##
# Add external Pseudo-Builders
#
# Some methods are added to manage external packages:
#    'PrepareLib': Checks the existence of an external library, if it
# doesn't exist, calls the script user provided to download(if required)
# and build the source code of the external library or notify user to
# install the library.
#   'Download': Download package from specify URL
#   'UnpackAll': Unpack the package
#   'Configure': Execute specify script(configure, bootstrap etc)
#   'InstallHeadFile': Install head files
#   'InstallLib': Install library binaries(.so, .a etc)
#
# for more on Pseudo-Builders see scons offical documentation
# 'Pseudo-Builders: the AddMethod function'
##
import os, subprocess
import urllib2, urlparse
import SCons.Errors

Import('env')

# Check whether a library exists, if not, notify user to install it or try to
# download the source code and build it
# @param libname - the name of the library try to prepare
# @param lib - the lib(.so, .a etc) to check (a library may include more then
#      one lib, e.g. boost, includes boost_thread, boost_system ...
# @param path - the directory of the library building script, if it's not set,
#            by default, it's <src_dir>/extlibs/<libname>/
# @param script - the building script, by default, it's 'SConscript'
#
def __prepare_lib(ienv, libname, lib = None, path = None, script = None):
    p_env = ienv.Clone(LIBS = [])
    if p_env.GetOption('clean') or p_env.GetOption('help'):
        return

    conf = Configure(p_env)

    if not lib:
        lib = libname
    if not conf.CheckLib(lib):
        if path:
            dir = path
        else:
            dir = os.path.join(env.get('SRC_DIR'), 'extlibs', libname)

        # Execute the script to download(if required) and build source code
        if script:
            st = os.path.join(dir, script)
        else:
            st = os.path.join(dir, 'SConscript')

        if os.path.exists(st):
            SConscript(st)
        else:
            if target_os in ['linux', 'darwin', 'tizen']:
                print 'Don\'t find library(%s), please intall it, exit ...' % libname
            else:
                print 'Don\'t find library(%s) and don\'t find the process script (%s), exit ...' % (libname, st)
            Exit(1)

    conf.Finish()

# Run configure command (usually it's done before build a library)
def __configure(env, cwd, cmd) :
    print "Configuring using [%s/%s] ..." % (cwd, cmd)
    # build it now (we need the shell, because some programs need it)
    devnull = open(os.devnull, "wb")
    handle  = subprocess.Popen(cmd, shell=True, cwd=cwd, stdout=devnull)

    if handle.wait() <> 0 :
        raise SCons.Errors.BuildError( "Run configuring script [%s]" % (cmd) )

# Download from URL 'url', will save as 'target'
def __download(ienv, target, url) :
    if os.path.exists(target) :
        return target

    try :
        print "Download %s from %s" % (target, url)
        print "Downloading ..."
        stream = urllib2.urlopen(url)
        file = open(target, 'wb')
        file.write(stream.read())
        file.close()
        print "Download %s from %s complete" % (target, url)
        return target
    except Exception, e :
        raise SCons.Errors.StopError( '%s [%s]' % (e, url) )

# Install header file(s) to <src_dir>/deps/<target_os>/include
def __install_head_file(ienv, file):
        return ienv.Install(os.path.join(env.get('SRC_DIR'), 'dep', target_os, target_arch, 'usr', 'include'), file)

# Install library binaries to <src_dir>/deps/<target_os>/lib/<arch>
def __install_lib(ienv, lib):
        return ienv.Install(os.path.join(env.get('SRC_DIR'), 'dep', target_os, target_arch, 'usr', 'lib'), lib)

SConscript('tools/UnpackAll.py')

env.AddMethod(__prepare_lib, "PrepareLib")
env.AddMethod(__configure, "Configure")
env.AddMethod(__download, "Download")
env.AddMethod(__install_head_file, "InstallHeadFile")
env.AddMethod(__install_lib, "InstallLib")