#!/usr/bin/env python3
# Startdate: 2024-09-22-1 15:33
# Purpose: backend for fprintd_tk that uses fprintd-* binaries, in case I ever rewrite this to use dbus directly?
# Dependencies:
#    /usr/bin/fprintd-*
# Improve:
#    add a verbose/debug param to everything?

import os, subprocess, re

_user = os.getenv("USER")
fre = re.compile ("^.* - #[0-9]+: ([^ ]+)$")
prevent_success_messages = [
   "no-match",
   "failed to claim",
   "not enrolled for user"
]

def get_enrolled_fingers(user = None):
   # return list of full strings of fingers that are enrolled.
   enrolled_fingers = []
   if user is None:
      user = _user
   proc = subprocess.Popen(
      ["fprintd-list",user],
      stdout = subprocess.PIPE,
      universal_newlines = True # or maybe text=True
   )
   #print(result.stdout)
   while True:
      line = proc.stdout.readline()
      if not line:
         break
      if fre.match(line):
         #print(f"Got {fre.match(line).groups()[0]}")
         enrolled_fingers.append(fre.match(line).groups()[0].strip())
      elif re.match("^.*No devices available.*", line):
         # WORKHERE: we should rerun the program in a second or two
         return []
      else:
         #print(f"Not-matching: {line}",end="")
         pass
   return enrolled_fingers

def fprintd_action(action, finger, status_function = None, user = None):
   if user is None:
      user = _user
   if action == "enroll":
      command = ["fprintd-enroll","-f",finger,user]
   elif action == "verify":
      command = ["fprintd-verify","-f",finger,user]
   elif action == "delete":
      command = ["fprintd-delete",user]
   else:
      if status_function:
         status_function(f"Invalid action {action}")
         return False
   proc = subprocess.Popen(
      command,
      stdout = subprocess.PIPE,
      universal_newlines = True
   )
   old_line = "INITIAL_LINE"
   dupe_count = 0
   while True:
      line = proc.stdout.readline()
      if not line:
         break
      display_line = line
      if line == old_line:
         dupe_count = dupe_count + 1
         display_line = line.strip() + str(f" (x{dupe_count})")
      else:
         dupe_count = 1
      old_line = line
      if status_function:
         status_function(display_line)
      # If you want to react to any lines.
      #if re.match("^.*verify-match (done).*",line):
      #   proc.kill()
      #   return "verify-match"
   # so the process has ended, now what?
   proc.kill()
   if status_function:
      if display_line:
         display = True
         for i in prevent_success_messages:
            if i in display_line:
               display = False
               break
         if display:
            status_function(f"Succeeded! {display_line}")