#!/usr/bin/env python3

import glob
import logging
import os
from typing import Callable, List, NamedTuple, Optional, Set
import warnings

import argparse_utils
import config

logger = logging.getLogger(__name__)
parser = config.add_commandline_args(
    f"ML Quick Labeler ({__file__})",
    "Args related to quick labeling of ML training data",
)
parser.add_argument(
    "--ml_quick_label_skip_list_path",
    default="./qlabel_skip_list.txt",
    metavar="FILENAME",
    type=argparse_utils.valid_filename,
    help="Path to file in which to store already labeled data.",
)
parser.add_argument(
    "--ml_quick_label_use_skip_lists",
    default=True,
    action=argparse_utils.ActionNoYes,
    help='Should we use a skip list file to speed up execution?',
)
parser.add_argument(
    "--ml_quick_label_overwrite_labels",
    default=False,
    action=argparse_utils.ActionNoYes,
    help='Enable overwriting existing labels; default is to not relabel.',
)


class InputSpec(NamedTuple):
    image_file_glob: Optional[str]
    image_file_prepopulated_list: Optional[List[str]]
    image_file_to_features_file: Callable[[str], str]
    label: str
    valid_keystrokes: List[str]
    prompt: str
    keystroke_to_label: Callable[[str], str]


def read_skip_list() -> Set[str]:
    ret: Set[str] = set()
    if config.config['ml_quick_label_use_skip_lists']:
        quick_skip_file = config.config['ml_quick_label_skip_list_path']
        if os.path.exists(quick_skip_file):
            with open(quick_skip_file, 'r') as f:
                lines = f.readlines()
            for line in lines:
                line = line[:-1]
                line.strip()
                ret.add(line)
        logger.debug(f'Read {quick_skip_file} and found {len(ret)} entries.')
    return ret


def write_skip_list(skip_list) -> None:
    if config.config['ml_quick_label_use_skip_lists']:
        quick_skip_file = config.config['ml_quick_label_skip_list_path']
        with open(quick_skip_file, 'w') as f:
            for filename in skip_list:
                filename = filename.strip()
                if len(filename) > 0:
                    f.write(f'{filename}\n')
        logger.debug(f'Updated {quick_skip_file}')


def label(in_spec: InputSpec) -> None:
    import input_utils

    images = []
    if in_spec.image_file_glob is not None:
        images += glob.glob(in_spec.image_file_glob)
    elif in_spec.image_file_prepopulated_list is not None:
        images += in_spec.image_file_prepopulated_list
    else:
        raise ValueError(
            'One of image_file_glob or image_file_prepopulated_list is required'
        )

    skip_list = read_skip_list()
    for image in images:
        if image in skip_list:
            logger.debug(f'Skipping {image} because of the skip list')
            continue
        features = in_spec.image_file_to_features_file(image)
        if features is None or not os.path.exists(features):
            msg = f'File {image} yielded file {features} which does not exist, SKIPPING.'
            logger.warning(msg)
            warnings.warn(msg)
            continue

        # Render features and image.
        filtered_lines = []
        with open(features, "r") as f:
            lines = f.readlines()
        saw_label = False
        for line in lines:
            line = line[:-1]
            if in_spec.label not in line:
                filtered_lines.append(line)
            else:
                saw_label = True

        if not saw_label or config.config['ml_quick_label_overwrite_labels']:
            logger.info(features)
            os.system(f'xv {image} &')
            keystroke = input_utils.single_keystroke_response(
                in_spec.valid_keystrokes,
                prompt=in_spec.prompt,
            )
            os.system('killall xv')
            label_value = in_spec.keystroke_to_label(keystroke)
            filtered_lines.append(f"{in_spec.label}: {label_value}\n")
            with open(features, 'w') as f:
                f.writelines("%s\n" % line for line in filtered_lines)
            skip_list.add(image)
    write_skip_list(skip_list)