"""Build NSIS installers for Python applications.
"""
import errno
import io
import logging
import ntpath
import operator
import os
import re
import shutil
from subprocess import call
import sys
import fnmatch

PY2 = sys.version_info[0] == 2

if os.name == 'nt':
    if PY2:
        import _winreg as winreg
    else:
        import winreg
else:
    winreg = None

from .copymodules import copy_modules
from .nsiswriter import NSISFileWriter
from .util import download, text_types

__version__ = '1.0'

pjoin = os.path.join
logger = logging.getLogger(__name__)

_PKGDIR = os.path.abspath(os.path.dirname(__file__))
DEFAULT_PY_VERSION = '2.7.8' if PY2 else '3.4.2'
DEFAULT_BUILD_DIR = pjoin('build', 'nsis')
DEFAULT_NSI_TEMPLATE = pjoin(_PKGDIR, 'template.nsi')
DEFAULT_ICON = pjoin(_PKGDIR, 'glossyorb.ico')
if os.name == 'nt' and sys.maxsize == (2**63)-1:
    DEFAULT_BITNESS = 64
else:
    DEFAULT_BITNESS = 32

def find_makensis_win():
    """Locate makensis.exe on Windows by querying the registry"""
    try:
        nsis_install_dir = winreg.QueryValue(winreg.HKEY_LOCAL_MACHINE, 'SOFTWARE\\NSIS')
    except OSError:
        nsis_install_dir = winreg.QueryValue(winreg.HKEY_LOCAL_MACHINE, 'SOFTWARE\\Wow6432Node\\NSIS')

    return pjoin(nsis_install_dir, 'makensis.exe')

class InputError(ValueError):
    def __init__(self, param, value, expected):
        self.param = param
        self.value = value
        self.expected = expected

    def __str__(self):
        return "{e.value!r} is not valid for {e.param}, expected {e.expected}".format(e=self)

class InstallerBuilder(object):
    """Controls building an installer. This includes three main steps:
    
    1. Arranging the necessary files in the build directory.
    2. Filling out the template NSI file to control NSIS.
    3. Running ``makensis`` to build the installer.
    
    :param str appname: Application name
    :param str version: Application version
    :param list shortcuts: List of dictionaries, with keys matching
            :ref:`shortcut_config` in the config file
    :param str icon: Path to an icon for the application
    :param list packages: List of strings for importable packages to include
    :param list extra_files: List of 2-tuples (file, destination) of files to include
    :param str py_version: Full version of Python to bundle
    :param int py_bitness: Bitness of bundled Python (32 or 64)
    :param str build_dir: Directory to run the build in
    :param str installer_name: Filename of the installer to produce
    :param str nsi_template: Path to a template NSI file to use
    """
    def __init__(self, appname, version, shortcuts, icon=DEFAULT_ICON,
                packages=None, extra_files=None, py_version=DEFAULT_PY_VERSION,
                py_bitness=DEFAULT_BITNESS, build_dir=DEFAULT_BUILD_DIR,
                installer_name=None, nsi_template=DEFAULT_NSI_TEMPLATE,
                exclude=None):
        self.appname = appname
        self.version = version
        self.shortcuts = shortcuts
        self.icon = icon
        self.packages = packages or []
        self.exclude = exclude or []
        self.extra_files = extra_files or []
        self.py_version = py_version
        if not self._py_version_pattern.match(py_version):
            raise InputError('py_version', py_version, "a full Python version like '3.4.0'")
        self.py_bitness = py_bitness
        if py_bitness not in {32, 64}:
            raise InputError('py_bitness', py_bitness, "32 or 64")
        self.build_dir = build_dir
        self.installer_name = installer_name or self.make_installer_name()
        self.nsi_template = nsi_template
        self.nsi_file = pjoin(self.build_dir, 'installer.nsi')
        self.py_major_version = self.py_qualifier = '.'.join(self.py_version.split('.')[:2])
        if self.py_bitness == 32:
            self.py_qualifier += '-32'
        
        # To be filled later
        self.install_files = []
        self.install_dirs = []
    
    _py_version_pattern = re.compile(r'\d\.\d+\.\d+$')

    def make_installer_name(self):
        """Generate the filename of the installer exe
        
        e.g. My_App_1.0.exe
        """
        s = self.appname + '_' + self.version + '.exe'
        return s.replace(' ', '_')

    def fetch_python(self):
        """Fetch the MSI for the specified version of Python.
        
        It will be placed in the build directory.
        if possible.
        """
        version = self.py_version
        arch_tag = '.amd64' if (self.py_bitness==64) else ''
        url = 'https://python.org/ftp/python/{0}/python-{0}{1}.msi'.format(version, arch_tag)
        target = pjoin(self.build_dir, 'python-{0}{1}.msi'.format(version, arch_tag))
        if os.path.isfile(target):
            logger.info('Python MSI already in build directory.')
            return
        logger.info('Downloading Python MSI...')
        download(url, target)

    def fetch_pylauncher(self):
        """Fetch the MSI for PyLauncher (required for Python2.x).
    
