#!/usr/bin/env python

"""
Botan install script

(C) 2014,2015,2017 Jack Lloyd

Botan is released under the Simplified BSD License (see license.txt)
"""

import errno
import json
import logging
import optparse # pylint: disable=deprecated-module
import os
import shutil
import string
import sys
import subprocess

def parse_command_line(args):

    parser = optparse.OptionParser()

    parser.add_option('--verbose', action='store_true', default=False,
                      help='Show debug messages')
    parser.add_option('--quiet', action='store_true', default=False,
                      help='Show only warnings and errors')

    build_group = optparse.OptionGroup(parser, 'Source options')
    build_group.add_option('--build-dir', metavar='DIR', default='build',
                           help='Location of build output (default \'%default\')')
    parser.add_option_group(build_group)

    install_group = optparse.OptionGroup(parser, 'Installation options')
    install_group.add_option('--prefix', default='/usr/local',
                             help='Set output directory (default %default)')
    install_group.add_option('--bindir', default='bin', metavar='DIR',
                             help='Set binary subdir (default %default)')
    install_group.add_option('--libdir', default='lib', metavar='DIR',
                             help='Set library subdir (default %default)')
    install_group.add_option('--includedir', default='include', metavar='DIR',
                             help='Set include subdir (default %default)')
    install_group.add_option('--docdir', default='share/doc', metavar='DIR',
                             help='Set documentation subdir (default %default)')
    install_group.add_option('--pkgconfigdir', default='pkgconfig', metavar='DIR',
                             help='Set pkgconfig subdir (default %default)')

    install_group.add_option('--umask', metavar='MASK', default='022',
                             help='Umask to set (default %default)')
    parser.add_option_group(install_group)

    (options, args) = parser.parse_args(args)

    def log_level():
        if options.verbose:
            return logging.DEBUG
        if options.quiet:
            return logging.WARNING
        return logging.INFO

    logging.getLogger().setLevel(log_level())

    return (options, args)


class PrependDestdirError(Exception):
    pass


def is_subdir(path, subpath):
    return os.path.relpath(path, start=subpath).startswith("..")


def prepend_destdir(path):
    """
    Needed because os.path.join() discards the first path if the
    second one is absolute, which is usually the case here. Still, we
    want relative paths to work and leverage the os awareness of
    os.path.join().
    """
    destdir = os.environ.get('DESTDIR', "")

    if destdir:
        # DESTDIR is non-empty, but we only join absolute paths on UNIX-like file systems
        if os.path.sep != "/":
            raise PrependDestdirError("Only UNIX-like file systems using forward slash " \
                                      "separator supported when DESTDIR is set.")
        if not os.path.isabs(path):
            raise PrependDestdirError("--prefix must be an absolute path when DESTDIR is set.")

        path = os.path.normpath(path)
        # Remove / or \ prefixes if existent to accomodate for os.path.join()
        path = path.lstrip(os.path.sep)
        path = os.path.join(destdir, path)

        if not is_subdir(destdir, path):
            raise PrependDestdirError("path escapes DESTDIR (path='%s', destdir='%s')" % (path, destdir))

    return path


def makedirs(dirname, exist_ok=True):
    try:
        logging.debug('Creating directory %s' % (dirname))
        os.makedirs(dirname)
    except OSError as e:
        if e.errno != errno.EEXIST or not exist_ok:
            raise e

# Clear link and create new one
def force_symlink(target, linkname):
    try:
        os.unlink(linkname)
    except OSError as e:
        if e.errno != errno.ENOENT:
            raise e
    os.symlink(target, linkname)

def calculate_exec_mode(options):
    out = 0o777
    if 'umask' in os.__dict__:
        umask = int(options.umask, 8)
        logging.debug('Setting umask to %s' % oct(umask))
        os.umask(int(options.umask, 8))
        out &= (umask ^ 0o777)
    return out

def main(args):
    # pylint: disable=too-many-locals,too-many-branches,too-many-statements

    logging.basicConfig(stream=sys.stdout,
                        format='%(levelname) 7s: %(message)s')

    (options, args) = parse_command_line(args)

    exe_mode = calculate_exec_mode(options)

    def copy_file(src, dst):
        logging.debug('Copying %s to %s' % (src, dst))
        shutil.copyfile(src, dst)

    def copy_executable(src, dst):
        copy_file(src, dst)
        logging.debug('Make %s executable' % dst)
        os.chmod(dst, exe_mode)

    with open(os.path.join(options.build_dir, 'build_config.json')) as f:
        cfg = json.load(f)

    def process_template(template_str):
        class PercentSignTemplate(string.Template):
            delimiter = '%'

        try:
            template = PercentSignTemplate(template_str)
            return template.substitute(cfg)
        except KeyError as e:
            raise Exception('Unbound var %s in template' % (e))
        except Exception as e:
            raise Exception('Exception %s in template' % (e))

    ver_major = int(cfg['version_major'])
    ver_minor = int(cfg['version_minor'])
    ver_patch = int(cfg['version_patch'])
    target_os = cfg['os']
    build_shared_lib = bool(cfg['build_shared_lib'])

