import { ResponseError } from "vscode-jsonrpc";
import type WebSocket from "ws";
import type { CharacterCard, CharacterSummary } from "../../config/character-card.js";
import type { GroupChatState } from "../../data/group-chat-state.js";
import type { ClientMessage } from "../../protocol/messages.js";
import { ERROR_CHARACTER_UNAVAILABLE, ERROR_CODE_CHARACTER_UNAVAILABLE } from "../../shared/messages.js";

type ClaimCharacterMessage = Extract<ClientMessage, { method: "claim_character" }>;

/** 连接上下文窄接口（creator-runtime 的 ConnectionContext 结构子集）。 */
interface ClaimConnectionLike {
	sessionId: string | null;
	online: boolean;
	reservedCharacterId: string | null;
}

interface ClaimPipelineDependencies {
	state: GroupChatState;
	characters: ReadonlyMap<string, CharacterCard>;
	isCharacterAvailable: (characterId: string) => boolean;
	/** 预留超时定时器（runtime 方法注入：超时释放 + close，跨消息编排归 runtime）。 */
	startReadyTimer: (socket: WebSocket, connection: ClaimConnectionLike) => void;
	toCharacterSummaryMessage: (character: CharacterSummary) => {
		character_id: string;
		name: string;
		description: string;
	};
}

/**
 * claim_character 门面（短流程：粒度约束不建管线）。阶段：
 * validate（会话归属/在线/重复预留/角色存在可用）→ commit 预留 → 定时器 + 响应。
 * 只显式读写 runtime 会话状态（决策 7），不缓存跨消息状态。
 */
export class ClaimPipeline {
	constructor(private readonly deps: ClaimPipelineDependencies) {}

	run(
		socket: WebSocket,
		connection: ClaimConnectionLike,
		message: ClaimCharacterMessage,
	): {
		character: { character_id: string; name: string; description: string; path: string };
	} {
		const character = this.deps.characters.get(message.params.character_id);
		if (
			connection.sessionId === null ||
			connection.online ||
			connection.reservedCharacterId !== null ||
			!character ||
			!this.deps.isCharacterAvailable(message.params.character_id)
		) {
			throw new ResponseError(ERROR_CODE_CHARACTER_UNAVAILABLE, ERROR_CHARACTER_UNAVAILABLE);
		}

		this.deps.state.characterReservations.set(character.characterId, connection.sessionId);
		connection.reservedCharacterId = character.characterId;
		this.deps.startReadyTimer(socket, connection);
		return {
			character: {
				...this.deps.toCharacterSummaryMessage(character),
				path: character.path,
			},
		};
	}
}