from __future__ import annotations

from dataclasses import dataclass, field
from typing import Any

from .fixtures import (
    BENCHMARK_NAME,
    DEFAULT_SUCCESS_THRESHOLD,
    KB_ARTICLES,
    KnowledgeBaseArticle,
    TaskFixture,
    get_task_fixture,
    list_task_ids,
)
from .models import (
    ACTION_TYPE_NAMES,
    AccountLookupResult,
    ConversationTurn,
    KBSearchResult,
    ErrorToolResult,
    EscalateTicketAction,
    EscalationResult,
    IssueRefundAction,
    LookupAccountAction,
    RefundResult,
    ReplyResult,
    ResolveResult,
    SearchKBAction,
    SupportTicketAction,
    SupportTicketObservation,
    SupportTicketStepResult,
    ToolResult,
    parse_action,
)
from .scoring import build_scorecard, normalize_text


@dataclass
class SessionState:
    fixture: TaskFixture
    ticket_status: str = "open"
    steps_taken: int = 0
    conversation_history: list[ConversationTurn] = field(default_factory=list)
    action_history: list[dict[str, Any]] = field(default_factory=list)
    reply_history: list[dict[str, Any]] = field(default_factory=list)
    known_facts: dict[str, Any] = field(default_factory=dict)
    kb_articles_seen: set[str] = field(default_factory=set)
    search_signatures: set[str] = field(default_factory=set)
    lookup_performed: bool = False
    lookup_customer_id: str | None = None
    refund_record: dict[str, Any] | None = None
    refund_attempted: bool = False
    resolution_code: str | None = None
    escalation: dict[str, Any] | None = None
    done: bool = False
    terminal_reason: str | None = None
    previous_score: float = 0.0
    last_tool_result: ToolResult | None = None
    last_action_error: str | None = None


class SupportTicketEnvironment:
    benchmark_name = BENCHMARK_NAME
    max_steps = 8
    step_cost = 0.01
    invalid_action_penalty = 0.10
    repeated_action_penalty = 0.02
    success_threshold = DEFAULT_SUCCESS_THRESHOLD

    def __init__(self, task_id: str | None = None) -> None:
        self._default_task_id = task_id or list_task_ids()[0]
        self._session: SessionState | None = None

    def reset(self, task_id: str | None = None) -> SupportTicketStepResult:
        fixture = get_task_fixture(task_id or self._default_task_id)
        self._session = SessionState(
            fixture=fixture,
            conversation_history=[
                ConversationTurn(
                    role="customer",
                    message=fixture.ticket.message,
                    step_index=0,
                )
            ],
        )
        return self._build_result(reward=0.0)

    def step(self, action: SupportTicketAction | dict[str, Any]) -> SupportTicketStepResult:
        session = self._require_session()
        if session.done:
            session.last_action_error = "episode_already_done"
            session.last_tool_result = ErrorToolResult(
                tool_name="error",
                success=False,
                error_code="episode_already_done",
                message="This ticket is already terminal. Reset the environment before stepping again.",
            )
            return self._build_result(reward=-self.invalid_action_penalty)

        invalid_penalty = 0.0
        redundancy_penalty = 0.0
        session.last_action_error = None

        try:
            parsed_action = parse_action(action)
        except Exception as exc:
            session.steps_taken += 1
            session.last_action_error = f"invalid_action: {exc}"
            session.last_tool_result = ErrorToolResult(
                tool_name="error",
                success=False,
                error_code="invalid_action",
                message=str(exc),
            )
            invalid_penalty = self.invalid_action_penalty
            self._record_action({"action_type": "invalid"}, False)
            if session.steps_taken >= self.max_steps:
                session.done = True
                session.terminal_reason = "max_steps_exceeded"
            return self._finalize_step(invalid_penalty=invalid_penalty, redundancy_penalty=0.0)

        session.steps_taken += 1
        session.last_tool_result, invalid_penalty, redundancy_penalty = self._apply_action(parsed_action)
        action_succeeded = bool(getattr(session.last_tool_result, "success", False))
        self._record_action(parsed_action.model_dump(mode="json"), action_succeeded)

        if not session.done and session.steps_taken >= self.max_steps:
            session.done = True
            session.terminal_reason = "max_steps_exceeded"

        return self._finalize_step(
            invalid_penalty=invalid_penalty,
            redundancy_penalty=redundancy_penalty,
        )

    def state(self) -> dict[str, Any]:
        session = self._require_session()
        scorecard = build_scorecard(session.fixture, session)
        return {
            "benchmark_name": self.benchmark_name,
            "task_id": session.fixture.task_id,
            "ticket_status": session.ticket_status,
            "steps_taken": session.steps_taken,
            "steps_remaining": max(self.max_steps - session.steps_taken, 0),
            "conversation_history": [turn.model_dump(mode="json") for turn in session.conversation_history],
            "audit_log": list(session.action_history),
            "known_facts": dict(session.known_facts),
            "current_rubric_score": scorecard.score,
            "score_breakdown": scorecard.model_dump(mode="json"),
            "terminal_reason": session.terminal_reason,
            "done": session.done,
        }