    bin_dir = os.path.join(options.prefix, options.bindir)
    lib_dir = os.path.join(options.prefix, options.libdir)
    target_doc_dir = os.path.join(options.prefix,
                                  options.docdir,
                                  'botan-%d.%d.%d' % (ver_major, ver_minor, ver_patch))
    target_include_dir = os.path.join(options.prefix,
                                      options.includedir,
                                      'botan-%d' % (ver_major),
                                      'botan')

    out_dir = process_template('%{out_dir}')
    if target_os == "windows":
        app_exe = 'botan-cli.exe'
    else:
        app_exe = process_template('botan%{program_suffix}')

    for d in [options.prefix, lib_dir, bin_dir, target_doc_dir, target_include_dir]:
        makedirs(prepend_destdir(d))

    build_include_dir = os.path.join(options.build_dir, 'include', 'botan')

    for include in sorted(os.listdir(build_include_dir)):
        if include == 'internal':
            continue
        copy_file(os.path.join(build_include_dir, include),
                  prepend_destdir(os.path.join(target_include_dir, include)))

    build_external_include_dir = os.path.join(options.build_dir, 'include', 'external')

    for include in sorted(os.listdir(build_external_include_dir)):
        copy_file(os.path.join(build_external_include_dir, include),
                  prepend_destdir(os.path.join(target_include_dir, include)))

    static_lib = process_template('%{lib_prefix}%{libname}.%{static_suffix}')
    copy_file(os.path.join(out_dir, static_lib),
              prepend_destdir(os.path.join(lib_dir, os.path.basename(static_lib))))

    if build_shared_lib:
        if target_os == "windows":
            libname = process_template('%{libname}')
            soname_base = libname + '.dll'
            copy_executable(os.path.join(out_dir, soname_base),
                            prepend_destdir(os.path.join(lib_dir, soname_base)))
        else:
            soname_patch = process_template('%{soname_patch}')
            soname_abi = process_template('%{soname_abi}')
            soname_base = process_template('%{soname_base}')

            copy_executable(os.path.join(out_dir, soname_patch),
                            prepend_destdir(os.path.join(lib_dir, soname_patch)))

            if target_os != "openbsd":
                prev_cwd = os.getcwd()
                try:
                    os.chdir(prepend_destdir(lib_dir))
                    force_symlink(soname_patch, soname_abi)
                    force_symlink(soname_patch, soname_base)
                finally:
                    os.chdir(prev_cwd)

    copy_executable(os.path.join(out_dir, app_exe),
                    prepend_destdir(os.path.join(bin_dir, app_exe)))

    # On Darwin, if we are using shared libraries and we install, we should fix
    # up the library name, otherwise the botan command won't work; ironically
    # we only need to do this because we previously changed it from a setting
    # that would be correct for installation to one that lets us run it from
    # the build directory
    if target_os == 'darwin' and build_shared_lib:
        soname_abi = process_template('%{soname_abi}')

        subprocess.check_call(['install_name_tool',
                               '-change',
                               os.path.join('@executable_path', soname_abi),
                               os.path.join(lib_dir, soname_abi),
                               os.path.join(bin_dir, app_exe)])

    if 'botan_pkgconfig' in cfg:
        pkgconfig_dir = os.path.join(options.prefix, options.libdir, options.pkgconfigdir)
        makedirs(prepend_destdir(pkgconfig_dir))
        copy_file(cfg['botan_pkgconfig'],
                  prepend_destdir(os.path.join(pkgconfig_dir, os.path.basename(cfg['botan_pkgconfig']))))

    if 'ffi' in cfg['mod_list'].split('\n'):
        for ver in cfg['python_version'].split(','):
            py_lib_path = os.path.join(lib_dir, 'python%s' % (ver), 'site-packages')
            logging.debug('Installing python module to %s' % (py_lib_path))
            makedirs(prepend_destdir(py_lib_path))

            py_dir = cfg['python_dir']
            for py in os.listdir(py_dir):
                copy_file(os.path.join(py_dir, py), prepend_destdir(os.path.join(py_lib_path, py)))

    shutil.rmtree(prepend_destdir(target_doc_dir), True)
    shutil.copytree(cfg['doc_output_dir'], prepend_destdir(target_doc_dir))

    for f in [f for f in os.listdir(cfg['doc_dir']) if f.endswith('.txt')]:
        copy_file(os.path.join(cfg['doc_dir'], f), prepend_destdir(os.path.join(target_doc_dir, f)))

    copy_file(os.path.join(cfg['base_dir'], 'license.txt'),
              prepend_destdir(os.path.join(target_doc_dir, 'license.txt')))
    copy_file(os.path.join(cfg['base_dir'], 'news.rst'),
              prepend_destdir(os.path.join(target_doc_dir, 'news.txt')))

    logging.info('Botan %s installation complete', cfg['version'])
    return 0

if __name__ == '__main__':
    try:
        sys.exit(main(sys.argv))
    except Exception as e: # pylint: disable=broad-except
        logging.error('Failure: %s' % (e))
        import traceback
        logging.info(traceback.format_exc())
        sys.exit(1)
