package com.rit.whatsapp.handler;

import com.rit.whatsapp.model.UserState;
import com.rit.whatsapp.service.ImsApiService;
import com.rit.whatsapp.service.SessionService;
import com.rit.whatsapp.service.WhatsAppMessageBuilder;
import com.rit.whatsapp.service.WhatsAppMessageService;
import com.rit.whatsapp.util.MessageFormatter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Component
public class StudentMenuHandler {

    private final WhatsAppMessageService messageService;
    private final SessionService sessionService;
    private final GrievanceHandler grievanceHandler;
    private final ImsApiService imsApiService;

    @Autowired
    public StudentMenuHandler(WhatsAppMessageService messageService, 
                              SessionService sessionService, 
                              GrievanceHandler grievanceHandler,
                              ImsApiService imsApiService) {
        this.messageService = messageService;
        this.sessionService = sessionService;
        this.grievanceHandler = grievanceHandler;
        this.imsApiService = imsApiService;
    }

    public void sendMainMenu(String phoneNumber) {
        sessionService.setUserState(phoneNumber, UserState.MAIN_MENU);

        String token = sessionService.getImsToken(phoneNumber);
        String studentName = "Student";
        if (token != null) {
            studentName = sessionService.getStudentName(phoneNumber, token);
        }

        Map<String, Object> interactiveList = WhatsAppMessageBuilder.buildListMessage(
                "RIT Digital Assistant",
                "Welcome " + studentName + "! Please select an option from the menu below.",
                "Student Menu",
                getStudentMenuRows()
        );

        messageService.sendInteractiveMessage(phoneNumber, interactiveList);
    }


    public void handleMenuSelection(String phoneNumber, String selectedOptionId) {
        String token = sessionService.getImsToken(phoneNumber);
        if (token == null) {
            messageService.sendMessage(phoneNumber, "Your session has expired. Please type 'Reset' to login again.");
            return;
        }

        switch (selectedOptionId) {
            case "student_attendance":
                String rawAttendance = imsApiService.getAttendance(token);
                String rawLeaves = imsApiService.getLeaves(token);
                sendResponseWithMenu(phoneNumber, MessageFormatter.formatAttendanceAndLeaves(rawAttendance, rawLeaves));
                break;
                
            case "student_timetable":
                sendTimetableMenu(phoneNumber, token);
                break;
 
            case "student_internal_marks":
                sendInternalMarksMenu(phoneNumber);
                break;

             case "student_cat1_marks":
                handleCat1Marks(phoneNumber);
                break;

             case "student_cat2_marks":
                handleCat2Marks(phoneNumber);
                break;

             case "student_cat3_marks":
                handleCat3Marks(phoneNumber);
                break;

             case "student_assignment_marks":
                handleAssignmentMarks(phoneNumber);
                break;
                  
            case "student_semester_results":
                sendSemesterSelection(phoneNumber, token);
                break;
                  
            case "student_fee_details":
                sendFeeDetailsMenu(phoneNumber, token);
                break;

            case "student_raise_grievance":
                grievanceHandler.startGrievanceFlow(phoneNumber);
                break;

            case "student_help_menu":
                sendHelpMenu(phoneNumber);
                break;
                
            case "student_logout":
                sessionService.logoutUser(phoneNumber);
                messageService.sendMessage(phoneNumber, "You have been logged out successfully. Type 'Hi' to log in again.");
                break;
                
            case "student_contact_department":
                messageService.sendMessage(phoneNumber, "Contact Department is currently under development. Please check back later!");
                sendMainMenu(phoneNumber);
                break;
                
            default:
                messageService.sendMessage(phoneNumber, "You selected an option that is currently under development. Please check back later!");
                // Resend main menu
                sendMainMenu(phoneNumber);
                break;
        }
    }

    public void sendSemesterSelection(String phoneNumber, String token) {
        sessionService.setUserState(phoneNumber, UserState.AWAITING_SEMESTER_SELECTION);

        List<Map<String, String>> rows = new ArrayList<>();
        for (int i = 1; i <= 8; i++) {
            rows.add(createRow("sem_" + i, "Semester " + i, ""));
        }

