tools/gen_web.py

"""Generate web/city/constants.js + web/mock/world.json from engine constants
and genesis — the ONE source of truth crossing the Python/JS boundary.

Run from the repo root (the integrator runs this; output is deterministic, no
timestamps):

    python tools/gen_web.py
"""

from __future__ import annotations

import json
import sys
from pathlib import Path

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

from engine import constants as C  # noqa: E402
from engine.genesis import genesis_features  # noqa: E402


def _js(value) -> str:
    return json.dumps(value, indent=2, sort_keys=False)


def constants_js() -> str:
    buildings = {
        kind: {
            "w": spec["w"], "d": spec["d"],
            "floors": list(spec["floors"]),
            "residents": spec["residents"], "jobs": spec["jobs"],
            "attract": spec["attract"],
            # both spellings: engine uses duration_s, the JS kit reads duration
            "duration": spec["duration_s"], "duration_s": spec["duration_s"],
        }
        for kind, spec in C.BUILDINGS.items()
    }
    durations = {kind: spec["duration_s"] for kind, spec in C.BUILDINGS.items()}
    parts = [
        "// GENERATED by tools/gen_web.py from engine/constants.py — do not edit.",
        "// Values are the ARCHITECTURE.md contract; regenerate, never hand-tune.",
        "",
        f"export const GRID = {C.GRID};",
        f"export const CELL = {C.CELL};",
        f"export const COORD_MIN = {C.COORD_MIN};",
        f"export const COORD_MAX = {C.COORD_MAX};",
        f"export const CITY_EPOCH_S = {C.CITY_EPOCH_S};",
        f"export const DAY_S = {C.DAY_S};",
        "",
        "export function riverCols(cz) {",
        "  return cz <= -5 ? [7, 8] : cz <= 3 ? [8, 9] : [9, 10];",
        "}",
        "",
        f"export const BUILDINGS = {_js(buildings)};",
        "",
        f"export const ROAD_CLASSES = {_js(C.ROAD_CLASSES)};",
        f"export const ROAD_DURATION_S = {C.ROAD_DURATION_S};",
        f"export const DURATIONS = {_js(durations)};",
        f"export const SYNONYMS = {_js(C.SYNONYMS)};",
        f"export const STREET_NAMES = {_js(list(C.STREET_NAMES))};",
        "",
        "// traffic (mirrors engine/traffic.py — the Python side owns the facts)",
        f"export const RUSH_HOURS = {_js(list(C.RUSH_HOURS))};",
        f"export const RUSH_SIGMA = {C.RUSH_SIGMA};",
        f"export const RUSH_BASE = {C.RUSH_BASE};",
        f"export const RUSH_AMP = {C.RUSH_AMP};",
        f"export const CAR_RATE = {C.CAR_RATE};",
        f"export const CAR_MIN = {C.CAR_MIN};",
        f"export const CAR_MAX = {C.CAR_MAX};",
        f"export const CITIZENS_PER_POP = {C.CITIZENS_PER_POP};",
        f"export const CITIZENS_MIN = {C.CITIZENS_MIN};",
        f"export const CITIZENS_MAX = {C.CITIZENS_MAX};",
        f"export const EMA_TAU_S = {C.EMA_TAU_S};",
        f"export const TRIP_ATTRACT_FACTOR = {C.TRIP_ATTRACT_FACTOR};",
        f"export const TRIP_DIST_EXP = {C.TRIP_DIST_EXP};",
        f"export const DEMAND_PER_COMMUTER = {C.DEMAND_PER_COMMUTER};",
        f"export const CONGESTION_COST_FACTOR = {C.CONGESTION_COST_FACTOR};",
        f"export const TRAFFIC_TOP_CELLS = {C.TRAFFIC_TOP_CELLS};",
        f"export const JAM_RATIO = {C.JAM_RATIO};",
        f"export const GROWTH_RADIUS_MIN = {C.GROWTH_RADIUS_MIN};",
        "",
    ]
    return "\n".join(parts)


def world_json() -> str:
    features = genesis_features()
    payload = {
        "world": {
            "version": len(features),
            "epoch": 0,
            "features": features,
        }
    }
    return json.dumps(payload, indent=2) + "\n"


def main() -> None:
    constants_path = ROOT / "web" / "city" / "constants.js"
    world_path = ROOT / "web" / "mock" / "world.json"
    world_path.parent.mkdir(parents=True, exist_ok=True)
    constants_path.write_text(constants_js(), encoding="utf-8")
    world_path.write_text(world_json(), encoding="utf-8")
    print(f"wrote {constants_path.relative_to(ROOT)}")
    print(f"wrote {world_path.relative_to(ROOT)}")


if __name__ == "__main__":
    main()