import { IncrementalCacheKind, CachedRouteKind } from '../../response-cache';
import FetchCache from './fetch-cache';
import FileSystemCache from './file-system-cache';
import { normalizePagePath } from '../../../shared/lib/page-path/normalize-page-path';
import { CACHE_ONE_YEAR, NEXT_CACHE_REVALIDATED_TAGS_HEADER, NEXT_CACHE_REVALIDATE_TAG_TOKEN_HEADER, PRERENDER_REVALIDATE_HEADER } from '../../../lib/constants';
import { toRoute } from '../to-route';
import { SharedRevalidateTimings } from './shared-revalidate-timings';
export class CacheHandler {
    // eslint-disable-next-line
    constructor(_ctx){}
    async get(..._args) {
        return {};
    }
    async set(..._args) {}
    async revalidateTag(..._args) {}
    resetRequestCache() {}
}
export class IncrementalCache {
    constructor({ fs, dev, flushToDisk, fetchCache, minimalMode, serverDistDir, requestHeaders, requestProtocol, maxMemoryCacheSize, getPrerenderManifest, fetchCacheKeyPrefix, CurCacheHandler, allowedRevalidateHeaderKeys }){
        var _this_prerenderManifest_preview, _this_prerenderManifest, _this_prerenderManifest_preview1, _this_prerenderManifest1;
        this.locks = new Map();
        this.unlocks = new Map();
        const debug = !!process.env.NEXT_PRIVATE_DEBUG_CACHE;
        this.hasCustomCacheHandler = Boolean(CurCacheHandler);
        if (!CurCacheHandler) {
            if (fs && serverDistDir) {
                if (debug) {
                    console.log('using filesystem cache handler');
                }
                CurCacheHandler = FileSystemCache;
            }
            if (FetchCache.isAvailable({
                _requestHeaders: requestHeaders
            }) && minimalMode && fetchCache) {
                if (debug) {
                    console.log('using fetch cache handler');
                }
                CurCacheHandler = FetchCache;
            }
        } else if (debug) {
            console.log('using custom cache handler', CurCacheHandler.name);
        }
        if (process.env.__NEXT_TEST_MAX_ISR_CACHE) {
            // Allow cache size to be overridden for testing purposes
            maxMemoryCacheSize = parseInt(process.env.__NEXT_TEST_MAX_ISR_CACHE, 10);
        }
        this.dev = dev;
        this.disableForTestmode = process.env.NEXT_PRIVATE_TEST_PROXY === 'true';
        // this is a hack to avoid Webpack knowing this is equal to this.minimalMode
        // because we replace this.minimalMode to true in production bundles.
        const minimalModeKey = 'minimalMode';
        this[minimalModeKey] = minimalMode;
        this.requestHeaders = requestHeaders;
        this.requestProtocol = requestProtocol;
        this.allowedRevalidateHeaderKeys = allowedRevalidateHeaderKeys;
        this.prerenderManifest = getPrerenderManifest();
        this.revalidateTimings = new SharedRevalidateTimings(this.prerenderManifest);
        this.fetchCacheKeyPrefix = fetchCacheKeyPrefix;
        let revalidatedTags = [];
        if (requestHeaders[PRERENDER_REVALIDATE_HEADER] === ((_this_prerenderManifest = this.prerenderManifest) == null ? void 0 : (_this_prerenderManifest_preview = _this_prerenderManifest.preview) == null ? void 0 : _this_prerenderManifest_preview.previewModeId)) {
            this.isOnDemandRevalidate = true;
        }
        if (minimalMode && typeof requestHeaders[NEXT_CACHE_REVALIDATED_TAGS_HEADER] === 'string' && requestHeaders[NEXT_CACHE_REVALIDATE_TAG_TOKEN_HEADER] === ((_this_prerenderManifest1 = this.prerenderManifest) == null ? void 0 : (_this_prerenderManifest_preview1 = _this_prerenderManifest1.preview) == null ? void 0 : _this_prerenderManifest_preview1.previewModeId)) {
            revalidatedTags = requestHeaders[NEXT_CACHE_REVALIDATED_TAGS_HEADER].split(',');
        }
        if (CurCacheHandler) {
            this.cacheHandler = new CurCacheHandler({
                dev,
                fs,
                flushToDisk,
                serverDistDir,
                revalidatedTags,
                maxMemoryCacheSize,
                _requestHeaders: requestHeaders,
                fetchCacheKeyPrefix
            });
        }
    }
    calculateRevalidate(pathname, fromTime, dev, isFallback) {
        // in development we don't have a prerender-manifest
        // and default to always revalidating to allow easier debugging
        if (dev) return new Date().getTime() - 1000;
        // if an entry isn't present in routes we fallback to a default
        // of revalidating after 1 second unless it's a fallback request.
