import { EditMetadataState } from '@/types';
import { showLoader, hideLoader, showAlert } from '../ui.js';
import { downloadFile, formatBytes } from '../utils/helpers.js';
import { createIcons, icons } from 'lucide';
import { PDFDocument as PDFLibDocument, PDFName, PDFString } from 'pdf-lib';
import { loadPdfWithPasswordPrompt } from '../utils/password-prompt.js';

const pageState: EditMetadataState = {
  file: null,
  pdfDoc: null,
};

function resetState() {
  pageState.file = null;
  pageState.pdfDoc = null;

  const fileDisplayArea = document.getElementById('file-display-area');
  if (fileDisplayArea) fileDisplayArea.innerHTML = '';

  const toolOptions = document.getElementById('tool-options');
  if (toolOptions) toolOptions.classList.add('hidden');

  const fileInput = document.getElementById('file-input') as HTMLInputElement;
  if (fileInput) fileInput.value = '';

  // Clear form fields
  const fields = [
    'meta-title',
    'meta-author',
    'meta-subject',
    'meta-keywords',
    'meta-creator',
    'meta-producer',
    'meta-creation-date',
    'meta-mod-date',
  ];
  fields.forEach(function (fieldId) {
    const field = document.getElementById(fieldId) as HTMLInputElement;
    if (field) field.value = '';
  });

  // Clear custom fields
  const customFieldsContainer = document.getElementById(
    'custom-fields-container'
  );
  if (customFieldsContainer) customFieldsContainer.innerHTML = '';
}

function formatDateForInput(date: Date | undefined): string {
  if (!date) return '';
  try {
    const year = date.getFullYear();
    const month = String(date.getMonth() + 1).padStart(2, '0');
    const day = String(date.getDate()).padStart(2, '0');
    const hours = String(date.getHours()).padStart(2, '0');
    const minutes = String(date.getMinutes()).padStart(2, '0');
    return `${year}-${month}-${day}T${hours}:${minutes}`;
  } catch {
    return '';
  }
}

function addCustomFieldRow(key: string = '', value: string = '') {
  const container = document.getElementById('custom-fields-container');
  if (!container) return;

  const row = document.createElement('div');
  row.className = 'flex flex-col gap-2';

  const keyInput = document.createElement('input');
  keyInput.type = 'text';
  keyInput.placeholder = 'Key (e.g., Department)';
  keyInput.value = key;
  keyInput.className =
    'custom-meta-key w-full bg-gray-700 border border-gray-600 text-white text-sm rounded-lg focus:ring-indigo-500 focus:border-indigo-500 p-2.5';

  const valueInput = document.createElement('input');
  valueInput.type = 'text';
  valueInput.placeholder = 'Value (e.g., Marketing)';
  valueInput.value = value;
  valueInput.className =
    'custom-meta-value w-full bg-gray-700 border border-gray-600 text-white text-sm rounded-lg focus:ring-indigo-500 focus:border-indigo-500 p-2.5';

  const removeBtn = document.createElement('button');
  removeBtn.type = 'button';
  removeBtn.className = 'text-red-400 hover:text-red-300 p-2 self-center';
  removeBtn.innerHTML = '<i data-lucide="trash-2" class="w-5 h-5"></i>';
  removeBtn.onclick = function () {
    row.remove();
  };

  row.append(keyInput, valueInput, removeBtn);
  container.appendChild(row);
  createIcons({ icons });
}

function populateMetadataFields() {
  if (!pageState.pdfDoc) return;

  const titleInput = document.getElementById('meta-title') as HTMLInputElement;
  const authorInput = document.getElementById(
    'meta-author'
  ) as HTMLInputElement;
  const subjectInput = document.getElementById(
    'meta-subject'
  ) as HTMLInputElement;
  const keywordsInput = document.getElementById(
    'meta-keywords'
  ) as HTMLInputElement;
  const creatorInput = document.getElementById(
    'meta-creator'
  ) as HTMLInputElement;
  const producerInput = document.getElementById(
    'meta-producer'
  ) as HTMLInputElement;
  const creationDateInput = document.getElementById(
    'meta-creation-date'
  ) as HTMLInputElement;
  const modDateInput = document.getElementById(
    'meta-mod-date'
  ) as HTMLInputElement;

  if (titleInput) titleInput.value = pageState.pdfDoc.getTitle() || '';
  if (authorInput) authorInput.value = pageState.pdfDoc.getAuthor() || '';
  if (subjectInput) subjectInput.value = pageState.pdfDoc.getSubject() || '';
  if (keywordsInput) keywordsInput.value = pageState.pdfDoc.getKeywords() || '';
  if (creatorInput) creatorInput.value = pageState.pdfDoc.getCreator() || '';
  if (producerInput) producerInput.value = pageState.pdfDoc.getProducer() || '';
  if (creationDateInput)
    creationDateInput.value = formatDateForInput(
      pageState.pdfDoc.getCreationDate()
    );
  if (modDateInput)
    modDateInput.value = formatDateForInput(
      pageState.pdfDoc.getModificationDate()
    );

