'use strict';

exports = module.exports = {
    getAvailableSize,

    upload,
    exists,
    download,
    copy,

    listDir,

    remove,
    removeDir,

    cleanup,

    testConfig,
    removePrivateFields,
    injectPrivateFields,

    // Used to mock AWS
    _chunk: chunk
};

const assert = require('assert'),
    async = require('async'),
    BoxError = require('../boxerror.js'),
    { ConfiguredRetryStrategy } = require('@smithy/util-retry'),
    constants = require('../constants.js'),
    consumers = require('node:stream/consumers'),
    debug = require('debug')('box:storage/s3'),
    http = require('http'),
    https = require('https'),
    { NodeHttpHandler } = require('@smithy/node-http-handler'),
    { PassThrough } = require('node:stream'),
    path = require('path'),
    { Readable } = require('stream'),
    { S3, NoSuchKey, NoSuchBucket } = require('@aws-sdk/client-s3'),
    safe = require('safetydance'),
    { Upload } = require('@aws-sdk/lib-storage');

function S3_NOT_FOUND(error) {
    return error instanceof NoSuchKey || error instanceof NoSuchBucket;
}

const RETRY_STRATEGY = new ConfiguredRetryStrategy(10 /* max attempts */, (/* attempt */) => 20000 /* constant backoff */);

function createS3Client(apiConfig, options) {
    assert.strictEqual(typeof apiConfig, 'object');
    assert.strictEqual(typeof options, 'object');

    const credentials = {
        accessKeyId: apiConfig.accessKeyId,
        secretAccessKey: apiConfig.secretAccessKey
    };

    const requestHandler = new NodeHttpHandler({
        connectionTimeout: 60000,
        socketTimeout: 20 * 60 * 1000
    });

    // sdk v3 only has signature support v4
    const clientConfig = {
        forcePathStyle: apiConfig.s3ForcePathStyle === true ? true : false, // Use vhost style instead of path style - https://forums.aws.amazon.com/ann.jspa?annID=6776
        region: apiConfig.region || 'us-east-1',
        credentials,
        requestHandler: requestHandler
    };

    if (options.retryStrategy) clientConfig.retryStrategy = options.retryStrategy;
    if (apiConfig.endpoint) clientConfig.endpoint = apiConfig.endpoint;

    // s3 endpoint names come from the SDK
    const isHttps = clientConfig.endpoint?.startsWith('https://') || apiConfig.provider === 's3';
    if (isHttps) {
        if (apiConfig.acceptSelfSignedCerts || apiConfig.bucket.includes('.')) {
            requestHandler.agent = new https.Agent({ rejectUnauthorized: false });
        }
    } else { // http agent is required for http endpoints
        requestHandler.agent = new http.Agent({});
    }

    return constants.TEST ? new globalThis.S3Mock(clientConfig) : new S3(clientConfig);
}

async function getAvailableSize(apiConfig) {
    assert.strictEqual(typeof apiConfig, 'object');

    return Number.POSITIVE_INFINITY;
}

async function upload(apiConfig, backupFilePath) {
    assert.strictEqual(typeof apiConfig, 'object');
    assert.strictEqual(typeof backupFilePath, 'string');

    const s3 = createS3Client(apiConfig, { retryStrategy: RETRY_STRATEGY });

    // s3.upload automatically does a multi-part upload. we set queueSize to 3 to reduce memory usage
    // uploader will buffer at most queueSize * partSize bytes into memory at any given time.
    // scaleway only supports 1000 parts per object (https://www.scaleway.com/en/docs/s3-multipart-upload/)
    // s3: https://docs.aws.amazon.com/AmazonS3/latest/dev/qfacts.html (max 10k parts and no size limit on the last part!)
    const partSize = apiConfig.limits?.uploadPartSize || (apiConfig.provider === 'scaleway-objectstorage' ? 100 * 1024 * 1024 : 10 * 1024 * 1024);

    const passThrough = new PassThrough();

    const options = {
        client: s3,
        params: {
            Bucket: apiConfig.bucket,
            Key: backupFilePath,
            Body: passThrough
        },
        partSize,
        queueSize: 3,
        leavePartsOnError: false
    };

