import json
import os
import subprocess
import sys

from devbot import config
from devbot import git
from devbot import distro
from devbot import command
from devbot import state
from devbot import utils
from devbot import xvfb


def check_binary(check):
    return subprocess.call(["which", check],
                           stdout=utils.devnull,
                           stderr=subprocess.STDOUT)


def check_pkgconfig(check):
    return subprocess.call(["pkg-config", "--exists", check]) == 1


def check_python(check):
    return subprocess.call(["python", "-c", check],
                           stdout=utils.devnull,
                           stderr=subprocess.STDOUT) == 1


def check_gtkmodule(check):
    # Not sure we can do better than this, the gtkmodule stuff is private
    missing = True

    for libdir in config.system_lib_dirs:
        if os.path.exists("%s/gtk-2.0/modules/lib%s.so" % (libdir, check)):
            missing = False

    return missing


def check_include(check):
    return not os.path.exists(os.path.join("/usr/include/", check))


def check_dbus(check):
    return not os.path.exists("/usr/share/dbus-1/services/%s.service" % check)


def check_metacity_theme(check):
    theme = "/usr/share/themes/%s/metacity-1/metacity-theme-3.xml"
    return not os.path.exists(theme % check)


def check_gstreamer(check, version):
    missing = True

    for libdir in config.system_lib_dirs:
        if os.path.exists("%s/gstreamer-%s/libgst%s.so" %
                          (libdir, version, check)):
            missing = False

    return missing


def check_gstreamer_0_10(check):
    return check_gstreamer(check, "0.10")


def check_gstreamer_1_0(check):
    return check_gstreamer(check, "1.0")

checkers = {"binary": check_binary,
            "python": check_python,
            "pkgconfig": check_pkgconfig,
            "gtkmodule": check_gtkmodule,
            "dbus": check_dbus,
            "gstreamer-0.10": check_gstreamer_0_10,
            "gstreamer-1.0": check_gstreamer_1_0,
            "metacity-theme": check_metacity_theme,
            "include": check_include}


def _print_checks(checks):
    for check in checks:
        print "[%s] %s" % (check["checker"], check["check"])


def _eval_check_if(check):
    if "check_if" not in check:
        return True

    distro_info = distro.get_distro_info()
    globals = {"distro": "%s-%s" % (distro_info.name, distro_info.version)}

    print eval(check["check_if"], globals)

    return eval(check["check_if"], globals) == "True"


def run_checks(package_manager, checks, packages):
    distro_info = distro.get_distro_info()

    failed_checks = []
    packages_not_found = []
    to_install = []

    for check in checks:
        if not _eval_check_if(check):
            continue

        checker = checkers[check["checker"]]
        if checker(check["check"]):
            try:
                packages_for_check = packages[check["name"]][distro_info.name]
            except KeyError:
                packages_for_check = []
                packages_not_found.append(check)

            for package in packages_for_check:
                if package not in to_install:
                    to_install.append(package)

            failed_checks.append(check)

    if distro_info.supported:
        if packages_not_found:
            print "\nPackages not found for"
            _print_checks(packages_not_found)
            return False

        if to_install:
            package_manager.install_packages(to_install)
    elif failed_checks:
        print "Failed checks\n"
        _print_checks(failed_checks)

        if to_install:
            print "\nYou might try to install the following packages\n"
            print " ".join(to_install)

        return False

    return True


def remove_packages(package_manager, packages):
    distro_name = distro.get_distro_info().name

    to_keep = []
    for package_info in packages.values():
        if distro_name in package_info:
            for package in package_info[distro_name]:
                if package not in to_keep:
                    to_keep.append(package)

    try:
        to_keep = package_manager.find_with_deps(to_keep)
    except NotImplementedError:
        return

    all = package_manager.find_all()

    to_remove = []
    for package in all:
        if package not in to_keep:
            to_remove.append(package)

    if to_remove:
        package_manager.remove_packages(to_remove)


def check(remove=False, update=False, test=False, interactive=True,
          skip_if_unchanged=False):
    if skip_if_unchanged:
        if state.system_check_is_unchanged():
            return True

    package_manager = \
        distro.get_package_manager(test=test, interactive=interactive)

    distro.print_distro_info()
    distro_name = distro.get_distro_info().name
    packages = config.load_packages()

    checks = config.load_prerequisites()
    if not run_checks(package_manager, checks, packages):
        return False

    xvfb_proc, orig_display = xvfb.start()

    if not run_checks(package_manager, config.load_checks(), packages):
        return False

    xvfb.stop(xvfb_proc, orig_display)

    print "All the required dependencies are installed."

    if update:
        package_manager.update()

    if remove:
        remove_packages(package_manager, packages)

    state.system_check_touch()

    return True