import defaults from "@nodecg/json-schema-defaults";
import AjvDraft07, {
	type ErrorObject,
	type Options,
	type ValidateFunction,
} from "ajv";
import Ajv2019 from "ajv/dist/2019";
import Ajv2020 from "ajv/dist/2020";
import AjvDraft04 from "ajv-draft-04";
import addFormats from "ajv-formats";
import * as E from "fp-ts/Either";

import { stringifyError } from "./errors";

const options: Options = {
	allErrors: true,
	verbose: true,
	strict: "log",
};

const ajv = {
	draft04: addFormats(new AjvDraft04(options)),
	draft07: addFormats(new AjvDraft07(options)),
	"draft2019-09": addFormats(new Ajv2019(options)),
	"draft2020-12": addFormats(new Ajv2020(options)),
};

export function compileJsonSchema(
	schema: Record<any, unknown>,
): ValidateFunction {
	const schemaVersion = extractSchemaVersion(schema);
	if (schemaVersion.includes("draft-04")) {
		return ajv.draft04.compile(schema);
	}

	if (schemaVersion.includes("draft-07")) {
		return ajv.draft07.compile(schema);
	}

	if (schemaVersion.includes("draft/2019-09")) {
		return ajv["draft2019-09"].compile(schema);
	}

	if (schemaVersion.includes("draft/2020-12")) {
		return ajv["draft2020-12"].compile(schema);
	}

	throw new Error(`Unsupported JSON Schema version "${schemaVersion}"`);
}

export function formatJsonSchemaErrors(
	schema: Record<any, unknown>,
	errors?: ErrorObject[] | null,
): string {
	const schemaVersion = extractSchemaVersion(schema);
	if (schemaVersion.includes("draft-04")) {
		return ajv.draft04.errorsText(errors).replace(/^data\//gm, "");
	}

	if (schemaVersion.includes("draft-07")) {
		return ajv.draft07.errorsText(errors).replace(/^data\//gm, "");
	}

	if (schemaVersion.includes("draft/2019-09")) {
		return ajv["draft2019-09"].errorsText(errors).replace(/^data\//gm, "");
	}

	if (schemaVersion.includes("draft/2020-12")) {
		return ajv["draft2020-12"].errorsText(errors).replace(/^data\//gm, "");
	}

	throw new Error(`Unsupported JSON Schema version "${schemaVersion}"`);
}

export function getSchemaDefault(
	schema: Record<any, unknown>,
	labelForDebugging: string,
): unknown {
	try {
		return defaults(schema);
	} catch (error: unknown) {
		throw new Error(
			`Error generating default value(s) for schema "${labelForDebugging}":\n\t${stringifyError(error)}`,
		);
	}
}

export const getSchemaDefaultFp = (
	schema: Record<any, unknown>,
	labelForDebugging: string,
) =>
	E.tryCatch(
		() => defaults(schema),
		(error) =>
			new Error(
				`Error generating default value(s) for schema "${labelForDebugging}":\n\t${stringifyError(error)}`,
			),
	);

function extractSchemaVersion(schema: Record<any, unknown>): string {
	// For backwards compat, we default to draft-04.
	const defaultVersion = "https://json-schema.org/draft-04/schema";
	const extractedVersion = schema.$schema;
	return typeof extractedVersion === "string"
		? extractedVersion
		: defaultVersion;
}