        const initialRevalidateSeconds = this.revalidateTimings.get(toRoute(pathname)) ?? (isFallback ? false : 1);
        const revalidateAfter = typeof initialRevalidateSeconds === 'number' ? initialRevalidateSeconds * 1000 + fromTime : initialRevalidateSeconds;
        return revalidateAfter;
    }
    _getPathname(pathname, fetchCache) {
        return fetchCache ? pathname : normalizePagePath(pathname);
    }
    resetRequestCache() {
        var _this_cacheHandler_resetRequestCache, _this_cacheHandler;
        (_this_cacheHandler = this.cacheHandler) == null ? void 0 : (_this_cacheHandler_resetRequestCache = _this_cacheHandler.resetRequestCache) == null ? void 0 : _this_cacheHandler_resetRequestCache.call(_this_cacheHandler);
    }
    async unlock(cacheKey) {
        const unlock = this.unlocks.get(cacheKey);
        if (unlock) {
            unlock();
            this.locks.delete(cacheKey);
            this.unlocks.delete(cacheKey);
        }
    }
    async lock(cacheKey) {
        let unlockNext = ()=>Promise.resolve();
        const existingLock = this.locks.get(cacheKey);
        if (existingLock) {
            await existingLock;
        } else {
            const newLock = new Promise((resolve)=>{
                unlockNext = async ()=>{
                    resolve();
                };
            });
            this.locks.set(cacheKey, newLock);
            this.unlocks.set(cacheKey, unlockNext);
        }
        return unlockNext;
    }
    async revalidateTag(tags) {
        var _this_cacheHandler_revalidateTag, _this_cacheHandler;
        return (_this_cacheHandler = this.cacheHandler) == null ? void 0 : (_this_cacheHandler_revalidateTag = _this_cacheHandler.revalidateTag) == null ? void 0 : _this_cacheHandler_revalidateTag.call(_this_cacheHandler, tags);
    }
    // x-ref: https://github.com/facebook/react/blob/2655c9354d8e1c54ba888444220f63e836925caa/packages/react/src/ReactFetch.js#L23
    async generateCacheKey(url, init = {}) {
        // this should be bumped anytime a fix is made to cache entries
        // that should bust the cache
        const MAIN_KEY_PREFIX = 'v3';
        const bodyChunks = [];
        const encoder = new TextEncoder();
        const decoder = new TextDecoder();
        if (init.body) {
            // handle ReadableStream body
            if (typeof init.body.getReader === 'function') {
                const readableBody = init.body;
                const chunks = [];
                try {
                    await readableBody.pipeTo(new WritableStream({
                        write (chunk) {
                            if (typeof chunk === 'string') {
                                chunks.push(encoder.encode(chunk));
                                bodyChunks.push(chunk);
                            } else {
                                chunks.push(chunk);
                                bodyChunks.push(decoder.decode(chunk, {
                                    stream: true
                                }));
                            }
                        }
                    }));
                    // Flush the decoder.
                    bodyChunks.push(decoder.decode());
                    // Create a new buffer with all the chunks.
                    const length = chunks.reduce((total, arr)=>total + arr.length, 0);
                    const arrayBuffer = new Uint8Array(length);
                    // Push each of the chunks into the new array buffer.
                    let offset = 0;
                    for (const chunk of chunks){
                        arrayBuffer.set(chunk, offset);
                        offset += chunk.length;
                    }
                    init._ogBody = arrayBuffer;
                } catch (err) {
                    console.error('Problem reading body', err);
                }
            } else if (typeof init.body.keys === 'function') {
                const formData = init.body;
                init._ogBody = init.body;
                for (const key of new Set([
                    ...formData.keys()
                ])){
                    const values = formData.getAll(key);
                    bodyChunks.push(`${key}=${(await Promise.all(values.map(async (val)=>{
                        if (typeof val === 'string') {
                            return val;
                        } else {
                            return await val.text();
                        }
                    }))).join(',')}`);
                }
            // handle blob body
            } else if (typeof init.body.arrayBuffer === 'function') {
                const blob = init.body;
                const arrayBuffer = await blob.arrayBuffer();
                bodyChunks.push(await blob.text());
                init._ogBody = new Blob([
                    arrayBuffer
                ], {
                    type: blob.type
                });
            } else if (typeof init.body === 'string') {
                bodyChunks.push(init.body);
                init._ogBody = init.body;
            }
        }
        const headers = typeof (init.headers || {}).keys === 'function' ? Object.fromEntries(init.headers) : Object.assign({}, init.headers);
        if ('traceparent' in headers) delete headers['traceparent'];
        const cacheString = JSON.stringify([
            MAIN_KEY_PREFIX,
            this.fetchCacheKeyPrefix || '',
            url,
            init.method,
            headers,
            init.mode,
