"""Load a capture CSV and step through it as a virtual live feed."""
from __future__ import annotations

import csv
from pathlib import Path


def load_capture(path: Path) -> list[tuple[float, int, bytes]]:
    """Returns (t_seconds, arbitration_id, data) sorted by time, t relative to first frame.

    Mirrors files/decode_ptcan.py: sort by timestamp_ms first since these logs can contain
    the odd corrupt row, and the adapter's ms counter wraps every 60000ms anyway.
    """
    rows = []
    with open(path, newline="") as f:
        for row in csv.DictReader(f):
            hx = row["data_hex"].strip()
            rows.append((int(row["timestamp_ms"]), int(row["arbitration_id"], 16), bytes.fromhex(hx)))
    rows.sort(key=lambda r: r[0])
    if not rows:
        return []
    t0 = rows[0][0]
    return [((ms - t0) / 1000, aid, data) for ms, aid, data in rows]


class ReplayPlayer:
    """Feeds a FrameStore at a scaled real-time rate, tracking position in the log."""

    def __init__(self, frames: list[tuple[float, int, bytes]]):
        self.frames = frames
        self.duration = frames[-1][0] if frames else 0.0
        self.index = 0
        self.clock = 0.0

    def reset(self) -> None:
        self.index = 0
        self.clock = 0.0

    def at_end(self) -> bool:
        return self.index >= len(self.frames)

    def advance(self, dt_wall: float, speed: float, store) -> None:
        self.clock += dt_wall * speed
        while self.index < len(self.frames) and self.frames[self.index][0] <= self.clock:
            t, aid, data = self.frames[self.index]
            store.feed(aid, data, t)
            self.index += 1

    def seek(self, t: float, store) -> None:
        """Jump to time t, replaying everything up to it into a freshly reset store."""
        store.reset()
        self.index = 0
        self.clock = t
        while self.index < len(self.frames) and self.frames[self.index][0] <= self.clock:
            frame_t, aid, data = self.frames[self.index]
            store.feed(aid, data, frame_t)
            self.index += 1