        String rawDashboard = imsApiService.getDashboard(token);
        String bodyText = MessageFormatter.formatDashboardCgpa(rawDashboard);

        Map<String, Object> interactiveList = WhatsAppMessageBuilder.buildListMessage(
                "Semester Results",
                bodyText,
                "Select Semester",
                rows
        );

        messageService.sendInteractiveMessage(phoneNumber, interactiveList);
        sendStudentMenuDirectly(phoneNumber);
    }

    public void handleSemesterSelection(String phoneNumber, String selectedOptionId) {
        String token = sessionService.getImsToken(phoneNumber);
        if (token == null) {
            messageService.sendMessage(phoneNumber, "Your session has expired. Please type 'Reset' to login again.");
            return;
        }

        try {
            int semester = Integer.parseInt(selectedOptionId.replace("sem_", ""));
            byte[] pdfBytes = imsApiService.getResultsPdf(token, semester);
            
            if (pdfBytes != null) {
                String fileName = "Semester_" + semester + "_Results.pdf";
                String mediaId = messageService.uploadMedia(pdfBytes, fileName, "application/pdf");
                
                if (mediaId != null) {
                    messageService.sendDocumentMessage(phoneNumber, mediaId, "Here are your Semester " + semester + " results!", fileName);
                    sendSemesterSelection(phoneNumber, token);
                } else {
                    messageService.sendMessage(phoneNumber, "Failed to upload the results document to WhatsApp.");
                    sendSemesterSelection(phoneNumber, token);
                }
            } else {
                messageService.sendMessage(phoneNumber, "Failed to download your results. They may not be published yet.");
                sendSemesterSelection(phoneNumber, token);
            }
        } catch (Exception e) {
            messageService.sendMessage(phoneNumber, "Invalid semester selected.");
            sendSemesterSelection(phoneNumber, token);
        }
        
        sessionService.resetState(phoneNumber); // Reset state after fetching results
    }

    public void handleReceiptSelection(String phoneNumber, String selectedOptionId) {
        String token = sessionService.getImsToken(phoneNumber);
        if (token == null) {
            messageService.sendMessage(phoneNumber, "Your session has expired. Please type 'Reset' to login again.");
            return;
        }

        try {
            byte[] pdfBytes = null;
            String fileName = "Receipt.pdf";
            String docMessage = "Here is your Fee Receipt!";
            
            if (selectedOptionId.startsWith("exam_")) {
                String longId = sessionService.getReceiptIdMapping(phoneNumber, selectedOptionId);
                pdfBytes = imsApiService.getExamFeeReceiptPdf(token, longId);
                fileName = "Exam_Receipt.pdf";
                docMessage = "Here is your Exam Fee Receipt!";
            } else if (selectedOptionId.startsWith("acad_")) {
                String longId = sessionService.getReceiptIdMapping(phoneNumber, selectedOptionId);
                pdfBytes = imsApiService.getAcademicFeeReceiptPdf(token, longId);
                fileName = "Academic_Receipt.pdf";
                docMessage = "Here is your Academic Fee Receipt!";
            } else if (selectedOptionId.startsWith("cons_")) {
                String longId = sessionService.getReceiptIdMapping(phoneNumber, selectedOptionId);
                pdfBytes = imsApiService.getConsolidatedAcademicFeeReceiptPdf(token, longId);
                fileName = "Consolidated_Receipt.pdf";
                docMessage = "Here is your Consolidated Academic Fee Receipt!";
            }
            
            if (pdfBytes != null) {
                String mediaId = messageService.uploadMedia(pdfBytes, fileName, "application/pdf");
                if (mediaId != null) {
                    messageService.sendDocumentMessage(phoneNumber, mediaId, docMessage, fileName);
                    sendPaymentHistoryMenu(phoneNumber, token);
                } else {
                    messageService.sendMessage(phoneNumber, "Failed to upload the receipt document to WhatsApp.");
                    sendPaymentHistoryMenu(phoneNumber, token);
                }
            } else {
                messageService.sendMessage(phoneNumber, "Failed to download your receipt. It may not be available.");
                sendPaymentHistoryMenu(phoneNumber, token);
            }
        } catch (Exception e) {
            messageService.sendMessage(phoneNumber, "Invalid receipt selected.");
            sendPaymentHistoryMenu(phoneNumber, token);
        }
        
