#! /bin/python3
import sys
import configparser
import os.path
import os
import shutil


help_string = f"""
usage: config [options...]

Configuration script for the Vhex unikernel. You should build out-of-tree by
creating a build directory and configuring from there.

Options:
    -h,--help
        display this message

    --verbose
        display more information during the compilation step

    --format=FORMAT[,format[,...]]
        select the format of the library generation. You can use two format:
            <> static  - generate a static library
            <> dynamic - generate a dynamic library
            <> all     - same behaviour as "--format=static,dynamic"
        By default, only "dynamic" is used.

    --board[=BOARD,board[,...]]
        select boards. If no board name is given, a list of all available board
        will be printed.

    --prefix=PATH
        installation path for all generated libraries
""".strip()

#
# create and apply the arguments parser
#

def parse_arguments():
    """
    The objectif of this function is to generate the "arguments object" with
    all arguments passed throuth this script correctly isolated.
    """
    args = {
        'board' : [],
        'format' : [],
        'verbose': False,
        'prefix': ''
    }
    arg_name = [
            "-h",
            "--help",
            "--format",
            "--verbose",
            "--board",
            "--prefix"
    ]
    for arg in sys.argv[1:]:
        info = arg.split("=")
        if (info[0] in arg_name) == False:
            print("%s: unreconized option '%s'" % (sys.argv[0],info[0]))
            print("Try '%s --help' for more information" % sys.argv[0])
            exit(84)
        if (info[0] in ["-h", "--help"]) == True:
            print(help_string)
            exit(0)
        if info[0] == "--verbose":
            args["verbose"] = True
            continue
        if info[0] == "--prefix":
            args["prefix"] = info[1]
            continue
        if len(info) > 1:
            args[info[0][2:]] = info[1].split(",")
    return args


#
# part handlers
#

def board_check(file, board_list):
    boards = list(os.walk('../board'))[0][1]
    archs  = list(os.walk('../src/drivers/mpu'))[0][1]

    if not board_list:
        print('board available:')
        for board in boards:
            path = '../board/%s/board.ini' % board
            if not os.path.exists(path):
                print('board \'%s\' does not exists' % board)
                continue
            conf = configparser.ConfigParser()
            conf.read(path)
            if not ('meta' in conf) or not ('description' in conf['meta']):
                print('<> %s\t\tNo description available' % board)
                continue
            print('<> %s\t\t%s' % (board, conf['meta']['description']))
        exit(0)


    valid_board_list = []
    for board in board_list:
        if not (board in boards):
            print("board '%s' does not exist" % board)
            continue
        path = '../board/%s/board.ini' % board
        if not os.path.exists(path):
            print("board '%s' does not have INI descriptor file" % board)
            continue
        conf = configparser.ConfigParser()
        conf.read(path)
        if not ('drivers' in conf) or not ('mpu' in conf['drivers']):
            print("board '%s' does not have MPU information" % board)
            continue
        arch = ''
        mpu = conf['drivers']['mpu']
        for _arch in archs:
            if not os.path.exists('../src/drivers/mpu/%s/%s' % (_arch,mpu)):
                continue
            arch = _arch
            break
        if not arch:
            print("board '%s': unreconized MPU '%s'" % (board,mpu))
            continue

        pathlist = [
            '../board/%s' % board,
            '../src/drivers/mpu/%s/%s' % (_arch,mpu)
        ]
        for driver in conf['drivers']:
            if driver == 'mpu':
                continue
            dpath = '../src/drivers/%s' % driver
            if not os.path.exists(dpath):
                print("board '%s': unreconized driver \'%s\'" % (board, dpath))
                continue
            for t in conf['drivers'][driver].split(','):
                tpath = dpath + '/' + t
                if not os.path.exists(tpath):
                    print("board '%s': unreconized driver \'%s\'" % (board, t))
                    continue
                pathlist.append(tpath)
                tpath = tpath + '/target/' + arch
                if os.path.exists(tpath):
                    pathlist.append(tpath)
        for dirent in os.listdir('../src'):
            if not (dirent in ['drivers', 'arch']):
                pathlist.append('../src/' + dirent)

        ldflags,cflags,prefix,libs = [],[],[],[]
        if 'toolchain' in conf:
            if 'prefix' in conf['toolchain']:
                prefix = conf['toolchain']['prefix']
            if 'cflags' in conf['toolchain']:
                cflags = conf['toolchain']['cflags'].split(',')
            if 'libs' in conf['toolchain']:
                libs = conf['toolchain']['libs'].split(',')

        confstr = 'CONFIG.' + board;
        file.write(
                confstr + '.SRC-MODULE-PATH  :=' + ' '.join(pathlist) + '\n'
              + confstr + '.TOOLCHAIN.LDFLAGS :=' + ' '.join(ldflags) + '\n'
              + confstr + '.TOOLCHAIN.CFLAGS  :=' + ' '.join(cflags) + '\n'
              + confstr + '.TOOLCHAIN.PREFIX  :=' + prefix + '\n'
              + confstr + '.LIBS :=' + ' '.join(libs) + '\n'
        )

        if not os.path.exists(board):
            os.mkdir(board)
            os.symlink(
                '../../board/%s/%s.ld' % (board,board),
                '%s/%s.ld' % (board,board)
            )

        valid_board_list.append(board)

    file.write('CONFIG.BOARD-LIST := ' + ' '.join(valid_board_list) + '\n')

def format_check(file, format_list):
    file.write('CONFIG.FORMAT-LIST :=')
    for _format in format_list:
        if not (_format in ["static", "dynamic", "all"]):
            print("%s: unreconized format '%s'" % (sys.argv[0], _format))
            exit(84)
        if _format == 'all':
            file.write(' dynamic static\n')
            return
        file.write(' ' + _format)
    if not format_list:
        file.write(' dynamic')
    file.write('\n')

def prefix_check(file, prefix):
    file.write('CONFIG.INSTALL-PREFIX :=' + prefix + '\n')

def verbose_check(file, verbose):
    file.write(f"CONFIG.VERBOSE := {'true' if verbose else 'false'}\n")

#
# "real" entry of the script
#

def main():
    args = parse_arguments()

    if os.path.exists('../src') == False:
        print('error: you should configure from a build directory, like this:')
        print('  mkdir build && cd build && ../configure [options..]')
        exit(84)

    file = open('kernel.cfg', 'w')

    board_check(file, args['board'])
    format_check(file, args['format'])
    prefix_check(file, args['prefix'])
    verbose_check(file, args['verbose'])

    if os.path.exists('Makefile'):
        os.remove('Makefile')
    os.symlink('../make/Makefile', 'Makefile')

main()