    const managedUpload = constants.TEST ? new globalThis.S3MockUpload(options) : new Upload(options);
    managedUpload.on('httpUploadProgress', (progress) => debug(`Upload progress: ${JSON.stringify(progress)}`));
    const uploadPromise = managedUpload.done();

    return {
        stream: passThrough,
        async finish() {
            const [error, data] = await safe(uploadPromise);
            if (error) throw new BoxError(BoxError.EXTERNAL_ERROR, `Upload error: code: ${error.Code} message: ${error.message}`); // sometimes message is null
            debug(`Upload finished. ${JSON.stringify(data)}`);
        }
    };
}

async function exists(apiConfig, backupFilePath) {
    assert.strictEqual(typeof apiConfig, 'object');
    assert.strictEqual(typeof backupFilePath, 'string');

    const s3 = createS3Client(apiConfig, { retryStrategy: null });

    if (!backupFilePath.endsWith('/')) { // check for file
        const params = {
            Bucket: apiConfig.bucket,
            Key: backupFilePath
        };

        const [error, response] = await safe(s3.headObject(params));
        if (error && S3_NOT_FOUND(error)) return false;
        if (error) throw new BoxError(BoxError.EXTERNAL_ERROR, `Error headObject ${backupFilePath}. Message: ${error.message} HTTP Code: ${error.$metadata.httpStatusCode}`);
        if (!response || typeof response.Metadata !== 'object') throw new BoxError(BoxError.EXTERNAL_ERROR, 'not a s3 endpoint');

        return true;
    } else { // list dir contents
        const listParams = {
            Bucket: apiConfig.bucket,
            Prefix: backupFilePath,
            MaxKeys: 1
        };

        const [error, listData] = await safe(s3.listObjectsV2(listParams));
        if (error) throw new BoxError(BoxError.EXTERNAL_ERROR, `Error listing objects ${backupFilePath}. Message: ${error.message} HTTP Code: ${error.$metadata.httpStatusCode}`);

        return listData.Contents.length !== 0;
    }
}

// Download the object in small parts. By downloading small parts, we reduce the chance of sporadic network errors when downloading large objects
// We can retry each part individually, but we haven't had the need for this yet
class S3MultipartDownloadStream extends Readable {
    constructor (s3, params, options) {
        super(options);
        this._s3 = s3;
        this._params = params;
        this._readSize = 0;
        this._fileSize = -1;
        this._path = params.Bucket + '/' + params.Key;

        this._blockSize = options.blockSize || 64 * 1048576; // MB
    }

    _done() {
        this._readSize = 0;
        this.push(null); // EOF
    }

    _handleError(error) {
        if (S3_NOT_FOUND(error)) {
            this.destroy(new BoxError(BoxError.NOT_FOUND, `Backup not found: ${this._path}`));
        } else {
            debug(`download: ${this._path} s3 stream error. %o`, error);
            this.destroy(new BoxError(BoxError.EXTERNAL_ERROR, `Error multipartDownload ${this._path}. Message: ${error.message} HTTP Code: ${error.$metadata.httpStatusCode}`));
        }
    }

    async _downloadRange(offset, length) {
        const params = Object.assign({}, this._params);
        const lastPos = offset + length - 1;
        const range = `bytes=${offset}-${lastPos}`;
        params['Range'] = range;

        const [error, data] = await safe(this._s3.getObject(params));
        if (error) return this._handleError(error);

        const contentLength = parseInt(data.ContentLength, 10); // should be same as length

        if (contentLength > 0) {
            this._readSize += contentLength;
            const body = await consumers.buffer(data.Body); // data.Body.transformToString('binary') also works
            this.push(body);
        } else {
            this._done();
        }
    }

    _nextDownload() {
        let len = 0;
        if (this._readSize + this._blockSize < this._fileSize) {
            len = this._blockSize;
        } else {
            len = this._fileSize - this._readSize;
        }
        this._downloadRange(this._readSize, len);
    }

    async _fetchSize() {
        const [error, data] = await safe(this._s3.headObject(this._params));
        if (error) return this._handleError(error);

        const length = parseInt(data.ContentLength, 10);

        if (length > 0) {
            this._fileSize = length;
            this._nextDownload();
        } else {
            this._done();
        }
    }

