"""Install all modules (extensions and pure Python)."""

import os
import imp

from packaging import logger
from packaging.command.cmd import Command
from packaging.errors import PackagingOptionError


# Extension for Python source files.
# XXX dead code?  most of the codebase checks for literal '.py'
if hasattr(os, 'extsep'):
    PYTHON_SOURCE_EXTENSION = os.extsep + "py"
else:
    PYTHON_SOURCE_EXTENSION = ".py"


class install_lib(Command):

    description = "install all modules (extensions and pure Python)"

    # The options for controlling byte compilation are two independent sets:
    # 'compile' is strictly boolean, and only decides whether to
    # generate .pyc files.  'optimize' is three-way (0, 1, or 2), and
    # decides both whether to generate .pyo files and what level of
    # optimization to use.

    user_options = [
        ('install-dir=', 'd', "directory to install to"),
        ('build-dir=', 'b', "build directory (where to install from)"),
        ('force', 'f', "force installation (overwrite existing files)"),
        ('compile', 'c', "compile .py to .pyc [default]"),
        ('no-compile', None, "don't compile .py files"),
        ('optimize=', 'O',
         "also compile with optimization: -O1 for \"python -O\", "
         "-O2 for \"python -OO\", and -O0 to disable [default: -O0]"),
        ('skip-build', None, "skip the build steps"),
        ]

    boolean_options = ['force', 'compile', 'skip-build']

    negative_opt = {'no-compile': 'compile'}

    def initialize_options(self):
        # let the 'install_dist' command dictate our installation directory
        self.install_dir = None
        self.build_dir = None
        self.force = False
        self.compile = None
        self.optimize = None
        self.skip_build = None

    def finalize_options(self):
        # Get all the information we need to install pure Python modules
        # from the umbrella 'install_dist' command -- build (source) directory,
        # install (target) directory, and whether to compile .py files.
        self.set_undefined_options('install_dist',
                                   ('build_lib', 'build_dir'),
                                   ('install_lib', 'install_dir'),
                                   'force', 'compile', 'optimize',
                                   'skip_build')

        if self.compile is None:
            self.compile = True
        if self.optimize is None:
            self.optimize = 0

        if not isinstance(self.optimize, int):
            try:
                self.optimize = int(self.optimize)
                if self.optimize not in (0, 1, 2):
                    raise AssertionError
            except (ValueError, AssertionError):
                raise PackagingOptionError("optimize must be 0, 1, or 2")

    def run(self):
        # Make sure we have built everything we need first
        self.build()

        # Install everything: simply dump the entire contents of the build
        # directory to the installation directory (that's the beauty of
        # having a build directory!)
        outfiles = self.install()

        # (Optionally) compile .py to .pyc and/or .pyo
        if outfiles is not None and self.distribution.has_pure_modules():
            # XXX comment from distutils: "This [prefix stripping] is far from
            # complete, but it should at least generate usable bytecode in RPM
            # distributions." -> need to find exact requirements for
            # byte-compiled files and fix it
            install_root = self.get_finalized_command('install_dist').root
            self.byte_compile(outfiles, prefix=install_root)

    # -- Top-level worker functions ------------------------------------
    # (called from 'run()')

    def build(self):
        if not self.skip_build:
            if self.distribution.has_pure_modules():
                self.run_command('build_py')
            if self.distribution.has_ext_modules():
                self.run_command('build_ext')

    def install(self):
        if os.path.isdir(self.build_dir):
            outfiles = self.copy_tree(self.build_dir, self.install_dir)
        else:
            logger.warning(
                '%s: %r does not exist -- no Python modules to install',
                self.get_command_name(), self.build_dir)
            return
        return outfiles

    # -- Utility methods -----------------------------------------------

    def _mutate_outputs(self, has_any, build_cmd, cmd_option, output_dir):
        if not has_any:
            return []

        build_cmd = self.get_finalized_command(build_cmd)
        build_files = build_cmd.get_outputs()
        build_dir = getattr(build_cmd, cmd_option)

        prefix_len = len(build_dir) + len(os.sep)
        outputs = []
        for file in build_files:
            outputs.append(os.path.join(output_dir, file[prefix_len:]))

        return outputs

    def _bytecode_filenames(self, py_filenames):
        bytecode_files = []
        for py_file in py_filenames:
            # Since build_py handles package data installation, the
            # list of outputs can contain more than just .py files.
            # Make sure we only report bytecode for the .py files.
            ext = os.path.splitext(os.path.normcase(py_file))[1]
            if ext != PYTHON_SOURCE_EXTENSION:
                continue
            if self.compile:
                bytecode_files.append(imp.cache_from_source(py_file, True))
            if self.optimize:
                bytecode_files.append(imp.cache_from_source(py_file, False))

        return bytecode_files

    # -- External interface --------------------------------------------
    # (called by outsiders)

    def get_outputs(self):
        """Return the list of files that would be installed if this command
        were actually run.  Not affected by the "dry-run" flag or whether
        modules have actually been built yet.
        """
        pure_outputs = \
            self._mutate_outputs(self.distribution.has_pure_modules(),
                                 'build_py', 'build_lib',
                                 self.install_dir)
        if self.compile:
            bytecode_outputs = self._bytecode_filenames(pure_outputs)
        else:
            bytecode_outputs = []

        ext_outputs = \
            self._mutate_outputs(self.distribution.has_ext_modules(),
                                 'build_ext', 'build_lib',
                                 self.install_dir)

        return pure_outputs + bytecode_outputs + ext_outputs

    def get_inputs(self):
        """Get the list of files that are input to this command, ie. the
        files that get installed as they are named in the build tree.
        The files in this list correspond one-to-one to the output
        filenames returned by 'get_outputs()'.
        """
        inputs = []

        if self.distribution.has_pure_modules():
            build_py = self.get_finalized_command('build_py')
            inputs.extend(build_py.get_outputs())

        if self.distribution.has_ext_modules():
            build_ext = self.get_finalized_command('build_ext')
            inputs.extend(build_ext.get_outputs())

        return inputs