#!/usr/bin/env python3

import argparse
import datetime
import sys, tempfile, os
import sqlite3
from subprocess import call

EDITOR = os.environ.get('EDITOR', 'nano')
DATABASE = os.environ.get('TTRACKER_BD', 'ttracker.db')

def db_init(cur):
  cur.execute("CREATE TABLE IF NOT EXISTS ttracker (start INTEGER, end INTEGER, text TEXT)")

def db_get_current_entry(cur):
  res = cur.execute("SELECT * FROM ttracker ORDER BY start DESC").fetchone()
  if res is not None and res[1] is None:
    return res
  return (None, None, None)

def show_last_entries(cur):
  res = cur.execute("SELECT * FROM ttracker ORDER BY start DESC LIMIT 10").fetchall()
  for e in res:
    start = datetime.datetime.fromtimestamp(e[0])
    if e[1] is not None:
      end = datetime.datetime.fromtimestamp(e[1])
      print(f'{when_are_we(start.date())}, {start.strftime("%H:%M")}-{end.strftime("%H:%M")}: {e[2]}')
    else:
      print(f'{when_are_we(start.date())}, {start.strftime("%H:%M")}-')


def new_entry(cur, now):
  cur.execute(f'INSERT INTO ttracker VALUES (?, null, null)', (int(now.timestamp()),))

def cancel_last_entry(cur, entry):
  if entry[0] != None:
    cur.execute("DELETE FROM ttracker WHERE start = ?", (entry[0],))
  else:
   cur.execute("UPDATE ttracker SET end=null, text=null WHERE start = (SELECT start FROM ttracker ORDER BY start DESC LIMIT 1)")

def end_entry(cur, entry, now):
  entry_start = datetime.datetime.fromtimestamp(entry[0])

  res = cur.execute("SELECT * FROM ttracker ORDER BY start DESC LIMIT 11").fetchall()


  initial_message = '\n\n' + \
    f'# What did you do since {when_are_we(entry_start.date())} ({entry_start.strftime("%H:%M")})?\n' + \
    "#\n"

  for e in res:
    if e[1] is not None:
      start = datetime.datetime.fromtimestamp(e[0])
      end = datetime.datetime.fromtimestamp(e[1])
      initial_message += f'# {when_are_we(start.date())}, {start.strftime("%H:%M")}-{end.strftime("%H:%M")}: {e[2]}\n'


  with tempfile.NamedTemporaryFile(suffix=".tmp") as tf:
    tf.write(initial_message.encode('utf_8'))
    tf.flush()
    call([EDITOR, tf.name])

    tf.seek(0)
    edited_message = [l.decode('utf_8') for l in tf.readlines()]
    stripped_message = [l.strip() for l in edited_message if l.strip() and l != "" and l[0] != "#"]
    if len(stripped_message) == 0:
      return


  cur.execute('UPDATE ttracker SET end = ?, text = ? WHERE start = ?', (int(now.timestamp()), stripped_message[0], entry[0]))
  print(f'Close entry ending at {now.strftime("%a %d %b")} - {now.strftime("%H:%M")}: {stripped_message[0]}')


def when_are_we(date):
  delta = (datetime.date.today() - date).days
  if delta == 0:
    return "Today"
  elif delta == 1:
    return "Yesterday"
  else:
    return f'{delta} days ago'

def main():
  parser = argparse.ArgumentParser(
                    prog='ttracker',
                    description='Simple time tracker')

  subparsers = parser.add_subparsers()
  parser_show = subparsers.add_parser('show')
  parser_show.set_defaults(show=True)

  parser_show = subparsers.add_parser('cancel')
  parser_show.set_defaults(cancel=True)

  args = parser.parse_args()

  now = datetime.datetime.now()
  con = sqlite3.connect(DATABASE)
  cur = con.cursor()
  db_init(cur)

  if 'show' in args:
    show_last_entries(cur)
    return

  entry = db_get_current_entry(cur)

  if 'cancel' in args:
    cancel_last_entry(cur, entry)
    con.commit()
    show_last_entries(cur)
    return

  if entry[0] is None:
    new_entry(cur, now)
    print(f'Add new entry starting at {now.strftime("%a %d %b")} ({when_are_we(now.date())}) - {now.strftime("%H:%M")}')
  else:
    end_entry(cur, entry, now)
  con.commit()


if __name__ == "__main__":
    main()