    _read() { // reimp
        if (this._readSize === this._fileSize) return this._done();
        if (this._readSize === 0) return this._fetchSize();

        this._nextDownload();
    }
}

async function download(apiConfig, backupFilePath) {
    assert.strictEqual(typeof apiConfig, 'object');
    assert.strictEqual(typeof backupFilePath, 'string');

    const params = {
        Bucket: apiConfig.bucket,
        Key: backupFilePath
    };

    const s3 = createS3Client(apiConfig, { retryStrategy: RETRY_STRATEGY });
    return new S3MultipartDownloadStream(s3, params, { blockSize: 64 * 1024 * 1024 });
}

async function listDir(apiConfig, dir, batchSize, marker) {
    assert.strictEqual(typeof apiConfig, 'object');
    assert.strictEqual(typeof dir, 'string');
    assert.strictEqual(typeof batchSize, 'number');
    assert(typeof marker !== 'undefined');

    const s3 = createS3Client(apiConfig, { retryStrategy: RETRY_STRATEGY });
    const listParams = {
        Bucket: apiConfig.bucket,
        Prefix: dir,
        MaxKeys: batchSize
    };
    if (marker) listParams.ContinuationToken = marker;

    const [error, listData] = await safe(s3.listObjectsV2(listParams));
    if (error) throw new BoxError(BoxError.EXTERNAL_ERROR, `Error listing objects in ${dir}. Message: ${error.message} HTTP Code: ${error.$metadata.httpStatusCode}`);
    if (listData.Contents.length === 0) return { entries: [], marker: null }; // no more
    const entries = listData.Contents.map(function (c) { return { fullPath: c.Key, size: c.Size }; });
    return { entries, marker: !listData.IsTruncated ? null : listData.NextContinuationToken };
}

// https://github.com/aws/aws-sdk-js/blob/2b6bcbdec1f274fe931640c1b61ece999aae7a19/lib/util.js#L41
// https://github.com/GeorgePhillips/node-s3-url-encode/blob/master/index.js
// See aws-sdk-js/issues/1302
function encodeCopySource(bucket, path) {
    // AWS percent-encodes some extra non-standard characters in a URI
    const output = encodeURI(path).replace(/[+!"#$@&'()*+,:;=?@]/g, function(ch) {
        return '%' + ch.charCodeAt(0).toString(16).toUpperCase();
    });

    // the slash at the beginning is optional
    return `/${bucket}/${output}`;
}

async function copyFile(apiConfig, oldFilePath, newFilePath, entry, progressCallback) {
    assert.strictEqual(typeof apiConfig, 'object');
    assert.strictEqual(typeof oldFilePath, 'string');
    assert.strictEqual(typeof newFilePath, 'string');
    assert.strictEqual(typeof entry, 'object');
    assert.strictEqual(typeof progressCallback, 'function');

    const s3 = createS3Client(apiConfig, { retryStrategy: RETRY_STRATEGY }); // https://docs.aws.amazon.com/sdkref/latest/guide/feature-retry-behavior.html
    const relativePath = path.relative(oldFilePath, entry.fullPath);

    function throwError(error) {
        if (error) debug(`copy: s3 copy error when copying ${entry.fullPath}: ${error}`);

        if (error && S3_NOT_FOUND(error)) throw new BoxError(BoxError.NOT_FOUND, `Old backup not found: ${entry.fullPath}`);
        if (error) throw new BoxError(BoxError.EXTERNAL_ERROR, `Error copying ${entry.fullPath} (${entry.size} bytes): ${error.Code || ''} ${error}`);
    }

    const copyParams = {
        Bucket: apiConfig.bucket,
        Key: path.join(newFilePath, relativePath)
    };

