#!/usr/bin/env python
# Copyright 2018 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.

### Generates documentation for a Rust target

import argparse
import os
import platform
import subprocess
import sys

ROOT_PATH = os.path.abspath(__file__ + "/../../..")
CONFIG_PATH = os.path.join(ROOT_PATH, ".config")

# Runs the given command and returns its return code and output.
def run_command(args, env, cwd):
    job = subprocess.Popen(args, env=env, cwd=cwd, stdout=subprocess.PIPE,
                           stderr=subprocess.PIPE)
    stdout, stderr = job.communicate()
    return (job.returncode, stdout, stderr)

def main():
    parser = argparse.ArgumentParser("Compiles all third-party Rust crates")
    parser.add_argument("gn_target",
                        nargs=1,
                        help="GN target to generate a symlink for. \
                              Use the absolute path to the target \
                              (relative to $FUCHSIA_DIR). \
                              For example: //garnet/bin/foo/bar:baz. \
                              Alternatively, this can be a path to a \
                              Cargo.toml file of a package for which to \
                              generate docs.")
    parser.add_argument("--target",
                        help="Target triple for which this crate is being compiled",
                        default="x86_64-unknown-fuchsia")
    parser.add_argument("--no-deps",
                        action="store_true",
                        help="Disable building of docs for dependencies")
    parser.add_argument("--open",
                        action="store_true",
                        help="Open the generated documentation")

    args = parser.parse_args()

    out_dir = ""
    with open(CONFIG_PATH, "r") as config:
        for line in config.readlines():
            if line.startswith("FUCHSIA_BUILD_DIR="):
                segments = line.split("=")
                assert(len(segments) == 2)
                out_dir = segments[1].strip().strip("'")
    if out_dir == "":
        print "Invalid fuchsia/.config: no FUCHSIA_BUILD_DIR entry found"

    gn_target = args.gn_target[0]
    if gn_target.endswith("Cargo.toml"):
        manifest_path = os.path.abspath(gn_target)
    else:
        gn_target = gn_target.lstrip("/")
        gn_target_parts = gn_target.split(":", 1)
        if len(gn_target_parts) == 1:
            # Turn foo/bar into foo/bar/bar
            path = os.path.join(gn_target, os.path.basename(gn_target))
        elif len(gn_target_parts) == 2:
            # Turn foo/bar:baz into foo/bar/baz
            path = gn_target.replace(":", os.sep)
        else:
            print "Invalid gn_target: explected at most one colon."
            return 1
        manifest_path = os.path.join(ROOT_PATH, out_dir, "gen", path, "Cargo.toml")

    env = os.environ.copy()

    host_platform = "%s-%s" % (
        platform.system().lower().replace("darwin", "mac"),
        {
            "x86_64": "x64",
            "aarch64": "arm64",
        }[platform.machine()],
    )

    # run cargo from third_party/rust-crtaes/rustc_deps which has an appropriate .cargo/config
    cwd = os.path.join(ROOT_PATH, "third_party", "rust-crates", "rustc_deps")
    buildtools_dir = os.path.join(ROOT_PATH, "buildtools", host_platform)
    clang_prefix = os.path.join(buildtools_dir, "clang", "bin")
    cmake_dir = os.path.join(buildtools_dir, "cmake", "bin")
    cargo = os.path.join(buildtools_dir, "rust", "bin", "cargo")
    rustc = os.path.join(buildtools_dir, "rust", "bin", "rustc")
    rustdoc = os.path.join(buildtools_dir, "rust", "bin", "rustdoc")

    shared_libs_root = os.path.join(ROOT_PATH, out_dir)
    sysroot = os.path.join(ROOT_PATH, out_dir, "sdks", "zircon_sysroot", "sysroot")

    clang_c_compiler = os.path.join(clang_prefix, "clang")

    env["CARGO_TARGET_LINKER"] = clang_c_compiler
    env["CARGO_TARGET_X86_64_APPLE_DARWIN_LINKER"] = clang_c_compiler
    env["CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER"] = clang_c_compiler
    env["CARGO_TARGET_%s_LINKER" % args.target.replace("-", "_").upper()] = clang_c_compiler
    if "fuchsia" in args.target:
        env["CARGO_TARGET_%s_RUSTFLAGS" % args.target.replace("-", "_").upper()] = (
            "-Clink-arg=--target=" + args.target +
            " -Clink-arg=--sysroot=" + sysroot +
            " -Lnative=" + shared_libs_root
        )
    else:
        env["CARGO_TARGET_%s_RUSTFLAGS" % args.target.replace("-", "_").upper()] = (
            "-Clink-arg=--target=" + args.target
        )
    env["RUSTC"] = rustc
    env["RUSTDOC"] = rustdoc
    env["RUST_BACKTRACE"] = "1"
    env["CC"] = clang_c_compiler
    if "fuchsia" in args.target:
        env["CFLAGS"] = "--sysroot=%s -L %s" % (sysroot, shared_libs_root)
    env["CXX"] = os.path.join(clang_prefix, "clang++")
    env["AR"] = os.path.join(clang_prefix, "llvm-ar")
    env["RANLIB"] = os.path.join(clang_prefix, "llvm-ranlib")
    env["PATH"] = "%s:%s" % (env["PATH"], cmake_dir)

    call_args = [
        cargo,
        "doc",
        "--manifest-path=%s" % manifest_path,
        "--color=always",
        "--target=%s" % args.target,
    ]

    if args.no_deps:
        call_args.append("--no-deps")

    if args.open:
        call_args.append("--open")

    retcode, stdout, stderr = run_command(call_args, env, cwd)
    print(stdout + stderr)
    return retcode

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