from __future__ import annotations

import json
import os
import time
from copy import deepcopy
from dataclasses import dataclass
from http import HTTPStatus
from pathlib import Path
from threading import Lock, Thread
from typing import Any, Protocol
from urllib.error import HTTPError, URLError
from urllib.request import Request, urlopen

from world_simulator.api.modal_auth import modal_proxy_auth_headers
from world_simulator.api.persistence import (
    BackgroundSnapshotWriter,
    SnapshotStore,
    build_snapshot,
)
from world_simulator.api.players import (
    PlayerCharacter,
    PlayerError,
    PlayerManager,
)
from world_simulator.config import ConnectorConfig, GameConfig
from world_simulator.domain import WorldLogEvent, WorldState
from world_simulator.observability import RunLedger, append_record, set_active_tick_buffer
from world_simulator.rendering.scene_contract import to_scene_snapshot
from world_simulator.simulation.connectors.base import TickPlan, WorldSimulator
from world_simulator.simulation.connectors.factory import create_world_simulator
from world_simulator.simulation.directives import expire_directives
from world_simulator.simulation.spawning import create_world
from world_simulator.simulation.tick import apply_tick_plan, plan_world_tick


class GameRuntime:
    def __init__(
        self,
        *,
        world: WorldState,
        simulator: WorldSimulator,
        modal_health_warmer: HealthWarmer | None = None,
        players: PlayerManager | None = None,
        ledger: RunLedger | None = None,
        config: GameConfig | None = None,
        snapshot_writer: BackgroundSnapshotWriter | None = None,
        snapshot_store: SnapshotStore | None = None,
    ) -> None:
        self._world = world
        self._simulator = simulator
        self._modal_health_warmer = modal_health_warmer
        self._players = players or PlayerManager()
        self._ledger = ledger or RunLedger()
        self._config = config
        self._snapshot_writer = snapshot_writer
        self._snapshot_store = snapshot_store
        self._lock = Lock()
        self._tick_status = TickStatus()
        self._pending_commands: list[PendingCommand] = []

    @property
    def simulator_name(self) -> str:
        return self._simulator.name

    def health(self) -> dict[str, Any]:
        with self._lock:
            return {
                "status": "ok",
                "tick": self._world.tick,
                "simulator": self._simulator.name,
                "last_tick_source": self._world.last_tick_source,
                **tick_status_payload(self._tick_status),
            }

    def state(self) -> dict[str, Any]:
        with self._lock:
            payload = self._world.to_dict()
            payload["simulation"] = tick_status_payload(self._tick_status)
            return payload

    def scene_state(self, *, warmup: bool = False) -> dict[str, Any]:
        if warmup and self._modal_health_warmer is not None:
            self._modal_health_warmer.trigger(force=True)

        with self._lock:
            payload = to_scene_snapshot(
                self._world,
                tick_in_progress=self._tick_status.in_progress,
                pending_tick=self._tick_status.pending_tick,
            )
        if self._modal_health_warmer is not None:
            payload["simulation"]["models"] = self._modal_health_warmer.statuses()
        return payload

    def tick(self) -> tuple[HTTPStatus, dict[str, Any]]:
        planning_world, next_tick, pending_commands, conflict = self._begin_tick()
        if conflict is not None:
            return HTTPStatus.CONFLICT, conflict
        assert planning_world is not None
        assert next_tick is not None
        assert pending_commands is not None

        buffer = self._ledger.start_tick(
            next_tick,
            npc_order=[npc.id for npc in planning_world.living_npcs()],
        )
        set_active_tick_buffer(buffer)

        try:
            expire_directives(planning_world, tick=next_tick)
            planned_tick, plan = plan_world_tick(
                planning_world,
                self._simulator,
                next_tick,
            )
        except Exception as exc:
            with self._lock:
                self._tick_status.in_progress = False
                self._tick_status.pending_tick = None
                self._pending_commands = [*pending_commands, *self._pending_commands]
            set_active_tick_buffer(None)
            return HTTPStatus.INTERNAL_SERVER_ERROR, {
                "error": "tick_failed",
                "message": str(exc),
            }