    def _apply_action(self, action: SupportTicketAction) -> tuple[ToolResult, float, float]:
        session = self._require_session()
        invalid_penalty = 0.0
        redundancy_penalty = 0.0

        if isinstance(action, SearchKBAction):
            query_signature = normalize_text(action.query)
            if query_signature in session.search_signatures:
                redundancy_penalty = self.repeated_action_penalty
            session.search_signatures.add(query_signature)
            articles = self._search_knowledge_base(action.query)
            article_ids = [article.article_id for article in articles]
            session.kb_articles_seen.update(article_ids)
            session.known_facts["kb_articles_seen"] = sorted(session.kb_articles_seen)
            session.known_facts["kb_titles_seen"] = [KB_ARTICLES[article_id].title for article_id in sorted(session.kb_articles_seen)]
            result = KBSearchResult(
                tool_name="search_kb",
                success=bool(articles),
                query=action.query,
                article_ids=article_ids,
                snippets=[article.snippet for article in articles],
                message="Knowledge base search completed." if articles else "No KB articles matched the query.",
            )
            return result, invalid_penalty, redundancy_penalty

        if isinstance(action, LookupAccountAction):
            if action.customer_id != session.fixture.account.customer_id:
                session.last_action_error = "unknown_customer_id"
                result = ErrorToolResult(
                    tool_name="error",
                    success=False,
                    error_code="unknown_customer_id",
                    message=f"No account found for customer_id={action.customer_id}.",
                )
                return result, self.invalid_action_penalty, redundancy_penalty

            if session.lookup_performed and session.lookup_customer_id == action.customer_id:
                redundancy_penalty = self.repeated_action_penalty

            account = session.fixture.account
            session.lookup_performed = True
            session.lookup_customer_id = action.customer_id
            account_summary = {
                "customer_id": account.customer_id,
                "organization_name": account.organization_name,
                "plan": account.plan,
                "tenure_years": account.tenure_years,
                "arr_usd": account.arr_usd,
                "duplicate_charge_amount_cents": account.duplicate_charge_amount_cents,
                "duplicate_charge_count": account.duplicate_charge_count,
                "duplicate_charge_refund_eligible": account.duplicate_charge_refund_eligible,
                "legal_threat": account.legal_threat,
                "incident_severity": account.incident_severity,
            }
            session.known_facts["account"] = account_summary
            result = AccountLookupResult(
                tool_name="lookup_account",
                success=True,
                customer_id=action.customer_id,
                account_summary=account_summary,
                message="Account lookup completed.",
            )
            return result, invalid_penalty, redundancy_penalty

        if action.action_type == "send_reply":
            reply = action.message.strip()
            session.reply_history.append({"message": reply, "step_index": session.steps_taken})
            session.conversation_history.append(
                ConversationTurn(role="agent", message=reply, step_index=session.steps_taken)
            )
            result = ReplyResult(
                tool_name="send_reply",
                success=True,
                message_preview=reply[:120],
                message="Reply sent to the customer.",
            )
            return result, invalid_penalty, redundancy_penalty

        if isinstance(action, IssueRefundAction):
            session.refund_attempted = True
            account = session.fixture.account
            if not session.lookup_performed:
                session.last_action_error = "lookup_required_before_refund"
                result = ErrorToolResult(
                    tool_name="error",
                    success=False,
                    error_code="lookup_required_before_refund",
                    message="lookup_account must succeed before issue_refund can be used.",
                )
                return result, self.invalid_action_penalty, redundancy_penalty

            if not account.duplicate_charge_refund_eligible or not account.duplicate_charge_amount_cents:
                session.last_action_error = "refund_not_applicable"
                result = RefundResult(
                    tool_name="issue_refund",
                    success=False,
                    refunded=False,
                    amount_cents=action.amount_cents,
                    reason_code=action.reason_code,
                    message="No duplicate charge is eligible for refund on this account.",
                )
                return result, self.invalid_action_penalty, redundancy_penalty

            if action.amount_cents != account.duplicate_charge_amount_cents or action.reason_code != "duplicate_charge":
                session.last_action_error = "incorrect_refund_payload"
                result = RefundResult(
                    tool_name="issue_refund",
                    success=False,
                    refunded=False,
                    amount_cents=action.amount_cents,
                    reason_code=action.reason_code,
                    message="Refund payload does not match the verified duplicate charge.",
                )
                return result, self.invalid_action_penalty, redundancy_penalty

            session.refund_record = {
                "amount_cents": action.amount_cents,
                "reason_code": action.reason_code,
                "step_index": session.steps_taken,
            }
            result = RefundResult(
                tool_name="issue_refund",
                success=True,
                refunded=True,
                amount_cents=action.amount_cents,
                reason_code=action.reason_code,
                message="Refund recorded successfully.",
            )
            return result, invalid_penalty, redundancy_penalty

