#!/usr/bin/env python3
#
# Copyright (C) 2019, VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# 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/>.
#
# File: build-config
# Purpose:
#  This script serves the same purpose as ./configure in traditional
#   autoconf setups.
#  It takes build configuration options from command line, checks them,
#  builds a config dictionary, augments it with some default and/or
#  computed values and saves it to build/build-config.json
#  for other build scripts to read.

import argparse
import re
import sys
import os
import getpass
import platform
import json

import defaults

# argparse converts hyphens to underscores,
# so for lookups in the original options hash we have to
# convert them back
def field_to_option(s):
    return re.sub(r'_', '-', s)

def get_default_build_by():
    return "{user}@{host}".format(user= getpass.getuser(), host=platform.node())

def get_validator(optdict, name):
    try:
        return optdict[name][2]
    except KeyError:
        return None

def load_config(filename):
    with open(filename, 'r') as f:
        print(f'Loading {filename}')
        this_config = json.load(f)

    if not 'inherit_from' in this_config:
      print(f'No inheritance detected')
      return this_config

    inherited_config = load_config(this_config['inherit_from'])
    del this_config['inherit_from']
    inherited_config.update(this_config)
    return inherited_config


# Load the build flavor file
build_flavor = os.getenv('VYOS_BUILD_FLAVOR')
if build_flavor is None:
    build_flavor = defaults.DEFAULT_BUILD_FLAVOR
try:
    build_defaults = load_config(build_flavor)
except Exception as e:
    print("Failed to open the build flavor file {0}: {1}".format(build_flavor, e))
    sys.exit(1)


# Options dict format:
# '$option_name_without_leading_dashes': { ('$help_string', $default_value_generator_thunk, $value_checker_thunk) }
options = {
   'architecture': ('Image target architecture (amd64 or i386 or armhf or arm64)', lambda: build_defaults['architecture'], lambda x: x in ['amd64', 'i386', 'armhf', 'arm64']),
   'build-by': ('Builder identifier (e.g. jrandomhacker@example.net)', get_default_build_by, None),
   'debian-mirror': ('Debian repository mirror for ISO build', lambda: build_defaults['debian_mirror'], None),
   'debian-security-mirror': ('Debian security updates mirror', lambda: build_defaults['debian_security_mirror'], None),
   'pbuilder-debian-mirror': ('Debian repository mirror for pbuilder env bootstrap', lambda: build_defaults['debian_mirror'], None),
   'vyos-mirror': ('VyOS package mirror', lambda: build_defaults["vyos_mirror"], None),
   'build-type': ('Build type, release or development', lambda: 'development', lambda x: x in ['release', 'development']),
   'version': ('Version number (release builds only)', None, None),
   'build-comment': ('Optional build comment', lambda: '', None)
}

# Create the option parser
parser = argparse.ArgumentParser()
for k, v in options.items():
    help_string, default_value_thunk = v[0], v[1]
    if default_value_thunk is None:
        parser.add_argument('--' + k, type=str, help=help_string)
    else:
        parser.add_argument('--' + k, type=str, help=help_string, default=default_value_thunk())

# The debug option is a bit special since it's different type
parser.add_argument('--debug', help="Enable debug output", action='store_true')

# Custom APT entry and APT key options can be used multiple times
parser.add_argument('--custom-apt-entry', help="Custom APT entry", action='append')
parser.add_argument('--custom-apt-key', help="Custom APT key file", action='append')
parser.add_argument('--custom-package', help="Custom package to install from repositories", action='append')

args = vars(parser.parse_args())

# Validate options
for k, v in args.items():
    key = field_to_option(k)
    func = get_validator(options, k)
    if func is not None:
        if not func(v):
            print("{v} is not a valid value for --{o} option".format(o=key, v=v))
            sys.exit(1)

# Some fixup for mirror settings.
# The idea is: if --debian-mirror is specified but --pbuilder-debian-mirror is not,
# use the --debian-mirror value for both lb and pbuilder bootstrap
if (args['debian_mirror'] != build_defaults["debian_mirror"]) and \
   (args['pbuilder_debian_mirror'] == build_defaults["debian_mirror"]):
    args['pbuilder_debian_mirror'] = args['debian_mirror']

# Version can only be set for release builds,
# for dev builds it hardly makes any sense
if args['build_type'] == 'development':
    if args['version'] is not None:
        print("Version can only be set for release builds")
        print("Use --build-type=release option if you want to set version number")
        sys.exit(1)

# Populate some defaults that are not configurable,
# but that are handy to have in the options hash
args['distribution'] = build_defaults["debian_distribution"]
args['build_dir'] = defaults.BUILD_DIR
args['pbuilder_config'] = defaults.PBUILDER_CONFIG
args['vyos_branch'] = build_defaults["vyos_branch"]
args['release_train'] = build_defaults["release_train"]

# Add custom packages from build defaults
if not args['custom_package']:
    args['custom_package'] = []
args['custom_package'] = args['custom_package'] + build_defaults['custom_packages']

if not args['custom_apt_entry']:
    args['custom_apt_entry'] = []
args['custom_apt_entry'] = args['custom_apt_entry'] + build_defaults['additional_repositories']


# Check the build environment and dependencies
env_check_retval = os.system("scripts/check-build-env")
if env_check_retval > 0:
    print("Build environment check failed, fix the issues and retry")

args['kernel_version'] = build_defaults['kernel_version']
args['kernel_flavor'] = build_defaults['kernel_flavor']
args['bootloaders'] = build_defaults['bootloaders']


# Save to file
os.makedirs(defaults.BUILD_DIR, exist_ok=True)
print("Saving the build config to {0}".format(defaults.BUILD_CONFIG))
with open(defaults.BUILD_CONFIG, 'w') as f:
    json.dump(args, f, indent=4, sort_keys=True)
    print("\n", file=f)