import { HUB_URL } from "../consts";
import { HubApiError, createApiError, InvalidApiResponseFormatError } from "../error";
import type {
	ApiCommitHeader,
	ApiCommitLfsFile,
	ApiCommitOperation,
	ApiLfsBatchRequest,
	ApiLfsBatchResponse,
	ApiLfsCompleteMultipartRequest,
	ApiPreuploadRequest,
	ApiPreuploadResponse,
} from "../types/api/api-commit";
import type { CredentialsParams, RepoDesignation } from "../types/public";
import { checkCredentials } from "../utils/checkCredentials";
import { chunk } from "../utils/chunk";
import { promisesQueue } from "../utils/promisesQueue";
import { promisesQueueStreaming } from "../utils/promisesQueueStreaming";
import { sha256 } from "../utils/sha256";
import { toRepoId } from "../utils/toRepoId";
import { WebBlob } from "../utils/WebBlob";
import { createBlob } from "../utils/createBlob";
import { eventToGenerator } from "../utils/eventToGenerator";
import { base64FromBytes } from "../utils/base64FromBytes";
import { isFrontend } from "../utils/isFrontend";

const CONCURRENT_SHAS = 5;
const CONCURRENT_LFS_UPLOADS = 5;
const MULTIPART_PARALLEL_UPLOAD = 5;

export interface CommitDeletedEntry {
	operation: "delete";
	path: string;
}

export type ContentSource = Blob | URL;

export interface CommitFile {
	operation: "addOrUpdate";
	path: string;
	content: ContentSource;
	// forceLfs?: boolean
}

type CommitBlob = Omit<CommitFile, "content"> & { content: Blob };

// TODO: find a nice way to handle LFS & non-LFS files in an uniform manner, see https://github.com/huggingface/moon-landing/issues/4370
// export type CommitRenameFile = {
// 	operation: "rename";
// 	path:      string;
// 	oldPath:   string;
// 	content?:  ContentSource;
// };

export type CommitOperation = CommitDeletedEntry | CommitFile /* | CommitRenameFile */;
type CommitBlobOperation = Exclude<CommitOperation, CommitFile> | CommitBlob;

export type CommitParams = {
	title: string;
	description?: string;
	repo: RepoDesignation;
	operations: CommitOperation[];
	/** @default "main" */
	branch?: string;
	/**
	 * Parent commit. Optional
	 *
	 * - When opening a PR: will use parentCommit as the parent commit
	 * - When committing on a branch: Will make sure that there were no intermediate commits
	 */
	parentCommit?: string;
	isPullRequest?: boolean;
	hubUrl?: string;
	/**
	 * Whether to use web workers to compute SHA256 hashes.
	 *
	 * We load hash-wasm from a CDN inside the web worker. Not sure how to do otherwise and still have a "clean" bundle.
	 */
	useWebWorkers?: boolean | { minSize?: number; poolSize?: number };
	/**
	 * Custom fetch function to use instead of the default one, for example to use a proxy or edit headers.
	 */
	fetch?: typeof fetch;
	abortSignal?: AbortSignal;
	// Credentials are optional due to custom fetch functions or cookie auth
} & Partial<CredentialsParams>;

export interface CommitOutput {
	pullRequestUrl?: string;
	commit: {
		oid: string;
		url: string;
	};
	hookOutput: string;
}

function isFileOperation(op: CommitOperation): op is CommitBlob {
	const ret = op.operation === "addOrUpdate";

	if (ret && !(op.content instanceof Blob)) {
		throw new TypeError("Precondition failed: op.content should be a Blob");
	}

	return ret;
}

export type CommitProgressEvent =
	| {
			event: "phase";
			phase: "preuploading" | "uploadingLargeFiles" | "committing";
	  }
	| {
			event: "fileProgress";
			path: string;
			progress: number;
			state: "hashing" | "uploading";
	  };

/**
 * Internal function for now, used by commit.
 *
 * Can be exposed later to offer fine-tuned progress info
 */
export async function* commitIter(params: CommitParams): AsyncGenerator<CommitProgressEvent, CommitOutput> {
	const accessToken = checkCredentials(params);
	const repoId = toRepoId(params.repo);
	yield { event: "phase", phase: "preuploading" };

	const lfsShas = new Map<string, string | null>();

	const abortController = new AbortController();
	const abortSignal = abortController.signal;

