_CONTEXT:
            help_path = help_path + '#<id=' + str(data)
        elif command == HH_DISPLAY_INDEX:
            help_path = help_path + '#<cmd=idx'
        elif command == HH_DISPLAY_SEARCH:
            help_path = help_path + '#<cmd=fts'
        elif command == HH_DISPLAY_TOC:
            pass # don't need to append '#<cmd=toc' to get the TOC;
                 # it causes an extra window in Mozilla.
        if len(help_path) > 0:
            if window and len(window) > 0:
                help_path = help_path + '>>wnd=' + window

            # NOTE: With Windows and Linux Mozilla, you get a spare browser
            # window lying around, for any command other than 'toc'.
            # The generated Javascript for WebHelp attempts to close this
            # window, which IE allows but Mozilla does not.
            try:
                #logger.debug("HELP: Calling webbrowser.open")
                webbrowser.open(path2js(help_path))
            except (OSError, webbrowser.Error), msg:
                logger.error(msg)
    return

def path2js(path):
    logger.debug("\tHELP: path2js(%s)" % path)
    # Escape Windows path separators
    import re
    path = re.sub(r'\\', r'\\\\', path)

    import tempfile
    
    fd, fn = tempfile.mkstemp(suffix='.htm', text=True)
    #logger.debug("\tHELP: tempfile: %s" % fn)
    try:
        f = os.fdopen(fd, 'w')
        f.write('''
<html>
<script language="Javascript">
<!--
document.location.href="file:///%s";
//-->
</script>
</html>
''' % (path))
        f.close()
    except (IOError, Error), msg:
        logger.error(msg)
    def rm_file(name=fn):
        try: os.remove(name)
        except OSError: pass
    atexit.register(rm_file)
    return fn

def is_html_help(help_source):
    #logger.debug("\tHELP: is_html_help(%s)", help_source)
    if help_source.find('.chm') != -1:
        return True
    else:
        return False

def is_web_help(help_source):
    if help_source.find('.htm') != -1:
        return True
    else:
        return False