#!/usr/bin/env python3
# (c) 2014 Taeyeon MORI

import os
import argparse
import subprocess
import hashlib
import contextlib
import sys
import termios
import shutil


system = lambda *a: subprocess.check_call(a)


class Package:
    def __init__(self, x):
        self.fqn = x
        self.repo, self.name = x.split("/")


def parse_args(argv):
    parser = argparse.ArgumentParser(prog=argv[0])

    def add_option(option, default, help=None):
        parser.add_argument(option, default=default)

    def add_switch(option, default=False, help=None):
        parser.add_argument(option, default=default, action="store_const", const=not default)

    parser.add_argument("package", type=Package)

    add_option("-buildroot", "/tmp/abs-%i" % os.getuid())
    add_option("-makepkg", "makepkg")
    
    add_switch("-nobuild")
    add_switch("-install")
    
    return parser.parse_args(argv[1:])


def file_sha1(name):
    with open(name, "rb") as f:
        hash = hashlib.sha1()
        while True:
            data = f.read(2048)
            if not data:
                return hash.digest()
            hash.update(data)


@contextlib.contextmanager
def rawinput(file):
    fd = file.fileno() if hasattr(file, "fileno") else file
    flags = save = termios.tcgetattr(fd)
    flags[3] &= ~termios.ICANON
    flags[6][termios.VMIN] = 1
    flags[6][termios.VTIME] = 0
    termios.tcsetattr(fd, termios.TCSADRAIN, flags)
    yield
    termios.tcsetattr(fd, termios.TCSADRAIN, save)


def yesno(prompt):
    ch = ""
    while ch not in "yYnN":
        sys.stdout.write(prompt)
        sys.stdout.write(" [Y/N] ")
        sys.stdout.flush()
        with rawinput(sys.stdin):
            ch = sys.stdin.read(1)
        sys.stdout.write("\r")
    sys.stdout.write("\n")
    return ch in "yY"


def main(argv):
    args = parse_args(argv)

    print("===> Synchronizing ABS")
    system("sudo", "abs", args.package.fqn)

    print("===> Updating build directory")
    ABS_DIR = os.path.join("/var/abs", args.package.fqn)
    if not os.path.exists(ABS_DIR):
        print("=ERROR=> No such pacakge: %s" % args.package.fqn)
        return 1
    REPODIR = os.path.join(args.buildroot, args.package.repo)
    PACKDIR = os.path.join(REPODIR, args.package.name)
    if not os.path.exists(PACKDIR):
        os.makedirs(PACKDIR)
    for path, dirs, files in os.walk(ABS_DIR):
        rel_path = os.path.relpath(path, ABS_DIR)
        dest_path = os.path.join(PACKDIR, rel_path)
        for dir in dirs:
            dest = os.path.join(dest_path, dir)
            os.path.exists(dest) or os.mkdir(dest)
        for file in files:
            source = os.path.join(path, file)
            dest = os.path.join(dest_path, file)
            (not os.path.exists(dest) or (file_sha1(source) != file_sha1(dest) and yesno("=> Overwrite %s?" % os.path.join(rel_path, file)))) and shutil.copy(source, dest)

    yesno("=> Edit %s PKGBUILD?" % args.package.fqn) and system(os.environ.get("EDITOR", "vim"), os.path.join(PACKDIR, "PKGBUILD"))

    if not args.nobuild:
        print("===> Building Package %s" % args.package.fqn)
        os.chdir(PACKDIR)
        if args.install:
            system(args.makepkg, "-i")
        else:
            system(args.makepkg)
    
    return 0


if __name__ == "__main__":
    sys.exit(main(sys.argv))