	// Polyfill see https://discuss.huggingface.co/t/why-cant-i-upload-a-parquet-file-to-my-dataset-error-o-throwifaborted-is-not-a-function/62245
	if (!abortSignal.throwIfAborted) {
		abortSignal.throwIfAborted = () => {
			if (abortSignal.aborted) {
				throw new DOMException("Aborted", "AbortError");
			}
		};
	}

	if (params.abortSignal) {
		params.abortSignal.addEventListener("abort", () => abortController.abort());
	}

	try {
		const allOperations = await Promise.all(
			params.operations.map(async (operation) => {
				if (operation.operation !== "addOrUpdate") {
					return operation;
				}

				if (!(operation.content instanceof URL)) {
					/** TS trick to enforce `content` to be a `Blob` */
					return { ...operation, content: operation.content };
				}

				const lazyBlob = await createBlob(operation.content, { fetch: params.fetch });

				abortSignal?.throwIfAborted();

				return {
					...operation,
					content: lazyBlob,
				};
			})
		);

		const gitAttributes = allOperations.filter(isFileOperation).find((op) => op.path === ".gitattributes")?.content;

		for (const operations of chunk(allOperations.filter(isFileOperation), 100)) {
			const payload: ApiPreuploadRequest = {
				gitAttributes: gitAttributes && (await gitAttributes.text()),
				files: await Promise.all(
					operations.map(async (operation) => ({
						path: operation.path,
						size: operation.content.size,
						sample: base64FromBytes(new Uint8Array(await operation.content.slice(0, 512).arrayBuffer())),
					}))
				),
			};

			abortSignal?.throwIfAborted();

			const res = await (params.fetch ?? fetch)(
				`${params.hubUrl ?? HUB_URL}/api/${repoId.type}s/${repoId.name}/preupload/${encodeURIComponent(
					params.branch ?? "main"
				)}` + (params.isPullRequest ? "?create_pr=1" : ""),
				{
					method: "POST",
					headers: {
						...(accessToken && { Authorization: `Bearer ${accessToken}` }),
						"Content-Type": "application/json",
					},
					body: JSON.stringify(payload),
					signal: abortSignal,
				}
			);

			if (!res.ok) {
				throw await createApiError(res);
			}

			const json: ApiPreuploadResponse = await res.json();

			for (const file of json.files) {
				if (file.uploadMode === "lfs") {
					lfsShas.set(file.path, null);
				}
			}
		}

		yield { event: "phase", phase: "uploadingLargeFiles" };

		for (const operations of chunk(
			allOperations.filter(isFileOperation).filter((op) => lfsShas.has(op.path)),
			100
		)) {
			const shas = yield* eventToGenerator<
				{ event: "fileProgress"; state: "hashing"; path: string; progress: number },
				string[]
			>((yieldCallback, returnCallback, rejectCallack) => {
				return promisesQueue(
					operations.map((op) => async () => {
						const iterator = sha256(op.content, { useWebWorker: params.useWebWorkers, abortSignal: abortSignal });
						let res: IteratorResult<number, string>;
						do {
							res = await iterator.next();
							if (!res.done) {
								yieldCallback({ event: "fileProgress", path: op.path, progress: res.value, state: "hashing" });
							}
						} while (!res.done);
						const sha = res.value;
						lfsShas.set(op.path, res.value);
						return sha;
					}),
					CONCURRENT_SHAS
				).then(returnCallback, rejectCallack);
			});

			abortSignal?.throwIfAborted();

			const payload: ApiLfsBatchRequest = {
				operation: "upload",
				// multipart is a custom protocol for HF
				transfers: ["basic", "multipart"],
				hash_algo: "sha_256",
				...(!params.isPullRequest && {
					ref: {
						name: params.branch ?? "main",
					},
				}),
				objects: operations.map((op, i) => ({
					oid: shas[i],
					size: op.content.size,
				})),
			};

			const res = await (params.fetch ?? fetch)(
				`${params.hubUrl ?? HUB_URL}/${repoId.type === "model" ? "" : repoId.type + "s/"}${
					repoId.name
				}.git/info/lfs/objects/batch`,
				{
					method: "POST",
					headers: {
						...(accessToken && { Authorization: `Bearer ${accessToken}` }),
						Accept: "application/vnd.git-lfs+json",
						"Content-Type": "application/vnd.git-lfs+json",
					},
					body: JSON.stringify(payload),
					signal: abortSignal,
				}
			);

			if (!res.ok) {
				throw await createApiError(res);
			}

			const json: ApiLfsBatchResponse = await res.json();
			const batchRequestId = res.headers.get("X-Request-Id") || undefined;

