#!/usr/bin/env python3

import glob
import os
import os.path
import sys
import argparse
from textwrap import dedent
import subprocess
import re

cwd = os.getcwd()

parser = argparse.ArgumentParser()
parser.add_argument('--validate', action='store_true', help='Run in validate mode')
parser.add_argument('--hadrian', action='store_true', help='Do not assume the make base build system')
args = parser.parse_args()

# Packages whose libraries aren't in the submodule root
EXCEPTIONS = {
    'libraries/containers/': 'libraries/containers/containers/'
}

def print_err(s):
    print(dedent(s), file=sys.stderr)

def die(mesg):
    print_err(mesg)
    sys.exit(1)

def check_boot_packages():
    # Check that we have all boot packages.
    for l in open('packages', 'r'):
        if l.startswith('#'):
            continue

        parts = [part for part in l.split(' ') if part]
        if len(parts) != 4:
            die("Error: Bad line in packages file: " + l)

        dir_ = parts[0]
        tag = parts[1]

        # If tag is not "-" then it is an optional repository, so its
        # absence isn't an error.
        if tag == '-':
            # We would like to just check for a .git directory here,
            # but in an lndir tree we avoid making .git directories,
            # so it doesn't exist. We therefore require that every repo
            # has a LICENSE file instead.
            license_path = os.path.join(EXCEPTIONS.get(dir_+'/', dir_), 'LICENSE')
            if not os.path.isfile(license_path):
                die("""\
                    Error: %s doesn't exist
                    Maybe you haven't run 'git submodule update --init'?
                    """ % license_path)

# Create libraries/*/{ghc.mk,GNUmakefile}
def boot_pkgs():
    library_dirs = []

    for package in glob.glob("libraries/*/"):
        packages_file = os.path.join(package, 'ghc-packages')
        print(package)
        if os.path.isfile(packages_file):
            for subpkg in open(packages_file, 'r'):
                library_dirs.append(os.path.join(package, subpkg.strip()))
        elif package in EXCEPTIONS:
            library_dirs.append(EXCEPTIONS[package])
        else:
            library_dirs.append(package)

    for package in library_dirs:
        if package[-1] == '/':
            # drop trailing '/'
            package = package[:-1]

        dir_ = os.path.relpath(package, 'libraries')
        cabals = glob.glob(os.path.join(package, '*.cabal.in'))
        if len(cabals) == 0:
            cabals = glob.glob(os.path.join(package, '*.cabal'))

        if len(cabals) > 1:
            die('Too many .cabal files in %s' % package)
        elif len(cabals) == 1:
            cabal = cabals[0]

            if os.path.isfile(cabal):
                # strip both .cabal and .in
                pkg = os.path.splitext(os.path.splitext(os.path.basename(cabal))[0])[0]
                top = os.path.join(*['..'] * len(os.path.normpath(package).split(os.path.sep)))

                ghc_mk = os.path.join(package, 'ghc.mk')
                if os.path.exists(ghc_mk):
                    print('Skipping %s which already exists' % ghc_mk)
                    continue
                print('Creating %s' % ghc_mk)
                with open(ghc_mk, 'w') as f:
                    f.write(dedent(
                        """\
                        {package}_PACKAGE = {pkg}
                        {package}_dist-install_GROUP = libraries
                        $(if $(filter {dir},$(PACKAGES_STAGE0)),$(eval $(call build-package,{package},dist-boot,0)))
                        $(if $(filter {dir},$(PACKAGES_STAGE1)),$(eval $(call build-package,{package},dist-install,1)))
                        $(if $(filter {dir},$(PACKAGES_STAGE2)),$(eval $(call build-package,{package},dist-install,2)))
                        """.format(package = package,
                                pkg = pkg,
                                dir = dir_)))

                makefile = os.path.join(package, 'GNUmakefile')
                with open(makefile, 'w') as f:
                    f.write(dedent(
                        """\
                        dir = {package}
                        TOP = {top}
                        include $(TOP)/mk/sub-makefile.mk
                        FAST_MAKE_OPTS += stage=0
                        """.format(package = package, top = top)
                    ))


def autoreconf():
    # Run autoreconf on everything that needs it.
    processes = {}
    if os.name == 'nt':
        # Get the normalized ACLOCAL_PATH for Windows
        # This is necessary since on Windows this will be a Windows
        # path, which autoreconf doesn't know doesn't know how to handle.
        ac_local = os.getenv('ACLOCAL_PATH', '')
        ac_local_arg = re.sub(r';', r':', ac_local)
        ac_local_arg = re.sub(r'\\', r'/', ac_local_arg)
        ac_local_arg = re.sub(r'(\w):/', r'/\1/', ac_local_arg)
        reconf_cmd = 'ACLOCAL_PATH=%s autoreconf' % ac_local_arg
    else:
        reconf_cmd = 'autoreconf'

    for dir_ in ['.'] + glob.glob('libraries/*/'):
        if os.path.isfile(os.path.join(dir_, 'configure.ac')):
            print("Booting %s" % dir_)
            processes[dir_] = subprocess.Popen(['sh', '-c', reconf_cmd], cwd=dir_)

    # Wait for all child processes to finish.
    fail = False
    for k,v in processes.items():
        code = v.wait()
        if code != 0:
            print_err('autoreconf in %s failed with exit code %d' % (k, code))
            fail = True

    if fail:
        sys.exit(1)

def check_build_mk():
    if not args.validate and not os.path.isfile("mk/build.mk"):
        print(dedent(
            """
            WARNING: You don't have a mk/build.mk file.

            By default a standard GHC build will be done, which uses optimisation
            and builds the profiling libraries. This will take a long time, so may
            not be what you want if you are developing GHC or the libraries, rather
            than simply building it to use it.

            For information on creating a mk/build.mk file, please see:
                https://gitlab.haskell.org/ghc/ghc/wikis/building/using#build-configuration
            """))

check_boot_packages()
if not args.hadrian:
    boot_pkgs()
autoreconf()
if not args.hadrian:
    check_build_mk()