/**
 * create-survey.page.ts
 * Page for creating a new survey or editing an existing one.
 *
 * When accessed via /create-survey         → creates a new survey
 * When accessed via /create-survey/:id    → loads and edits the existing survey
 */

import { Component, OnInit } from '@angular/core';
import { ActivatedRoute, Router } from '@angular/router';
import { ToastController } from '@ionic/angular';
import { SurveyService } from '../../services/survey.service';
import type { Survey, Question } from '../../shared/models/survey.models';

@Component({
  selector: 'app-create-survey',
  templateUrl: './create-survey.page.html',
  styleUrls: ['./create-survey.page.scss'],
  standalone: false,
})
export class CreateSurveyPage implements OnInit {
  /** True when editing an existing survey */
  isEditMode = false;
  existingSurveyId?: string;

  // Form fields
  title = '';
  description = '';
  questions: Question[] = [];

  /** Track which question's options are being edited */
  expandedQuestionIndex: number | null = null;

  constructor(
    private route: ActivatedRoute,
    private router: Router,
    private surveyService: SurveyService,
    private toastCtrl: ToastController
  ) {}

  async ngOnInit(): Promise<void> {
    const id = this.route.snapshot.paramMap.get('id');
    if (id) {
      this.isEditMode = true;
      this.existingSurveyId = id;
      await this.loadSurvey(id);
    } else {
      // Start with one empty question for a better UX
      this.addQuestion();
    }
  }

  private async loadSurvey(id: string): Promise<void> {
    const survey = await this.surveyService.getSurvey(id);
    if (!survey) {
      const toast = await this.toastCtrl.create({
        message: 'Survey not found.',
        duration: 2000,
        color: 'danger',
      });
      await toast.present();
      this.router.navigate(['/home']);
      return;
    }
    this.title = survey.title;
    this.description = survey.description ?? '';
    // Deep copy so edits don't mutate the original until saved
    this.questions = JSON.parse(JSON.stringify(survey.questions));
  }

  // -------------------------------------------------------------------------
  // Question management
  // -------------------------------------------------------------------------

  addQuestion(): void {
    const question: Question = {
      id: crypto.randomUUID(),
      text: '',
      type: 'text',
      required: false,
    };
    this.questions.push(question);
    this.expandedQuestionIndex = this.questions.length - 1;
  }

  removeQuestion(index: number): void {
    this.questions.splice(index, 1);
    if (this.expandedQuestionIndex === index) {
      this.expandedQuestionIndex = null;
    }
  }

  moveQuestionUp(index: number): void {
    if (index === 0) return;
    const temp = this.questions[index - 1];
    this.questions[index - 1] = this.questions[index];
    this.questions[index] = temp;
  }

  moveQuestionDown(index: number): void {
    if (index === this.questions.length - 1) return;
    const temp = this.questions[index + 1];
    this.questions[index + 1] = this.questions[index];
    this.questions[index] = temp;
  }

  toggleExpand(index: number): void {
    this.expandedQuestionIndex =
      this.expandedQuestionIndex === index ? null : index;
  }

  onTypeChange(question: Question): void {
    // Initialise options array when switching to multiple_choice
    if (question.type === 'multiple_choice' && !question.options?.length) {
      question.options = ['Option 1', 'Option 2'];
    }
  }

  addOption(question: Question): void {
    if (!question.options) question.options = [];
    question.options.push(`Option ${question.options.length + 1}`);
  }

  removeOption(question: Question, optIndex: number): void {
    question.options?.splice(optIndex, 1);
  }

  trackOption(index: number): number {
    return index;
  }

  trackQuestion(index: number): number {
    return index;
  }

  // -------------------------------------------------------------------------
  // Validation
  // -------------------------------------------------------------------------

  get isFormValid(): boolean {
    if (!this.title.trim()) return false;
    if (this.questions.length === 0) return false;
    return this.questions.every(
      (q) =>
        q.text.trim() &&
        (q.type !== 'multiple_choice' || (q.options && q.options.length >= 2))
    );
  }

  // -------------------------------------------------------------------------
  // Save / Update
  // -------------------------------------------------------------------------

  async save(): Promise<void> {
    if (!this.isFormValid) return;

    const questionsToSave = this.questions.map((q) => ({
      ...q,
      text: q.text.trim(),
      // Strip empty options for multiple_choice
      options:
        q.type === 'multiple_choice'
          ? q.options?.filter((o) => o.trim()) ?? []
          : undefined,
    }));

    if (this.isEditMode && this.existingSurveyId) {
      await this.surveyService.updateSurvey(this.existingSurveyId, {
        title: this.title.trim(),
        description: this.description.trim() || undefined,
        questions: questionsToSave,
      });
      const toast = await this.toastCtrl.create({
        message: 'Survey updated.',
        duration: 2000,
        color: 'success',
      });
      await toast.present();
      this.router.navigate(['/survey', this.existingSurveyId]);
    } else {
      const survey = await this.surveyService.createSurvey({
        title: this.title.trim(),
        description: this.description.trim() || undefined,
        questions: questionsToSave,
      });
      const toast = await this.toastCtrl.create({
        message: 'Survey created.',
        duration: 2000,
        color: 'success',
      });
      await toast.present();
      this.router.navigate(['/survey', survey.id]);
    }
  }

  cancel(): void {
    if (this.isEditMode && this.existingSurveyId) {
      this.router.navigate(['/survey', this.existingSurveyId]);
    } else {
      this.router.navigate(['/home']);
    }
  }
}