"""Terminal progress on stderr; dataset statistics remain machine-readable on stdout."""
from rich.console import Console
from rich.progress import (
    BarColumn, MofNCompleteColumn, Progress, ProgressColumn,
    TaskProgressColumn, TextColumn, TimeElapsedColumn, TimeRemainingColumn,
)
from rich.text import Text


class RateColumn(ProgressColumn):
    def render(self, task):
        speed = task.finished_speed or task.speed
        return Text(f'{speed:.1f} зап/с' if speed is not None else '— зап/с')


class ProgressDisplay:
    def __init__(self, label, total, *, initial=0, enabled=True):
        self.label = label
        self.total = total
        self.progress = Progress(
            TextColumn('{task.description}'), BarColumn(bar_width=None),
            TaskProgressColumn(), MofNCompleteColumn(), RateColumn(),
            TextColumn('прошло'), TimeElapsedColumn(),
            TextColumn('осталось'), TimeRemainingColumn(),
            console=Console(stderr=True), refresh_per_second=4,
            redirect_stdout=False, redirect_stderr=False, disable=not enabled,
        )
        self.task = self.progress.add_task(label, total=total, completed=min(initial, total))

    def __enter__(self):
        self.progress.start()
        return self

    def update(self, completed=None, *, status=None):
        kwargs = {}
        if completed is not None:
            kwargs['completed'] = min(completed, self.total)
        if status is not None:
            kwargs['description'] = f'{self.label}: {status}' if status else self.label
        self.progress.update(self.task, **kwargs)

    def __exit__(self, exc_type, exc, traceback):
        if exc_type is not None:
            self.update(status='прервано' if issubclass(exc_type, (KeyboardInterrupt, SystemExit)) else 'ошибка')
        self.progress.stop()