# -*- mode: python; coding: utf-8; -*-

#  Codezero -- a microkernel for embedded systems.
#
#  Copyright © 2009  B Labs Ltd
#
#  This program is free software: you can redistribute it and/or modify it under the terms of the GNU
#  General Public License as published by the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
#  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
#  License for more details.
#
#  You should have received a copy of the GNU General Public License along with this program.  If not, see
#  <http://www.gnu.org/licenses/>.
#
#  Author: Russel Winder

import os

includeDirectory = 'include'
toolsDirectory = 'tools'
cml2ToolsDirectory = toolsDirectory + '/cml2-tools'
buildDirectory = 'build'

cml2CompileRulesFile = buildDirectory + '/cml2Rules.out'
cml2ConfigPropertiesFile = buildDirectory + '/cml2Config.out'
cml2ConfigHeaderFile = buildDirectory + '/cml2Config.h'

#  The choice of which parts of the kernel to compile and include in the build depends on the configuration
#  which is managed using CML2.  CML2 uses a base configuration file (currently #configs/arm.cml) to drive
#  an interaction with the user which results in a trio of files that specify the user choice.
#
#  cml2RulesFile is the pickled version of the source configuration driver.
#
#  cml2Config.out is a properties type representation of the user selected configuration data.
#
#  cml2Config.h is a C include file representation of the user selected configuration data derived from
#  cml2Config.out, it is essential for the compilation of the C code of the kernel and the tasks.
#
#  Since the DAG for building the kernel relies on the information from the configuration split the build
#  into two distinct phases as Autotools and Waf do, configure then build.  Achieve this by partitioning the
#  SCons DAG building in two depending on the command line.

if 'configure' in COMMAND_LINE_TARGETS  :

    def performCML2Configuration ( target , source , env ) :
        if not os.path.isdir ( buildDirectory ) : os.mkdir ( buildDirectory )
        os.system ( cml2ToolsDirectory + '/cmlcompile.py -o ' + cml2CompileRulesFile + ' ' + source[0].path )
        os.system ( cml2ToolsDirectory +  '/cmlconfigure.py -c -o ' + cml2ConfigPropertiesFile + ' ' + cml2CompileRulesFile )
        os.system ( toolsDirectory +  '/cml2header.py -o ' + cml2ConfigHeaderFile + ' -i ' + cml2ConfigPropertiesFile )

    if len ( COMMAND_LINE_TARGETS ) != 1 :
        print '#### Warning####: configure is part of the command line, all the other targets are being ignored as this is a configure step.'
    Command ( 'configure' ,  [ '#configs/arm.cml' ] , performCML2Configuration )
    Clean ( 'configure' , buildDirectory )

else :

    if not os.path.exists ( cml2ConfigPropertiesFile ) :
        print "####\n#### Configuration has not been undertaken, please run 'scons configure'.\n####"
        Exit ( )

##########  Create the base environment and process the configuration ########################

    def processCML2Config ( ) :
        configItems = { }
        with file ( cml2ConfigPropertiesFile ) as configFile :
            for line in configFile :
                item = line.split ( '=' )
                if len ( item ) == 2 :
                    configItems[item[0].strip ( )] = ( item[1].strip ( ) == 'y' )
        return configItems
                
    baseEnvironment = Environment ( tools = [ 'gnulink' , 'gcc' , 'gas' , 'ar' ] ,
                                    ENV = { 'PATH' : os.environ['PATH'] } ,
                                    configFiles = ( '#' + cml2CompileRulesFile ,  '#' + cml2ConfigPropertiesFile ,  '#' + cml2ConfigHeaderFile ) )

    kernelSConscriptPaths = [ 'generic' , 'api' , 'lib' ]

    #  It is assumed that the C code is assuming that the configuration file will be found at l4/config.h so create it there.
    #
    #  Kernel code include config.h in a different way to all the other bits of code.
    #
    #  TODO:  Decide if this is an issue or not.

