#!/usr/bin/env python3
#
# ===- run-clang-tidy.py - Parallel clang-tidy runner ---------*- python -*--===#
#
#                     The LLVM Compiler Infrastructure
#
# This file is distributed under the University of Illinois Open Source
# License. See LICENSE.TXT for details.
#
# Modified from the LLVM project for the Terrier project.
#
# Added `only_diff` cli arg to run clang-tidy on git diff.
# ===------------------------------------------------------------------------===#
# FIXME: Integrate with clang-tidy-diff.py

"""
Parallel clang-tidy runner
==========================
Runs clang-tidy over all files in a compilation database. Requires clang-tidy
and clang-apply-replacements in $PATH.
Example invocations.
- Run clang-tidy on all files in the current working directory with a default
  set of checks and show warnings in the cpp files and all project headers.
    run-clang-tidy.py $PWD
- Fix all header guards.
    run-clang-tidy.py -fix -checks=-*,llvm-header-guard
- Fix all header guards included from clang-tidy and header guards
  for clang-tidy headers.
    run-clang-tidy.py -fix -checks=-*,llvm-header-guard extra/clang-tidy \
                      -header-filter=extra/clang-tidy
Compilation database setup:
http://clang.llvm.org/docs/HowToSetupToolingForLLVM.html
"""

import argparse
import glob
import json
import multiprocessing
import os
import pprint  # TERRIER: we want to print out formatted lists of files
import re
import shutil
import subprocess
import sys
import tempfile
import threading
import traceback

import yaml  # TERRIER: not necessary if we don't want automatic fixes
from run_clang_tidy_extra import CheckConfig

is_py2 = sys.version[0] == "2"

if is_py2:
    import Queue as queue
else:
    import queue as queue


def find_compilation_database(path):
    """Adjusts the directory until a compilation database is found."""
    result = "./"
    while not os.path.isfile(os.path.join(result, path)):
        if os.path.realpath(result) == "/":
            print("Error: could not find compilation database.")
            sys.exit(1)
        result += "../"
    return os.path.realpath(result)


def make_absolute(f, directory):
    if os.path.isabs(f):
        return f
    return os.path.normpath(os.path.join(directory, f))


def supports_color():
    """
    Modified from https://github.com/django/django/blob/main/django/core/management/color.py
    Return True if the running system's terminal supports color,
    and False otherwise.
    """

    # isatty is not always implemented, #6223.
    is_a_tty = hasattr(sys.stdout, "isatty") and sys.stdout.isatty()

    return is_a_tty and (
        sys.platform != "win32"
        or "ANSICON" in os.environ
        or
        # Windows Terminal supports VT codes.
        "WT_SESSION" in os.environ
        or
        # Microsoft Visual Studio Code's built-in terminal supports colors.
        os.environ.get("TERM_PROGRAM") == "vscode"
    )


def get_tidy_invocation(
    f,
    clang_tidy_binary,
    checks,
    tmpdir,
    build_path,
    header_filter,
    extra_arg,
    extra_arg_before,
    quiet,
    config,
):
    """Gets a command line for clang-tidy."""
    start = [clang_tidy_binary]

    if supports_color():
        start.append("--use-color")

    if header_filter is not None:
        start.append("-header-filter=" + header_filter)
    else:
        # Show warnings in all in-project headers by default.
        # start.append('-header-filter=^' + build_path + '/.*')
        # TERRIER: we have our .clang-tidy file
        pass
    if checks:
        start.append("-checks=" + checks)
    if tmpdir is not None:
        start.append("-export-fixes")
        # Get a temporary file. We immediately close the handle so clang-tidy can
        # overwrite it.
        (handle, name) = tempfile.mkstemp(suffix=".yaml", dir=tmpdir)
        os.close(handle)
        start.append(name)
    for arg in extra_arg:
        start.append(f"-extra-arg={arg}")
    for arg in extra_arg_before:
        start.append(f"-extra-arg-before={arg}")
    start.append("-p=" + build_path)
    if quiet:
        start.append("-quiet")
    if config:
        start.append("-config=" + config)
    start.append(f)
    return start


def merge_replacement_files(tmpdir, mergefile):
    """Merge all replacement files in a directory into a single file"""
    # The fixes suggested by clang-tidy >= 4.0.0 are given under
    # the top level key 'Diagnostics' in the output yaml files
    mergekey = "Diagnostics"
    merged = []
    for replacefile in glob.iglob(os.path.join(tmpdir, "*.yaml")):
        content = yaml.safe_load(open(replacefile))
        if not content:
            continue  # Skip empty files.
        merged.extend(content.get(mergekey, []))

    if merged:
        # MainSourceFile: The key is required by the definition inside
        # include/clang/Tooling/ReplacementsYaml.h, but the value
        # is actually never used inside clang-apply-replacements,
        # so we set it to '' here.
        output = {"MainSourceFile": "", mergekey: merged}
        with open(mergefile, "w") as out:
            yaml.safe_dump(output, out)
    else:
        # Empty the file:
        open(mergefile, "w").close()