  // Load custom fields
  const customFieldsContainer = document.getElementById(
    'custom-fields-container'
  );
  if (customFieldsContainer) customFieldsContainer.innerHTML = '';

  try {
    // @ts-expect-error getInfoDict is private but accessible at runtime
    const infoDict = pageState.pdfDoc.getInfoDict();
    const standardKeys = new Set([
      'Title',
      'Author',
      'Subject',
      'Keywords',
      'Creator',
      'Producer',
      'CreationDate',
      'ModDate',
    ]);

    const allKeys = infoDict.keys().map(function (key: {
      asString: () => string;
    }) {
      return key.asString().substring(1);
    });

    allKeys.forEach(function (key: string) {
      if (!standardKeys.has(key)) {
        const rawValue = infoDict.lookup(key);
        let displayValue = '';

        if (rawValue && typeof rawValue.decodeText === 'function') {
          displayValue = rawValue.decodeText();
        } else if (rawValue && typeof rawValue.asString === 'function') {
          displayValue = rawValue.asString();
        } else if (rawValue) {
          displayValue = String(rawValue);
        }

        addCustomFieldRow(key, displayValue);
      }
    });
  } catch (e) {
    console.warn('Could not read custom metadata fields:', e);
  }
}

async function updateUI() {
  const fileDisplayArea = document.getElementById('file-display-area');
  const toolOptions = document.getElementById('tool-options');

  if (!fileDisplayArea) return;

  fileDisplayArea.innerHTML = '';

  if (pageState.file) {
    const fileDiv = document.createElement('div');
    fileDiv.className =
      'flex items-center justify-between bg-gray-700 p-3 rounded-lg text-sm';

    const infoContainer = document.createElement('div');
    infoContainer.className = 'flex flex-col overflow-hidden';

    const nameSpan = document.createElement('div');
    nameSpan.className = 'truncate font-medium text-gray-200 text-sm mb-1';
    nameSpan.textContent = pageState.file.name;

    const metaSpan = document.createElement('div');
    metaSpan.className = 'text-xs text-gray-400';
    metaSpan.textContent = `${formatBytes(pageState.file.size)} • Loading...`;

    infoContainer.append(nameSpan, metaSpan);

    const removeBtn = document.createElement('button');
    removeBtn.className = 'ml-4 text-red-400 hover:text-red-300 flex-shrink-0';
    removeBtn.innerHTML = '<i data-lucide="trash-2" class="w-4 h-4"></i>';
    removeBtn.onclick = function () {
      resetState();
    };

    fileDiv.append(infoContainer, removeBtn);
    fileDisplayArea.appendChild(fileDiv);
    createIcons({ icons });

    try {
      const result = await loadPdfWithPasswordPrompt(pageState.file);
      if (!result) {
        resetState();
        return;
      }
      showLoader('Loading PDF...');
      result.pdf.destroy();
      pageState.file = result.file;
      pageState.pdfDoc = await PDFLibDocument.load(result.bytes, {
        throwOnInvalidObject: false,
      });
      hideLoader();

      const pageCount = pageState.pdfDoc.getPageCount();
      metaSpan.textContent = `${formatBytes(pageState.file.size)} • ${pageCount} pages`;

      populateMetadataFields();

      if (toolOptions) toolOptions.classList.remove('hidden');
    } catch (error) {
      console.error('Error loading PDF:', error);
      hideLoader();
      showAlert('Error', 'Failed to load PDF file.');
      resetState();
    }
  } else {
    if (toolOptions) toolOptions.classList.add('hidden');
  }
}

async function saveMetadata() {
  if (!pageState.pdfDoc || !pageState.file) {
    showAlert('Error', 'Please upload a PDF first.');
    return;
  }

  showLoader('Updating metadata...');

  try {
    const titleInput = document.getElementById(
      'meta-title'
    ) as HTMLInputElement;
    const authorInput = document.getElementById(
      'meta-author'
    ) as HTMLInputElement;
    const subjectInput = document.getElementById(
      'meta-subject'
    ) as HTMLInputElement;
    const keywordsInput = document.getElementById(
      'meta-keywords'
    ) as HTMLInputElement;
    const creatorInput = document.getElementById(
      'meta-creator'
    ) as HTMLInputElement;
    const producerInput = document.getElementById(
      'meta-producer'
    ) as HTMLInputElement;
    const creationDateInput = document.getElementById(
      'meta-creation-date'
    ) as HTMLInputElement;
    const modDateInput = document.getElementById(
      'meta-mod-date'
    ) as HTMLInputElement;

    pageState.pdfDoc.setTitle(titleInput.value);
    pageState.pdfDoc.setAuthor(authorInput.value);
    pageState.pdfDoc.setSubject(subjectInput.value);
    pageState.pdfDoc.setCreator(creatorInput.value);
    pageState.pdfDoc.setProducer(producerInput.value);

    const keywords = keywordsInput.value;
    pageState.pdfDoc.setKeywords(
      keywords
        .split(',')
        .map(function (k) {
          return k.trim();
        })
        .filter(Boolean)
    );

