#!/usr/bin/env python3
"""Score a route's travelling-salesman heuristic on six fixed point sets: its tour's length over nearest neighbour's.

Usage: score.py ROUTE_FOLDER. The route's solve.py (or the baseline's, at the top of the project, if the route has
none) reads the points as JSON on stdin and prints the tour as JSON. It runs in its own process and only the tour it
prints is used. Writes metrics.json; the last line sums up."""
import json
import math
import random
import subprocess
import sys
import time
from pathlib import Path


def points(n, seed):
    rng = random.Random(seed)
    return [[round(rng.random(), 6), round(rng.random(), 6)] for _ in range(n)]


SETS = {f"n{n}-{s}": points(n, s) for n, s in [(40, 1), (40, 2), (80, 3), (80, 4), (160, 5), (160, 6)]}


def length(p, tour):
    return sum(math.dist(p[tour[i - 1]], p[tour[i]]) for i in range(len(tour)))


def nearest(p):
    left, tour = set(range(1, len(p))), [0]
    while left:
        nxt = min(left, key=lambda j: math.dist(p[tour[-1]], p[j]))
        left.remove(nxt)
        tour.append(nxt)
    return tour


folder = Path(sys.argv[1])
solver = folder / "solve.py" if (folder / "solve.py").is_file() else Path("input/solve.py")
subtasks, seconds = {}, 0.0
for name, p in SETS.items():
    start = time.perf_counter()
    try:
        out = subprocess.run([sys.executable, str(solver)], input=json.dumps(p), capture_output=True, text=True, timeout=30)
        tour = json.loads(out.stdout)
        ok = isinstance(tour, list) and sorted(tour) == list(range(len(p)))
    except Exception as e:
        print(f"{name}: the solver failed ({type(e).__name__})")
        sys.exit(1)
    seconds += time.perf_counter() - start
    if not ok:
        print(f"{name}: the tour must visit every point exactly once")
        sys.exit(1)
    subtasks[name] = round(length(p, tour) / length(p, nearest(p)), 4)
if seconds > 30:
    print(f"took {seconds:.1f} s; the limit is 30 s")
    sys.exit(1)
score = round(sum(subtasks.values()) / len(subtasks), 4)
Path("metrics.json").write_text(json.dumps({"score": score, "cost": round(seconds, 2), "subtasks": subtasks}))
print(f"{score} of nearest neighbour's tour length on {len(subtasks)} point sets, in {seconds:.1f} s")