"""
Provides factory methods to assemble the Galaxy web application
"""

import logging, atexit, os, os.path, sys, config

from inspect import isclass

from paste.request import parse_formvars
from paste.util import import_string
from paste import httpexceptions
from paste.deploy.converters import asbool

import pkg_resources

import galaxy.webapps.community.model
import galaxy.webapps.community.model.mapping
import galaxy.web.framework
from galaxy.webapps.community.framework.middleware import hg

log = logging.getLogger( __name__ )

def add_ui_controllers( webapp, app ):
    """
    Search for controllers in the 'galaxy.webapps.controllers' module and add 
    them to the webapp.
    """
    from galaxy.web.base.controller import BaseUIController
    from galaxy.web.base.controller import ControllerUnavailable
    import galaxy.webapps.community.controllers
    controller_dir = galaxy.webapps.community.controllers.__path__[0]
    for fname in os.listdir( controller_dir ):
        if not fname.startswith( "_" ) and fname.endswith( ".py" ):
            name = fname[:-3]
            module_name = "galaxy.webapps.community.controllers." + name
            module = __import__( module_name )
            for comp in module_name.split( "." )[1:]:
                module = getattr( module, comp )
            # Look for a controller inside the modules
            for key in dir( module ):
                T = getattr( module, key )
                if isclass( T ) and T is not BaseUIController and issubclass( T, BaseUIController ):
                    webapp.add_ui_controller( name, T( app ) )
    import galaxy.web.controllers
    controller_dir = galaxy.web.controllers.__path__[0]
    for fname in os.listdir( controller_dir ):
        # TODO: fix this if we decide to use, we don't need to inspect all controllers...
        if fname.startswith( 'user' ) and fname.endswith( ".py" ):
            name = fname[:-3]
            module_name = "galaxy.web.controllers." + name
            module = __import__( module_name )
            for comp in module_name.split( "." )[1:]:
                module = getattr( module, comp )
            # Look for a controller inside the modules
            for key in dir( module ):
                T = getattr( module, key )
                if isclass( T ) and T is not BaseUIController and issubclass( T, BaseUIController ):
                    webapp.add_ui_controller( name, T( app ) )

def app_factory( global_conf, **kwargs ):
    """Return a wsgi application serving the root object"""
    # Create the Galaxy tool shed application unless passed in
    if 'app' in kwargs:
        app = kwargs.pop( 'app' )
    else:
        try:
            from galaxy.webapps.community.app import UniverseApplication
            app = UniverseApplication( global_conf=global_conf, **kwargs )
        except:
            import traceback, sys
            traceback.print_exc()
            sys.exit( 1 )
    atexit.register( app.shutdown )
    # Create the universe WSGI application
    webapp = galaxy.web.framework.WebApplication( app, session_cookie='galaxycommunitysession' )
    add_ui_controllers( webapp, app )
    webapp.add_route( '/:controller/:action', action='index' )
    webapp.add_route( '/:action', controller='repository', action='index' )
    webapp.add_route( '/repos/*path_info', controller='hg', action='handle_request', path_info='/' )
    webapp.finalize_config()
    # Wrap the webapp in some useful middleware
    if kwargs.get( 'middleware', True ):
        webapp = wrap_in_middleware( webapp, global_conf, **kwargs )
    if kwargs.get( 'static_enabled', True ):
        webapp = wrap_in_static( webapp, global_conf, **kwargs )
    # Close any pooled database connections before forking
    try:
        galaxy.webapps.community.model.mapping.metadata.engine.connection_provider._pool.dispose()
    except:
        pass
    # Return
    return webapp

