"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const body_parser_1 = require("body-parser");
const exceptions_1 = require("./exceptions");
const Types = require("./types");
const validate_signature_1 = require("./validate-signature");
function isValidBody(body) {
    return (body && typeof body === "string") || Buffer.isBuffer(body);
}
function middleware(config) {
    if (!config.channelSecret) {
        throw new Error("no channel secret");
    }
    const secret = config.channelSecret;
    const _middleware = async (req, res, next) => {
        // header names are lower-cased
        // https://nodejs.org/api/http.html#http_message_headers
        const signature = req.headers[Types.LINE_SIGNATURE_HTTP_HEADER_NAME];
        if (!signature) {
            next(new exceptions_1.SignatureValidationFailed("no signature"));
            return;
        }
        const body = await (async () => {
            if (isValidBody(req.rawBody)) {
                // rawBody is provided in Google Cloud Functions and others
                return req.rawBody;
            }
            else if (isValidBody(req.body)) {
                return req.body;
            }
            else {
                // body may not be parsed yet, parse it to a buffer
                return new Promise((resolve, reject) => body_parser_1.raw({ type: "*/*" })(req, res, (error) => error ? reject(error) : resolve(req.body)));
            }
        })();
        if (!validate_signature_1.default(body, secret, signature)) {
            next(new exceptions_1.SignatureValidationFailed("signature validation failed", signature));
            return;
        }
        const strBody = Buffer.isBuffer(body) ? body.toString() : body;
        try {
            req.body = JSON.parse(strBody);
            next();
        }
        catch (err) {
            next(new exceptions_1.JSONParseError(err.message, strBody));
        }
    };
    return (req, res, next) => {
        _middleware(req, res, next).catch(next);
    };
}
exports.default = middleware;