import { CACHE_ONE_YEAR } from "../../../lib/constants";
import { addImplicitTags, validateRevalidate, validateTags } from "../../lib/patch-fetch";
import { staticGenerationAsyncStorage } from "../../../client/components/static-generation-async-storage.external";
let noStoreFetchIdx = 0;
async function cacheNewResult(result, incrementalCache, cacheKey, tags, revalidate, fetchIdx, fetchUrl) {
    await incrementalCache.set(cacheKey, {
        kind: "FETCH",
        data: {
            headers: {},
            // TODO: handle non-JSON values?
            body: JSON.stringify(result),
            status: 200,
            url: ""
        },
        revalidate: typeof revalidate !== "number" ? CACHE_ONE_YEAR : revalidate
    }, {
        revalidate,
        fetchCache: true,
        tags,
        fetchIdx,
        fetchUrl
    });
    return;
}
/**
 * This function allows you to cache the results of expensive operations, like database queries, and reuse them across multiple requests.
 *
 * Read more: [Next.js Docs: `unstable_cache`](https://nextjs.org/docs/app/api-reference/functions/unstable_cache)
 */ export function unstable_cache(cb, keyParts, options = {}) {
    if (options.revalidate === 0) {
        throw new Error(`Invariant revalidate: 0 can not be passed to unstable_cache(), must be "false" or "> 0" ${cb.toString()}`);
    }
    // Validate the tags provided are valid
    const tags = options.tags ? validateTags(options.tags, `unstable_cache ${cb.toString()}`) : [];
    // Validate the revalidate options
    validateRevalidate(options.revalidate, `unstable_cache ${cb.name || cb.toString()}`);
    // Stash the fixed part of the key at construction time. The invocation key will combine
    // the fixed key with the arguments when actually called
    // @TODO if cb.toString() is long we should hash it
    // @TODO come up with a collision-free way to combine keyParts
    // @TODO consider validating the keyParts are all strings. TS can't provide runtime guarantees
    // and the error produced by accidentally using something that cannot be safely coerced is likely
    // hard to debug
    const fixedKey = `${cb.toString()}-${Array.isArray(keyParts) && keyParts.join(",")}`;
    const cachedCb = async (...args)=>{
        const store = staticGenerationAsyncStorage.getStore();
        // We must be able to find the incremental cache otherwise we throw
        const maybeIncrementalCache = (store == null ? void 0 : store.incrementalCache) || globalThis.__incrementalCache;
        if (!maybeIncrementalCache) {
            throw new Error(`Invariant: incrementalCache missing in unstable_cache ${cb.toString()}`);
        }
        const incrementalCache = maybeIncrementalCache;
        // Construct the complete cache key for this function invocation
        // @TODO stringify is likely not safe here. We will coerce undefined to null which will make
        // the keyspace smaller than the execution space
        const invocationKey = `${fixedKey}-${JSON.stringify(args)}`;
        const cacheKey = await incrementalCache.fetchCacheKey(invocationKey);
        const fetchUrl = `unstable_cache ${cb.name ? ` ${cb.name}` : cacheKey}`;
        const fetchIdx = (store ? store.nextFetchId : noStoreFetchIdx) ?? 1;
        if (store) {
            store.nextFetchId = fetchIdx + 1;
            // We are in an App Router context. We try to return the cached entry if it exists and is valid
            // If the entry is fresh we return it. If the entry is stale we return it but revalidate the entry in
            // the background. If the entry is missing or invalid we generate a new entry and return it.
            // We update the store's revalidate property if the option.revalidate is a higher precedence
            if (typeof options.revalidate === "number") {
                if (typeof store.revalidate === "number" && store.revalidate < options.revalidate) {
                // The store is already revalidating on a shorter time interval, leave it alone
                } else {
                    store.revalidate = options.revalidate;
                }
            } else if (options.revalidate === false && typeof store.revalidate === "undefined") {
                // The store has not defined revalidate type so we can use the false option
                store.revalidate = options.revalidate;
            }
            // We need to accumulate the tags for this invocation within the store
            if (!store.tags) {
                store.tags = tags.slice();
            } else {
                for (const tag of tags){
                    // @TODO refactor tags to be a set to avoid this O(n) lookup
                    if (!store.tags.includes(tag)) {
                        store.tags.push(tag);
                    }
                }
            }
            // @TODO check on this API. addImplicitTags mutates the store and returns the implicit tags. The naming
            // of this function is potentially a little confusing
            const implicitTags = addImplicitTags(store);
            if (// when we are nested inside of other unstable_cache's
            // we should bypass cache similar to fetches
            store.fetchCache !== "force-no-store" && !store.isOnDemandRevalidate && !incrementalCache.isOnDemandRevalidate && !store.isDraftMode) {
                // We attempt to get the current cache entry from the incremental cache.
                const cacheEntry = await incrementalCache.get(cacheKey, {
                    kindHint: "fetch",
                    revalidate: options.revalidate,
                    tags,
                    softTags: implicitTags,
                    fetchIdx
                });
                if (cacheEntry && cacheEntry.value) {
                    // The entry exists and has a value
                    if (cacheEntry.value.kind !== "FETCH") {
                        // The entry is invalid and we need a special warning
                        // @TODO why do we warn this way? Should this just be an error? How are these errors surfaced
                        // so bugs can be reported
                        // @TODO the invocation key can have sensitive data in it. we should not log this entire object
                        console.error(`Invariant invalid cacheEntry returned for ${invocationKey}`);
                    // will fall through to generating a new cache entry below
                    } else {
                        // We have a valid cache entry so we will be returning it. We also check to see if we need
                        // to background revalidate it by checking if it is stale.
