# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

import os
import subprocess

import buildconfig
import mozpack.path as mozpath
import toml


# Try to read the package name or otherwise assume same name as the crate path.
def _get_crate_name(crate_path):
    try:
        with open(mozpath.join(crate_path, "Cargo.toml"), encoding="utf-8") as f:
            return toml.load(f)["package"]["name"]
    except Exception:
        return mozpath.basename(crate_path)


CARGO_LOCK = mozpath.join(buildconfig.topsrcdir, "Cargo.lock")
CARGO_TOML = mozpath.join(buildconfig.topsrcdir, "Cargo.toml")


def _run_process(args):
    env = os.environ.copy()
    env["CARGO"] = str(buildconfig.substs["CARGO"])
    env["RUSTC"] = str(buildconfig.substs["RUSTC"])

    p = subprocess.Popen(
        args, env=env, stdout=subprocess.PIPE, stderr=subprocess.PIPE, encoding="utf-8"
    )

    stdout, stderr = p.communicate()
    if p.returncode != 0:
        print(stdout)
        print(stderr)
    return (stdout, p.returncode)


def generate_metadata(output, cargo_config):
    args = [
        buildconfig.substs["CARGO"],
        "metadata",
        "--all-features",
        "--format-version",
        "1",
        "--manifest-path",
        CARGO_TOML,
    ]

    # The Spidermonkey library can be built from a package tarball outside the
    # tree, so we want to let Cargo create lock files in this case. When built
    # within a tree, the Rust dependencies have been vendored in so Cargo won't
    # touch the lock file.
    if not buildconfig.substs.get("JS_STANDALONE"):
        args.append("--frozen")

    stdout, returncode = _run_process(args)

    if returncode != 0:
        return returncode

    if stdout:
        output.write(stdout)

    # This is not quite accurate, but cbindgen only cares about a subset of the
    # data which, when changed, causes these files to change.
    return set([CARGO_LOCK, CARGO_TOML])


def generate(output, metadata_path, cbindgen_crate_path, *in_tree_dependencies):
    stdout, returncode = _run_process(
        [
            buildconfig.substs["CBINDGEN"],
            buildconfig.topsrcdir,
            "--lockfile",
            CARGO_LOCK,
            "--crate",
            _get_crate_name(cbindgen_crate_path),
            "--metadata",
            metadata_path,
            "--cpp-compat",
        ]
    )

    if returncode != 0:
        return returncode

    if stdout:
        output.write(stdout)

    deps = set()
    deps.add(CARGO_LOCK)
    deps.add(mozpath.join(cbindgen_crate_path, "cbindgen.toml"))
    for directory in in_tree_dependencies + (cbindgen_crate_path,):
        for path, dirs, files in os.walk(directory):
            for file in files:
                if os.path.splitext(file)[1] == ".rs":
                    deps.add(mozpath.join(path, file))

    return deps
