/**
 * Copyright since 2025 Mifos Initiative
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

import { Component, OnInit, inject } from '@angular/core';
import {
  MatDialog,
  MatDialogRef,
  MAT_DIALOG_DATA,
  MatDialogTitle,
  MatDialogActions,
  MatDialogClose
} from '@angular/material/dialog';
import { ImageCropperDialogComponent } from '../image-cropper-dialog/image-cropper-dialog.component';
import { CaptureImageDialogComponent } from '../capture-image-dialog/capture-image-dialog.component';
import { UntypedFormGroup, UntypedFormBuilder, Validators, ReactiveFormsModule } from '@angular/forms';
import { FileUploadComponent } from '../../../../shared/file-upload/file-upload.component';
import { MatIconButton } from '@angular/material/button';
import { STANDALONE_SHARED_IMPORTS } from 'app/standalone-shared.module';
import { ClientsService } from '../../../clients.service';
import { ProofType, normalizeProofType, groupProofsByCategory } from '../../../shared/kyc-proof-types';
import { dataUrlToFile } from '../../../../shared/utils/data-url.util';

type SectionKey = 'id' | 'address';

@Component({
  selector: 'mifosx-upload-document-dialog',
  templateUrl: './upload-document-dialog.component.html',
  styleUrls: ['./upload-document-dialog.component.scss'],
  imports: [
    ...STANDALONE_SHARED_IMPORTS,
    MatDialogTitle,
    FileUploadComponent,
    MatDialogActions,
    MatDialogClose,
    MatIconButton
  ]
})
export class UploadDocumentDialogComponent implements OnInit {
  dialogRef = inject<MatDialogRef<UploadDocumentDialogComponent>>(MatDialogRef);
  private formBuilder = inject(UntypedFormBuilder);
  private clientsService = inject(ClientsService);
  private dialog = inject(MatDialog);
  data = inject(MAT_DIALOG_DATA);

  uploadDocumentForm: UntypedFormGroup;
  uploadDocumentData: any = [];
  documentIdentifier = false;
  entityType: string;

  /** Prefilled values from client registration (identifier mode) */
  clientName = '';
  clientAddress = '';

  /** Identifier-mode state */
  idProofs: ProofType[] = [];
  addressProofs: ProofType[] = [];
  addressGroups: { label: string; items: ProofType[] }[] = [];
  loadingProofs = false;

  selectedIdProof: ProofType | null = null;
  selectedAddrProof: ProofType | null = null;

  idFiles: { front: File | null; back: File | null } = { front: null, back: null };
  addrFiles: { front: File | null; back: File | null } = { front: null, back: null };

  /** Merged front+back PNG previews (data URLs) and File objects */
  idMergedFile: File | null = null;
  idMergedPreview: string | null = null;
  addrMergedFile: File | null = null;
  addrMergedPreview: string | null = null;

  /** Non-identifier (generic) mode only — set after a webcam capture, since
   * `FileUploadComponent` only reflects files picked through its own native input and has
   * no input for one supplied programmatically. Cleared if the user then picks a file via
   * Browse instead, so only one confirmation shows at a time. */
  capturedFileName: string | null = null;

  constructor() {
    const data = this.data;
    this.documentIdentifier = !!data?.documentIdentifier;
    this.entityType = data?.entityType;
    this.clientName = data?.clientName || '';
    this.clientAddress = data?.clientAddress || '';
  }

  ngOnInit() {
    this.createUploadDocumentForm();
    if (this.documentIdentifier) {
      this.loadProofTypes();
    }
  }

  createUploadDocumentForm() {
    if (this.documentIdentifier) {
      this.uploadDocumentForm = this.formBuilder.group({
        id: this.formBuilder.group({
          proofId: [''],
          documentKey: ['']
        }),
        address: this.formBuilder.group({
          proofId: [''],
          issueDate: ['']
        }),
        description: ['']
      });
    } else {
      this.uploadDocumentForm = this.formBuilder.group({
        fileName: [
          '',
          Validators.required
        ],
        description: [''],
        file: ['']
      });
    }
  }

  private loadProofTypes(): void {
    this.loadingProofs = true;
    this.clientsService.getKycProofTypes().subscribe({
      next: (res: any) => {
        const activeFilter = (p: any) => p?.active !== false;
        this.idProofs = (res?.idProofs || []).filter(activeFilter).map(normalizeProofType);
        this.addressProofs = (res?.addressProofs || []).filter(activeFilter).map(normalizeProofType);
        this.addressGroups = groupProofsByCategory(this.addressProofs);
        this.loadingProofs = false;
      },
      error: () => {
        this.loadingProofs = false;
      }
    });
  }

  onIdProofChange(proofId: any): void {
    this.selectedIdProof = this.idProofs.find((p) => String(p.id) === String(proofId)) || null;
    this.idFiles = { front: null, back: null };
    this.idMergedFile = null;
    this.idMergedPreview = null;
  }

