"""CaPAgent — the core code-as-policy agent.

Generates Python robot control code, executes in sandbox, iterates
with multi-turn feedback. Orchestrates VDM, ensemble, and skill library.
"""

from __future__ import annotations

import argparse
import logging
import time
from pathlib import Path
from typing import Any

import numpy as np

from anima_naka.agent.ensemble import EnsembleReasoner
from anima_naka.agent.llm_client import LLMClient
from anima_naka.agent.prompts import build_initial_prompt, build_multiturn_prompt
from anima_naka.agent.vdm import VisualDifferencingModule
from anima_naka.config import NakaConfig
from anima_naka.constants import SINGLE_TURN_TIERS
from anima_naka.executor.code_parser import CodeParser
from anima_naka.skills.library import SkillLibrary
from anima_naka.types import TrialResult

logger = logging.getLogger("anima_naka.agent")


class CaPAgent:
    """Code-as-Policy agent — NAKA's heart.

    Takes task description + API docs -> generates Python code -> executes -> iterates.
    """

    def __init__(self, config: NakaConfig):
        self.config = config
        self.llm = LLMClient(model=config.agent_model, temperature=config.agent_temperature)

        self.vdm: VisualDifferencingModule | None = None
        if config.use_visual_differencing:
            self.vdm = VisualDifferencingModule(self.llm)

        self.skill_library: SkillLibrary | None = None
        if config.use_skill_library:
            self.skill_library = SkillLibrary(config.skill_library_path)

        self.ensemble: EnsembleReasoner | None = None
        if config.use_parallel_ensemble:
            self.ensemble = EnsembleReasoner()

    def run_trial(self, env: Any) -> TrialResult:
        """Execute a complete trial: reset -> code gen -> execute -> multi-turn -> result."""
        start_time = time.perf_counter()
        obs, info = env.reset()

        skill_code = ""
        if self.skill_library:
            skill_code = self.skill_library.get_prompt_injection()

        messages = build_initial_prompt(
            task_description=info["task_description"],
            api_documentation=info["api_documentation"],
            skill_library_code=skill_code,
        )

        if self.vdm and "robot0_robotview" in obs:
            rgb = self._get_rgb(obs)
            if rgb is not None:
                scene_desc = self.vdm.describe_scene(rgb, info["task_description"])
                messages[-1]["content"] += f"\n\nCurrent scene observation:\n{scene_desc}"

        response = self._generate(messages)

        code_blocks: list[str] = []
        execution_results = []
        prev_rgb = self._get_rgb(obs)
        reward = 0.0

        for _ in range(self.config.multiturn_limit):
            code_blocks_raw = CodeParser.extract_code_blocks(response)
            if not code_blocks_raw:
                break
            code = code_blocks_raw[0]
            code_blocks.append(code)

            obs, reward, terminated, truncated, exec_info = env.step(code)
            execution_results.append(exec_info["execution_result"])

            if terminated or reward >= 1.0:
                break

            if truncated:
                break

            if self.config.tier in SINGLE_TURN_TIERS:
                break

            visual_diff = None
            if self.vdm and prev_rgb is not None:
                curr_rgb = self._get_rgb(obs)
                if curr_rgb is not None:
                    visual_diff = self.vdm.describe_changes(
                        prev_rgb,
                        curr_rgb,
                        info["task_description"],
                    )

            decision_messages = build_multiturn_prompt(
                executed_code=code,
                stdout=exec_info["stdout"],
                stderr=exec_info["stderr"],
                visual_diff=visual_diff,
                reward=reward,
                task_completed=exec_info.get("task_completed", False),
            )
            decision_response = self._generate(decision_messages)
            decision, new_code = CodeParser.parse_decision(decision_response)
            if decision == "finish" or new_code is None:
                break

            response = new_code
            prev_rgb = self._get_rgb(obs)

        if reward >= 1.0 and self.skill_library:
            self.skill_library.extract_and_add(code_blocks, info.get("task_description", ""))

        duration = time.perf_counter() - start_time
        return TrialResult(
            trial_id=0,
            reward=reward,
            task_completed=reward >= 1.0,
            turns=len(code_blocks),
            code_blocks=code_blocks,
            execution_results=execution_results,
            duration_s=duration,
        )

    def _generate(self, messages: list[dict[str, str]]) -> str:
        """Generate code using LLM (single or ensemble)."""
        if self.ensemble:
            return self.ensemble.generate(messages)
        return self.llm.query(messages)

    @staticmethod
    def _get_rgb(obs: dict) -> np.ndarray | None:
        """Extract RGB image from observation dict."""
        try:
            return obs["robot0_robotview"]["images"]["rgb"]
        except (KeyError, TypeError):
            return None


def _normalize_simulator(value: str | None) -> str:
    if value is None:
        return "mock"
    normalized = value.strip().lower()
    if normalized in {"real", "robosuite"}:
        return "robosuite"
    if normalized in {"mock", "none", "sim", ""}:
        return "mock"
    raise ValueError(f"Unsupported simulator '{value}'. Use mock or robosuite.")


def main() -> None:
    """Entrypoint for module execution.

    Performs a smoke-load check and prints resolved configuration.
    """
    parser = argparse.ArgumentParser(description="Run CaP-Agent smoke check")
    parser.add_argument("--config", type=str, default="configs/debug.toml")
    parser.add_argument("--sim", type=_normalize_simulator, default=None)
    args = parser.parse_args()

    cfg_path = Path(args.config)
    config = NakaConfig.from_toml(cfg_path) if cfg_path.exists() else NakaConfig()
    if args.sim is not None:
        config = config.model_copy(update={"simulator": args.sim})

    print(
        f"CaP-Agent initialized | config={args.config} | "
        f"simulator={config.simulator} | task={config.task} | tier={config.tier}"
    )


if __name__ == "__main__":
    main()