        It will be placed in the build directory.
        """
        arch_tag = '.amd64' if (self.py_bitness == 64) else ''
        url = ("https://bitbucket.org/vinay.sajip/pylauncher/downloads/"
               "launchwin{0}.msi".format(arch_tag))
        target = pjoin(self.build_dir, 'launchwin{0}.msi'.format(arch_tag))
        if os.path.isfile(target):
            logger.info('PyLauncher MSI already in build directory.')
            return
        logger.info('Downloading PyLauncher MSI...')
        download(url, target)

    SCRIPT_TEMPLATE = """#!python{qualifier}
import sys, os
scriptdir, script = os.path.split(__file__)
pkgdir = os.path.join(scriptdir, 'pkgs')
sys.path.insert(0, pkgdir)
os.environ['PYTHONPATH'] = pkgdir + os.pathsep + os.environ.get('PYTHONPATH', '')

appdata = os.environ.get('APPDATA', None)
def excepthook(etype, value, tb):
    "Write unhandled exceptions to a file rather than exiting silently."
    import traceback
    with open(os.path.join(appdata, script+'.log'), 'w') as f:
        traceback.print_exception(etype, value, tb, file=f)

if appdata:
    sys.excepthook = excepthook

{extra_preamble}

if __name__ == '__main__':
    from {module} import {func}
    {func}()
"""
    
    def write_script(self, entrypt, target, extra_preamble=''):
        """Write a launcher script from a 'module:function' entry point
        
        python_version and bitness are used to write an appropriate shebang line
        for the PEP 397 Windows launcher.
        """
        module, func = entrypt.split(":")
        with open(target, 'w') as f:
            f.write(self.SCRIPT_TEMPLATE.format(qualifier=self.py_qualifier,
                    module=module, func=func, extra_preamble=extra_preamble))

        pkg = module.split('.')[0]
        if pkg not in self.packages:
            self.packages.append(pkg)

    def prepare_shortcuts(self):
        """Prepare shortcut files in the build directory.
        
        If entry_point is specified, write the script. If script is specified,
        copy to the build directory. Prepare target and parameters for these
        shortcuts.
        
        Also copies shortcut icons
        """
        files = set()
        for scname, sc in self.shortcuts.items():
            if not sc.get('target'):
                if sc.get('entry_point'):
                    sc['script'] = script = scname.replace(' ', '_') + '.launch.py' \
                                                + ('' if sc['console'] else 'w')

                    specified_preamble = sc.get('extra_preamble', None)
                    if isinstance(specified_preamble, text_types):
                        # Filename
                        extra_preamble = io.open(specified_preamble, encoding='utf-8')
                    elif specified_preamble is None:
                        extra_preamble = io.StringIO()  # Empty
                    else:
                        # Passed a StringIO or similar object
                        extra_preamble = specified_preamble

                    self.write_script(sc['entry_point'], pjoin(self.build_dir, script),
                                      extra_preamble.read().rstrip())
                else:
                    shutil.copy2(sc['script'], self.build_dir)

                sc['target'] = 'py' if sc['console'] else 'pyw'
                sc['parameters'] = '"%s"' % ntpath.join('$INSTDIR', sc['script'])
                files.add(os.path.basename(sc['script']))

            shutil.copy2(sc['icon'], self.build_dir)
            sc['icon'] = os.path.basename(sc['icon'])
            files.add(sc['icon'])
    
        self.install_files.extend([(f, '$INSTDIR') for f in files])
    
    def prepare_packages(self):
        """Move requested packages into the build directory.
        
        If a pynsist_pkgs directory exists, it is copied into the build
        directory as pkgs/ . Any packages not already there are found on
        sys.path and copied in.
        """
        logger.info("Copying packages into build directory...")
        build_pkg_dir = pjoin(self.build_dir, 'pkgs')
        if os.path.isdir(build_pkg_dir):
            shutil.rmtree(build_pkg_dir)
        if os.path.isdir('pynsist_pkgs'):
            shutil.copytree('pynsist_pkgs', build_pkg_dir)
        else:
            os.mkdir(build_pkg_dir)
        copy_modules(self.packages, build_pkg_dir,
                     py_version=self.py_version, exclude=self.exclude)

    def copytree_ignore_callback(self, directory, files):
        """This is being called back by our shutil.copytree call to implement the
        'exclude' feature.
        """
        ignored = set()

        # Filter by file names relative to the build directory
        files = [os.path.join(directory, fname) for fname in files]