        sessionService.resetState(phoneNumber); // Reset state after fetching receipt
    }

    public void handleWeeklyTimetable(String phoneNumber) {
        String token = sessionService.getImsToken(phoneNumber);
        if (token == null) {
            messageService.sendMessage(phoneNumber, "Your session has expired. Please type 'Reset' to login again.");
            return;
        }

        String rawTimetable = imsApiService.getTimetable(token);
        String weeklyTimetable = MessageFormatter.formatWeeklyTimetable(rawTimetable);
        
        // Send weekly timetable as standard message (up to 4096 characters limit)
        messageService.sendMessage(phoneNumber, weeklyTimetable);
        
        // Follow up with Timetable sub-menu again
        sendTimetableMenu(phoneNumber, token);
    }

    public void handleExamFees(String phoneNumber) {
        String token = sessionService.getImsToken(phoneNumber);
        if (token == null) {
            messageService.sendMessage(phoneNumber, "Your session has expired. Please type 'Reset' to login again.");
            return;
        }

        String rawExamFees = imsApiService.getExamFees(token);
        String formattedExamFees = MessageFormatter.formatExamFees(rawExamFees);
        messageService.sendMessage(phoneNumber, formattedExamFees);
        sendFeeDetailsMenu(phoneNumber, token);
    }

    public void handlePaymentHistory(String phoneNumber) {
        String token = sessionService.getImsToken(phoneNumber);
        if (token == null) {
            messageService.sendMessage(phoneNumber, "Your session has expired. Please type 'Reset' to login again.");
            return;
        }
        sendPaymentHistoryMenu(phoneNumber, token);
    }

    public void sendTimetableMenu(String phoneNumber, String token) {
        String rawTimetable = imsApiService.getTimetable(token);
        String todaySchedule = MessageFormatter.formatTimetable(rawTimetable);
        
        // Truncate to stay safely within WhatsApp 1024 character limit for button bodies
        if (todaySchedule.length() > 1020) {
            todaySchedule = todaySchedule.substring(0, 1017) + "...";
        }
        
        List<Map<String, String>> buttons = new ArrayList<>();
        Map<String, String> weeklyBtn = new HashMap<>();
        weeklyBtn.put("id", "student_weekly_timetable");
        weeklyBtn.put("title", "Weekly Timetable");
        buttons.add(weeklyBtn);
        
        Map<String, String> menuBtn = new HashMap<>();
        menuBtn.put("id", "student_show_menu");
        menuBtn.put("title", "Student Menu");
        buttons.add(menuBtn);
        
        System.out.println("FINAL TODAY TIMETABLE MESSAGE:\n" + todaySchedule);
        
        Map<String, Object> buttonMessage = WhatsAppMessageBuilder.buildButtonMessage(todaySchedule, buttons);
        messageService.sendInteractiveMessage(phoneNumber, buttonMessage);
        sendStudentMenuDirectly(phoneNumber);
    }

    public void sendFeeDetailsMenu(String phoneNumber, String token) {
        String rawFees = imsApiService.getFees(token);
        String bodyText = MessageFormatter.formatAcademicFeesOnly(rawFees);
        
        List<Map<String, String>> feeButtons = new ArrayList<>();
        Map<String, String> examBtn = new HashMap<>();
        examBtn.put("id", "student_exam_fees");
        examBtn.put("title", "Exam Fees");
        feeButtons.add(examBtn);
        
        Map<String, String> historyBtn = new HashMap<>();
        historyBtn.put("id", "student_payment_history");
        historyBtn.put("title", "Payment History");
        feeButtons.add(historyBtn);
        
        if (bodyText.length() > 1020) {
            bodyText = bodyText.substring(0, 1017) + "...";
        }
        
