#!/usr/bin/python3
"""Fuzzy-find a file and check which package owns it.

Dependencies
============
* fzf
* mlocate
"""

import argparse
import subprocess

# ========== Constants ==========
# Commands
PACMAN_CMD = "/usr/bin/pacman"
FZF_CMD = "/usr/bin/fzf"
FZF_OPTS = ["--read0", "--select-1", "--exit-0", "--print0"]
LOCATE_CMD = "/usr/bin/locate"
LOCATE_OPTS = ["--all", "--ignore-case", "--null"]
LOCALE = "utf-8"


# ========== Functions ==========
def run_fzf(files):
    """Run fzf on a stream of searched files for the user to select.

    :param files: stream of null-terminated files to read
    :type files: bytes stream (stdout of a completed process)
    :returns: selected file
    :rtype: str
    """
    selected_file = subprocess.run(
        [FZF_CMD] + FZF_OPTS, input=files, stdout=subprocess.PIPE
    ).stdout

    return selected_file.decode(LOCALE).strip("\x00")


def locate_files(patterns):
    """Use a locate-based program to locate files, then pass to fzf.

    :param patterns: patterns to pass to locate
    :type patterns: list
    :returns: path of user-selected file
    :rtype: bytes
    """
    cmd = [LOCATE_CMD] + LOCATE_OPTS
    cmd.extend(patterns)

    return subprocess.run(cmd, capture_output=True).stdout


# ========== Main Script ==========
def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("patterns", nargs="+", help="file pattern to search for")

    args = parser.parse_args()

    try:
        files = locate_files(args.patterns)
    # Locate binary is optional for package, but required for script
    except FileNotFoundError:
        print("locate binary not found, install and re-run script")
    else:
        selected_file = run_fzf(files)

    subprocess.run([PACMAN_CMD, "-Qo", selected_file])


if __name__ == "__main__":
    main()