def check_clang_apply_replacements_binary(args):
    """Checks if invoking supplied clang-apply-replacements binary works."""
    try:
        subprocess.check_call([args.clang_apply_replacements_binary, "--version"])
    except Exception:
        print(
            "Unable to run clang-apply-replacements. Is clang-apply-replacements binary correctly specified?",
            file=sys.stderr,
        )
        traceback.print_exc()
        sys.exit(1)


def apply_fixes(args, tmpdir):
    """Calls clang-apply-fixes on a given directory."""
    invocation = [args.clang_apply_replacements_binary]
    if args.format:
        invocation.append("-format")
    if args.style:
        invocation.append("-style=" + args.style)
    invocation.append(tmpdir)
    subprocess.call(invocation)


def run_tidy(args, tmpdir, build_path, queue, lock, failed_files):
    """Takes filenames out of queue and runs clang-tidy on them."""
    while True:
        name = queue.get()
        print(f"Checking: {name}")
        sys.stdout.flush()
        invocation = get_tidy_invocation(
            name,
            args.clang_tidy_binary,
            args.checks,
            tmpdir,
            build_path,
            args.header_filter,
            args.extra_arg,
            args.extra_arg_before,
            args.quiet,
            args.config,
        )
        cc = CheckConfig()
        # name is the full path of the file for clang-tidy to check
        if cc.should_skip(name):
            print(f"Ignored dependence:{name}")
            queue.task_done()
            continue

        proc = subprocess.Popen(invocation, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        output, err = proc.communicate()
        if proc.returncode != 0:
            failed_files.append(name)
        # TERRIER: we write our own printing logic
        # with lock:
        #     sys.stdout.write(' '.join(invocation) + '\n' + output + '\n')
        #     if err > 0:
        #         sys.stderr.write(err + '\n')
        # In particular, we only want important lines:
        with lock:
            output = output.decode("utf-8") if output is not None else None
            err = err.decode("utf-8") if output is not None else None
            # unfortunately, our error messages are actually on STDOUT
            # STDERR tells how many warnings are generated,
            # but this includes non-user-code warnings, so it is useless...
            if output:
                sys.stdout.write("\n")
                sys.stdout.write(output)
        queue.task_done()


def main():
    parser = argparse.ArgumentParser(
        description="Runs clang-tidy over all files "
        "in a compilation database. Requires "
        "clang-tidy and clang-apply-replacements in "
        "$PATH."
    )
    parser.add_argument(
        "-clang-tidy-binary",
        metavar="PATH",
        default="clang-tidy",
        help="path to clang-tidy binary",
    )
    parser.add_argument(
        "-clang-apply-replacements-binary",
        metavar="PATH",
        default="clang-apply-replacements",
        help="path to clang-apply-replacements binary",
    )
    parser.add_argument(
        "-checks",
        default=None,
        help="checks filter, when not specified, use clang-tidy default",
    )
    parser.add_argument(
        "-config",
        default=None,
        help="Specifies a configuration in YAML/JSON format: "
        "  -config=\"{Checks: '*' "
        "               CheckOptions: [{key: x, "
        "                               value: y}]}"
        "When the value is empty, clang-tidy will "
        "attempt to find a file named .clang-tidy for "
        "each source file in its parent directories.",
    )
    parser.add_argument(
        "-header-filter",
        default=None,
        help="regular expression matching the names of the "
        "headers to output diagnostics from. Diagnostics from "
        "the main file of each translation unit are always "
        "displayed.",
    )
    parser.add_argument(
        "-export-fixes",
        metavar="filename",
        dest="export_fixes",
        help="Create a yaml file to store suggested fixes in, which can be applied with clang-apply-replacements.",
    )
    parser.add_argument(
        "-j",
        type=int,
        default=0,
        help="number of tidy instances to be run in parallel.",
    )
    parser.add_argument("files", nargs="*", default=[".*"], help="files to be processed (regex on path)")
    parser.add_argument("-fix", action="store_true", help="apply fix-its")
    parser.add_argument("-format", action="store_true", help="Reformat code after applying fixes")
    parser.add_argument(
        "-style",
        default="file",
        help="The style of reformat code after applying fixes",
    )
    parser.add_argument("-p", dest="build_path", help="Path used to read a compile command database.")
    parser.add_argument(
        "-extra-arg",
        dest="extra_arg",
        action="append",
        default=[],
        help="Additional argument to append to the compiler command line.",
    )
    parser.add_argument(
        "-extra-arg-before",
        dest="extra_arg_before",
        action="append",
        default=[],
        help="Additional argument to prepend to the compiler command line.",
    )
    parser.add_argument("-quiet", action="store_true", help="Run clang-tidy in quiet mode")
    parser.add_argument(
        "-only-diff",
        action="store_true",
        help="Only run clang-tidy on diff file to master branch",
    )
    args = parser.parse_args()

    db_path = "compile_commands.json"

    if args.build_path is not None:
        build_path = args.build_path
    else:
        # Find our database
        build_path = find_compilation_database(db_path)

    try:
        invocation = [args.clang_tidy_binary, "-list-checks"]
        invocation.append("-p=" + build_path)
        if args.checks:
            invocation.append("-checks=" + args.checks)
        invocation.append("-")
        subprocess.check_call(invocation)
    except Exception:
        print("Unable to run clang-tidy.", file=sys.stderr)
        sys.exit(1)