    configuration = Configure ( baseEnvironment , config_h =  buildDirectory + '/l4/config.h' )
    configData = processCML2Config ( )
    arch = None
    platform = None
    subarch = None
    for key , value in configData.items ( ) :
        if value :
            items = key.split ( '_' )
            if items[0] == 'ARCH' :
                arch = items[1].lower ( )
    for key , value in configData.items ( ) :
        if value :
            items = key.split ( '_' )
            if items[0] == arch.upper ( ) :
                if items[1] == 'PLATFORM' :
                    platform = items[2].lower ( )
                if items[1] == 'SUBARCH' :
                    subarch = items[2].lower ( )
            if items[0] == 'DRIVER' :
                kernelSConscriptPaths.append ( 'drivers/' + ( 'irq' if items[1] == 'IRQCTRL' else items[1].lower ( ) ) + '/' + items[2].lower ( ) )
    configuration.Define ( '__ARCH__' , arch )
    configuration.Define ( '__PLATFORM__' , platform )
    configuration.Define ( '__SUBARCH__' , subarch )
    kernelSConscriptPaths += [
        'arch/' + arch ,
        'glue/' + arch ,
        'platform/' + platform ,
        'arch/' + arch + '/' + subarch ]
    configuration.env['ARCH'] = arch
    configuration.env['PLATFORM'] = platform
    configuration.env['SUBARCH'] = subarch
    baseEnvironment = configuration.Finish ( )

##########  Build the libraries ########################

    libraryEnvironment = baseEnvironment.Clone (
        CC = 'arm-none-linux-gnueabi-gcc' ,
        CCFLAGS = [ '-g' , '-nostdinc' , '-nostdlib' , '-ffreestanding'  , '-std=gnu99' , '-Wall' , '-Werror' ] ,
        LINKFLAGS = [ '-nostdlib' ] ,
        LIBS = 'gcc' ,
        ARCH = arch , 
        PLATFORM = platform )

    libs = { }
    crts = { }
    for variant in [ 'baremetal' , 'userspace' ] :
        ( libs[variant] , crts[variant] ) = SConscript ( 'libs/c/SConscript' , variant_dir = buildDirectory + '/lib/c/' + variant , duplicate = 0 , exports = { 'environment' : libraryEnvironment , 'variant' : variant } )
        Depends (  ( libs[variant] , crts[variant] ) , libraryEnvironment['configFiles'] )

    baseEnvironment['libc'] = libs['userspace']
    baseEnvironment['crt0'] = crts['userspace']

    libelf = SConscript ( 'libs/elf/SConscript' , variant_dir = buildDirectory + '/lib/elf' , duplicate = 0 , exports = { 'environment' : libraryEnvironment } )
    Depends ( libelf , libraryEnvironment['configFiles'] )

    Alias ( 'libs' , crts.values ( ) + libs.values ( ) + [ libelf ] )

##########  Build the kernel ########################

    kernelEnvironment = baseEnvironment.Clone (
        CC = 'arm-none-eabi-gcc' ,
        # We don't use -nostdinc because sometimes we need standard headers, such as stdarg.h e.g. for variable
        # args, as in printk().
        CCFLAGS = [ '-mcpu=arm926ej-s' , '-g' , '-nostdlib' , '-ffreestanding' , '-std=gnu99' , '-Wall' , '-Werror' ] ,
        LINKFLAGS = [ '-nostdlib' , '-T' +  includeDirectory + '/l4/arch/' + arch + '/mylink.lds' ] ,
        ASFLAGS = [ '-D__ASSEMBLY__' ] ,
        PROGSUFFIX = '.axf' ,
        LIBS = 'gcc' ,
        CPPPATH = [ '#' + buildDirectory , '#' + buildDirectory + '/l4' , '#' + includeDirectory , '#' + includeDirectory + '/l4' ] ,

        ####
        ####  TODO:  Why are these files forcibly included, why not just leave it up to the C code to include things?
        ####