        try:
            with self._lock:
                before_events = len(self._world.event_log)
                plan = self._override_player_directives(planning_world, plan)
                apply_tick_plan(self._world, planned_tick, plan)
                append_record(
                    {
                        "tick": planned_tick,
                        "phase": "engine_events",
                        "events": [
                            event
                            for event in self._world.to_dict()["event_log"][before_events:]
                        ],
                    }
                )
                self._tick_status.in_progress = False
                self._tick_status.pending_tick = None
                payload = self._world.to_dict()
                payload["simulation"] = tick_status_payload(self._tick_status)
                self._persist_snapshot()
            self._ledger.flush_tick(buffer)
            return HTTPStatus.OK, payload
        except Exception as exc:
            # The apply phase failed AFTER planning (the LLM calls already
            # finished). Clear the in-progress flag so the next tick is not
            # blocked forever by a stale "tick in progress" - otherwise the
            # simulation hangs even though no API call is running.
            with self._lock:
                self._tick_status.in_progress = False
                self._tick_status.pending_tick = None
            return HTTPStatus.INTERNAL_SERVER_ERROR, {
                "error": "tick_failed",
                "message": str(exc),
            }
        finally:
            set_active_tick_buffer(None)

    def _persist_snapshot(self) -> None:
        """Submit a full world+players snapshot to the background writer.

        Called while holding ``self._lock`` so the captured state is consistent;
        the actual (slow, bucket) write happens off-lock on the writer thread.
        ``build_snapshot`` makes its own ``to_dict`` copy, so the writer never
        races with the ``payload`` dict returned to the caller.
        """
        if self._snapshot_writer is None:
            return
        self._snapshot_writer.submit(build_snapshot(self._world, self._players.snapshot()))

    def reset_world(self) -> tuple[HTTPStatus, dict[str, Any]]:
        """Wipe the live world: fresh world, no players, deleted snapshot files.

        Used by the Admin panel. Drops any in-flight snapshot first so the
        background writer cannot resurrect the deleted state, then clears the
        store on disk.
        """
        if self._config is None:
            return HTTPStatus.INTERNAL_SERVER_ERROR, {
                "error": "reset_unavailable",
                "message": "Runtime has no config to rebuild the world from.",
            }
        with self._lock:
            if self._snapshot_writer is not None:
                self._snapshot_writer.drop_pending()
            self._world = create_world(self._config)
            self._players = PlayerManager()
            self._tick_status = TickStatus()
            self._pending_commands = []
            if self._snapshot_store is not None:
                self._snapshot_store.clear()
            return HTTPStatus.OK, {"ok": True, "tick": self._world.tick}

    # -- player characters (external agents over MCP) ---------------------- #
    def create_player(
        self,
        *,
        name: str,
        icon: str,
        country_id: str = "nemotron",
    ) -> tuple[HTTPStatus, dict[str, Any]]:
        with self._lock:
            try:
                character = self._players.create(
                    name=name,
                    icon=icon,
                    country_id=country_id,
                    created_tick=self._world.tick,
                )
            except PlayerError as exc:
                return HTTPStatus.BAD_REQUEST, _player_error_payload(exc)
            return HTTPStatus.OK, _character_summary(character)

    def player_status(self, token: str) -> tuple[HTTPStatus, dict[str, Any]]:
        with self._lock:
            try:
                character = self._players.get(token)
                return HTTPStatus.OK, self._players.character_status(character, self._world)
            except PlayerError as exc:
                return HTTPStatus.NOT_FOUND, _player_error_payload(exc)

    def player_observe(self, token: str) -> tuple[HTTPStatus, dict[str, Any]]:
        with self._lock:
            try:
                character = self._players.get(token)
                return HTTPStatus.OK, self._players.observation(character, self._world)
            except PlayerError as exc:
                return _player_error_status(exc), _player_error_payload(exc)

    def player_act(
        self,
        token: str,
        payload: dict[str, Any],
    ) -> tuple[HTTPStatus, dict[str, Any]]:
        with self._lock:
            try:
                character = self._players.get(token)
                self._players.queue_action(character, payload, self._world)
                observation = self._players.observation(character, self._world)
            except PlayerError as exc:
                return _player_error_status(exc), _player_error_payload(exc)
            return HTTPStatus.OK, {
                "queued_action": character.pending_action,
                "message": (
                    f"Action '{character.pending_action['action']}' queued for the next tick."
                    if character.pending_action
                    else "Action queued."
                ),
                "observation": observation,
            }

    def player_vote_available(self, token: str) -> bool:
        with self._lock:
            try:
                character = self._players.get(token)
            except PlayerError:
                return False
            for election in self._world.elections:
                if election.country_id != character.country_id or election.completed:
                    continue
                if election.start_tick <= self._world.tick <= election.end_tick:
                    return True
            return False