  selectAddrProof(proof: ProofType): void {
    this.selectedAddrProof = proof;
    this.uploadDocumentForm.get('address.proofId').setValue(proof.id);
    this.addrFiles = { front: null, back: null };
    this.addrMergedFile = null;
    this.addrMergedPreview = null;
  }

  isAddrProofSelected(proof: ProofType): boolean {
    return this.selectedAddrProof?.id === proof.id;
  }

  onFilePick(section: SectionKey, slot: 'front' | 'back', event: any): void {
    const file = event?.target?.files?.[0];
    // reset the input so picking the same file again still triggers change
    if (event?.target) event.target.value = '';
    if (!file) return;

    // Non-image (e.g. PDF) — bypass cropping
    if (!file.type.startsWith('image/')) {
      this.setSlotFile(section, slot, file);
      this.maybeMerge(section);
      return;
    }

    const ref = this.dialog.open(ImageCropperDialogComponent, {
      width: '720px',
      maxWidth: '95vw',
      data: { file, title: `Crop ${slot} side` }
    });

    ref.afterClosed().subscribe((cropped: File | null) => {
      if (!cropped) return;
      this.setSlotFile(section, slot, cropped);
      this.maybeMerge(section);
    });
  }

  reCrop(section: SectionKey, slot: 'front' | 'back'): void {
    const current = section === 'id' ? this.idFiles[slot] : this.addrFiles[slot];
    if (!current || !current.type.startsWith('image/')) return;
    const ref = this.dialog.open(ImageCropperDialogComponent, {
      width: '720px',
      maxWidth: '95vw',
      data: { file: current, title: `Re-crop ${slot} side` }
    });
    ref.afterClosed().subscribe((cropped: File | null) => {
      if (!cropped) return;
      this.setSlotFile(section, slot, cropped);
      this.maybeMerge(section);
    });
  }

  private setSlotFile(section: SectionKey, slot: 'front' | 'back', file: File): void {
    if (section === 'id') this.idFiles[slot] = file;
    else this.addrFiles[slot] = file;
  }

  /**
   * If a section has both image sides ready, build a single merged PNG
   * (front stacked above back) and store it as the file we'll actually upload.
   */
  private maybeMerge(section: SectionKey): void {
    const proof = section === 'id' ? this.selectedIdProof : this.selectedAddrProof;
    if (!proof || proof.sides !== 2) {
      this.resetMerged(section);
      return;
    }
    const front = section === 'id' ? this.idFiles.front : this.addrFiles.front;
    const back = section === 'id' ? this.idFiles.back : this.addrFiles.back;
    if (!front || !back) {
      this.resetMerged(section);
      return;
    }
    if (!front.type.startsWith('image/') || !back.type.startsWith('image/')) {
      // Cannot merge non-image files (PDFs); leave as separate.
      this.resetMerged(section);
      return;
    }

    Promise.all([
      this.fileToImage(front),
      this.fileToImage(back)
    ])
      .then(
        ([
          fImg,
          bImg
        ]) => {
          const targetWidth = Math.max(fImg.width, bImg.width);
          const fScale = targetWidth / fImg.width;
          const bScale = targetWidth / bImg.width;
          const fH = fImg.height * fScale;
          const bH = bImg.height * bScale;
          const gap = 20;
          const totalH = Math.round(fH + bH + gap);

          const canvas = document.createElement('canvas');
          canvas.width = targetWidth;
          canvas.height = totalH;
          const ctx = canvas.getContext('2d');
          if (!ctx) return;

          ctx.fillStyle = '#ffffff';
          ctx.fillRect(0, 0, canvas.width, canvas.height);
          ctx.drawImage(fImg, 0, 0, targetWidth, fH);
          ctx.drawImage(bImg, 0, fH + gap, targetWidth, bH);

          canvas.toBlob((blob) => {
            if (!blob) return;
            const merged = new File([blob], `${proof.name || 'document'}-combined.png`, { type: 'image/png' });
            const preview = canvas.toDataURL('image/png');
            if (section === 'id') {
              this.idMergedFile = merged;
              this.idMergedPreview = preview;
            } else {
              this.addrMergedFile = merged;
              this.addrMergedPreview = preview;
            }
          }, 'image/png');
        }
      )
      .catch(() => this.resetMerged(section));
  }

  private resetMerged(section: SectionKey): void {
    if (section === 'id') {
      this.idMergedFile = null;
      this.idMergedPreview = null;
    } else {
      this.addrMergedFile = null;
      this.addrMergedPreview = null;
    }
  }

