backend/render.py

"""
render.py — turn engine state into the terse prompt strings the templates expect. Pure view
layer: reads state + the turn's legal actions, returns strings. No model calls, no rules
decisions. Keeps the LLM contract in one place so prompt tweaks don't leak into the engine.
"""
from __future__ import annotations
import os
from engine import STATIONS, MAJORS, INTERCHANGES, CARDS, B
from rules import legal_cards, card_available

PROMPT_DIR = os.path.join(os.path.dirname(__file__), "prompts")


def load_prompts(prompt_dir=PROMPT_DIR):
    # MLP_DISPATCHER_SYSTEM lets a run swap in a variant system prompt without editing the file.
    disp_sys = os.environ.get("MLP_DISPATCHER_SYSTEM", "dispatcher_system.txt")

    def rd(name):
        path = name if os.path.isabs(name) else os.path.join(prompt_dir, name)
        with open(path, encoding="utf-8") as f:
            return f.read()

    return {
        "dispatcher_system": rd(disp_sys),
        "dispatcher_user": rd("dispatcher_user_template.txt"),
        "chaos_system": rd("chaos_system.txt"),
        "chaos_user": rd("chaos_user_template.txt"),
    }


def _dir(d):
    return "DOWN" if d == +1 else "UP"        # +1 increases index toward Virar = DOWN


def _fill(template, mapping):
    out = template
    for k, v in mapping.items():
        out = out.replace("{{" + k + "}}", str(v))
    return "\n".join(l for l in out.splitlines() if not l.lstrip().startswith("#"))


# ---------------------------------------------------------------- action description
def describe_action(a):
    t = a["type"]
    if t.startswith("deploy_"):
        return f"{t}  {a['unit']} -> {a['to']} ({a['target']}, resolves in {a['resolves_in']}t)"
    if t == "move_train":
        return f"move_train  {a['train']} -> {a['to']}"
    if t == "hold_train":
        return f"hold_train  {a['train']} @{a['at']}"
    if t in ("switch_to_fast", "switch_to_slow"):
        return f"{t}  {a['train']} @{a['at']}"
    if t == "prioritize_train":
        return f"prioritize_train  {a['train']}"
    if t == "clear_platform_priority":
        return f"clear_platform_priority  @{a['at']}"
    if t == "issue_announcement":
        return f"issue_announcement  {a.get('scope', 'line')}-wide"
    extra = " ".join(f"{k}={v}" for k, v in a.items() if k not in ("action_id", "type"))
    return f"{t}  {extra}".rstrip()


# ---------------------------------------------------------------- blocks
def _stations_block(g):
    out = []
    for s in g.stations:
        pct = s.pct()
        flag = "!!" if pct > 100 else "!" if pct > 85 else ""
        tag = " [MAJOR]" if s.name in MAJORS else ""
        out.append(f"- {s.name}{tag}  {int(s.crowd)}/{s.cap} ({pct:.0f}%{flag})")
    return "\n".join(out)


def _incidents_block(g):
    if not g.incidents:
        return "- none"
    return "\n".join(f"- [{i.itype}] {i.location} {i.track}  sev{i.severity}  age{i.age}t"
                     + ("  (unit en route)" if i.assigned else "") for i in g.incidents)


def _trains_block(g):
    return "\n".join(f'- {t.id} "{t.name}" [{t.ttype}] @{STATIONS[t.pos]} {_dir(t.direction)} {t.track}  '
                     f'delay+{t.delay}  ' + ("held" if t.held else (f"stuck{t.stuck_turns}t" if t.stuck_turns else "running"))
                     for t in g.trains)


def _personnel_block(g):
    return "\n".join(f"- {u.id} {u.utype} @{STATIONS[u.loc]}  {'busy' if u.busy else 'available'}  "
                     f"used {u.used}/{B['personnel_max']}" for u in g.units)


def _legal_actions_block(A):
    return "\n".join(f"{a['action_id']}  {describe_action(a)}" for a in A)


def _legal_cards_block(g):
    cards = legal_cards(g)
    if not cards:
        return "- (no playable cards — hoard energy)"
    return "\n".join(f"{c['card']}  cost {c['cost']}" for c in cards)


def _peak_banner(g):
    if g.phase != "peak":
        return ""
    return (">>> PEAK RUSH (the escalator): inflow +40%, anger growth +30%, a SIGNAL FAILURE now "
            "blocks ALL tracks, TRAIN TROUBLE card unlocks (+2 trains), monsoon flood drops to 8, "
            "rain won't quit <<<")


# ---------------------------------------------------------------- public renderers
def render_dispatcher_user(template, g, A):
    return _fill(template, {
        "turn": g.turn + 1, "total_turns": B["turns_to_win"], "phase": g.phase,
        "peak_rush_banner": _peak_banner(g),
        "score": f"{g.score:.0f}", "delay": f"{g.delay:.0f}", "safety": f"{g.safety:.0f}",
        "anger": f"{g.anger:.0f}", "pressure": f"{g.pressure:.0f}", "patience": f"{g.patience:.0f}",
        "incidents_block": _incidents_block(g), "stations_block": _stations_block(g),
        "trains_block": _trains_block(g), "personnel_block": _personnel_block(g),
        "legal_actions_block": _legal_actions_block(A),
    })


def render_chaos_user(template, g):
    return _fill(template, {
        "turn": g.turn + 1, "total_turns": B["turns_to_win"], "phase": g.phase,
        "peak_rush_banner": _peak_banner(g),
        "safety": f"{g.safety:.0f}", "anger": f"{g.anger:.0f}", "pressure": f"{g.pressure:.0f}",
        "delay": f"{g.delay:.0f}", "stations_block": _stations_block(g),
        "incidents_block": _incidents_block(g), "energy": g.energy,
        "regen": B["chaos_energy_regen"], "legal_cards_block": _legal_cards_block(g),
    })