"""Build pure Python modules (just copy to build directory)."""

import os
import sys
from glob import glob

from packaging import logger
from packaging.command.cmd import Command
from packaging.errors import PackagingOptionError, PackagingFileError
from packaging.util import convert_path
from packaging.compat import Mixin2to3

# marking public APIs
__all__ = ['build_py']

class build_py(Command, Mixin2to3):

    description = "build pure Python modules (copy to build directory)"

    user_options = [
        ('build-lib=', 'd', "directory to build (copy) to"),
        ('compile', 'c', "compile .py to .pyc"),
        ('no-compile', None, "don't compile .py files [default]"),
        ('optimize=', 'O',
         "also compile with optimization: -O1 for \"python -O\", "
         "-O2 for \"python -OO\", and -O0 to disable [default: -O0]"),
        ('force', 'f', "forcibly build everything (ignore file timestamps)"),
        ('use-2to3', None,
         "use 2to3 to make source python 3.x compatible"),
        ('convert-2to3-doctests', None,
         "use 2to3 to convert doctests in seperate text files"),
        ('use-2to3-fixers', None,
         "list additional fixers opted for during 2to3 conversion"),
        ]

    boolean_options = ['compile', 'force']
    negative_opt = {'no-compile' : 'compile'}

    def initialize_options(self):
        self.build_lib = None
        self.py_modules = None
        self.package = None
        self.package_data = None
        self.package_dir = None
        self.compile = False
        self.optimize = 0
        self.force = None
        self._updated_files = []
        self._doctests_2to3 = []
        self.use_2to3 = False
        self.convert_2to3_doctests = None
        self.use_2to3_fixers = None

    def finalize_options(self):
        self.set_undefined_options('build',
                                   'use_2to3', 'use_2to3_fixers',
                                   'convert_2to3_doctests', 'build_lib',
                                   'force')

        # Get the distribution options that are aliases for build_py
        # options -- list of packages and list of modules.
        self.packages = self.distribution.packages
        self.py_modules = self.distribution.py_modules
        self.package_data = self.distribution.package_data
        self.package_dir = None
        if self.distribution.package_dir is not None:
            self.package_dir = convert_path(self.distribution.package_dir)
        self.data_files = self.get_data_files()

        # Ick, copied straight from install_lib.py (fancy_getopt needs a
        # type system!  Hell, *everything* needs a type system!!!)
        if not isinstance(self.optimize, int):
            try:
                self.optimize = int(self.optimize)
                assert 0 <= self.optimize <= 2
            except (ValueError, AssertionError):
                raise PackagingOptionError("optimize must be 0, 1, or 2")

    def run(self):
        # XXX copy_file by default preserves atime and mtime.  IMHO this is
        # the right thing to do, but perhaps it should be an option -- in
        # particular, a site administrator might want installed files to
        # reflect the time of installation rather than the last
        # modification time before the installed release.

        # XXX copy_file by default preserves mode, which appears to be the
        # wrong thing to do: if a file is read-only in the working
        # directory, we want it to be installed read/write so that the next
        # installation of the same module distribution can overwrite it
        # without problems.  (This might be a Unix-specific issue.)  Thus
        # we turn off 'preserve_mode' when copying to the build directory,
        # since the build directory is supposed to be exactly what the
        # installation will look like (ie. we preserve mode when
        # installing).

        # Two options control which modules will be installed: 'packages'
        # and 'py_modules'.  The former lets us work with whole packages, not
        # specifying individual modules at all; the latter is for
        # specifying modules one-at-a-time.

        if self.py_modules:
            self.build_modules()
        if self.packages:
            self.build_packages()
            self.build_package_data()

        if self.use_2to3 and self._updated_files:
            self.run_2to3(self._updated_files, self._doctests_2to3,
                                            self.use_2to3_fixers)

        self.byte_compile(self.get_outputs(include_bytecode=False))

    # -- Top-level worker functions ------------------------------------

    def get_data_files(self):
        """Generate list of '(package,src_dir,build_dir,filenames)' tuples.

        Helper function for `finalize_options()`.
        """
        data = []
        if not self.packages:
            return data
        for package in self.packages:
            # Locate package source directory
            src_dir = self.get_package_dir(package)

            # Compute package build directory
            build_dir = os.path.join(*([self.build_lib] + package.split('.')))

            # Length of path to strip from found files
            plen = 0
            if src_dir:
                plen = len(src_dir)+1

            # Strip directory from globbed filenames
            filenames = [
                file[plen:] for file in self.find_data_files(package, src_dir)
                ]
            data.append((package, src_dir, build_dir, filenames))
        return data

    def find_data_files(self, package, src_dir):
        """Return filenames for package's data files in 'src_dir'.