			const shaToOperation = new Map(operations.map((op, i) => [shas[i], op]));

			yield* eventToGenerator<CommitProgressEvent, void>((yieldCallback, returnCallback, rejectCallback) => {
				return promisesQueueStreaming(
					json.objects.map((obj) => async () => {
						const op = shaToOperation.get(obj.oid);

						if (!op) {
							throw new InvalidApiResponseFormatError("Unrequested object ID in response");
						}

						abortSignal?.throwIfAborted();

						if (obj.error) {
							const errorMessage = `Error while doing LFS batch call for ${operations[shas.indexOf(obj.oid)].path}: ${
								obj.error.message
							}${batchRequestId ? ` - Request ID: ${batchRequestId}` : ""}`;
							throw new HubApiError(res.url, obj.error.code, batchRequestId, errorMessage);
						}
						if (!obj.actions?.upload) {
							// Already uploaded
							yieldCallback({
								event: "fileProgress",
								path: op.path,
								progress: 1,
								state: "uploading",
							});
							return;
						}
						yieldCallback({
							event: "fileProgress",
							path: op.path,
							progress: 0,
							state: "uploading",
						});
						const content = op.content;
						const header = obj.actions.upload.header;
						if (header?.chunk_size) {
							const chunkSize = parseInt(header.chunk_size);

							// multipart upload
							// parts are in upload.header['00001'] to upload.header['99999']

							const completionUrl = obj.actions.upload.href;
							const parts = Object.keys(header).filter((key) => /^[0-9]+$/.test(key));

							if (parts.length !== Math.ceil(content.size / chunkSize)) {
								throw new Error("Invalid server response to upload large LFS file, wrong number of parts");
							}

							const completeReq: ApiLfsCompleteMultipartRequest = {
								oid: obj.oid,
								parts: parts.map((part) => ({
									partNumber: +part,
									etag: "",
								})),
							};

							// Defined here so that it's not redefined at each iteration (and the caller can tell it's for the same file)
							const progressCallback = (progress: number) =>
								yieldCallback({ event: "fileProgress", path: op.path, progress, state: "uploading" });

							await promisesQueueStreaming(
								parts.map((part) => async () => {
									abortSignal?.throwIfAborted();

									const index = parseInt(part) - 1;
									const slice = content.slice(index * chunkSize, (index + 1) * chunkSize);

									const res = await (params.fetch ?? fetch)(header[part], {
										method: "PUT",
										/** Unfortunately, browsers don't support our inherited version of Blob in fetch calls */
										body: slice instanceof WebBlob && isFrontend ? await slice.arrayBuffer() : slice,
										signal: abortSignal,
										...({
											progressHint: {
												path: op.path,
												part: index,
												numParts: parts.length,
												progressCallback,
											},
											// eslint-disable-next-line @typescript-eslint/no-explicit-any
										} as any),
									});

									if (!res.ok) {
										throw await createApiError(res, {
											requestId: batchRequestId,
											message: `Error while uploading part ${part} of ${
												operations[shas.indexOf(obj.oid)].path
											} to LFS storage`,
										});
									}

									const eTag = res.headers.get("ETag");

									if (!eTag) {
										throw new Error("Cannot get ETag of part during multipart upload");
									}

									completeReq.parts[Number(part) - 1].etag = eTag;
								}),
								MULTIPART_PARALLEL_UPLOAD
							);

							abortSignal?.throwIfAborted();

							const res = await (params.fetch ?? fetch)(completionUrl, {
								method: "POST",
								body: JSON.stringify(completeReq),
								headers: {
									Accept: "application/vnd.git-lfs+json",
									"Content-Type": "application/vnd.git-lfs+json",
								},
								signal: abortSignal,
							});

							if (!res.ok) {
								throw await createApiError(res, {
									requestId: batchRequestId,
									message: `Error completing multipart upload of ${
										operations[shas.indexOf(obj.oid)].path
									} to LFS storage`,
								});
							}

							yieldCallback({
								event: "fileProgress",
								path: op.path,
								progress: 1,
								state: "uploading",
							});
						} else {
							const res = await (params.fetch ?? fetch)(obj.actions.upload.href, {
								method: "PUT",
								headers: {
									...(batchRequestId ? { "X-Request-Id": batchRequestId } : undefined),
								},
								/** Unfortunately, browsers don't support our inherited version of Blob in fetch calls */
								body: content instanceof WebBlob && isFrontend ? await content.arrayBuffer() : content,
								signal: abortSignal,
								...({
									progressHint: {
										path: op.path,
										progressCallback: (progress: number) =>
											yieldCallback({
												event: "fileProgress",
												path: op.path,
												progress,
												state: "uploading",
											}),
									},
									// eslint-disable-next-line @typescript-eslint/no-explicit-any
								} as any),
							});

