#!/usr/bin/env fuchsia-vendored-python
# Copyright 2017 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import argparse
import errno
import json
import os
import shutil
import sys


def make_dir(path, is_dir=False):
    """Creates the directory at `path`."""
    target = path if is_dir else os.path.dirname(path)
    try:
        os.makedirs(target)
    except OSError as exception:
        if exception.errno == errno.EEXIST and os.path.isdir(target):
            pass
        else:
            raise


def force_symlink(target_path, link_path):
    target_path = os.path.relpath(target_path, os.path.dirname(link_path))
    try:
        os.symlink(target_path, link_path)
    except OSError as e:
        if e.errno == errno.EEXIST:
            os.remove(link_path)
            os.symlink(target_path, link_path)
        else:
            raise


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "--out-dir",
        help="Path to the directory where to install the SDK",
        required=True,
    )
    parser.add_argument(
        "--stamp-file", help="Path to the victory file", required=True
    )
    parser.add_argument(
        "--manifest", help="Path to the SDK's manifest file", required=True
    )
    parser.add_argument("--depfile", help="Path to depfile", required=True)
    args = parser.parse_args()

    # Remove any existing outputs. Manually removing all subdirectories and
    # files instead of using shutil.rmtree, to avoid registering spurious reads
    # on stale subdirectories.
    if os.path.exists(args.out_dir):
        for root, dirs, files in os.walk(args.out_dir, topdown=False):
            for file in files:
                os.unlink(os.path.join(root, file))
            for dir in dirs:
                os.rmdir(os.path.join(root, dir))

    with open(args.manifest, "r") as manifest_file:
        mappings = [l.strip().split("=", 1) for l in manifest_file.readlines()]

    sources, destinations = [], []
    for dest, source in mappings:
        destination = os.path.join(args.out_dir, dest)
        make_dir(destination)
        force_symlink(source, destination)
        # Relative path required in depfile.
        sources.append(os.path.relpath(source))
        destinations.append(destination)

    with open(args.stamp_file, "w") as stamp_file:
        stamp_file.write("Now go use it\n")

    with open(args.depfile, "w") as depfile:
        depfile.write(
            "{} {}: {}\n".format(
                args.stamp_file, " ".join(destinations), " ".join(sources)
            )
        )


if __name__ == "__main__":
    sys.exit(main())