  private fileToImage(file: File): Promise<HTMLImageElement> {
    return new Promise((resolve, reject) => {
      const url = URL.createObjectURL(file);
      const img = new Image();
      img.onload = () => {
        URL.revokeObjectURL(url);
        resolve(img);
      };
      img.onerror = () => {
        URL.revokeObjectURL(url);
        reject(new Error('image load failed'));
      };
      img.src = url;
    });
  }

  getFileName(section: SectionKey, slot: 'front' | 'back'): string {
    const f = section === 'id' ? this.idFiles[slot] : this.addrFiles[slot];
    if (!f) return '';
    return f.name.length > 30 ? f.name.slice(0, 27) + '...' : f.name;
  }

  isIdComplete(): boolean {
    return this.isSectionComplete('id');
  }

  isAddressComplete(): boolean {
    return this.isSectionComplete('address');
  }

  /** Section is "filled in" — has a proof selected */
  private isSectionTouched(section: SectionKey): boolean {
    return section === 'id' ? !!this.selectedIdProof : !!this.selectedAddrProof;
  }

  /** Section has all required fields + files */
  private isSectionComplete(section: SectionKey): boolean {
    if (section === 'id') {
      const proof = this.selectedIdProof;
      if (!proof) return false;
      const v = this.uploadDocumentForm.get('id').value;
      if (!v.documentKey) return false;
      if (!this.idFiles.front) return false;
      if (proof.sides === 2 && !this.idFiles.back) return false;
      return true;
    }
    const proof = this.selectedAddrProof;
    if (!proof) return false;
    if (!this.addrFiles.front) return false;
    if (proof.sides === 2 && !this.addrFiles.back) return false;
    return true;
  }

  get canSubmit(): boolean {
    if (!this.documentIdentifier) {
      return this.uploadDocumentForm?.valid;
    }
    const idTouched = this.isSectionTouched('id');
    const addrTouched = this.isSectionTouched('address');
    if (!idTouched && !addrTouched) return false;
    if (idTouched && !this.isSectionComplete('id')) return false;
    if (addrTouched && !this.isSectionComplete('address')) return false;
    return true;
  }

  submit(): void {
    if (!this.documentIdentifier) {
      this.dialogRef.close(this.uploadDocumentForm.value);
      return;
    }
    const result: any = { description: this.uploadDocumentForm.get('description').value, id: null, address: null };
    if (this.isSectionComplete('id')) {
      const v = this.uploadDocumentForm.get('id').value;
      result.id = {
        proof: this.selectedIdProof,
        proofId: this.selectedIdProof.id,
        documentKey: v.documentKey,
        fullName: this.clientName,
        files: this.buildSectionFiles('id')
      };
    }
    if (this.isSectionComplete('address')) {
      const v = this.uploadDocumentForm.get('address').value;
      result.address = {
        proof: this.selectedAddrProof,
        proofId: this.selectedAddrProof.id,
        address: this.clientAddress,
        issueDate: v.issueDate,
        files: this.buildSectionFiles('address')
      };
    }
    this.dialogRef.close(result);
  }

  /**
   * Build the files payload for a section. When both sides are images and
   * have been merged into a single combined PNG, send only that one file.
   * Otherwise fall back to the individual front/back files.
   */
  private buildSectionFiles(section: SectionKey): { slot: string; file: File }[] {
    const proof = section === 'id' ? this.selectedIdProof : this.selectedAddrProof;
    const front = section === 'id' ? this.idFiles.front : this.addrFiles.front;
    const back = section === 'id' ? this.idFiles.back : this.addrFiles.back;
    const merged = section === 'id' ? this.idMergedFile : this.addrMergedFile;

    if (proof?.sides === 2 && merged) {
      return [{ slot: 'Combined', file: merged }];
    }

    const files: { slot: string; file: File }[] = [];
    if (front) files.push({ slot: 'Front', file: front });
    if (proof?.sides === 2 && back) files.push({ slot: 'Back', file: back });
    return files;
  }

  /** Legacy: kept for non-identifier mode file upload component */
  onFileSelect($event: any) {
    if ($event.target.files.length > 0) {
      const file = $event.target.files[0];
      this.uploadDocumentForm.get('file').setValue(file);
      this.capturedFileName = null;
    }
  }

  /** Non-identifier (generic Documents tab) mode only — lets staff photograph a document
   * with the webcam instead of only being able to browse for an existing file. Reuses the
   * same capture dialog as the profile-photo/signature flows. */
  captureFromWebcam(): void {
    const ref = this.dialog.open(CaptureImageDialogComponent, {
      width: '720px',
      maxWidth: '95vw',
      data: { captureTarget: 'profile' }
    });
    ref.afterClosed().subscribe((dataUrl: string | null) => {
      if (!dataUrl) return;
      const file = dataUrlToFile(dataUrl, `webcam-capture-${Date.now()}.jpg`);
      this.uploadDocumentForm.get('file').setValue(file);
      this.capturedFileName = file.name;
    });
  }
}