    # -- admin ------------------------------------------------------------- #
    def admin_logs_runs(self) -> dict[str, Any]:
        root = self._ledger.run_dir.parent
        runs: list[dict[str, Any]] = []
        for run_dir in sorted(root.glob("run_*"), key=lambda item: item.name, reverse=True):
            if not run_dir.is_dir():
                continue
            ledger_path = run_dir / "ledger.jsonl"
            runs.append(
                {
                    "run_id": run_dir.name,
                    "current": run_dir == self._ledger.run_dir,
                    "ledger_path": str(ledger_path),
                    "exists": ledger_path.is_file(),
                    "size_bytes": ledger_path.stat().st_size if ledger_path.is_file() else 0,
                }
            )
        return {"runs": runs}

    def admin_log_records(
        self,
        *,
        run_id: str | None = None,
        since_line: int = 0,
        limit: int = 200,
        phase: str | None = None,
        npc_id: str | None = None,
        tick_from: int | None = None,
        tick_to: int | None = None,
    ) -> tuple[HTTPStatus, dict[str, Any]]:
        run_dir = self._ledger.run_dir if run_id in (None, "current") else self._run_dir(run_id)
        if run_dir is None:
            return HTTPStatus.NOT_FOUND, {"error": "run_not_found", "message": "Unknown ledger run."}
        ledger_path = run_dir / "ledger.jsonl"
        if not ledger_path.is_file():
            return HTTPStatus.NOT_FOUND, {"error": "ledger_not_found", "message": "Run has no ledger.jsonl."}

        records: list[dict[str, Any]] = []
        next_line = max(0, since_line)
        limit = max(1, min(limit, 1000))
        with ledger_path.open("r", encoding="utf-8") as ledger_file:
            for line_no, line in enumerate(ledger_file):
                next_line = line_no + 1
                if line_no < since_line:
                    continue
                try:
                    record = json.loads(line)
                except json.JSONDecodeError:
                    continue
                if not _record_matches(
                    record,
                    phase=phase,
                    npc_id=npc_id,
                    tick_from=tick_from,
                    tick_to=tick_to,
                ):
                    continue
                records.append(_normalize_log_record(line_no, record))
                if len(records) >= limit:
                    break
        return HTTPStatus.OK, {
            "run_id": run_dir.name,
            "ledger_path": str(ledger_path),
            "next_line": next_line,
            "records": records,
        }

    def admin_models(self) -> dict[str, Any]:
        return {
            "profiles": self._model_profiles(),
            "npcs": [
                {
                    "id": npc.id,
                    "name": npc.name,
                    "country_id": npc.country_id,
                    "model_profile_id": npc.model_profile_id,
                    "connector_id": npc.connector_id,
                }
                for npc in self._world.npcs
            ],
        }

    def admin_set_npc_model(self, npc_id: str, profile_id: str) -> tuple[HTTPStatus, dict[str, Any]]:
        profiles = {profile["id"]: profile for profile in self._model_profiles()}
        if profile_id not in profiles:
            return HTTPStatus.BAD_REQUEST, {"error": "unknown_profile", "message": "Unknown model profile."}
        profile = profiles[profile_id]
        connector_id = profile.get("connector_id")
        with self._lock:
            npc = next((candidate for candidate in self._world.npcs if candidate.id == npc_id), None)
            if npc is None:
                return HTTPStatus.NOT_FOUND, {"error": "npc_not_found", "message": "Unknown NPC."}
            npc.model_profile_id = profile_id
            npc.connector_id = connector_id if isinstance(connector_id, str) and connector_id else None
            self._world.event_log.append(
                WorldLogEvent(
                    tick=self._world.tick,
                    type="model_profile_changed",
                    summary=f"{npc.name} model profile set to {profile_id}",
                    severity="neutral",
                    actor_id=npc.id,
                )
            )
        self._ledger.write_records(
            [
                {
                    "tick": self._world.tick,
                    "phase": "admin_model_switch",
                    "npc_id": npc_id,
                    "model_profile_id": profile_id,
                    "connector_id": connector_id,
                }
            ]
        )
        return HTTPStatus.OK, {"npc_id": npc_id, "profile": profile}

