#!/usr/bin/env python3

import argparse
import os
import queue
import re
import subprocess
import sys
import threading

import click
import colorama
from helpers import (
    filter_changed,
    get_binary,
    get_usable_cpu_count,
    git_ls_files,
    print_error_for_file,
)


def run_format(executable, args, queue, lock, failed_files):
    """Takes filenames out of queue and runs clang-format on them."""
    while True:
        path = queue.get()
        invocation = [executable]
        if args.inplace:
            invocation.append("-i")
        else:
            invocation.extend(["--dry-run", "-Werror"])
        invocation.append(path)

        proc = subprocess.run(
            invocation,
            capture_output=True,
            encoding="utf-8",
            check=False,
            close_fds=False,
        )
        if proc.returncode != 0:
            with lock:
                print_error_for_file(path, proc.stderr)
                failed_files.append(path)
        queue.task_done()


def progress_bar_show(value):
    return value if value is not None else ""


def main():
    colorama.init()

    parser = argparse.ArgumentParser()
    parser.add_argument(
        "-j",
        "--jobs",
        type=int,
        default=get_usable_cpu_count(),
        help="number of format instances to be run in parallel.",
    )
    parser.add_argument(
        "files", nargs="*", default=[], help="files to be processed (regex on path)"
    )
    parser.add_argument(
        "-i", "--inplace", action="store_true", help="reformat files in-place"
    )
    parser.add_argument(
        "-c", "--changed", action="store_true", help="only run on changed files"
    )
    args = parser.parse_args()

    cwd = os.getcwd()
    files = [
        os.path.relpath(path, cwd) for path in git_ls_files(["*.cpp", "*.h", "*.tcc"])
    ]

    if args.files:
        # Match against files specified on command-line
        file_name_re = re.compile("|".join(args.files))
        files = [p for p in files if file_name_re.search(p)]

    if args.changed:
        files = filter_changed(files)

    files.sort()

    failed_files = []
    try:
        executable = get_binary("clang-format", 13)
        task_queue = queue.Queue(args.jobs)
        lock = threading.Lock()
        for _ in range(args.jobs):
            t = threading.Thread(
                target=run_format,
                args=(executable, args, task_queue, lock, failed_files),
            )
            t.daemon = True
            t.start()

        # Fill the queue with files.
        with click.progressbar(
            files, width=30, file=sys.stderr, item_show_func=progress_bar_show
        ) as bar:
            for name in bar:
                task_queue.put(name)

        # Wait for all threads to be done.
        task_queue.join()

    except FileNotFoundError:
        return 1
    except KeyboardInterrupt:
        print()
        print("Ctrl-C detected, goodbye.")
        # Kill subprocesses (and ourselves!)
        # No simple, clean alternative appears to be available.
        os.kill(0, 9)
        return 2  # Will not execute.

    return len(failed_files)


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