                        const cachedResponse = cacheEntry.value.data.body !== undefined ? JSON.parse(cacheEntry.value.data.body) : undefined;
                        if (cacheEntry.isStale) {
                            // In App Router we return the stale result and revalidate in the background
                            if (!store.pendingRevalidates) {
                                store.pendingRevalidates = {};
                            }
                            // We run the cache function asynchronously and save the result when it completes
                            store.pendingRevalidates[invocationKey] = staticGenerationAsyncStorage.run({
                                ...store,
                                // force any nested fetches to bypass cache so they revalidate
                                // when the unstable_cache call is revalidated
                                fetchCache: "force-no-store",
                                isUnstableCacheCallback: true
                            }, cb, ...args).then((result)=>{
                                return cacheNewResult(result, incrementalCache, cacheKey, tags, options.revalidate, fetchIdx, fetchUrl);
                            })// @TODO This error handling seems wrong. We swallow the error?
                            .catch((err)=>console.error(`revalidating cache with key: ${invocationKey}`, err));
                        }
                        // We had a valid cache entry so we return it here
                        return cachedResponse;
                    }
                }
            }
            // If we got this far then we had an invalid cache entry and need to generate a new one
            const result = await staticGenerationAsyncStorage.run({
                ...store,
                // force any nested fetches to bypass cache so they revalidate
                // when the unstable_cache call is revalidated
                fetchCache: "force-no-store",
                isUnstableCacheCallback: true
            }, cb, ...args);
            cacheNewResult(result, incrementalCache, cacheKey, tags, options.revalidate, fetchIdx, fetchUrl);
            return result;
        } else {
            noStoreFetchIdx += 1;
            // We are in Pages Router or were called outside of a render. We don't have a store
            // so we just call the callback directly when it needs to run.
            // If the entry is fresh we return it. If the entry is stale we return it but revalidate the entry in
            // the background. If the entry is missing or invalid we generate a new entry and return it.
            if (!incrementalCache.isOnDemandRevalidate) {
                // We aren't doing an on demand revalidation so we check use the cache if valid
                const cacheEntry = await incrementalCache.get(cacheKey, {
                    kindHint: "fetch",
                    revalidate: options.revalidate,
                    tags
                });
                if (cacheEntry && cacheEntry.value) {
                    // The entry exists and has a value
                    if (cacheEntry.value.kind !== "FETCH") {
                        // The entry is invalid and we need a special warning
                        // @TODO why do we warn this way? Should this just be an error? How are these errors surfaced
                        // so bugs can be reported
                        console.error(`Invariant invalid cacheEntry returned for ${invocationKey}`);
                    // will fall through to generating a new cache entry below
                    } else if (!cacheEntry.isStale) {
                        // We have a valid cache entry and it is fresh so we return it
                        return cacheEntry.value.data.body !== undefined ? JSON.parse(cacheEntry.value.data.body) : undefined;
                    }
                }
            }
            // If we got this far then we had an invalid cache entry and need to generate a new one
            // @TODO this storage wrapper is included here because it existed prior to the latest refactor
            // however it is incorrect logic because it causes any internal cache calls to follow the App Router
            // path rather than Pages router path. This may mean there is existing buggy behavior however no specific
            // issues are known at this time. The whole static generation storage pathways should be reworked
            // to allow tracking which "mode" we are in without the presence of a store or not. For now I have
            // maintained the existing behavior to limit the impact of the current refactor
            const result = await staticGenerationAsyncStorage.run(// We are making a fake store that is useful for scoping fetchCache: 'force-no-store' and isUnstableCacheCallback: true
            // The fact that we need to construct this kind of fake store indicates the code is not factored correctly
            // @TODO refactor to not require this fake store object
            {
                // force any nested fetches to bypass cache so they revalidate
                // when the unstable_cache call is revalidated
                fetchCache: "force-no-store",
                isUnstableCacheCallback: true,
                urlPathname: "/",
                isStaticGeneration: false,
                prerenderState: null
            }, cb, ...args);
            cacheNewResult(result, incrementalCache, cacheKey, tags, options.revalidate, fetchIdx, fetchUrl);
            return result;
        }
    };
    // TODO: once AsyncLocalStorage.run() returns the correct types this override will no longer be necessary
    return cachedCb;
}

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