"""Replay recorded ball_track events through try_fit, report why predictions fire or fail."""

from __future__ import annotations

import json

import sys

from collections import defaultdict

from pathlib import Path

import numpy as np

from rich.console import Console

sys.path.insert(0, str(Path(__file__).resolve().parents[1]))

from cv._common import load_config

console = Console()

def fit_and_explain(pts: list[dict], plate_y_px: float) -> str:

    if len(pts) < 4:

        return f"SKIP n={len(pts)}<4"

    ys = np.array([p["y"] for p in pts], dtype=np.float64)

    xs = np.array([p["x"] for p in pts], dtype=np.float64)

    if ys.max() - ys.min() < 30:

        return f"REJECT dy={ys.max()-ys.min():.0f}<30"

    if ys[-1] - ys[0] <= 0:

        return f"REJECT not moving down (y0={ys[0]:.0f} -> yN={ys[-1]:.0f})"

    t0 = pts[0]["ts_ns"]

    ts = np.array([(p["ts_ns"] - t0) / 1e9 for p in pts], dtype=np.float64)

    try:

        ay, by, cy = np.polyfit(ts, ys, 2)

        bx, cx = np.polyfit(ts, xs, 1)

    except Exception as e:

        return f"FIT_ERR {e}"

    disc = by * by - 4 * ay * (cy - plate_y_px)

    if disc < 0:

        return f"REJECT disc<0 (ay={ay:.1f} by={by:.1f} cy={cy:.1f} plate={plate_y_px:.0f})"

    if abs(ay) < 1e-6:

        return f"REJECT ay~0 ({ay:.3e})"

    sqrt_d = float(np.sqrt(disc))

    t_cand = [(-by + sqrt_d) / (2 * ay), (-by - sqrt_d) / (2 * ay)]

    future = [tc for tc in t_cand if tc > ts[-1]]

    if not future:

        past_best = max(tc for tc in t_cand if tc <= ts[-1])

        return f"REJECT crossing in past: t_cand={[f'{t:.3f}' for t in t_cand]} ts[-1]={ts[-1]:.3f} (past_best={past_best:.3f})"

    t_cross = min(future)

    plate_x = bx * t_cross + cx

    eta_ms = (t_cross - ts[-1]) * 1000.0

    if eta_ms > 2000:

        return f"REJECT eta={eta_ms:.0f}ms>2000"

    return f"FIT OK plate_x={plate_x:.0f} eta={eta_ms:.1f}ms t_cross={t_cross:.3f} ts[-1]={ts[-1]:.3f} ay={ay:.1f} by={by:.1f}"

def main() -> int:

    if len(sys.argv) < 2:

        console.print("usage: fit_debug.py <events.jsonl>")

        return 2

    cfg = load_config()

    plate_y_px = 1080 * float(cfg["cv"]["plate_y_frac"])

    console.print(f"plate_y_px = {plate_y_px:.0f} (plate_y_frac={cfg['cv']['plate_y_frac']})\n")

    pitches: dict[int, list[dict]] = defaultdict(list)

    with open(sys.argv[1], "r", encoding="utf-8") as f:

        for line in f:

            try:

                ev = json.loads(line)

            except Exception:

                continue

            if ev.get("type") != "ball_track":

                continue

            pid = int(ev.get("pitch_id", 0))

            pitches[pid].append(ev)

    for pid in sorted(pitches.keys()):

        pts = pitches[pid]

        if len(pts) < 4:

            continue

        ys = [p["y"] for p in pts]

        xs = [p["x"] for p in pts]

        dy = max(ys) - min(ys)

        if dy < 100:

            continue

        res = fit_and_explain(pts, plate_y_px)

        console.print(f"pitch #{pid:3d} n={len(pts):2d} dy={dy:4.0f}  {res}")

    return 0

if __name__ == "__main__":

    sys.exit(main())