        CPPFLAGS = [ '-include' , 'config.h' , '-include' , 'cml2Config.h' , '-include' , 'macros.h' , '-include' , 'types.h' , '-D__KERNEL__' ] )
    
    kernelComponents = [ ]
    for scriptPath in [ 'src/' + path for path in kernelSConscriptPaths ] :
        kernelComponents.append ( SConscript ( scriptPath + '/SConscript' , variant_dir = buildDirectory + '/' + scriptPath , duplicate = 0 , exports = { 'environment' : kernelEnvironment } ) )
    startAxf = kernelEnvironment.Program ( buildDirectory + '/start.axf' ,  kernelComponents )
    Depends (  kernelComponents + [ startAxf ] , kernelEnvironment['configFiles'] )
    
    Alias ( 'kernel' , startAxf )

##########  Build the tasks ########################

    taskSupportLibraryEnvironment = baseEnvironment.Clone (
        CC = 'arm-none-linux-gnueabi-gcc' ,
        CCFLAGS = [ '-g' , '-nostdlib' , '-ffreestanding' , '-std=gnu99' , '-Wall' , '-Werror' ] ,
        LINKFLAGS = [ '-nostdlib' ] ,
        ASFLAGS = [ '-D__ASSEMBLY__' ] ,
        LIBS = 'gcc' ,
        CPPPATH = [ '#' + buildDirectory , '#' + buildDirectory + '/l4' , '#' + includeDirectory ] )

    taskLibraryNames = [ f.name for f in Glob ( 'tasks/lib*' ) ]

    taskLibraries = [ ]
    for library in taskLibraryNames :
        taskLibraries.append ( SConscript ( 'tasks/' + library + '/SConscript' , variant_dir = buildDirectory + '/tasks/' + library , duplicate = 0 , exports = { 'environment' : taskSupportLibraryEnvironment } ) )

    Depends ( taskLibraries , taskSupportLibraryEnvironment['configFiles'] )

    Alias ( 'tasklibs' , taskLibraries )
    
    tasksEnvironment = baseEnvironment.Clone (
        CC = 'arm-none-linux-gnueabi-gcc' ,
        CCFLAGS = [ '-g' , '-nostdlib' , '-ffreestanding' , '-std=gnu99' , '-Wall' , '-Werror' ] ,
        LINKFLAGS = [ '-nostdlib' ] ,
        ASFLAGS = [ '-D__ASSEMBLY__' ] ,
        LIBS =  taskLibraries + [ 'gcc' , libs['userspace'] ] ,
        PROGSUFFIX = '.axf' ,
        CPPDEFINES = [ '__USERSPACE__' ] ,
        CPPPATH = [ '#' + buildDirectory , '#' + buildDirectory + '/l4' , '#' + includeDirectory , 'include' , '#tasks/libl4/include' , '#tasks/libmem' , '#tasks/libposix/include'] )

    tasks = [ ]
    for task in [ f.name for f in Glob ( 'tasks/*' ) if f.name not in taskLibraryNames + [ 'bootdesc' ] ] :
        tasks.append ( SConscript ( 'tasks/' + task + '/SConscript' , variant_dir = buildDirectory + '/tasks/' + task , duplicate = 0 , exports = { 'environment' : tasksEnvironment } ) )

    Depends ( tasks , tasksEnvironment['configFiles'] )

    Alias ( 'tasks' , tasks )

##########  Other rules. ########################

    Default ( crts.values ( ) + libs.values ( ) + [ libelf , startAxf ] + tasks )
    
    Clean ( '.' , [ buildDirectory ] )

##########  Be helpful ########################

Help ( '''
Explicit targets are:

  configure -- configure the build area ready for a build.

  libs -- build the support library.
  kernel -- build the kernel.
  tasklibs -- build all the support libraries for the tasks.
  tasks -- build all the tasks.

The default target is to compile everything and to do a final link.

Compilation can only be undertaken after a configuration.
''' )