        Helper function for `get_data_files()`.
        """
        globs = (self.package_data.get('', [])
                 + self.package_data.get(package, []))
        files = []
        for pattern in globs:
            # Each pattern has to be converted to a platform-specific path
            filelist = glob(os.path.join(src_dir, convert_path(pattern)))
            # Files that match more than one pattern are only added once
            files.extend(fn for fn in filelist if fn not in files)
        return files

    def build_package_data(self):
        """Copy data files into build directory.

        Helper function for `run()`.
        """
        # FIXME add tests for this method
        for package, src_dir, build_dir, filenames in self.data_files:
            for filename in filenames:
                target = os.path.join(build_dir, filename)
                srcfile = os.path.join(src_dir, filename)
                self.mkpath(os.path.dirname(target))
                outf, copied = self.copy_file(srcfile,
                               target, preserve_mode=False)
                if copied and srcfile in self.distribution.convert_2to3.doctests:
                    self._doctests_2to3.append(outf)

    # XXX - this should be moved to the Distribution class as it is not
    # only needed for build_py. It also has no dependencies on this class.
    def get_package_dir(self, package):
        """Return the directory, relative to the top of the source
           distribution, where package 'package' should be found
           (at least according to the 'package_dir' option, if any)."""

        path = package.split('.')
        if self.package_dir is not None:
            path.insert(0, self.package_dir)

        if len(path) > 0:
            return os.path.join(*path)

        return ''

    def check_package(self, package, package_dir):
        """Helper function for `find_package_modules()` and `find_modules()'.
        """
        # Empty dir name means current directory, which we can probably
        # assume exists.  Also, os.path.exists and isdir don't know about
        # my "empty string means current dir" convention, so we have to
        # circumvent them.
        if package_dir != "":
            if not os.path.exists(package_dir):
                raise PackagingFileError(
                      "package directory '%s' does not exist" % package_dir)
            if not os.path.isdir(package_dir):
                raise PackagingFileError(
                       "supposed package directory '%s' exists, "
                       "but is not a directory" % package_dir)

        # Require __init__.py for all but the "root package"
        if package:
            init_py = os.path.join(package_dir, "__init__.py")
            if os.path.isfile(init_py):
                return init_py
            else:
                logger.warning(("package init file '%s' not found " +
                                "(or not a regular file)"), init_py)

        # Either not in a package at all (__init__.py not expected), or
        # __init__.py doesn't exist -- so don't return the filename.
        return None

    def check_module(self, module, module_file):
        if not os.path.isfile(module_file):
            logger.warning("file %s (for module %s) not found",
                           module_file, module)
            return False
        else:
            return True

    def find_package_modules(self, package, package_dir):
        self.check_package(package, package_dir)
        module_files = glob(os.path.join(package_dir, "*.py"))
        modules = []
        if self.distribution.script_name is not None:
            setup_script = os.path.abspath(self.distribution.script_name)
        else:
            setup_script = None

        for f in module_files:
            abs_f = os.path.abspath(f)
            if abs_f != setup_script:
                module = os.path.splitext(os.path.basename(f))[0]
                modules.append((package, module, f))
            else:
                logger.debug("excluding %s", setup_script)
        return modules

    def find_modules(self):
        """Finds individually-specified Python modules, ie. those listed by
        module name in 'self.py_modules'.  Returns a list of tuples (package,
        module_base, filename): 'package' is a tuple of the path through
        package-space to the module; 'module_base' is the bare (no
        packages, no dots) module name, and 'filename' is the path to the
        ".py" file (relative to the distribution root) that implements the
        module.
        """
        # Map package names to tuples of useful info about the package:
        #    (package_dir, checked)
        # package_dir - the directory where we'll find source files for
        #   this package
        # checked - true if we have checked that the package directory
        #   is valid (exists, contains __init__.py, ... ?)
        packages = {}

        # List of (package, module, filename) tuples to return
        modules = []

        # We treat modules-in-packages almost the same as toplevel modules,
        # just the "package" for a toplevel is empty (either an empty
        # string or empty list, depending on context).  Differences:
        #   - don't check for __init__.py in directory for empty package
        for module in self.py_modules:
            path = module.split('.')
            package = '.'.join(path[0:-1])
            module_base = path[-1]

            try:
                package_dir, checked = packages[package]
            except KeyError:
                package_dir = self.get_package_dir(package)
                checked = False

            if not checked:
                init_py = self.check_package(package, package_dir)
                packages[package] = (package_dir, 1)
                if init_py:
                    modules.append((package, "__init__", init_py))

