Add offset while downloading courses for invoice button

- Fix #57

Author: therealsujitk

app/src/main/java/tk/therealsuji/vtopchennai/services/VTOPService.java

@@ -792,8 +792,9 @@ private void downloadCourses() {
                 "        if (!doc.getElementById('studentDetailsList')) {" +
                 "            return;" +
                 "        }" +
-                "        var table = doc.getElementById('studentDetailsList').getElementsByTagName('table')[0]; " +
+                "        var table = doc.getElementById('studentDetailsList').getElementsByTagName('table')[0];" +
                 "        var headings = table.getElementsByTagName('th');" +
+                "        var offset = headings[0].innerText.toLowerCase().includes('invoice') ? -1 : 0;" +
                 "        var courseIndex, creditsIndex, slotVenueIndex, facultyIndex;" +
                 "        for(var i = 0; i < headings.length; ++i) {" +
                 "            var heading = headings[i].innerText.toLowerCase();" +
@@ -810,11 +811,11 @@ private void downloadCourses() {
                 "        var cells = table.getElementsByTagName('td');" +
                 "        while (courseIndex < cells.length && creditsIndex < cells.length && slotVenueIndex < cells.length && facultyIndex < cells.length) {" +
                 "            var course = {};" +
-                "            var rawCourse = cells[courseIndex].innerText.replace(/\\t/g,'').replace(/\\n/g,' ');" +
+                "            var rawCourse = cells[courseIndex + offset].innerText.replace(/\\t/g,'').replace(/\\n/g,' ');" +
                 "            var rawCourseType = rawCourse.split('(').slice(-1)[0].toLowerCase();" +
-                "            var rawCredits = cells[creditsIndex].innerText.replace(/\\t/g,'').replace(/\\n/g,' ').trim().split(' ');" +
-                "            var rawSlotVenue = cells[slotVenueIndex].innerText.replace(/\\t/g,'').replace(/\\n/g,'').split('-');" +
-                "            var rawFaculty = cells[facultyIndex].innerText.replace(/\\t/g,'').replace(/\\n/g,'').split('-');" +
+                "            var rawCredits = cells[creditsIndex + offset].innerText.replace(/\\t/g,'').replace(/\\n/g,' ').trim().split(' ');" +
+                "            var rawSlotVenue = cells[slotVenueIndex + offset].innerText.replace(/\\t/g,'').replace(/\\n/g,'').split('-');" +
+                "            var rawFaculty = cells[facultyIndex + offset].innerText.replace(/\\t/g,'').replace(/\\n/g,'').split('-');" +
                 "            course.code = rawCourse.split('-')[0].trim();" +
                 "            course.title = rawCourse.split('-').slice(1).join('-').split('(')[0].trim();" +
                 "            course.type = (rawCourseType.includes('lab')) ? 'lab' : ((rawCourseType.includes('project')) ? 'project' : 'theory');" +
@@ -823,10 +824,10 @@ private void downloadCourses() {
                 "            course.venue = rawSlotVenue.slice(1, rawSlotVenue.length).join(' - ').trim();" +
                 "            course.faculty = rawFaculty[0].trim();" +
                 "            response.courses.push(course);" +
-                "            courseIndex += headings.length;" +
-                "            creditsIndex += headings.length;" +
-                "            slotVenueIndex += headings.length;" +
-                "            facultyIndex += headings.length;" +
+                "            courseIndex += headings.length + offset;" +
+                "            creditsIndex += headings.length + offset;" +
+                "            slotVenueIndex += headings.length + offset;" +
+                "            facultyIndex += headings.length + offset;" +
                 "        }" +
                 "    }" +
                 "});" +