        # Execute all patterns
        for pattern in self.exclude:
            ignored.update([
                os.path.basename(fname)
                for fname in fnmatch.filter(files, pattern)
            ])
        return ignored

    def copy_extra_files(self):
        """Copy a list of files into the build directory, and add them to
        install_files or install_dirs as appropriate.
        """
        for file, destination in self.extra_files:
            file = file.rstrip('/\\')
            basename = os.path.basename(file)

            if not destination:
                destination = '$INSTDIR'

            if os.path.isdir(file):
                target_name = pjoin(self.build_dir, basename)
                if os.path.isdir(target_name):
                    shutil.rmtree(target_name)
                elif os.path.exists(target_name):
                    os.unlink(target_name)
                if self.exclude:
                    shutil.copytree(file, target_name,
                                    ignore=self.copytree_ignore_callback)
                else:
                    # Don't use our exclude callback if we don't need to,
                    # as it slows things down.
                    shutil.copytree(file, target_name)
                self.install_dirs.append((basename, destination))
            else:
                shutil.copy2(file, self.build_dir)
                self.install_files.append((basename, destination))

    def write_nsi(self):
        """Write the NSI file to define the NSIS installer.

        Most of the details of this are in the template and the
        :class:`nsist.nsiswriter.NSISFileWriter` class.
        """
        nsis_writer = NSISFileWriter(self.nsi_template, installerbuilder=self,
            definitions = {'PRODUCT_NAME': self.appname,
                           'PRODUCT_VERSION': self.version,
                           'PY_VERSION': self.py_version,  # e.g. 3.4.1
                           'PY_MAJOR_VERSION': self.py_major_version,  #e.g. 3.4
                           'PY_QUALIFIER': self.py_qualifier,
                           'BITNESS' : str(self.py_bitness),
                           'PRODUCT_ICON': os.path.basename(self.icon),
                           'INSTALLER_NAME': self.installer_name,
                           'ARCH_TAG': '.amd64' if (self.py_bitness==64) else '',
                          },
            )

        logger.info('Writing NSI file to %s', self.nsi_file)
        # Sort by destination directory, so we can group them effectively
        self.install_files.sort(key=operator.itemgetter(1))
        nsis_writer.write(self.nsi_file)    

    def run_nsis(self):
        """Runs makensis using the specified .nsi file
        
        Returns the exit code.
        """
        try:
            if os.name == 'nt':
                makensis = find_makensis_win()
            else:
                makensis = 'makensis'
            return call([makensis, self.nsi_file])
        except OSError as e:
            # This should catch either the registry key or makensis being absent
            if e.errno == errno.ENOENT:
                print("makensis was not found. Install NSIS and try again.")
                print("http://nsis.sourceforge.net/Download")
                return 1

    def run(self):
        """Run all the steps to build an installer.
        """
        try:
            os.makedirs(self.build_dir)
        except OSError as e:
            if e.errno != errno.EEXIST:
                raise e
        self.fetch_python()
        if self.py_version < '3.3':
            self.fetch_pylauncher()
        
        self.prepare_shortcuts()
        
        # Packages
        self.prepare_packages()
        
        # Extra files
        self.copy_extra_files()

        self.write_nsi()
    
        exitcode = self.run_nsis()
        
        if not exitcode:
            logger.info('Installer written to %s', pjoin(self.build_dir, self.installer_name))

def main(argv=None):
    """Make an installer from the command line.
    
    This parses command line arguments and a config file, and calls
    :func:`all_steps` with the extracted information.
    """
    logger.setLevel(logging.INFO)
    logger.handlers = [logging.StreamHandler()]
    
    import argparse
    argp = argparse.ArgumentParser(prog='pynsist')
    argp.add_argument('config_file')
    options = argp.parse_args(argv)
    
    dirname, config_file = os.path.split(options.config_file)
    if dirname:
        os.chdir(dirname)
    
    try:
        from . import configreader
        cfg = configreader.read_and_validate(config_file)
        shortcuts = configreader.read_shortcuts_config(cfg)
    except configreader.InvalidConfig as e:
        logger.error('Error parsing configuration file:')
        logger.error(str(e))
        sys.exit(1)
    appcfg = cfg['Application']

    try:
        InstallerBuilder(
            appname = appcfg['name'],
            version = appcfg['version'],
            icon = appcfg.get('icon', DEFAULT_ICON),
            shortcuts = shortcuts,
            packages = cfg.get('Include', 'packages', fallback='').splitlines(),
            extra_files = configreader.read_extra_files(cfg),
            py_version = cfg.get('Python', 'version', fallback=DEFAULT_PY_VERSION),
            py_bitness = cfg.getint('Python', 'bitness', fallback=DEFAULT_BITNESS),
            build_dir = cfg.get('Build', 'directory', fallback=DEFAULT_BUILD_DIR),
            installer_name = cfg.get('Build', 'installer_name', fallback=None),
            nsi_template = cfg.get('Build', 'nsi_template', fallback=DEFAULT_NSI_TEMPLATE),
            exclude = cfg.get('Include', 'exclude', fallback='').splitlines(),
        ).run()
    except InputError as e:
        logger.error("Error in config values:")
        logger.error(str(e))
        sys.exit(1)