def wrap_in_middleware( app, global_conf, **local_conf ):
    """Based on the configuration wrap `app` in a set of common and useful middleware."""
    # Merge the global and local configurations
    conf = global_conf.copy()
    conf.update( local_conf )
    debug = asbool( conf.get( 'debug', False ) )
    # First put into place httpexceptions, which must be most closely
    # wrapped around the application (it can interact poorly with
    # other middleware):
    app = httpexceptions.make_middleware( app, conf )
    log.debug( "Enabling 'httpexceptions' middleware" )
    # The recursive middleware allows for including requests in other 
    # requests or forwarding of requests, all on the server side.
    if asbool(conf.get('use_recursive', True)):
        from paste import recursive
        app = recursive.RecursiveMiddleware( app, conf )
        log.debug( "Enabling 'recursive' middleware" )
    # Various debug middleware that can only be turned on if the debug
    # flag is set, either because they are insecure or greatly hurt
    # performance
    if debug:
        # Middleware to check for WSGI compliance
        if asbool( conf.get( 'use_lint', True ) ):
            from paste import lint
            app = lint.make_middleware( app, conf )
            log.debug( "Enabling 'lint' middleware" )
        # Middleware to run the python profiler on each request
        if asbool( conf.get( 'use_profile', False ) ):
            import profile
            app = profile.ProfileMiddleware( app, conf )
            log.debug( "Enabling 'profile' middleware" )
        # Middleware that intercepts print statements and shows them on the
        # returned page
        if asbool( conf.get( 'use_printdebug', True ) ):
            from paste.debug import prints
            app = prints.PrintDebugMiddleware( app, conf )
            log.debug( "Enabling 'print debug' middleware" )
    if debug and asbool( conf.get( 'use_interactive', False ) ):
        # Interactive exception debugging, scary dangerous if publicly
        # accessible, if not enabled we'll use the regular error printing
        # middleware.
        pkg_resources.require( "WebError" )
        from weberror import evalexception
        app = evalexception.EvalException( app, conf,
                                           templating_formatters=build_template_error_formatters() )
        log.debug( "Enabling 'eval exceptions' middleware" )
    else:
        # Not in interactive debug mode, just use the regular error middleware
        from paste.exceptions import errormiddleware
        app = errormiddleware.ErrorMiddleware( app, conf )
        log.debug( "Enabling 'error' middleware" )
    # Transaction logging (apache access.log style)
    if asbool( conf.get( 'use_translogger', True ) ):
        from paste.translogger import TransLogger
        app = TransLogger( app )
        log.debug( "Enabling 'trans logger' middleware" )
    # Config middleware just stores the paste config along with the request,
    # not sure we need this but useful
    from paste.deploy.config import ConfigMiddleware
    app = ConfigMiddleware( app, conf )
    log.debug( "Enabling 'config' middleware" )
    # X-Forwarded-Host handling
    from galaxy.web.framework.middleware.xforwardedhost import XForwardedHostMiddleware
    app = XForwardedHostMiddleware( app )
    log.debug( "Enabling 'x-forwarded-host' middleware" )
    app = hg.Hg( app, conf )
    log.debug( "Enabling hg middleware" )
    return app
    
def wrap_in_static( app, global_conf, **local_conf ):
    from paste.urlmap import URLMap
    from galaxy.web.framework.middleware.static import CacheableStaticURLParser as Static
    urlmap = URLMap()
    # Merge the global and local configurations
    conf = global_conf.copy()
    conf.update(local_conf)
    # Get cache time in seconds
    cache_time = conf.get( "static_cache_time", None )
    if cache_time is not None:
        cache_time = int( cache_time )
    # Send to dynamic app by default
    urlmap["/"] = app
    # Define static mappings from config
    urlmap["/static"] = Static( conf.get( "static_dir" ), cache_time )
    urlmap["/images"] = Static( conf.get( "static_images_dir" ), cache_time )
    urlmap["/static/scripts"] = Static( conf.get( "static_scripts_dir" ), cache_time )
    urlmap["/static/style"] = Static( conf.get( "static_style_dir" ), cache_time )
    urlmap["/favicon.ico"] = Static( conf.get( "static_favicon_dir" ), cache_time )
    # URL mapper becomes the root webapp
    return urlmap
    
def build_template_error_formatters():
    """
    Build a list of template error formatters for WebError. When an error
    occurs, WebError pass the exception to each function in this list until
    one returns a value, which will be displayed on the error page.
    """
    formatters = []
    # Formatter for mako
    import mako.exceptions
    def mako_html_data( exc_value ):
        if isinstance( exc_value, ( mako.exceptions.CompileException, mako.exceptions.SyntaxException ) ):
            return mako.exceptions.html_error_template().render( full=False, css=False )
        if isinstance( exc_value, AttributeError ) and exc_value.args[0].startswith( "'Undefined' object has no attribute" ):
            return mako.exceptions.html_error_template().render( full=False, css=False )
    formatters.append( mako_html_data )
    return formatters