import sys
import argparse
from pathlib import Path
from ..configuration import Config
from ..chat import ChatDB
from ..message import MessageFilter, Message


msg_suffix = Message.file_suffix_write  # currently '.msg'


def convert_messages(args: argparse.Namespace, config: Config) -> None:
    """
    Convert messages to a new format. Also used to change old suffixes
    ('.txt', '.yaml') to the latest default message file suffix ('.msg').
    """
    chat = ChatDB.from_dir(Path(config.cache),
                           Path(config.db))
    # read all known message files
    msgs = chat.msg_gather(loc='disk', glob='*.*')
    # make a set of all message IDs
    msg_ids = set([m.msg_id() for m in msgs])
    # set requested format and write all messages
    chat.set_msg_format(args.convert)
    # delete the current suffix
    # -> a new one will automatically be created
    for m in msgs:
        if m.file_path:
            m.file_path = m.file_path.with_suffix('')
    chat.msg_write(msgs)
    # read all messages with the current default suffix
    msgs = chat.msg_gather(loc='disk', glob=f'*{msg_suffix}')
    # make sure we converted all of the original messages
    for mid in msg_ids:
        if not any(mid == m.msg_id() for m in msgs):
            print(f"Message '{mid}' has not been found after conversion. Aborting.")
            sys.exit(1)
    # delete messages with old suffixes
    msgs = chat.msg_gather(loc='disk', glob='*.*')
    for m in msgs:
        if m.file_path and m.file_path.suffix != msg_suffix:
            m.rm_file()
    print(f"Successfully converted {len(msg_ids)} messages.")


def print_chat(args: argparse.Namespace, config: Config) -> None:
    """
    Print the DB chat history.
    """

    mfilter = MessageFilter(tags_or=args.or_tags,
                            tags_and=args.and_tags,
                            tags_not=args.exclude_tags,
                            question_contains=args.question,
                            answer_contains=args.answer)
    chat = ChatDB.from_dir(Path(config.cache),
                           Path(config.db),
                           mfilter=mfilter)
    chat.print(args.source_code_only,
               args.with_metadata)


def hist_cmd(args: argparse.Namespace, config: Config) -> None:
    """
    Handler for the 'hist' command.
    """
    if args.print:
        print_chat(args, config)
    elif args.convert:
        convert_messages(args, config)