# (c) Continuum Analytics, Inc. / http://continuum.io
# All Rights Reserved
#
# conda is distributed under the terms of the BSD 3-clause license.
# Consult LICENSE.txt or http://opensource.org/licenses/BSD-3-Clause.

from __future__ import absolute_import, division, print_function

from os.path import join, isdir, abspath, expanduser, exists
import shutil
import sys

from .conda_interface import string_types

from conda_build.post import mk_relative_osx
from conda_build.utils import check_call_env, rec_glob, get_site_packages
from conda_build.os_utils.external import find_executable


def relink_sharedobjects(pkg_path, build_prefix):
    '''
    invokes functions in post module to relink to libraries in conda env

    :param pkg_path: look for shared objects to relink in pkg_path
    :param build_prefix: path to conda environment which contains lib/. to find
        runtime libraries.

    .. note:: develop mode builds the extensions in place and makes a link to
        package in site-packages/. The build_prefix points to conda environment
        since runtime libraries should be loaded from environment's lib/. first
    '''
    # find binaries in package dir and make them relocatable
    bin_files = rec_glob(pkg_path, ['.so'])
    for b_file in bin_files:
        if sys.platform == 'darwin':
            mk_relative_osx(b_file, build_prefix)
        else:
            print("Nothing to do on Linux or Windows.")


def write_to_conda_pth(sp_dir, pkg_path):
    '''
    Append pkg_path to conda.pth in site-packages directory for current
    environment. Only add path if it doens't already exist.

    :param sp_dir: path to site-packages/. directory
    :param pkg_path: the package path to append to site-packes/. dir.
    '''
    c_file = join(sp_dir, 'conda.pth')
    with open(c_file, 'a') as f:
        with open(c_file, 'r') as cf:
            # make sure file exists, before we try to read from it hence nested
            # in append with block
            # expect conda.pth to be small so read it all in at once
            pkgs_in_dev_mode = cf.readlines()

        # only append pkg_path if it doesn't already exist in conda.pth
        if pkg_path + '\n' in pkgs_in_dev_mode:
            print("path exists, skipping " + pkg_path)
        else:
            f.write(pkg_path + '\n')
            print("added " + pkg_path)


def get_setup_py(path_):
    ''' Return full path to setup.py or exit if not found '''
    # build path points to source dir, builds are placed in the
    setup_py = join(path_, 'setup.py')

    if not exists(setup_py):
        sys.exit("No setup.py found in {0}. Exiting.".format(path_))

    return setup_py


def _clean(setup_py):
    '''
    This invokes:
    $ python setup.py clean

    :param setup_py: path to setup.py
    '''
    # first call setup.py clean
    cmd = ['python', setup_py, 'clean']
    check_call_env(cmd)
    print("Completed: " + " ".join(cmd))
    print("===============================================")


def _build_ext(setup_py):
    '''
    Define a develop function - similar to build function
    todo: need to test on win32 and linux

    It invokes:
    $ python setup.py build_ext --inplace

    :param setup_py: path to setup.py
    '''

    # next call setup.py develop
    cmd = ['python', setup_py, 'build_ext', '--inplace']
    check_call_env(cmd)
    print("Completed: " + " ".join(cmd))
    print("===============================================")


def _uninstall(sp_dir, pkg_path):
    '''
    Look for pkg_path in conda.pth file in site-packages directory and remove
    it. If pkg_path is not found in conda.pth, it means package is not
    installed in 'development mode' via conda develop.

    :param sp_dir: path to site-packages/. directory
    :param pkg_path: the package path to be uninstalled.
    '''
    o_c_pth = join(sp_dir, 'conda.pth')
    n_c_pth = join(sp_dir, 'conda.pth.temp')
    found = False
    with open(n_c_pth, 'w') as new_c:
        with open(o_c_pth, 'r') as orig_c:
            for line in orig_c:
                if line != pkg_path + '\n':
                    new_c.write(line)
                else:
                    print("uninstalled: " + pkg_path)
                    found = True

    if not found:
        print("conda.pth does not contain path: " + pkg_path)
        print("package not installed via conda develop")

    shutil.move(n_c_pth, o_c_pth)


def execute(recipe_dirs, prefix=sys.prefix, no_pth_file=False,
            build_ext=False, clean=False, uninstall=False):

    if not isdir(prefix):
        sys.exit("""\
Error: environment does not exist: %s
#
# Use 'conda create' to create the environment first.
#""" % prefix)

    assert find_executable('python', prefix=prefix)

    # current environment's site-packages directory
    sp_dir = get_site_packages(prefix, '.'.join((str(sys.version_info.major),
                                                 str(sys.version_info.minor))))

    if type(recipe_dirs) == string_types:
        recipe_dirs = [recipe_dirs]

    for path in recipe_dirs:
        pkg_path = abspath(expanduser(path))

        if uninstall:
            # uninstall then exit - does not do any other operations
            _uninstall(sp_dir, pkg_path)
            return

        if clean or build_ext:
            setup_py = get_setup_py(pkg_path)
            if clean:
                _clean(setup_py)
                if not build_ext:
                    return

            # build extensions before adding to conda.pth
            if build_ext:
                _build_ext(setup_py)

        if not no_pth_file:
            write_to_conda_pth(sp_dir, pkg_path)

        # go through the source looking for compiled extensions and make sure
        # they use the conda environment for loading libraries at runtime
        relink_sharedobjects(pkg_path, prefix)
        print("completed operation for: " + pkg_path)