const PathListCheck = require('pathListCheck');

const multiparty = require('multiparty');

const thunkify = require('thunkify');

var log = require('log')();

function MultipartParser() {

this.ignore = new PathListCheck();

}

MultipartParser.prototype.parse = thunkify(function(req, callback) {

var form = new multiparty.Form();

var hadError = false;

var fields = {};

form.on('field', function(name, value) {

fields[name] = value;

});

// multipart file must be the last

form.on('part', function(part) {

if (part.filename !== null) {

// error is made the same way as multiparty uses

callback(createError(400, 'Files are not allowed here'));

} else {

throw new Error("Must never reach this line (field event parses all fields)");

}

part.on('error', onError);

});

form.on('error', onError);

form.on('close', onDone);

form.parse(req);

function onDone() {

log.debug("multipart parse done", fields);

if (hadError) return;

callback(null, fields);

}

function onError(err) {

log.debug("multipart error", err);

if (hadError) return;

hadError = true;

callback(err);

}

});

MultipartParser.prototype.middleware = function() {

var self = this;

return function*(next) {

// skip these methods

var contentType = this.get('content-type') || '';

if (!~['DELETE', 'POST', 'PUT', 'PATCH'].indexOf(this.method) || !contentType.startsWith('multipart/form-data')) {

return yield* next;

}

if (!self.ignore.check(this.path)) {

this.log.debug("multipart will parse");

// this may throw an error w/ status 400 or 415 or...

this.request.body = yield self.parse(this.req);

this.log.debug("multipart done parse");

} else {

this.log.debug("multipart skip");

}

yield* next;

};

};

exports.init = function(app) {

app.multipartParser = new MultipartParser();

app.use(app.multipartParser.middleware());

};

function createError(status, message) {

var error = new Error(message);

Error.captureStackTrace(error, createError);

error.status = status;

error.statusCode = status;

return error;

}