import configparser
import glob
import itertools
import os
import queue
import shlex
import shutil
import threading

_browsers = {}

XDG_DATA_HOME = os.environ.get(
    "XDG_DATA_HOME", os.path.expanduser("~/.local/share")
)
XDG_DATA_DIRS = os.environ.get(
    "XDG_DATA_DIRS", "/usr/local/share/:/usr/share/"
)
XDG_DATA_DIRS = XDG_DATA_DIRS.split(os.pathsep)


def find_unix_browsers(*paths: str) -> int:
    files = ()
    if not paths:
        paths = (XDG_DATA_HOME, *XDG_DATA_DIRS)

    for appdata in paths:
        shortcuts = os.path.join(appdata, "applications")
        if not os.path.isdir(shortcuts):
            continue
        shortcuts = os.path.join(shortcuts, "**", "*.desktop")
        shortcuts = glob.iglob(shortcuts, recursive=True)
        files = itertools.chain(files, shortcuts)

    found = 0
    lock = threading.Lock()
    tasks = queue.SimpleQueue()

    def xdg_desktop_handler() -> None:
        nonlocal found
        parser = configparser.ConfigParser(interpolation=None)

        while True:
            shortcut = tasks.get()
            if shortcut is None:
                return

            try:
                parser.clear()
                if not parser.read(shortcut, encoding="utf-8"):
                    continue
            except (UnicodeDecodeError, configparser.Error):
                continue

            # Desktop Entry, Type, Name are required by specification
            if not parser.has_section("Desktop Entry"):
                continue
            entry = parser["Desktop Entry"]

            if entry.get("Type") != "Application":
                continue

            if "WebBrowser" not in entry.get("Categories", fallback=""):
                continue

            name = entry.get("Name")
            if not name:
                continue
            with lock:
                if name in _browsers:
                    continue

            command = entry.get("Exec", fallback="")
            command = shlex.split(command)
            urlcode = False

            for command in reversed(command):
                if urlcode:
                    if command := shutil.which(command):
                        break
                elif command in ("%U", "%u"):
                    urlcode = True
            else:
                continue

            with lock:
                _browsers[name] = command
                found += 1

    workers = []
    # process_cpu_count() replaced by cpu_count() to run on previous versions
    for worker in range(min(7, os.cpu_count() or 1)):
        worker = threading.Thread(target=xdg_desktop_handler)
        workers.append(worker)
        worker.start()

    files = itertools.chain(files, itertools.repeat(None, len(workers)))
    for file in files:
        tasks.put(file)

    for worker in workers:
        worker.join()

    return found


if __name__ == "__main__":
    print(find_unix_browsers())

    print(_browsers, "\n")

    for name, paths in _browsers.items():
        print(name)

    print()