"""Core Identity Environment - server-side implementation."""

import random
from typing import Any, Dict, Optional
from dataclasses import dataclass, field
from uuid import uuid4

try:
    from openenv.core.env_server.interfaces import Environment
    from openenv.core.env_server.types import Action, Observation, State
except ImportError:
    from openenv.core.env_server.interfaces import Environment
    from openenv.core.env_server.types import Action, Observation, State

from core_identity_env.models import (
    CoreIdentityObservation,
    CoreIdentityAction,
    VerificationResult,
    TaskType,
    IdentityDocument,
    UserCredentials,
    UserProfile,
)
from core_identity_env.tasks.definitions import (
    get_all_tasks,
    get_task_by_id,
    CoreIdentityTask,
    CoreIdentityTaskEvaluator,
    GradingResult,
)


@dataclass
class _EpisodeState:
    task: CoreIdentityTask
    episode_id: str
    current_step: int = 0
    cumulative_reward: float = 0.0
    submitted_verification: Dict[str, Any] = field(default_factory=dict)
    episode_complete: bool = False


DIFFICULTY_WEIGHTS = {
    "easy": 0.15,
    "medium": 0.12,
    "hard": 0.08,
}


class CoreIdentityEnvironment(Environment):
    """Server-side Core Identity Environment compliant with OpenEnv spec."""

    def __init__(
        self,
        task_id: Optional[str] = None,
        seed: Optional[int] = None,
        max_steps: int = 10,
    ):
        self._task_id = task_id
        self._seed = seed
        self._max_steps = max_steps
        self._ep: Optional[_EpisodeState] = None
        self._state = State(episode_id=str(uuid4()), step_count=0)

        if seed is not None:
            random.seed(seed)

    def reset(
        self,
        seed: Optional[int] = None,
        episode_id: Optional[str] = None,
        task_id: Optional[str] = None,
        **kwargs: Any,
    ) -> Observation:
        if seed is not None:
            random.seed(seed)

        target_task_id = task_id or self._task_id
        if target_task_id:
            task = get_task_by_id(target_task_id)
        else:
            task = random.choice(get_all_tasks())

        eid = episode_id or str(uuid4())

        document = None
        credentials = None
        profile = None

        if task.document:
            document = IdentityDocument(**task.document)
        if task.credentials:
            credentials = UserCredentials(**task.credentials)
        if task.profile:
            profile = UserProfile(**task.profile)

        self._ep = _EpisodeState(
            task=task,
            episode_id=eid,
            current_step=0,
            cumulative_reward=0.0,
            submitted_verification={},
            episode_complete=False,
        )
        self._state = State(episode_id=eid, step_count=0)

        obs = self._build_observation(document, credentials, profile)
        return Observation(
            done=False,
            reward=0.0,
            metadata=obs.model_dump(),
        )

    def step(
        self,
        action: Action,
        timeout_s: Optional[float] = None,
        **kwargs: Any,
    ) -> Observation:
        if self._ep is None:
            return Observation(
                done=True,
                reward=0.0,
                metadata={"error": "Environment not reset. Call reset() first."},
            )

        if self._ep.episode_complete:
            return Observation(
                done=True,
                reward=0.0,
                metadata={"error": "Episode already finished."},
            )

        action_data: Dict[str, Any] = {}
        if hasattr(action, "data") and isinstance(action.data, dict):
            action_data = action.data
        elif isinstance(action, dict):
            action_data = action
        elif hasattr(action, "__dict__"):
            action_data = vars(action)

        try:
            env_action = CoreIdentityAction.model_validate(action_data)
        except Exception:
            env_action = CoreIdentityAction(verification=VerificationResult())

        self._ep.current_step += 1
        self._state.step_count = self._ep.current_step

        verification_dict = env_action.verification.model_dump()
        self._ep.submitted_verification = verification_dict

        evaluator = CoreIdentityTaskEvaluator(self._ep.task)
        result = evaluator.grade(verification_dict)

        reward_value = result.score * DIFFICULTY_WEIGHTS.get(self._ep.task.difficulty, 0.1)

        terminal = env_action.submit or self._ep.current_step >= self._ep.task.max_steps

        if terminal:
            final_score = result.score
            if self._ep.current_step <= self._ep.task.max_steps * 0.5:
                final_score += 0.1
            reward_value = min(1.0, final_score)
            self._ep.episode_complete = True

        self._ep.cumulative_reward += reward_value

        document = None
        credentials = None
        profile = None
        if self._ep.task.document:
            document = IdentityDocument(**self._ep.task.document)
        if self._ep.task.credentials:
            credentials = UserCredentials(**self._ep.task.credentials)
        if self._ep.task.profile:
            profile = UserProfile(**self._ep.task.profile)

        obs = self._build_observation(document, credentials, profile)
        step_result = {
            "observation": obs.model_dump(),
            "reward": {
                "value": reward_value,
                "accuracy": result.accuracy,
                "completeness": result.completeness,
                "total": result.score,
                "feedback": result.feedback,
            },
            "done": self._ep.episode_complete,
            "info": {
                "step": self._ep.current_step,
                "is_final": self._ep.episode_complete,
            },
        }

        return Observation(
            done=self._ep.episode_complete,
            reward=reward_value,
            metadata=step_result,
        )

    @property
    def state(self) -> State:
        return self._state

    def _build_observation(
        self,
        document: Optional[IdentityDocument],
        credentials: Optional[UserCredentials],
        profile: Optional[UserProfile],
    ) -> CoreIdentityObservation:
        ep = self._ep
        return CoreIdentityObservation(
            task_id=ep.task.task_id,
            task_type=TaskType(ep.task.task_type),
            task_name=ep.task.name,
            task_description=ep.task.description,
            difficulty=ep.task.difficulty,
            document=document,
            credentials=credentials,
            profile=profile,
            expected_verification=ep.task.expected_verification,
            challenge_data=ep.task.challenge_data,
            max_steps=ep.task.max_steps,
        )

    def get_task_list(self) -> Dict[str, Any]:
        return [
            {
                "task_id": t.task_id,
                "name": t.name,
                "task_type": t.task_type,
                "difficulty": t.difficulty,
                "description": t.description,
            }
            for t in get_all_tasks()
        ]