"""
Re-evaluate existing teacher trajectories under the NEW grader (with belief_accuracy term).

For each episode in the JSONL:
  1. Replay the env from the recorded seed
  2. Step with the recorded action sequence
  3. Call env.record_belief(parsed_belief) at each step (using the LAST step's
     belief for the grader)
  4. Read final_score (now under new grader)

Also runs heuristic + random baselines on the same seeds for comparison, so
we can directly answer: does the teacher beat heuristic+random under the new
grader, and by how much?

Usage:
    python scripts/reeval_teacher_trajectories.py --jsonl data/teacher_30ep_validation.jsonl
"""

import argparse
import json
import os
import random
import sys
from collections import defaultdict
from pathlib import Path
from statistics import mean, median, stdev

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from models import ActionType, RhythmAction
from server.rhythm_environment import RhythmEnvironment, MAX_STEPS
from training.dataset import heuristic_action


def replay_with_beliefs(seed: int, action_seq: list[str], belief_seq: list[list[float]]) -> dict:
    """Replay an episode with given actions+beliefs, return final_score breakdown."""
    env = RhythmEnvironment()
    obs = env.reset(seed=seed)
    for action_name, belief in zip(action_seq, belief_seq):
        if obs.done:
            break
        env.record_belief(belief)
        obs = env.step(RhythmAction(action_type=ActionType(action_name)))
    final_score = obs.reward_breakdown.get("final_score", 0.0)
    return {
        "final_score": final_score,
        "vitality": obs.vitality,
        "cognition": obs.cognition,
        "progress": obs.progress,
        "serenity": obs.serenity,
        "connection": obs.connection,
    }


def play_heuristic(seed: int) -> float:
    env = RhythmEnvironment()
    obs = env.reset(seed=seed)
    for _ in range(MAX_STEPS):
        if obs.done:
            break
        action = heuristic_action(obs)
        obs = env.step(RhythmAction(action_type=action))
    return obs.reward_breakdown.get("final_score", 0.0)


def play_random(seed: int) -> float:
    env = RhythmEnvironment()
    obs = env.reset(seed=seed)
    rng = random.Random(seed + 12345)
    actions = list(ActionType)
    for _ in range(MAX_STEPS):
        if obs.done:
            break
        action = rng.choice(actions)
        obs = env.step(RhythmAction(action_type=action))
    return obs.reward_breakdown.get("final_score", 0.0)


def main() -> None:
    parser = argparse.ArgumentParser()
    parser.add_argument("--jsonl", type=str, required=True,
                        help="Teacher trajectories JSONL")
    args = parser.parse_args()

    # Group rows by seed
    by_seed: dict[int, list[dict]] = defaultdict(list)
    with open(args.jsonl) as f:
        for line in f:
            row = json.loads(line)
            by_seed[row["seed"]].append(row)
    for seed in by_seed:
        by_seed[seed].sort(key=lambda r: r["step"])

    seeds = sorted(by_seed.keys())
    print(f"Loaded {len(seeds)} episodes from {args.jsonl}\n")

    teacher_scores = []
    heuristic_scores = []
    random_scores = []

    for seed in seeds:
        rows = by_seed[seed]
        action_seq = [r["parsed_action"] for r in rows]
        belief_seq = [r["parsed_belief"] for r in rows]

        result = replay_with_beliefs(seed, action_seq, belief_seq)
        teacher_scores.append(result["final_score"])
        heuristic_scores.append(play_heuristic(seed))
        random_scores.append(play_random(seed))

    def stats(vs, label):
        return f"{label:<10} mean={mean(vs):.4f}  median={median(vs):.4f}  std={stdev(vs):.4f}  min={min(vs):.4f}  max={max(vs):.4f}"

    print("=" * 78)
    print("FINAL_SCORE UNDER NEW GRADER (belief_accuracy weighted 0.20)")
    print("=" * 78)
    print(stats(teacher_scores, "teacher:"))
    print(stats(heuristic_scores, "heuristic:"))
    print(stats(random_scores, "random:"))

    teacher_avg = mean(teacher_scores)
    heur_avg = mean(heuristic_scores)
    rand_avg = mean(random_scores)
    margin_h = teacher_avg - heur_avg
    margin_r = teacher_avg - rand_avg

    print()
    print(f"teacher - heuristic: {margin_h:+.4f}")
    print(f"teacher - random:    {margin_r:+.4f}")
    print()

    # Per-episode comparison
    teacher_beats_heur = sum(1 for t, h in zip(teacher_scores, heuristic_scores) if t > h)
    print(f"Episodes where teacher > heuristic: {teacher_beats_heur} / {len(seeds)}")

    # Verdict
    print()
    print("=" * 78)
    print("VERDICT")
    print("=" * 78)
    GATE = 0.05  # teacher must beat heuristic by at least 5pts on average
    if margin_h >= GATE:
        print(f"PASS — teacher beats heuristic by {margin_h:.3f} (>= {GATE} required)")
        print("       New grader differentiates inference from reflex. Proceed to scale + SFT.")
    elif margin_h > 0:
        print(f"WEAK — teacher beats heuristic by only {margin_h:.3f} (need {GATE}+)")
        print("       Consider raising belief_accuracy weight or improving teacher prompt.")
    else:
        print(f"FAIL — teacher does NOT beat heuristic ({margin_h:.3f})")
        print("       Either grader weights are wrong or teacher is genuinely weak.")


if __name__ == "__main__":
    main()