"""Obstacle generator for The Wizard's Oracles.

Produces 5 ``Obstacle`` objects per game. Trials 1-4 are LLM-generated
in the active theme's world. Trial 5 is always the fixed finale setup
for that theme (or, for the fantasy theme, the canonical
``prompts/dragon_setup.txt``).

The LLM is the source of truth — there is no offline mock bank. On
LLM failure, :func:`generate_obstacles` raises ``RuntimeError`` so the
caller can surface a clear error in the UI.
"""

from __future__ import annotations

import os
import random
from functools import lru_cache
from typing import Optional

from .llm_client import LLMClient
from .state import DRAGON_TRIAL, NUM_TRIALS, GameState, Obstacle
from .themes import get_theme


_THIS_DIR = os.path.dirname(os.path.abspath(__file__))
_PROMPTS_DIR = os.path.normpath(os.path.join(_THIS_DIR, "..", "prompts"))


# ---------------------------------------------------------------------------
# Cached prompt loaders
# ---------------------------------------------------------------------------


@lru_cache(maxsize=1)
def _load_obstacles_prompt() -> str:
    path = os.path.join(_PROMPTS_DIR, "obstacles_system.txt")
    with open(path, "r", encoding="utf-8") as fh:
        return fh.read()


@lru_cache(maxsize=1)
def _load_dragon_template() -> str:
    path = os.path.join(_PROMPTS_DIR, "dragon_setup.txt")
    with open(path, "r", encoding="utf-8") as fh:
        return fh.read()


# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------


def _call_llm_for_setups(
    state: GameState, client: LLMClient, language: str = "English",
) -> list[str]:
    """Call the live LLM for 4 obstacle setups in the active theme.

    Raises RuntimeError on any failure (network, malformed JSON, schema
    mismatch, duplicates). Never returns ``None``.
    """
    template = _load_obstacles_prompt()
    theme = get_theme(getattr(state, "theme", "fantasy"))
    system = template.format(
        hero_name=state.hero_name,
        village_name=state.village_name,
        language=language,
        theme_name=theme.display_name,
        mentor_archetype=theme.mentor_archetype,
        finale_descriptor=theme.finale_descriptor,
        finale_short=theme.finale_short,
        goal_verb=theme.goal_verb,
        hero_label=theme.hero_label,
        style_cues=theme.style_cues,
    )
    user = (
        f"Generate 4 obstacles for the {theme.hero_label} {state.hero_name} of "
        f"{state.village_name}, in the world of {theme.display_name}. "
        f"Remember: vivid, lethal, varied across the four shapes, and do NOT "
        f"include {theme.finale_short} — that is the fifth trial, fixed elsewhere."
    )
    try:
        from oracles.resolution import _model_for_lang, _wrap_with_language_force
        system = _wrap_with_language_force(system, language)
        payload = client.complete_json(
            system=system, user=user, model=_model_for_lang(language),
        )
    except Exception as e:
        raise RuntimeError(
            f"generate_obstacles: LLM call failed "
            f"[{type(e).__name__}] {e}"
        ) from e

    if not isinstance(payload, dict):
        raise RuntimeError(
            f"generate_obstacles: LLM returned non-JSON "
            f"({type(payload).__name__}, first 200 chars: "
            f"{str(payload)[:200]!r})"
        )
    items = payload.get("obstacles")
    if not isinstance(items, list) or len(items) < 4:
        raise RuntimeError(
            f"generate_obstacles: payload missing 4 entries (got "
            f"{type(items).__name__} of len "
            f"{len(items) if isinstance(items, list) else 'n/a'}, "
            f"keys={list(payload.keys())[:6]})"
        )
    setups: list[str] = []
    for entry in items[:4]:
        if not isinstance(entry, dict):
            raise RuntimeError("LLM obstacles entry not a dict")
        setup = entry.get("setup")
        if not isinstance(setup, str) or len(setup.strip()) < 30:
            raise RuntimeError("LLM obstacle setup missing or too short")
        setups.append(setup.strip())
    if len(set(setups)) != 4:
        raise RuntimeError("LLM returned duplicate obstacle setups")
    return setups


def _build_dragon(hero_name: str, theme_key: str = "fantasy",
                   village_name: str = "the Hollow") -> Obstacle:
    """Trial 5: the themed finale. Fantasy uses the canonical file
    template; every other theme uses its in-code ``finale_setup``."""
    theme = get_theme(theme_key)
    if theme.key == "fantasy" and not theme.finale_setup:
        template = _load_dragon_template()
    else:
        template = theme.finale_setup or _load_dragon_template()
    setup = (
        template
        .replace("{hero_name}", hero_name or "the hero")
        .replace("{village_name}", village_name or "his village")
        .strip()
    )
    return Obstacle(index=DRAGON_TRIAL, setup=setup, is_dragon=True)


# ---------------------------------------------------------------------------
# Public API
# ---------------------------------------------------------------------------


def generate_obstacles(
    state: GameState,
    client: LLMClient,
    rng: Optional[random.Random] = None,
    language: str = "English",
) -> list[Obstacle]:
    """Return exactly 5 ``Obstacle`` objects with indices 1..5.

    Every theme now walks the branching ``story_graph`` from root to a
    leaf:
      * Each fork is picked by the LLM seeded with one of the player's
        inscribed oracles (``walk_story_tree``).
      * For the **fantasy** theme the node setups are the hand-authored
        ``setup_en`` / ``setup_zh`` strings — instant, no LLM call.
      * For every other theme the abstract ``concept`` on each visited
        node is rendered by the LLM in the active theme's world via
        ``render_themed_setups`` (parallel calls).

    The path is stored on ``state.story_path`` so the epilogue can pick
    the leaf node's ``ending_id`` and the chronicle tree viz can mark
    visited vs. unexplored nodes.

    Raises RuntimeError if the LLM client is unconfigured. Mutates
    ``state.story_path`` and ``state.story_node_setups``.
    """
    if client is None or getattr(client, "using_mock", True):
        raise RuntimeError(
            "LLM client is not configured. Set MODAL_URL, MODAL_KEY and "
            "MODAL_SECRET so obstacles can be generated."
        )

    from oracles.story_graph import walk_story_tree, render_themed_setups
    from oracles.themes import get_theme

    theme_key = getattr(state, "theme", "fantasy") or "fantasy"
    theme = get_theme(theme_key)

    oracle_texts = [o.text for o in state.oracles] if state.oracles else []
    path = walk_story_tree(oracle_texts, client, language=language)
    state.story_path = [n.id for n in path]

    # Render each node's setup in the active theme. Fantasy uses hand-
    # authored text and short-circuits; other themes hit the LLM in
    # parallel (max 5 calls, one per node).
    setups_by_id = render_themed_setups(
        path, theme, client,
        language=language,
        hero_name=state.hero_name or "the hero",
        village_name=state.village_name or "his village",
    )

    def _fill(s: str) -> str:
        return (s or "") \
            .replace("{hero_name}", state.hero_name or "the hero") \
            .replace("{village_name}", state.village_name or "his village")

    obstacles: list[Obstacle] = []
    for i, node in enumerate(path):
        obstacles.append(Obstacle(
            index=i + 1,
            setup=_fill(setups_by_id.get(node.id, "")),
            is_dragon=node.is_dragon,
        ))

    assert len(obstacles) == NUM_TRIALS
    assert obstacles[-1].is_dragon
    assert obstacles[-1].index == DRAGON_TRIAL
    return obstacles