package com.rit.whatsapp.controller;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.rit.whatsapp.handler.GrievanceHandler;
import com.rit.whatsapp.handler.LoginHandler;
import com.rit.whatsapp.handler.StudentMenuHandler;
import com.rit.whatsapp.model.UserState;
import com.rit.whatsapp.service.SessionService;
import com.rit.whatsapp.service.WhatsAppMessageService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/webhook")
public class WebhookController {

    @Value("${whatsapp.verify-token:my_secure_verify_token}")
    private String verifyToken;

    @Value("${whatsapp.phone-number-id:}")
    private String configuredPhoneId;

    private final WhatsAppMessageService messageService;
    private final SessionService sessionService;
    private final StudentMenuHandler studentMenuHandler;
    private final GrievanceHandler grievanceHandler;
    private final LoginHandler loginHandler;
    private final ObjectMapper objectMapper;
    private final com.rit.whatsapp.handler.FacultyMenuHandler facultyMenuHandler;

    @Autowired
    public WebhookController(WhatsAppMessageService messageService, 
                             SessionService sessionService,
                             StudentMenuHandler studentMenuHandler,
                             GrievanceHandler grievanceHandler,
                             LoginHandler loginHandler,
                             com.rit.whatsapp.handler.FacultyMenuHandler facultyMenuHandler) {
        this.messageService = messageService;
        this.sessionService = sessionService;
        this.studentMenuHandler = studentMenuHandler;
        this.grievanceHandler = grievanceHandler;
        this.loginHandler = loginHandler;
        this.facultyMenuHandler = facultyMenuHandler;
        this.objectMapper = new ObjectMapper();
    }

    @GetMapping
    public ResponseEntity<String> verifyWebhook(
            @RequestParam(name = "hub.mode", required = false) String mode,
            @RequestParam(name = "hub.verify_token", required = false) String token,
            @RequestParam(name = "hub.challenge", required = false) String challenge) {

        if ("subscribe".equals(mode) && verifyToken.equals(token)) {
            return ResponseEntity.ok(challenge);
        } else {
            return ResponseEntity.status(HttpStatus.FORBIDDEN).build();
        }
    }

    @PostMapping
    public ResponseEntity<String> receiveMessage(@RequestBody String payload) {
        System.out.println("Received Webhook Payload: " + payload);
        try {
            JsonNode rootNode = objectMapper.readTree(payload);
            
            if (rootNode.has("entry") && rootNode.get("entry").isArray()) {
                JsonNode entryNode = rootNode.get("entry").get(0);
                
                if (entryNode.has("changes") && entryNode.get("changes").isArray()) {
                    JsonNode changesNode = entryNode.get("changes").get(0);
                    JsonNode valueNode = changesNode.get("value");
                    
                    if (valueNode != null) {
                        if (valueNode.has("metadata")) {
                            JsonNode metadataNode = valueNode.get("metadata");
                            if (metadataNode.has("phone_number_id")) {
                                String incomingPhoneId = metadataNode.get("phone_number_id").asText();
                                if (configuredPhoneId != null && !configuredPhoneId.trim().isEmpty() 
                                        && !incomingPhoneId.trim().equals(configuredPhoneId.trim())) {
                                    System.out.println("Incoming phone ID " + incomingPhoneId + " does not match configured ID " + configuredPhoneId + ". Ignoring webhook payload.");
                                    return ResponseEntity.ok("EVENT_IGNORED");
                                }
                            }
                        }
                    }

                    if (valueNode != null && valueNode.has("messages") && valueNode.get("messages").isArray()) {
                        JsonNode messageNode = valueNode.get("messages").get(0);
                        
                        String fromPhoneNumber = messageNode.get("from").asText();
                        String messageType = messageNode.get("type").asText();
                        
                        UserState currentState = sessionService.getUserState(fromPhoneNumber);
                        
                        boolean isInMemory = sessionService.isSessionCached(fromPhoneNumber);
                        boolean hasDbRecord = sessionService.hasSavedCredentials(fromPhoneNumber);
                        if (!isInMemory && hasDbRecord) {
                            messageService.sendMessage(fromPhoneNumber, "Authenticating User with IMS... ⏳");
                        }
                        
                        boolean isAuthenticated = sessionService.isAuthenticated(fromPhoneNumber);