        Map<String, Object> feeButtonMessage = WhatsAppMessageBuilder.buildButtonMessage(bodyText, feeButtons);
        messageService.sendInteractiveMessage(phoneNumber, feeButtonMessage);
        sendStudentMenuDirectly(phoneNumber);
    }

    public void sendPaymentHistoryMenu(String phoneNumber, String token) {
        String rawExamFees = imsApiService.getExamFees(token);
        String rawFeesHistory = imsApiService.getAcademicFeesHistory(token);
        
        String formattedHistory = MessageFormatter.formatCombinedPaymentHistory(rawExamFees, rawFeesHistory);
        
        Map<String, String> idMappings = new HashMap<>();
        List<Map<String, String>> examRows = MessageFormatter.extractReceiptRows(rawExamFees, idMappings);
        List<Map<String, String>> acadRows = MessageFormatter.extractAcademicReceiptRows(rawFeesHistory, idMappings);
        List<Map<String, String>> consRows = MessageFormatter.extractConsolidatedReceiptRows(rawFeesHistory, idMappings);
        
        sessionService.storeReceiptIdMappings(phoneNumber, idMappings);
        
        List<Map<String, String>> receiptRows = new ArrayList<>();
        receiptRows.addAll(examRows);
        receiptRows.addAll(acadRows);
        receiptRows.addAll(consRows);

        if (!receiptRows.isEmpty()) {
            if (receiptRows.size() > 10) receiptRows = receiptRows.subList(0, 10);
            sessionService.setUserState(phoneNumber, UserState.AWAITING_RECEIPT_SELECTION);
            
            if (formattedHistory.length() > 1024) {
                formattedHistory = formattedHistory.substring(0, 1021) + "...";
            }
            
            Map<String, Object> listMessage = WhatsAppMessageBuilder.buildListMessage(
                "Receipts", formattedHistory, "Download Receipt", receiptRows
            );
            messageService.sendInteractiveMessage(phoneNumber, listMessage);
            sendStudentMenuDirectly(phoneNumber);
        } else {
            sendResponseWithMenu(phoneNumber, formattedHistory);
        }
    }

    private void sendResponseWithMenu(String phoneNumber, String bodyText) {
        // Meta API interactive list body limit is 1024 characters
        if (bodyText.length() > 1024) {
            bodyText = bodyText.substring(0, 1021) + "...";
        }
        
        Map<String, Object> interactiveList = WhatsAppMessageBuilder.buildListMessage(
                null, 
                bodyText,
                "Student Menu",
                getStudentMenuRows()
        );
        messageService.sendInteractiveMessage(phoneNumber, interactiveList);
    }

    public void sendHelpMenu(String phoneNumber) {
        List<Map<String, String>> rows = new ArrayList<>();
        rows.add(createRow("student_contact_department", "Contact department", "Faculty mentor, HOD, etc."));
        rows.add(createRow("student_logout", "Logout", "Sign out of your account"));

        Map<String, Object> interactiveList = WhatsAppMessageBuilder.buildListMessage(
                "Help & Settings",
                "Please select an option below:",
                "Help Menu",
                rows
        );
        messageService.sendInteractiveMessage(phoneNumber, interactiveList);
        sendStudentMenuDirectly(phoneNumber);
    }

    public void sendStudentMenuDirectly(String phoneNumber) {
        sessionService.setUserState(phoneNumber, UserState.MAIN_MENU);
        
        Map<String, Object> interactiveList = WhatsAppMessageBuilder.buildListMessage(
                null, 
                "Select an option from the menu below",
                "Student Menu",
                getStudentMenuRows()
        );
        messageService.sendInteractiveMessage(phoneNumber, interactiveList);
    }

    public void sendInternalMarksMenu(String phoneNumber) {
        List<Map<String, String>> rows = new ArrayList<>();
        rows.add(createRow("student_cat1_marks", "CAT 1 Marks", "View CAT 1 (CO1) marks"));
        rows.add(createRow("student_cat2_marks", "CAT 2 Marks", "View CAT 2 (CO2) marks"));
        rows.add(createRow("student_cat3_marks", "CAT 3 Marks", "View CAT 3 (CO3) marks"));
        rows.add(createRow("student_assignment_marks", "Assignment Marks", "View assignments 1-5 marks"));

