import datetime
import urllib.parse
from typing import Any
from collections.abc import Iterator
from decimal import Decimal
from pathlib import Path
import dataclasses

from personal_data.util import load_csv_file

from ..data import WorkSample

@dataclasses.dataclass
class PossibleKeys:
    time_start: list[str]
    time_end: list[str]
    duration: list[str]
    name: list[str]
    image: list[str]
    misc: list[str]

def determine_possible_keys(event_data: dict[str, Any]) -> PossibleKeys:
    # Select data
    time_keys = [
        k for k, v in event_data.items() if isinstance(v, datetime.date)
    ]
    duration_keys = [
        k
        for k, v in event_data.items()
        if isinstance(v, Decimal) and 'duration_seconds' in k
    ]
    name_keys = [k for k, v in event_data.items() if isinstance(v, str)]
    image_keys = [
        k for k, v in event_data.items() if isinstance(v, urllib.parse.ParseResult)
    ]

    misc_keys = list(event_data.keys())
    for k in image_keys:
        if k in misc_keys:
            misc_keys.remove(k)
        del k
    for k in time_keys:
        if k in misc_keys:
            misc_keys.remove(k)
        del k

    time_start_keys = [k for k in time_keys if 'start' in k.lower() ]
    time_end_keys = [k for k in time_keys if 'end' in k.lower() or 'stop' in k.lower() ]

    return PossibleKeys(
            time_start = time_start_keys,
            time_end = time_end_keys,
            duration = duration_keys,
            name = name_keys,
            image = image_keys,
            misc = misc_keys,
    )

def start_end(sample: dict[str,Any], keys: PossibleKeys) -> tuple[datetime.datetime | None, datetime.datetime | None]:
    if keys.time_start and keys.time_end:
        return (sample[keys.time_start[0]], sample[keys.time_end[0]])

    if keys.time_start and keys.duration:
        start = sample[keys.time_start[0]]
        duration = datetime.timedelta(seconds=float(sample[keys.duration[0]]))
        return (start, start + duration)

    if keys.time_start:
        start = sample[keys.time_start[0]]
        return (start, None)
    if keys.time_end:
        return (None, sample[keys.time_end[0]])
    return (None, None)

def iterate_samples_from_dicts(rows: list[dict[str,Any]]) -> Iterator[WorkSample]:
    assert len(rows) > 0
    max_title_parts = 2


    if True:
        event_data = rows[len(rows)//2] # Hopefully select a useful representative.
        possible_keys = determine_possible_keys(event_data)
        del event_data

    assert len(possible_keys.time_start) + len(possible_keys.time_end) >= 1
    assert len(possible_keys.image) >= 0

    for event_data in rows:
        '''
        title = ': '.join(event_data[k] for k in possible_name_keys[:max_title_parts])
        description = '\n\n'.join(
            event_data[k] for k in possible_name_keys[max_title_parts:]
        )
        image = event_data[possible_keys.image[0]] if possible_keys.image else None
        '''


        (start_at, end_at) = start_end(event_data, possible_keys)
        labels = [f'{k}:{event_data[k]}' for k in possible_keys.misc]

        # Create event
        yield WorkSample(
            labels=tuple(labels),
            start_at=start_at,
            end_at=end_at,
        )

        del event_data


def iterate_samples_from_csv_file(file_path: Path) -> Iterator[WorkSample]:
    dicts = load_csv_file(file_path)
    samples = list(iterate_samples_from_dicts(dicts))
    assert len(samples) > 0, 'Did not found any samples'
    yield from samples