    // S3 copyObject has a file size limit of 5GB so if we have larger files, we do a multipart copy
    const largeFileLimit = (apiConfig.provider === 'vultr-objectstorage' || apiConfig.provider === 'exoscale-sos' || apiConfig.provider === 'backblaze-b2' || apiConfig.provider === 'digitalocean-spaces') ? 1024 * 1024 * 1024 : 3 * 1024 * 1024 * 1024;

    if (entry.size < largeFileLimit) {
        progressCallback({ message: `Copying ${relativePath || oldFilePath}` });

        copyParams.CopySource = encodeCopySource(apiConfig.bucket, entry.fullPath);
        const [copyError] = await safe(s3.copyObject(copyParams));
        if (copyError) return throwError(copyError);
        return;
    }

    progressCallback({ message: `Copying (multipart) ${relativePath || oldFilePath}` });

    const [createMultipartError, multipart] = await safe(s3.createMultipartUpload(copyParams));
    if (createMultipartError) return throwError(createMultipartError);

    // Exoscale (96M) was suggested by exoscale. 1GB for others is arbitrary size
    const chunkSize = apiConfig.provider === 'exoscale-sos' ? 96 * 1024 * 1024 : 1024 * 1024 * 1024;
    const uploadId = multipart.UploadId;
    const uploadedParts = [], ranges = [];

    let cur = 0;
    while (cur + chunkSize < entry.size) {
        ranges.push({ startBytes: cur, endBytes: cur + chunkSize - 1 });
        cur += chunkSize;
    }
    ranges.push({ startBytes: cur, endBytes: entry.size-1 });

    const [copyError] = await safe(async.eachOfLimit(ranges, 3, async function copyChunk(range, index) {
        const partCopyParams = {
            Bucket: apiConfig.bucket,
            Key: path.join(newFilePath, relativePath),
            CopySource: encodeCopySource(apiConfig.bucket, entry.fullPath), // See aws-sdk-js/issues/1302
            CopySourceRange: 'bytes=' + range.startBytes + '-' + range.endBytes,
            PartNumber: index+1,
            UploadId: uploadId
        };

        progressCallback({ message: `Copying part ${partCopyParams.PartNumber} - ${partCopyParams.CopySource} ${partCopyParams.CopySourceRange}` });

        const part = await s3.uploadPartCopy(partCopyParams);
        progressCallback({ message: `Copied part ${partCopyParams.PartNumber} - Etag: ${part.CopyPartResult.ETag}` });

        if (!part.CopyPartResult.ETag) throw new Error('Multi-part copy is broken or not implemented by the S3 storage provider');

        uploadedParts[index] = { ETag: part.CopyPartResult.ETag, PartNumber: partCopyParams.PartNumber };
    }));

    if (copyError) {
        const abortParams = {
            Bucket: apiConfig.bucket,
            Key: path.join(newFilePath, relativePath),
            UploadId: uploadId
        };
        progressCallback({ message: `Aborting multipart copy of ${relativePath || oldFilePath}` });
        await safe(s3.abortMultipartUpload(abortParams), { debug }); // ignore any abort errors
        return throwError(copyError);
    }

    const completeMultipartParams = {
        Bucket: apiConfig.bucket,
        Key: path.join(newFilePath, relativePath),
        MultipartUpload: { Parts: uploadedParts },
        UploadId: uploadId
    };

    progressCallback({ message: `Finishing multipart copy - ${completeMultipartParams.Key}` });

    const [completeMultipartError] = await safe(s3.completeMultipartUpload(completeMultipartParams));
    if (completeMultipartError) return throwError(completeMultipartError);
}

async function copy(apiConfig, oldFilePath, newFilePath, progressCallback) {
    assert.strictEqual(typeof apiConfig, 'object');
    assert.strictEqual(typeof oldFilePath, 'string');
    assert.strictEqual(typeof newFilePath, 'string');
    assert.strictEqual(typeof progressCallback, 'function');

    let total = 0;
    const concurrency = apiConfig.limits?.copyConcurrency || (apiConfig.provider === 's3' ? 500 : 10);
    progressCallback({ message: `Copying with concurrency of ${concurrency}` });