                        // Global reset command
                        if ("text".equals(messageType) && messageNode.get("text").get("body").asText().trim().equalsIgnoreCase("reset")) {
                            sessionService.resetState(fromPhoneNumber);
                            if (isAuthenticated) {
                                if (sessionService.isFaculty(fromPhoneNumber)) {
                                    facultyMenuHandler.sendMainMenu(fromPhoneNumber);
                                } else {
                                    studentMenuHandler.sendMainMenu(fromPhoneNumber);
                                }
                            } else {
                                loginHandler.startLoginFlow(fromPhoneNumber);
                            }
                            return ResponseEntity.ok("EVENT_RECEIVED");
                        }

                        // Global erase command
                        if ("text".equals(messageType) && messageNode.get("text").get("body").asText().trim().equalsIgnoreCase("erase")) {
                            sessionService.deleteUser(fromPhoneNumber);
                            messageService.sendMessage(fromPhoneNumber, "Your IMS credentials have been deleted from our records. Type 'Hi' to start again.");
                            return ResponseEntity.ok("EVENT_RECEIVED");
                        }

                        // Route unauthenticated users strictly to Login Flow
                        if (!isAuthenticated) {
                            if ("text".equals(messageType)) {
                                String body = messageNode.get("text").get("body").asText();
                                handleUnauthenticatedUser(fromPhoneNumber, body, currentState);
                            } else {
                                handleUnauthenticatedUser(fromPhoneNumber, "", currentState);
                            }
                            return ResponseEntity.ok("EVENT_RECEIVED");
                        }

                        // Authenticated users flow
                        if ("text".equals(messageType)) {
                            String messageBody = messageNode.get("text").get("body").asText();
                            handleAuthenticatedTextMessage(fromPhoneNumber, messageBody, currentState);
                        } else if ("image".equals(messageType)) {
                            if (currentState == UserState.AWAITING_GRIEVANCE_IMAGE) {
                                JsonNode imageNode = messageNode.get("image");
                                String mediaId = imageNode.get("id").asText();
                                String mimeType = imageNode.has("mime_type") ? imageNode.get("mime_type").asText() : "image/jpeg";
                                grievanceHandler.handleImageInput(fromPhoneNumber, mediaId, mimeType);
                            } else {
                                if (sessionService.isFaculty(fromPhoneNumber)) {
                                    facultyMenuHandler.sendMainMenu(fromPhoneNumber);
                                } else {
                                    studentMenuHandler.sendMainMenu(fromPhoneNumber);
                                }
                            }
                        } else if ("interactive".equals(messageType)) {
                            JsonNode interactiveNode = messageNode.get("interactive");
                            String interactiveType = interactiveNode.get("type").asText();
                            
                            if ("list_reply".equals(interactiveType)) {
                                String selectedListId = interactiveNode.get("list_reply").get("id").asText();
                                handleInteractiveListSelection(fromPhoneNumber, selectedListId, currentState);
                            } else if ("button_reply".equals(interactiveType)) {
                                String selectedButtonId = interactiveNode.get("button_reply").get("id").asText();
                                handleInteractiveButtonSelection(fromPhoneNumber, selectedButtonId, currentState);
                            }
                        }
                    }
                }
            }
        } catch (Exception e) {
            System.err.println("Error processing webhook payload: " + e.getMessage());
        }
        
        return ResponseEntity.ok("EVENT_RECEIVED");
    }

    private void handleUnauthenticatedUser(String phoneNumber, String messageBody, UserState currentState) {
        switch (currentState) {
            case AWAITING_LOGIN_ID:
                loginHandler.handleLoginIdInput(phoneNumber, messageBody);
                break;
            case AWAITING_LOGIN_PASSCODE:
                loginHandler.handlePasscodeInput(phoneNumber, messageBody);
                break;
            default:
                loginHandler.startLoginFlow(phoneNumber);
                break;
        }
    }

