# PATH: bot/core/progress.py
import time

class SpeedETA:
    def __init__(self):
        self.t0 = time.time()
        self.last_t = self.t0
        self.last_bytes = 0
        self.total = 0

    def update(self, done_bytes: int, total_bytes: int) -> dict:
        now = time.time()
        self.total = total_bytes
        dt = max(1e-6, now - self.last_t)
        db = done_bytes - self.last_bytes
        speed = db / dt  # bytes/sec
        remaining = max(0, total_bytes - done_bytes)
        eta = remaining / max(1e-6, speed)
        self.last_t = now
        self.last_bytes = done_bytes
        return {"done": done_bytes, "total": total_bytes, "speed_bps": speed, "eta_sec": eta}

def human_bytes(n: float) -> str:
    units = ["B", "KB", "MB", "GB"]
    x = float(n)
    for u in units:
        if x < 1024 or u == units[-1]:
            return f"{x:.2f}{u}"
        x /= 1024
    return f"{x:.2f}GB"

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