    let marker = null;
    while (true) {
        const batch = await listDir(apiConfig, oldFilePath, 1000, marker);
        total += batch.entries.length;
        progressCallback({ message: `Copying files from ${total-batch.entries.length}-${total}` });
        await async.eachLimit(batch.entries, concurrency, async (entry) => await copyFile(apiConfig, oldFilePath, newFilePath, entry, progressCallback));
        if (!batch.marker) break;
        marker = batch.marker;
    }

    progressCallback({ message: `Copied ${total} files` });
}

async function remove(apiConfig, filename) {
    assert.strictEqual(typeof apiConfig, 'object');
    assert.strictEqual(typeof filename, 'string');

    const s3 = createS3Client(apiConfig, { retryStrategy: RETRY_STRATEGY });

    const deleteParams = {
        Bucket: apiConfig.bucket,
        Delete: {
            Objects: [{ Key: filename }]
        }
    };

    // deleteObjects does not return error if key is not found
    const [error] = await safe(s3.deleteObjects(deleteParams));
    if (error) throw new BoxError(BoxError.EXTERNAL_ERROR, `Unable to remove ${deleteParams.Key}. error: ${error.message}`);
}

function chunk(array, size) {
    assert(Array.isArray(array));
    assert.strictEqual(typeof size, 'number');

    const length = array.length;
    if (!length) return [];
    let index = 0, resIndex = 0;
    const result = Array(Math.ceil(length / size));

    for (; index < length; index += size) {
        result[resIndex++] = array.slice(index, index+size);
    }

    return result;
}

async function removeDir(apiConfig, pathPrefix, progressCallback) {
    assert.strictEqual(typeof apiConfig, 'object');
    assert.strictEqual(typeof pathPrefix, 'string');
    assert.strictEqual(typeof progressCallback, 'function');

    const s3 = createS3Client(apiConfig, { retryStrategy: RETRY_STRATEGY });

    let total = 0;
    let marker = null;
    while (true) {
        const batch = await listDir(apiConfig, pathPrefix, 1000, marker);

        const entries = batch.entries;
        total += entries.length;

        const chunkSize = apiConfig.limits?.deleteConcurrency || (apiConfig.provider !== 'digitalocean-spaces' ? 1000 : 100); // throttle objects in each request
        const chunks = chunk(entries, chunkSize);

        await async.eachSeries(chunks, async function deleteFiles(objects) {
            const deleteParams = {
                Bucket: apiConfig.bucket,
                Delete: {
                    Objects: objects.map(function (o) { return { Key: o.fullPath }; })
                }
            };

            progressCallback({ message: `Removing ${objects.length} files from ${objects[0].fullPath} to ${objects[objects.length-1].fullPath}` });

            // deleteObjects does not return error if key is not found
            const [error] = await safe(s3.deleteObjects(deleteParams));
            if (error) {
                progressCallback({ message: `Unable to remove ${deleteParams.Key} ${error.message || error.Code}` });
                throw new BoxError(BoxError.EXTERNAL_ERROR, `Unable to remove ${deleteParams.Key}. error: ${error.message}`);
            }
        });

        if (!batch.marker) break;
        marker = batch.marker;
    }

    progressCallback({ message: `Removed ${total} files` });
}

// often, the AbortIncompleteMultipartUpload lifecycle rule is not added to the bucket resulting in large bucket sizes over time
async function cleanup(apiConfig, progressCallback) {
    assert.strictEqual(typeof apiConfig, 'object');
    assert.strictEqual(typeof progressCallback, 'function');

    const s3 = createS3Client(apiConfig, { retryStrategy: RETRY_STRATEGY });

    const uploads = await s3.listMultipartUploads({ Bucket: apiConfig.bucket, Prefix: apiConfig.prefix });
    progressCallback({ message: `Cleaning up any aborted multi-part uploads. count:${uploads.Uploads?.length || 0} truncated:${uploads.IsTruncated}` });
    if (!uploads.Uploads) return;