    def _run_dir(self, run_id: str | None) -> Path | None:
        if not run_id or "/" in run_id or "\\" in run_id or not run_id.startswith("run_"):
            return None
        run_dir = self._ledger.run_dir.parent / run_id
        if not run_dir.is_dir():
            return None
        return run_dir

    def _model_profiles(self) -> list[dict[str, Any]]:
        profiles: dict[str, dict[str, Any]] = {
            "default": {
                "id": "default",
                "label": "Default NPC model",
                "connector_id": None,
                "model": self._config.connector.model if self._config else None,
            }
        }
        if self._config is not None:
            for connector_id, connector in self._config.secondary_connectors.items():
                profiles[connector_id] = {
                    "id": connector_id,
                    "label": connector_id,
                    "connector_id": connector_id,
                    "model": connector.model,
                    "type": connector.type,
                }
        profiles_path = Path(os.getenv("MODEL_PROFILES_PATH", "config/model_profiles.json"))
        if profiles_path.is_file():
            try:
                raw = json.loads(profiles_path.read_text(encoding="utf-8"))
            except json.JSONDecodeError:
                raw = {}
            for item in raw.get("profiles", []) if isinstance(raw, dict) else []:
                if isinstance(item, dict) and isinstance(item.get("id"), str):
                    profiles[item["id"]] = {**profiles.get(item["id"], {}), **item}
        return list(profiles.values())

    def _override_player_directives(self, world: WorldState, plan: TickPlan) -> TickPlan:
        """Replace planner directives for player-owned NPCs with their queued actions."""
        player_ids = self._players.player_npc_ids
        if not player_ids:
            return plan
        directives = [
            directive for directive in plan.directives if directive.npc_id not in player_ids
        ]
        for character in self._players.all_characters():
            directive = self._players.take_directive(character, world)
            if directive is not None:
                directives.append(directive)
        return TickPlan(
            source=plan.source,
            directives=directives,
            overseer=plan.overseer,
            ledger_entries=plan.ledger_entries,
        )

    def _begin_tick(
        self,
    ) -> tuple[WorldState | None, int | None, list[PendingCommand] | None, dict[str, Any] | None]:
        with self._lock:
            if self._tick_status.in_progress:
                return None, None, None, {
                    "error": "tick_in_progress",
                    "tick": self._world.tick,
                    **tick_status_payload(self._tick_status),
                }
            next_tick = self._world.tick + 1
            planning_world = deepcopy(self._world)
            pending_commands = list(self._pending_commands)
            self._pending_commands.clear()
            self._tick_status.in_progress = True
            self._tick_status.pending_tick = next_tick
            return planning_world, next_tick, pending_commands, None


def create_game_runtime(
    *,
    world: WorldState,
    config: GameConfig,
    players: PlayerManager | None = None,
    snapshot_writer: BackgroundSnapshotWriter | None = None,
    snapshot_store: SnapshotStore | None = None,
) -> GameRuntime:
    simulator = create_world_simulator(config)
    return GameRuntime(
        world=world,
        simulator=simulator,
        modal_health_warmer=ModalHealthWarmer(modal_health_targets(config)),
        players=players,
        config=config,
        snapshot_writer=snapshot_writer,
        snapshot_store=snapshot_store,
    )


def _record_matches(
    record: dict[str, Any],
    *,
    phase: str | None,
    npc_id: str | None,
    tick_from: int | None,
    tick_to: int | None,
) -> bool:
    if phase and record.get("phase") != phase:
        return False
    if npc_id and record.get("npc_id") != npc_id:
        return False
    tick = record.get("tick")
    if tick_from is not None and isinstance(tick, int) and tick < tick_from:
        return False
    if tick_to is not None and isinstance(tick, int) and tick > tick_to:
        return False
    return True