    // Handle creation date
    if (creationDateInput.value) {
      pageState.pdfDoc.setCreationDate(new Date(creationDateInput.value));
    }

    // Handle modification date
    if (modDateInput.value) {
      pageState.pdfDoc.setModificationDate(new Date(modDateInput.value));
    } else {
      pageState.pdfDoc.setModificationDate(new Date());
    }

    // Handle custom fields
    // @ts-expect-error getInfoDict is private but accessible at runtime
    const infoDict = pageState.pdfDoc.getInfoDict();
    const standardKeys = new Set([
      'Title',
      'Author',
      'Subject',
      'Keywords',
      'Creator',
      'Producer',
      'CreationDate',
      'ModDate',
    ]);

    // Remove existing custom keys
    const allKeys = infoDict.keys().map(function (key: {
      asString: () => string;
    }) {
      return key.asString().substring(1);
    });

    allKeys.forEach(function (key: string) {
      if (!standardKeys.has(key)) {
        infoDict.delete(PDFName.of(key));
      }
    });

    // Add new custom fields
    const customKeys = document.querySelectorAll('.custom-meta-key');
    const customValues = document.querySelectorAll('.custom-meta-value');

    customKeys.forEach(function (keyInput, index) {
      const key = (keyInput as HTMLInputElement).value.trim();
      const value = (customValues[index] as HTMLInputElement).value.trim();
      if (key && value) {
        infoDict.set(PDFName.of(key), PDFString.of(value));
      }
    });

    const newPdfBytes = await pageState.pdfDoc.save();
    const originalName = pageState.file.name.replace(/\.pdf$/i, '');

    downloadFile(
      new Blob([new Uint8Array(newPdfBytes)], { type: 'application/pdf' }),
      `${originalName}_metadata-edited.pdf`
    );

    showAlert(
      'Success',
      'Metadata updated successfully!',
      'success',
      function () {
        resetState();
      }
    );
  } catch (e) {
    console.error(e);
    showAlert(
      'Error',
      'Could not update metadata. Please check that date formats are correct.'
    );
  } finally {
    hideLoader();
  }
}

function handleFileSelect(files: FileList | null) {
  if (files && files.length > 0) {
    const file = files[0];
    if (
      file.type === 'application/pdf' ||
      file.name.toLowerCase().endsWith('.pdf')
    ) {
      pageState.file = file;
      updateUI();
    }
  }
}

document.addEventListener('DOMContentLoaded', function () {
  const fileInput = document.getElementById('file-input') as HTMLInputElement;
  const dropZone = document.getElementById('drop-zone');
  const processBtn = document.getElementById('process-btn');
  const backBtn = document.getElementById('back-to-tools');
  const addCustomFieldBtn = document.getElementById('add-custom-field');

  if (backBtn) {
    backBtn.addEventListener('click', function () {
      window.location.href = import.meta.env.BASE_URL;
    });
  }

  if (addCustomFieldBtn) {
    addCustomFieldBtn.addEventListener('click', function () {
      addCustomFieldRow();
    });
  }

  if (fileInput && dropZone) {
    fileInput.addEventListener('change', function (e) {
      handleFileSelect((e.target as HTMLInputElement).files);
    });

    dropZone.addEventListener('dragover', function (e) {
      e.preventDefault();
      dropZone.classList.add('bg-gray-700');
    });

    dropZone.addEventListener('dragleave', function (e) {
      e.preventDefault();
      dropZone.classList.remove('bg-gray-700');
    });

    dropZone.addEventListener('drop', function (e) {
      e.preventDefault();
      dropZone.classList.remove('bg-gray-700');
      const files = e.dataTransfer?.files;
      if (files && files.length > 0) {
        const pdfFiles = Array.from(files).filter(function (f) {
          return (
            f.type === 'application/pdf' ||
            f.name.toLowerCase().endsWith('.pdf')
          );
        });
        if (pdfFiles.length > 0) {
          const dataTransfer = new DataTransfer();
          dataTransfer.items.add(pdfFiles[0]);
          handleFileSelect(dataTransfer.files);
        }
      }
    });

    fileInput.addEventListener('click', function () {
      fileInput.value = '';
    });
  }

  if (processBtn) {
    processBtn.addEventListener('click', saveMetadata);
  }
});