        if action.action_type == "resolve_ticket":
            session.resolution_code = action.resolution_code
            session.ticket_status = "resolved"
            session.done = True
            session.terminal_reason = "resolved"
            result = ResolveResult(
                tool_name="resolve_ticket",
                success=True,
                resolution_code=action.resolution_code,
                ticket_status="resolved",
                message="Ticket marked as resolved.",
            )
            return result, invalid_penalty, redundancy_penalty

        if isinstance(action, EscalateTicketAction):
            session.escalation = {
                "queue": action.queue,
                "priority": action.priority,
                "summary": action.summary,
                "step_index": session.steps_taken,
            }
            session.ticket_status = "escalated"
            session.done = True
            session.terminal_reason = "escalated"
            result = EscalationResult(
                tool_name="escalate_ticket",
                success=True,
                queue=action.queue,
                priority=action.priority,
                summary=action.summary,
                ticket_status="escalated",
                message="Ticket escalated.",
            )
            return result, invalid_penalty, redundancy_penalty

        session.last_action_error = "unsupported_action"
        return (
            ErrorToolResult(
                tool_name="error",
                success=False,
                error_code="unsupported_action",
                message=f"Unsupported action type: {type(action).__name__}",
            ),
            self.invalid_action_penalty,
            redundancy_penalty,
        )

    def _search_knowledge_base(self, query: str) -> list[KnowledgeBaseArticle]:
        query_terms = set(normalize_text(query).split())
        ranked: list[tuple[int, str, KnowledgeBaseArticle]] = []
        for article in KB_ARTICLES.values():
            searchable = normalize_text(" ".join((article.title, article.content, " ".join(article.tags))))
            article_terms = set(searchable.split())
            score = len(query_terms & article_terms)
            if score > 0:
                ranked.append((score, article.article_id, article))
        ranked.sort(key=lambda item: (-item[0], item[1]))
        return [article for _, _, article in ranked[:3]]

    def _record_action(self, action_payload: dict[str, Any], action_succeeded: bool) -> None:
        session = self._require_session()
        session.action_history.append(
            {
                "step_index": session.steps_taken,
                "action": action_payload,
                "success": action_succeeded,
                "ticket_status": session.ticket_status,
            }
        )

    def _finalize_step(self, invalid_penalty: float, redundancy_penalty: float) -> SupportTicketStepResult:
        session = self._require_session()
        scorecard = build_scorecard(session.fixture, session)
        reward = round(
            (scorecard.score - session.previous_score) - self.step_cost - invalid_penalty - redundancy_penalty,
            6,
        )
        session.previous_score = scorecard.score
        return SupportTicketStepResult(
            observation=self._build_observation(),
            reward=reward,
            done=session.done,
            info={
                "task_id": session.fixture.task_id,
                "benchmark_name": self.benchmark_name,
                "score": scorecard.score,
                "score_breakdown": scorecard.model_dump(mode="json"),
                "success": scorecard.score >= self.success_threshold,
                "success_threshold": self.success_threshold,
                "terminal_reason": session.terminal_reason,
                "invalid_penalty": invalid_penalty,
                "redundancy_penalty": redundancy_penalty,
            },
        )

    def _build_observation(self) -> SupportTicketObservation:
        session = self._require_session()
        ticket = session.fixture.ticket
        return SupportTicketObservation(
            task_id=session.fixture.task_id,
            ticket_id=ticket.ticket_id,
            ticket_status=session.ticket_status,
            customer_id=ticket.customer_id,
            organization_name=ticket.organization_name,
            subject=ticket.subject,
            customer_message=ticket.message,
            conversation_history=list(session.conversation_history),
            last_tool_result=session.last_tool_result,
            steps_taken=session.steps_taken,
            steps_remaining=max(self.max_steps - session.steps_taken, 0),
            available_action_types=list(ACTION_TYPE_NAMES),
            last_action_error=session.last_action_error,
            known_facts=dict(session.known_facts),
        )

    def _build_result(self, reward: float) -> SupportTicketStepResult:
        session = self._require_session()
        scorecard = build_scorecard(session.fixture, session)
        session.previous_score = scorecard.score
        return SupportTicketStepResult(
            observation=self._build_observation(),
            reward=reward,
            done=session.done,
            info={
                "task_id": session.fixture.task_id,
                "benchmark_name": self.benchmark_name,
                "score": scorecard.score,
                "score_breakdown": scorecard.model_dump(mode="json"),
                "success": scorecard.score >= self.success_threshold,
                "success_threshold": self.success_threshold,
                "terminal_reason": session.terminal_reason,
                "invalid_penalty": 0.0,
                "redundancy_penalty": 0.0,
            },
        )

    def _require_session(self) -> SessionState:
        if self._session is None:
            raise RuntimeError("Environment has not been reset yet.")
        return self._session