    for (const upload of uploads.Uploads) {
        if (Date.now() - new Date(upload.Initiated) < 3 * 24 * 60 * 60 * 1000) continue; // 3 days ago
        progressCallback({ message: `Cleaning up multi-part upload uploadId:${upload.UploadId} key:${upload.Key}` });
        await safe(s3.abortMultipartUpload({ Bucket: apiConfig.bucket, Key: upload.Key, UploadId: upload.UploadId }), { debug }); // ignore error
    }
}

async function testConfig(apiConfig) {
    assert.strictEqual(typeof apiConfig, 'object');

    if (typeof apiConfig.accessKeyId !== 'string') throw new BoxError(BoxError.BAD_FIELD, 'accessKeyId must be a string');
    if (typeof apiConfig.secretAccessKey !== 'string') throw new BoxError(BoxError.BAD_FIELD, 'secretAccessKey must be a string');

    if (typeof apiConfig.bucket !== 'string') throw new BoxError(BoxError.BAD_FIELD, 'bucket must be a string');
    // the node module seems to incorrectly accept bucket name with '/'
    if (apiConfig.bucket.includes('/')) throw new BoxError(BoxError.BAD_FIELD, 'bucket name cannot contain "/"');

    // names must be lowercase and start with a letter or number. can contain dashes
    if (apiConfig.bucket.includes('_') || apiConfig.bucket.match(/[A-Z]/)) throw new BoxError(BoxError.BAD_FIELD, 'bucket name cannot contain "_" or capitals');

    if (typeof apiConfig.prefix !== 'string') throw new BoxError(BoxError.BAD_FIELD, 'prefix must be a string');
    if ('signatureVersion' in apiConfig && typeof apiConfig.signatureVersion !== 'string') throw new BoxError(BoxError.BAD_FIELD, 'signatureVersion must be a string');
    if ('endpoint' in apiConfig && typeof apiConfig.endpoint !== 'string') throw new BoxError(BoxError.BAD_FIELD, 'endpoint must be a string');

    if ('acceptSelfSignedCerts' in apiConfig && typeof apiConfig.acceptSelfSignedCerts !== 'boolean') throw new BoxError(BoxError.BAD_FIELD, 'acceptSelfSignedCerts must be a boolean');
    if ('s3ForcePathStyle' in apiConfig && typeof apiConfig.s3ForcePathStyle !== 'boolean') throw new BoxError(BoxError.BAD_FIELD, 's3ForcePathStyle must be a boolean');

    const putParams = {
        Bucket: apiConfig.bucket,
        Key: path.join(apiConfig.prefix, 'snapshot/cloudron-testfile'),
        Body: 'testcontent'
    };

    const s3 = createS3Client(apiConfig, {});
    const [putError] = await safe(s3.putObject(putParams));
    if (putError) throw new BoxError(BoxError.EXTERNAL_ERROR, `Error put object cloudron-testfile. Message: ${putError.message} HTTP Code: ${putError.$metadata.httpStatusCode}`);

    const listParams = {
        Bucket: apiConfig.bucket,
        Prefix: path.join(apiConfig.prefix, 'snapshot'),
        MaxKeys: 1
    };

    const [listError] = await safe(s3.listObjectsV2(listParams));
    if (listError) throw new BoxError(BoxError.EXTERNAL_ERROR, `Error listing objects. Message: ${listError.message} HTTP Code: ${listError.$metadata.httpStatusCode}`);

    const delParams = {
        Bucket: apiConfig.bucket,
        Key: path.join(apiConfig.prefix, 'snapshot/cloudron-testfile')
    };

    const [delError] = await safe(s3.deleteObject(delParams));
    if (delError) throw new BoxError(BoxError.EXTERNAL_ERROR, `Error del object cloudron-testfile. Message: ${delError.message} HTTP Code: ${delError.$metadata.httpStatusCode}`);
}

function removePrivateFields(apiConfig) {
    apiConfig.secretAccessKey = constants.SECRET_PLACEHOLDER;
    return apiConfig;
}

function injectPrivateFields(newConfig, currentConfig) {
    if (newConfig.secretAccessKey === constants.SECRET_PLACEHOLDER) newConfig.secretAccessKey = currentConfig.secretAccessKey;
}