import type { WidgetType } from "@huggingface/tasks";
import { HF_HUB_URL } from "../config";
import { HARDCODED_MODEL_INFERENCE_MAPPING } from "../providers/consts";
import { EQUIVALENT_SENTENCE_TRANSFORMERS_TASKS } from "../providers/hf-inference";
import type { InferenceProvider, InferenceProviderOrPolicy, ModelId } from "../types";
import { typedInclude } from "../utils/typedInclude";

export const inferenceProviderMappingCache = new Map<ModelId, InferenceProviderMapping>();

export type InferenceProviderMapping = Partial<
	Record<InferenceProvider, Omit<InferenceProviderModelMapping, "hfModelId">>
>;

export interface InferenceProviderModelMapping {
	adapter?: string;
	adapterWeightsPath?: string;
	hfModelId: ModelId;
	providerId: string;
	status: "live" | "staging";
	task: WidgetType;
}

export async function fetchInferenceProviderMappingForModel(
	modelId: ModelId,
	accessToken?: string,
	options?: {
		fetch?: (input: RequestInfo, init?: RequestInit) => Promise<Response>;
	}
): Promise<InferenceProviderMapping> {
	let inferenceProviderMapping: InferenceProviderMapping | null;
	if (inferenceProviderMappingCache.has(modelId)) {
		// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
		inferenceProviderMapping = inferenceProviderMappingCache.get(modelId)!;
	} else {
		const resp = await (options?.fetch ?? fetch)(
			`${HF_HUB_URL}/api/models/${modelId}?expand[]=inferenceProviderMapping`,
			{
				headers: accessToken?.startsWith("hf_") ? { Authorization: `Bearer ${accessToken}` } : {},
			}
		);
		if (resp.status === 404) {
			throw new Error(`Model ${modelId} does not exist`);
		}
		inferenceProviderMapping = await resp
			.json()
			.then((json) => json.inferenceProviderMapping)
			.catch(() => null);

		if (inferenceProviderMapping) {
			inferenceProviderMappingCache.set(modelId, inferenceProviderMapping);
		}
	}

	if (!inferenceProviderMapping) {
		throw new Error(`We have not been able to find inference provider information for model ${modelId}.`);
	}
	return inferenceProviderMapping;
}

export async function getInferenceProviderMapping(
	params: {
		accessToken?: string;
		modelId: ModelId;
		provider: InferenceProvider;
		task: WidgetType;
	},
	options: {
		fetch?: (input: RequestInfo, init?: RequestInit) => Promise<Response>;
	}
): Promise<InferenceProviderModelMapping | null> {
	if (HARDCODED_MODEL_INFERENCE_MAPPING[params.provider][params.modelId]) {
		return HARDCODED_MODEL_INFERENCE_MAPPING[params.provider][params.modelId];
	}
	const inferenceProviderMapping = await fetchInferenceProviderMappingForModel(
		params.modelId,
		params.accessToken,
		options
	);
	const providerMapping = inferenceProviderMapping[params.provider];
	if (providerMapping) {
		const equivalentTasks =
			params.provider === "hf-inference" && typedInclude(EQUIVALENT_SENTENCE_TRANSFORMERS_TASKS, params.task)
				? EQUIVALENT_SENTENCE_TRANSFORMERS_TASKS
				: [params.task];
		if (!typedInclude(equivalentTasks, providerMapping.task)) {
			throw new Error(
				`Model ${params.modelId} is not supported for task ${params.task} and provider ${params.provider}. Supported task: ${providerMapping.task}.`
			);
		}
		if (providerMapping.status === "staging") {
			console.warn(
				`Model ${params.modelId} is in staging mode for provider ${params.provider}. Meant for test purposes only.`
			);
		}
		return { ...providerMapping, hfModelId: params.modelId };
	}
	return null;
}

export async function resolveProvider(
	provider?: InferenceProviderOrPolicy,
	modelId?: string,
	endpointUrl?: string
): Promise<InferenceProvider> {
	if (endpointUrl) {
		if (provider) {
			throw new Error("Specifying both endpointUrl and provider is not supported.");
		}
		/// Defaulting to hf-inference helpers / API
		return "hf-inference";
	}
	if (!provider) {
		console.log(
			"Defaulting to 'auto' which will select the first provider available for the model, sorted by the user's order in https://hf.co/settings/inference-providers."
		);
		provider = "auto";
	}
	if (provider === "auto") {
		if (!modelId) {
			throw new Error("Specifying a model is required when provider is 'auto'");
		}
		const inferenceProviderMapping = await fetchInferenceProviderMappingForModel(modelId);
		provider = Object.keys(inferenceProviderMapping)[0] as InferenceProvider | undefined;
	}
	if (!provider) {
		throw new Error(`No Inference Provider available for model ${modelId}.`);
	}
	return provider;
}