            # XXX perhaps we should also check for just .pyc files
            # (so greedy closed-source bastards can distribute Python
            # modules too)
            module_file = os.path.join(package_dir, module_base + ".py")
            if not self.check_module(module, module_file):
                continue

            modules.append((package, module_base, module_file))

        return modules

    def find_all_modules(self):
        """Compute the list of all modules that will be built, whether
        they are specified one-module-at-a-time ('self.py_modules') or
        by whole packages ('self.packages').  Return a list of tuples
        (package, module, module_file), just like 'find_modules()' and
        'find_package_modules()' do."""
        modules = []
        if self.py_modules:
            modules.extend(self.find_modules())
        if self.packages:
            for package in self.packages:
                package_dir = self.get_package_dir(package)
                m = self.find_package_modules(package, package_dir)
                modules.extend(m)
        return modules

    def get_source_files(self):
        sources = [module[-1] for module in self.find_all_modules()]
        sources += [
            os.path.join(src_dir, filename)
            for package, src_dir, build_dir, filenames in self.data_files
            for filename in filenames]
        return sources

    def get_module_outfile(self, build_dir, package, module):
        outfile_path = [build_dir] + list(package) + [module + ".py"]
        return os.path.join(*outfile_path)

    def get_outputs(self, include_bytecode=True):
        modules = self.find_all_modules()
        outputs = []
        for package, module, module_file in modules:
            package = package.split('.')
            filename = self.get_module_outfile(self.build_lib, package, module)
            outputs.append(filename)
            if include_bytecode:
                if self.compile:
                    outputs.append(filename + "c")
                if self.optimize > 0:
                    outputs.append(filename + "o")

        outputs += [
            os.path.join(build_dir, filename)
            for package, src_dir, build_dir, filenames in self.data_files
            for filename in filenames]

        return outputs

    def build_module(self, module, module_file, package):
        if isinstance(package, str):
            package = package.split('.')
        elif not isinstance(package, (list, tuple)):
            raise TypeError(
                  "'package' must be a string (dot-separated), list, or tuple")

        # Now put the module source file into the "build" area -- this is
        # easy, we just copy it somewhere under self.build_lib (the build
        # directory for Python source).
        outfile = self.get_module_outfile(self.build_lib, package, module)
        dir = os.path.dirname(outfile)
        self.mkpath(dir)
        return self.copy_file(module_file, outfile, preserve_mode=False)

    def build_modules(self):
        modules = self.find_modules()
        for package, module, module_file in modules:

            # Now "build" the module -- ie. copy the source file to
            # self.build_lib (the build directory for Python source).
            # (Actually, it gets copied to the directory for this package
            # under self.build_lib.)
            self.build_module(module, module_file, package)

    def build_packages(self):
        for package in self.packages:

            # Get list of (package, module, module_file) tuples based on
            # scanning the package directory.  'package' is only included
            # in the tuple so that 'find_modules()' and
            # 'find_package_tuples()' have a consistent interface; it's
            # ignored here (apart from a sanity check).  Also, 'module' is
            # the *unqualified* module name (ie. no dots, no package -- we
            # already know its package!), and 'module_file' is the path to
            # the .py file, relative to the current directory
            # (ie. including 'package_dir').
            package_dir = self.get_package_dir(package)
            modules = self.find_package_modules(package, package_dir)

            # Now loop over the modules we found, "building" each one (just
            # copy it to self.build_lib).
            for package_, module, module_file in modules:
                assert package == package_
                self.build_module(module, module_file, package)

    def byte_compile(self, files):
        if hasattr(sys, 'dont_write_bytecode') and sys.dont_write_bytecode:
            logger.warning('%s: byte-compiling is disabled, skipping.',
                           self.get_command_name())
            return

        from packaging.util import byte_compile  # FIXME use compileall
        prefix = self.build_lib
        if prefix[-1] != os.sep:
            prefix = prefix + os.sep

        # XXX this code is essentially the same as the 'byte_compile()
        # method of the "install_lib" command, except for the determination
        # of the 'prefix' string.  Hmmm.

        if self.compile:
            byte_compile(files, optimize=0,
                         force=self.force, prefix=prefix, dry_run=self.dry_run)
        if self.optimize > 0:
            byte_compile(files, optimize=self.optimize,
                         force=self.force, prefix=prefix, dry_run=self.dry_run)