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// deno-lint-ignore-file no-explicit-anyimport { getTypeAndConversation } from "./helpers.ts"import { AnyMiddlewareArgs, Middleware } from "./types/index.ts"
/** * Storage backend used by the conversation context middleware */export interface ConversationStore<ConversationState = any> {    // NOTE: expiresAt is in milliseconds    set(        conversationId: string,        value: ConversationState,        expiresAt?: number,    ): Promise<unknown>    get(conversationId: string): Promise<ConversationState>}
/** * Default implementation of ConversationStore, which stores data in memory. * * This should not be used in situations where there is more than once instance of the app running because state will * not be shared amongst the processes. */export class MemoryStore<ConversationState = any> implements ConversationStore<ConversationState> {    private state: Map<string, { value: ConversationState; expiresAt?: number }> = new Map()
    public set(        conversationId: string,        value: ConversationState,        expiresAt?: number,    ): Promise<void> {        return new Promise((resolve) => {            this.state.set(conversationId, { value, expiresAt })            resolve()        })    }
    public get(conversationId: string): Promise<ConversationState> {        return new Promise((resolve, reject) => {            const entry = this.state.get(conversationId)            if (entry !== undefined) {                if (entry.expiresAt !== undefined && Date.now() > entry.expiresAt) {                    // release the memory                    this.state.delete(conversationId)                    reject(new Error("Conversation expired"))                }                resolve(entry.value)            }            reject(new Error("Conversation not found"))        })    }}
/** * Conversation context global middleware. * * This middleware allows listeners (and other middleware) to store state related to the conversationId of an incoming * event using the `context.updateConversation()` function. That state will be made available in future events that * take place in the same conversation by reading from `context.conversation`. * * @param store storage backend used to store and retrieve all conversation state * @param logger a logger */export function conversationContext<ConversationState = any>(    store: ConversationStore<ConversationState>,): Middleware<AnyMiddlewareArgs> {    return async ({ body, context, next, logger }) => {        const { conversationId } = getTypeAndConversation(body)        if (conversationId !== undefined) {            // TODO: expiresAt is not passed through to store.set            context.updateConversation = (conversation: ConversationState) => store.set(conversationId, conversation)            try {                context.conversation = await store.get(conversationId)                logger.debug(`Conversation context loaded for ID ${conversationId}`)            } catch (error) {                logger.debug(                    `Conversation context failed loading for ID: ${conversationId}, error: ${error.message}`,                )            }        } else {            logger.debug("No conversation ID for incoming event")        }        // TODO: remove the non-null assertion operator        await next!()    }}