    private void handleAuthenticatedTextMessage(String phoneNumber, String messageBody, UserState currentState) {
        switch (currentState) {
            case AWAITING_GRIEVANCE_TITLE:
                grievanceHandler.handleTitleInput(phoneNumber, messageBody);
                break;
            case AWAITING_GRIEVANCE_DESC:
                grievanceHandler.handleDescriptionInput(phoneNumber, messageBody);
                break;
            case AWAITING_GRIEVANCE_IMAGE:
                if (messageBody.trim().equalsIgnoreCase("skip")) {
                    grievanceHandler.handleSkipImage(phoneNumber);
                } else {
                    messageService.sendMessage(phoneNumber, "Please send a photo or type 'skip' / click 'Skip Image' button.");
                }
                break;
            case AWAITING_ABSENTEES:
                facultyMenuHandler.handleAbsenteesInput(phoneNumber, messageBody);
                break;
            case MAIN_MENU:
            default:
                if (sessionService.isFaculty(phoneNumber)) {
                    facultyMenuHandler.sendMainMenu(phoneNumber);
                } else {
                    studentMenuHandler.sendMainMenu(phoneNumber);
                }
                break;
        }
    }

    private void handleInteractiveListSelection(String phoneNumber, String selectedListId, UserState currentState) {
        if (selectedListId.startsWith("grv_action_")) {
            grievanceHandler.handleActionSelection(phoneNumber, selectedListId);
        } else if (selectedListId.startsWith("grv_dept_")) {
            grievanceHandler.handleDepartmentSelection(phoneNumber, selectedListId);
        } else if (selectedListId.startsWith("grv_status_")) {
            grievanceHandler.handleStatusSelection(phoneNumber, selectedListId);
        } else if (selectedListId.startsWith("grv_delete_")) {
            grievanceHandler.handleDeleteSelection(phoneNumber, selectedListId);
        } else if (selectedListId.startsWith("student_")) {
            studentMenuHandler.handleMenuSelection(phoneNumber, selectedListId);
        } else if (selectedListId.startsWith("faculty_")) {
            facultyMenuHandler.handleMenuSelection(phoneNumber, selectedListId);
        } else if (selectedListId.startsWith("sem_")) {
            studentMenuHandler.handleSemesterSelection(phoneNumber, selectedListId);
        } else if (selectedListId.startsWith("receipt_") || selectedListId.startsWith("exam_") || selectedListId.startsWith("acad_") || selectedListId.startsWith("cons_")) {
            studentMenuHandler.handleReceiptSelection(phoneNumber, selectedListId);
        } else {
            if (sessionService.isFaculty(phoneNumber)) {
                facultyMenuHandler.sendMainMenu(phoneNumber);
            } else {
                studentMenuHandler.sendMainMenu(phoneNumber);
            }
        }
    }

    private void handleInteractiveButtonSelection(String phoneNumber, String selectedButtonId, UserState currentState) {
        if (selectedButtonId.startsWith("faculty_")) {
            facultyMenuHandler.handleButtonSelection(phoneNumber, selectedButtonId);
            return;
        }

        if ("student_logout".equals(selectedButtonId)) {
            sessionService.logoutUser(phoneNumber);
            messageService.sendMessage(phoneNumber, "You have been logged out successfully. Type 'Hi' to log in again.");
            return;
        }

        if ("student_weekly_timetable".equals(selectedButtonId)) {
            studentMenuHandler.handleWeeklyTimetable(phoneNumber);
            return;
        }

        if ("student_show_menu".equals(selectedButtonId)) {
            studentMenuHandler.sendStudentMenuDirectly(phoneNumber);
            return;
        }

        if ("student_exam_fees".equals(selectedButtonId)) {
            studentMenuHandler.handleExamFees(phoneNumber);
            return;
        }

        if ("student_cat1_marks".equals(selectedButtonId)) {
            studentMenuHandler.handleCat1Marks(phoneNumber);
            return;
        }

        if ("student_cat2_marks".equals(selectedButtonId)) {
            studentMenuHandler.handleCat2Marks(phoneNumber);
            return;
        }

        if ("student_cat3_marks".equals(selectedButtonId)) {
            studentMenuHandler.handleCat3Marks(phoneNumber);
            return;
        }

        if ("student_assignment_marks".equals(selectedButtonId)) {
            studentMenuHandler.handleAssignmentMarks(phoneNumber);
            return;
        }

        if ("student_payment_history".equals(selectedButtonId)) {
            studentMenuHandler.handlePaymentHistory(phoneNumber);
            return;
        }

        if ("grv_skip_image".equals(selectedButtonId)) {
            grievanceHandler.handleSkipImage(phoneNumber);
        } else {
            if (sessionService.isFaculty(phoneNumber)) {
                facultyMenuHandler.sendMainMenu(phoneNumber);
            } else {
                studentMenuHandler.sendMainMenu(phoneNumber);
            }
        }
    }
}