            init.redirect,
            init.credentials,
            init.referrer,
            init.referrerPolicy,
            init.integrity,
            init.cache,
            bodyChunks
        ]);
        if (process.env.NEXT_RUNTIME === 'edge') {
            function bufferToHex(buffer) {
                return Array.prototype.map.call(new Uint8Array(buffer), (b)=>b.toString(16).padStart(2, '0')).join('');
            }
            const buffer = encoder.encode(cacheString);
            return bufferToHex(await crypto.subtle.digest('SHA-256', buffer));
        } else {
            const crypto1 = require('crypto');
            return crypto1.createHash('sha256').update(cacheString).digest('hex');
        }
    }
    // get data from cache if available
    async get(cacheKey, ctx) {
        var _this_cacheHandler, _cacheData_value;
        // we don't leverage the prerender cache in dev mode
        // so that getStaticProps is always called for easier debugging
        if (this.disableForTestmode || this.dev && (ctx.kind !== IncrementalCacheKind.FETCH || this.requestHeaders['cache-control'] === 'no-cache')) {
            return null;
        }
        cacheKey = this._getPathname(cacheKey, ctx.kind === IncrementalCacheKind.FETCH);
        let entry = null;
        let revalidate = ctx.revalidate;
        const cacheData = await ((_this_cacheHandler = this.cacheHandler) == null ? void 0 : _this_cacheHandler.get(cacheKey, ctx));
        if ((cacheData == null ? void 0 : (_cacheData_value = cacheData.value) == null ? void 0 : _cacheData_value.kind) === CachedRouteKind.FETCH) {
            const combinedTags = [
                ...ctx.tags || [],
                ...ctx.softTags || []
            ];
            // if a tag was revalidated we don't return stale data
            if (combinedTags.some((tag)=>{
                var _this_revalidatedTags;
                return (_this_revalidatedTags = this.revalidatedTags) == null ? void 0 : _this_revalidatedTags.includes(tag);
            })) {
                return null;
            }
            revalidate = revalidate || cacheData.value.revalidate;
            const age = (Date.now() - (cacheData.lastModified || 0)) / 1000;
            const isStale = age > revalidate;
            const data = cacheData.value.data;
            return {
                isStale: isStale,
                value: {
                    kind: CachedRouteKind.FETCH,
                    data,
                    revalidate: revalidate
                },
                revalidateAfter: Date.now() + revalidate * 1000
            };
        }
        const curRevalidate = this.revalidateTimings.get(toRoute(cacheKey));
        let isStale;
        let revalidateAfter;
        if ((cacheData == null ? void 0 : cacheData.lastModified) === -1) {
            isStale = -1;
            revalidateAfter = -1 * CACHE_ONE_YEAR;
        } else {
            revalidateAfter = this.calculateRevalidate(cacheKey, (cacheData == null ? void 0 : cacheData.lastModified) || Date.now(), this.dev ? ctx.kind !== IncrementalCacheKind.FETCH : false, ctx.isFallback);
            isStale = revalidateAfter !== false && revalidateAfter < Date.now() ? true : undefined;
        }
        if (cacheData) {
            entry = {
                isStale,
                curRevalidate,
                revalidateAfter,
                value: cacheData.value
            };
        }
        if (!cacheData && this.prerenderManifest.notFoundRoutes.includes(cacheKey)) {
            // for the first hit after starting the server the cache
            // may not have a way to save notFound: true so if
            // the prerender-manifest marks this as notFound then we
            // return that entry and trigger a cache set to give it a
            // chance to update in-memory entries
            entry = {
                isStale,
                value: null,
                curRevalidate,
                revalidateAfter
            };
            this.set(cacheKey, entry.value, ctx);
        }
        return entry;
    }
    // populate the incremental cache with new data
    async set(pathname, data, ctx) {
        if (this.disableForTestmode || this.dev && !ctx.fetchCache) return;
        // FetchCache has upper limit of 2MB per-entry currently
        const itemSize = JSON.stringify(data).length;
        if (ctx.fetchCache && // we don't show this error/warning when a custom cache handler is being used
        // as it might not have this limit
        !this.hasCustomCacheHandler && itemSize > 2 * 1024 * 1024) {
            if (this.dev) {
                throw new Error(`Failed to set Next.js data cache, items over 2MB can not be cached (${itemSize} bytes)`);
            }
            return;
        }
        pathname = this._getPathname(pathname, ctx.fetchCache);
        try {
            var _this_cacheHandler;
            // Set the value for the revalidate seconds so if it changes we can
            // update the cache with the new value.
            if (typeof ctx.revalidate !== 'undefined' && !ctx.fetchCache) {
                this.revalidateTimings.set(toRoute(pathname), ctx.revalidate);
            }
            await ((_this_cacheHandler = this.cacheHandler) == null ? void 0 : _this_cacheHandler.set(pathname, data, ctx));
        } catch (error) {
            console.warn('Failed to update prerender cache for', pathname, error);
        }
    }
}

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