    # Load the database and extract all files.
    database = json.load(open(os.path.join(build_path, db_path)))
    files = [make_absolute(entry["file"], entry["directory"]) for entry in database]

    # Running clang-tidy in the whole project is slow. Therefore, we added
    # support for running clang-tidy on git diff. When `only_diff` is
    # specified in the command line, we only check files modified compared
    # with origin/master, so as to speed up clang-tidy check.
    #
    # This functionality is set as CMake target `check-clang-tidy-diff`.
    # You can use `make check-clang-tidy-diff` to do a fast clang-tidy
    # check.
    if args.only_diff:
        # Get the path of the repo, e.g. /Users/terrier/bustub
        git_repo = subprocess.run(["git", "rev-parse", "--show-toplevel"], capture_output=True)
        git_repo_path = git_repo.stdout.decode("utf-8").strip()
        # Get all files changed compared with origin/master
        result = subprocess.run(
            ["git", "--no-pager", "diff", "--name-only", "origin/master"],
            capture_output=True,
        )
        git_changed_file_list = [
            make_absolute(x, git_repo_path) for x in result.stdout.decode("utf-8").strip().split("\n")
        ]
        git_changed_file_set = set(git_changed_file_list)
        # Only retain files that exists in git diff
        files = list(filter(lambda x: x in git_changed_file_set, files))

    max_task = args.j
    if max_task == 0:
        max_task = multiprocessing.cpu_count()

    tmpdir = None
    if args.fix or args.export_fixes:
        check_clang_apply_replacements_binary(args)
        tmpdir = tempfile.mkdtemp()

    # Build up a big regexy filter from all command line arguments.
    file_name_re = re.compile("|".join(args.files))

    return_code = 0
    try:
        # Spin up a bunch of tidy-launching threads.
        task_queue = queue.Queue(max_task)
        # List of files with a non-zero return code.
        failed_files = []
        lock = threading.Lock()
        for _ in range(max_task):
            t = threading.Thread(
                target=run_tidy,
                args=(args, tmpdir, build_path, task_queue, lock, failed_files),
            )
            t.daemon = True
            t.start()

        def update_progress(current_file, num_files):
            pct = int(current_file / num_files * 100)
            if current_file == num_files or pct % max(2, num_files // 10) == 0:
                stars = pct // 10
                spaces = 10 - pct // 10
                print(
                    f"\rProgress: [{'x' * stars}{' ' * spaces}] ({pct}% / File {current_file} of {num_files})",
                    end="",
                )
                sys.stdout.flush()
                if current_file == num_files:
                    print()

        # Fill the queue with files.
        for name in files:
            if file_name_re.search(name):
                if name.endswith("tools/backtrace.cpp"):
                    continue
                put_file = False
                while not put_file:
                    try:
                        task_queue.put(name, block=True, timeout=300)
                        put_file = True
                        # update_progress(i, len(files))
                    except queue.Full:
                        print("Still waiting to put files into clang-tidy queue.")
                        sys.stdout.flush()

        # Wait for all threads to be done.
        task_queue.join()
        # update_progress(100, 100)
        if len(failed_files):
            return_code = 1
            # TERRIER: We want to see the failed files
            print("The files that failed were:")
            print(pprint.pformat(failed_files))
            print("Note that a failing .h file will fail all the .cpp files that include it.\n")

    except KeyboardInterrupt:
        # This is a sad hack. Unfortunately subprocess goes
        # bonkers with ctrl-c and we start forking merrily.
        print("\nCtrl-C detected, goodbye.")
        if tmpdir:
            shutil.rmtree(tmpdir)
        os.kill(0, 9)

    if args.export_fixes:
        print("Writing fixes to " + args.export_fixes + " ...")
        try:
            merge_replacement_files(tmpdir, args.export_fixes)
        except Exception:
            print("Error exporting fixes.\n", file=sys.stderr)
            traceback.print_exc()
            return_code = 1

    if args.fix:
        print("Applying fixes ...")
        try:
            apply_fixes(args, tmpdir)
        except Exception:
            print("Error applying fixes.\n", file=sys.stderr)
            traceback.print_exc()
            return_code = 1

    if tmpdir:
        shutil.rmtree(tmpdir)
    print("")
    sys.stdout.flush()
    sys.exit(return_code)


if __name__ == "__main__":
    main()