def _normalize_log_record(line: int, record: dict[str, Any]) -> dict[str, Any]:
    return {
        "line": line,
        "tick": record.get("tick"),
        "phase": record.get("phase"),
        "npc_id": record.get("npc_id"),
        "model": _record_model(record),
        "summary": _record_summary(record),
        "record": record,
    }


def _record_model(record: dict[str, Any]) -> str | None:
    model = record.get("model")
    if isinstance(model, str):
        return model
    request = record.get("request")
    if isinstance(request, dict) and isinstance(request.get("model"), str):
        return request["model"]
    return None


def _record_summary(record: dict[str, Any]) -> str:
    summary = record.get("summary")
    if isinstance(summary, str) and summary:
        return summary
    phase = str(record.get("phase") or "record")
    parsed = record.get("parsed_action") or record.get("action")
    verdict = record.get("validator") or record.get("verdict") or record.get("reason")
    parts = [phase]
    if parsed:
        parts.append(f"action={parsed}")
    if verdict:
        parts.append(str(verdict))
    return "; ".join(parts)


def _character_summary(character: PlayerCharacter) -> dict[str, Any]:
    return {
        "token": character.token,
        "name": character.name,
        "icon": character.icon,
        "country_id": character.country_id,
        "npc_id": character.npc_id,
    }


def _player_error_payload(exc: PlayerError) -> dict[str, Any]:
    return {"error": exc.code, "message": exc.message}


def _player_error_status(exc: PlayerError) -> HTTPStatus:
    if exc.code == "invalid_token":
        return HTTPStatus.NOT_FOUND
    if exc.code == "character_dead":
        return HTTPStatus.GONE
    return HTTPStatus.BAD_REQUEST


@dataclass(slots=True)
class TickStatus:
    in_progress: bool = False
    pending_tick: int | None = None


@dataclass(frozen=True, slots=True)
class PendingCommand:
    kind: str
    raw_input: str


def tick_status_payload(tick_status: TickStatus) -> dict[str, Any]:
    return {
        "tick_in_progress": tick_status.in_progress,
        "pending_tick": tick_status.pending_tick,
    }


class ModalHealthWarmer:
    def __init__(
        self,
        targets: list[ModalHealthTarget],
        *,
        cooldown_seconds: float = 300,
        warmup_after_seconds: float = 2,
        warmup_retry_seconds: float = 5,
        opener: UrlOpener = urlopen,
    ) -> None:
        self._states = {
            target.id: ModalHealthState(target=target)
            for target in targets
        }
        self._cooldown_seconds = cooldown_seconds
        self._warmup_after_seconds = warmup_after_seconds
        self._warmup_retry_seconds = warmup_retry_seconds
        self._opener = opener
        self._lock = Lock()

    def trigger(self, *, force: bool = False) -> None:
        if not self._states:
            return

        now = time.monotonic()
        launches: list[tuple[str, str, int]] = []

        with self._lock:
            for target_id, state in self._states.items():
                if state.in_progress:
                    continue
                if not force and now - state.last_started_at < self._cooldown_seconds:
                    continue
                state.in_progress = True
                state.status = "checking"
                state.http_status = None
                state.last_started_at = now
                state.generation += 1
                launches.append((target_id, state.target.health_url, state.generation))

        for target_id, health_url, generation in launches:
            Thread(
                target=self._mark_warmup_if_pending,
                args=(target_id, generation),
                name="modal-health-warmup-status",
                daemon=True,
            ).start()
            Thread(
                target=self._run_one,
                args=(target_id, health_url, generation),
                name="modal-health-warmer",
                daemon=True,
            ).start()

    def statuses(self) -> list[dict[str, Any]]:
        with self._lock:
            return [
                {
                    "id": state.target.id,
                    "label": state.target.label,
                    "model": state.target.model,
                    "status": state.status,
                    "http_status": state.http_status,
                }
                for state in self._states.values()
            ]