							if (!res.ok) {
								throw await createApiError(res, {
									requestId: batchRequestId,
									message: `Error while uploading ${operations[shas.indexOf(obj.oid)].path} to LFS storage`,
								});
							}

							yieldCallback({
								event: "fileProgress",
								path: op.path,
								progress: 1,
								state: "uploading",
							});
						}
					}),
					CONCURRENT_LFS_UPLOADS
				).then(returnCallback, rejectCallback);
			});
		}

		abortSignal?.throwIfAborted();

		yield { event: "phase", phase: "committing" };

		return yield* eventToGenerator<CommitProgressEvent, CommitOutput>(
			async (yieldCallback, returnCallback, rejectCallback) =>
				(params.fetch ?? fetch)(
					`${params.hubUrl ?? HUB_URL}/api/${repoId.type}s/${repoId.name}/commit/${encodeURIComponent(
						params.branch ?? "main"
					)}` + (params.isPullRequest ? "?create_pr=1" : ""),
					{
						method: "POST",
						headers: {
							...(accessToken && { Authorization: `Bearer ${accessToken}` }),
							"Content-Type": "application/x-ndjson",
						},
						body: [
							{
								key: "header",
								value: {
									summary: params.title,
									description: params.description,
									parentCommit: params.parentCommit,
								} satisfies ApiCommitHeader,
							},
							...((await Promise.all(
								allOperations.map((operation) => {
									if (isFileOperation(operation)) {
										const sha = lfsShas.get(operation.path);
										if (sha) {
											return {
												key: "lfsFile",
												value: {
													path: operation.path,
													algo: "sha256",
													size: operation.content.size,
													oid: sha,
												} satisfies ApiCommitLfsFile,
											};
										}
									}

									return convertOperationToNdJson(operation);
								})
							)) satisfies ApiCommitOperation[]),
						]
							.map((x) => JSON.stringify(x))
							.join("\n"),
						signal: abortSignal,
						...({
							progressHint: {
								progressCallback: (progress: number) => {
									// For now, we display equal progress for all files
									// We could compute the progress based on the size of `convertOperationToNdJson` for each of the files instead
									for (const op of allOperations) {
										if (isFileOperation(op) && !lfsShas.has(op.path)) {
											yieldCallback({
												event: "fileProgress",
												path: op.path,
												progress,
												state: "uploading",
											});
										}
									}
								},
							},
							// eslint-disable-next-line @typescript-eslint/no-explicit-any
						} as any),
					}
				)
					.then(async (res) => {
						if (!res.ok) {
							throw await createApiError(res);
						}

						const json = await res.json();

						returnCallback({
							pullRequestUrl: json.pullRequestUrl,
							commit: {
								oid: json.commitOid,
								url: json.commitUrl,
							},
							hookOutput: json.hookOutput,
						});
					})
					.catch(rejectCallback)
		);
	} catch (err) {
		// For parallel requests, cancel them all if one fails
		abortController.abort();
		throw err;
	}
}

export async function commit(params: CommitParams): Promise<CommitOutput> {
	const iterator = commitIter(params);
	let res = await iterator.next();
	while (!res.done) {
		res = await iterator.next();
	}
	return res.value;
}

async function convertOperationToNdJson(operation: CommitBlobOperation): Promise<ApiCommitOperation> {
	switch (operation.operation) {
		case "addOrUpdate": {
			// todo: handle LFS
			return {
				key: "file",
				value: {
					content: base64FromBytes(new Uint8Array(await operation.content.arrayBuffer())),
					path: operation.path,
					encoding: "base64",
				},
			};
		}
		// case "rename": {
		// 	// todo: detect when remote file is already LFS, and in that case rename as LFS
		// 	return {
		// 		key:   "file",
		// 		value: {
		// 			content: operation.content,
		// 			path:    operation.path,
		// 			oldPath: operation.oldPath
		// 		}
		// 	};
		// }
		case "delete": {
			return {
				key: "deletedFile",
				value: {
					path: operation.path,
				},
			};
		}
		default:
			throw new TypeError("Unknown operation: " + (operation as { operation: string }).operation);
	}
}