        Map<String, Object> interactiveList = WhatsAppMessageBuilder.buildListMessage(
                "Internal Marks",
                "Select which internal marks you want to view:",
                "Select Option",
                rows
        );
        messageService.sendInteractiveMessage(phoneNumber, interactiveList);
        sendStudentMenuDirectly(phoneNumber);
    }

    public void handleCat1Marks(String phoneNumber) {
        String token = sessionService.getImsToken(phoneNumber);
        if (token == null) {
            messageService.sendMessage(phoneNumber, "Your session has expired. Please type 'Reset' to login again.");
            return;
        }
        String rawCatMarks = imsApiService.getCatMarks(token);
        String formatted = com.rit.whatsapp.util.MessageFormatter.formatCat1Marks(rawCatMarks);
        messageService.sendMessage(phoneNumber, formatted);
        sendInternalMarksMenu(phoneNumber);
    }

    public void handleCat2Marks(String phoneNumber) {
        String token = sessionService.getImsToken(phoneNumber);
        if (token == null) {
            messageService.sendMessage(phoneNumber, "Your session has expired. Please type 'Reset' to login again.");
            return;
        }
        String rawCatMarks = imsApiService.getCatMarks(token);
        String formatted = com.rit.whatsapp.util.MessageFormatter.formatCat2Marks(rawCatMarks);
        messageService.sendMessage(phoneNumber, formatted);
        sendInternalMarksMenu(phoneNumber);
    }

    public void handleCat3Marks(String phoneNumber) {
        String token = sessionService.getImsToken(phoneNumber);
        if (token == null) {
            messageService.sendMessage(phoneNumber, "Your session has expired. Please type 'Reset' to login again.");
            return;
        }
        String rawCatMarks = imsApiService.getCatMarks(token);
        String formatted = com.rit.whatsapp.util.MessageFormatter.formatCat3Marks(rawCatMarks);
        messageService.sendMessage(phoneNumber, formatted);
        sendInternalMarksMenu(phoneNumber);
    }

    public void handleAssignmentMarks(String phoneNumber) {
        String token = sessionService.getImsToken(phoneNumber);
        if (token == null) {
            messageService.sendMessage(phoneNumber, "Your session has expired. Please type 'Reset' to login again.");
            return;
        }
        String rawAssignmentMarks = imsApiService.getAssignmentMarks(token);
        String formatted = com.rit.whatsapp.util.MessageFormatter.formatAssignmentMarks(rawAssignmentMarks);
        messageService.sendMessage(phoneNumber, formatted);
        sendInternalMarksMenu(phoneNumber);
    }

    private List<Map<String, String>> getStudentMenuRows() {
        List<Map<String, String>> rows = new ArrayList<>();
        rows.add(createRow("student_attendance", "Attendance", "Overall % and Subject-wise"));
        rows.add(createRow("student_timetable", "Timetable", "Today's classes and Weekly"));
        rows.add(createRow("student_internal_marks", "Internal marks", "CAT 1, CAT 2, Overall"));
        rows.add(createRow("student_semester_results", "Semester results", "Latest result and CGPA"));
        rows.add(createRow("student_fee_details", "Fee details & receipt", "Fee paid, Pending, Due date"));
        rows.add(createRow("student_academic_calendar", "Academic calendar", "Holidays and Important dates"));
        rows.add(createRow("student_exam_schedule", "Exam schedule", "Upcoming exams and Hall details"));
        rows.add(createRow("student_circulars", "Circulars & Notices", "Department circulars"));
        rows.add(createRow("student_raise_grievance", "Raise a grievance \u2B50", "Submit an issue ticket"));
        rows.add(createRow("student_help_menu", "Help & Settings", "Logout, Contact dept, etc."));
        return rows;
    }

    private Map<String, String> createRow(String id, String title, String description) {
        Map<String, String> row = new HashMap<>();
        row.put("id", id);
        row.put("title", title);
        row.put("description", description);
        return row;
    }
}