from __future__ import annotations
import time

def human_bytes(n: float) -> str:
    for unit in ["B", "KB", "MB", "GB", "TB"]:
        if n < 1024:
            return f"{n:.1f}{unit}"
        n /= 1024
    return f"{n:.1f}PB"

def fmt_eta(sec: float) -> str:
    sec = max(0, int(sec))
    if sec < 60:
        return f"{sec}s"
    m = sec // 60
    s = sec % 60
    if m < 60:
        return f"{m}m {s}s"
    h = m // 60
    m = m % 60
    return f"{h}h {m}m"

class RateProgress:
    def __init__(self, total: int, edit_every: float = 2.5):
        self.total = max(1, total)
        self.edit_every = edit_every
        self.t0 = time.time()
        self.last_edit = 0.0
        self.last_bytes = 0
        self.last_t = self.t0

    def snapshot(self, done: int) -> dict:
        now = time.time()
        done = max(0, min(done, self.total))
        dt = max(1e-6, now - self.last_t)
        dbytes = done - self.last_bytes
        speed = dbytes / dt  # B/s
        elapsed = now - self.t0
        pct = (done / self.total) * 100.0
        remaining = self.total - done
        eta = remaining / speed if speed > 1 else float("inf")
        return {
            "pct": pct,
            "done": done,
            "total": self.total,
            "speed": speed,
            "eta": eta,
            "elapsed": elapsed,
            "now": now
        }

    def should_edit(self, now: float) -> bool:
        return (now - self.last_edit) >= self.edit_every

    def mark_edit(self, done: int, now: float):
        self.last_edit = now
        self.last_bytes = done
        self.last_t = now