    def _mark_warmup_if_pending(self, target_id: str, generation: int) -> None:
        time.sleep(self._warmup_after_seconds)
        with self._lock:
            state = self._states.get(target_id)
            if (
                state is not None
                and state.generation == generation
                and state.in_progress
                and state.status == "checking"
            ):
                state.status = "warmup"

    def _run_one(self, target_id: str, health_url: str, generation: int) -> None:
        headers = modal_proxy_auth_headers()
        while True:
            try:
                request = Request(health_url, headers=headers) if headers else health_url
                response = self._opener(request)
                try:
                    http_status = int(getattr(response, "status", 0))
                finally:
                    response.close()
            except HTTPError as exc:
                http_status = int(exc.code)
                if http_status != HTTPStatus.SERVICE_UNAVAILABLE:
                    self._set_status(target_id, generation, "error", http_status)
                    print(f"Modal health check failed for {health_url}: {exc}", flush=True)
                    return
            except (TimeoutError, URLError, OSError) as exc:
                self._set_status(target_id, generation, "error", None)
                print(f"Modal health check failed for {health_url}: {exc}", flush=True)
                return

            if http_status == HTTPStatus.OK:
                self._set_status(target_id, generation, "ready", http_status)
                print(f"Modal health check warmed {health_url}: {http_status}", flush=True)
                return

            if http_status == HTTPStatus.SERVICE_UNAVAILABLE:
                if not self._set_status(
                    target_id,
                    generation,
                    "warmup",
                    http_status,
                    in_progress=True,
                ):
                    return
                print(f"Modal health check warming {health_url}: {http_status}", flush=True)
                time.sleep(self._warmup_retry_seconds)
                continue

            self._set_status(target_id, generation, "error", http_status)
            print(f"Modal health check failed for {health_url}: {http_status}", flush=True)
            return

    def _set_status(
        self,
        target_id: str,
        generation: int,
        status: str,
        http_status: int | None,
        *,
        in_progress: bool = False,
    ) -> bool:
        with self._lock:
            state = self._states.get(target_id)
            if state is None or state.generation != generation:
                return False
            state.status = status
            state.http_status = http_status
            state.in_progress = in_progress
            return True


@dataclass(frozen=True, slots=True)
class ModalHealthTarget:
    id: str
    label: str
    model: str | None
    health_url: str


@dataclass(slots=True)
class ModalHealthState:
    target: ModalHealthTarget
    status: str = "unknown"
    http_status: int | None = None
    last_started_at: float = 0.0
    generation: int = 0
    in_progress: bool = False


class UrlResponse(Protocol):
    status: int

    def close(self) -> None: ...


class UrlOpener(Protocol):
    def __call__(self, url: str | Request) -> UrlResponse: ...


class HealthWarmer(Protocol):
    def trigger(self, *, force: bool = False) -> None: ...

    def statuses(self) -> list[dict[str, Any]]: ...


def modal_health_urls(config: GameConfig) -> list[str]:
    return [target.health_url for target in modal_health_targets(config)]


def modal_health_targets(config: GameConfig) -> list[ModalHealthTarget]:
    targets: list[ModalHealthTarget] = []
    connector_targets: list[tuple[str, str, ConnectorConfig | None]] = [
        ("npc_model", "Nemotron NPC", config.connector),
    ]
    for connector_id, connector in config.secondary_connectors.items():
        connector_targets.append(
            (f"npc_{connector_id}", f"{connector_id.capitalize()} NPC", connector)
        )
    for target_id, label, connector in connector_targets:
        if connector is None:
            continue
        health_url = modal_health_url(connector)
        if health_url is not None:
            targets.append(
                ModalHealthTarget(
                    id=target_id,
                    label=label,
                    model=connector.model,
                    health_url=health_url,
                )
            )
    return targets


def modal_health_url(connector: ConnectorConfig) -> str | None:
    if connector.type != "openai_compatible":
        return None

    root = connector.base_url or connector.api_url
    if not root:
        return None

    root = root.strip().rstrip("/")
    for suffix in ("/v1/chat/completions", "/chat/completions", "/v1"):
        if root.endswith(suffix):
            root = root.removesuffix(suffix)

    if ".modal.run" not in root:
        return None
    return f"{root}/health"