import { showLoader, hideLoader, showAlert } from '../ui.js';
import {
    downloadFile,
    readFileAsArrayBuffer,
    formatBytes,
    getPDFDocument,
} from '../utils/helpers.js';
import { state } from '../state.js';
import { createIcons, icons } from 'lucide';
import { convertFileToPdfA, type PdfALevel } from '../utils/ghostscript-loader';

document.addEventListener('DOMContentLoaded', () => {
    const fileInput = document.getElementById('file-input') as HTMLInputElement;
    const dropZone = document.getElementById('drop-zone');
    const processBtn = document.getElementById('process-btn');
    const fileDisplayArea = document.getElementById('file-display-area');
    const optionsContainer = document.getElementById('options-container');
    const fileControls = document.getElementById('file-controls');
    const addMoreBtn = document.getElementById('add-more-btn');
    const clearFilesBtn = document.getElementById('clear-files-btn');
    const backBtn = document.getElementById('back-to-tools');
    const pdfaLevelSelect = document.getElementById('pdfa-level') as HTMLSelectElement;

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

    const updateUI = async () => {
        if (!fileDisplayArea || !optionsContainer || !processBtn || !fileControls) return;

        if (state.files.length > 0) {
            fileDisplayArea.innerHTML = '';

            for (let index = 0; index < state.files.length; index++) {
                const file = state.files[index];
                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 = file.name;

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

                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 = () => {
                    state.files = state.files.filter((_, i) => i !== index);
                    updateUI();
                };

                fileDiv.append(infoContainer, removeBtn);
                fileDisplayArea.appendChild(fileDiv);

                try {
                    const arrayBuffer = await readFileAsArrayBuffer(file);
                    const pdfDoc = await getPDFDocument({ data: arrayBuffer }).promise;
                    metaSpan.textContent = `${formatBytes(file.size)} • ${pdfDoc.numPages} pages`;
                } catch (error) {
                    console.error('Error loading PDF:', error);
                    metaSpan.textContent = `${formatBytes(file.size)} • Could not load page count`;
                }
            }

            createIcons({ icons });
            fileControls.classList.remove('hidden');
            optionsContainer.classList.remove('hidden');
            (processBtn as HTMLButtonElement).disabled = false;
        } else {
            fileDisplayArea.innerHTML = '';
            fileControls.classList.add('hidden');
            optionsContainer.classList.add('hidden');
            (processBtn as HTMLButtonElement).disabled = true;
        }
    };

    const resetState = () => {
        state.files = [];
        state.pdfDoc = null;

        if (pdfaLevelSelect) pdfaLevelSelect.value = 'PDF/A-2b';

        updateUI();
    };

    const convertToPdfA = async () => {
        const level = pdfaLevelSelect.value as PdfALevel;

        try {
            if (state.files.length === 0) {
                showAlert('No Files', 'Please select at least one PDF file.');
                hideLoader();
                return;
            }

            if (state.files.length === 1) {
                const originalFile = state.files[0];

                showLoader('Initializing Ghostscript...');

                const convertedBlob = await convertFileToPdfA(
                    originalFile,
                    level,
                    (msg) => showLoader(msg)
                );

                const fileName = originalFile.name.replace(/\.pdf$/i, '') + '_pdfa.pdf';

                downloadFile(convertedBlob, fileName);

                hideLoader();

                showAlert(
                    'Conversion Complete',
                    `Successfully converted ${originalFile.name} to ${level}.`,
                    'success',
                    () => resetState()
                );
            } else {
                showLoader('Converting multiple PDFs to PDF/A...');
                const JSZip = (await import('jszip')).default;
                const zip = new JSZip();

                for (let i = 0; i < state.files.length; i++) {
                    const file = state.files[i];
                    showLoader(`Converting ${i + 1}/${state.files.length}: ${file.name}...`);

                    const convertedBlob = await convertFileToPdfA(
                        file,
                        level,
                        (msg) => showLoader(msg)
                    );

                    const baseName = file.name.replace(/\.pdf$/i, '');
                    const blobBuffer = await convertedBlob.arrayBuffer();
                    zip.file(`${baseName}_pdfa.pdf`, blobBuffer);
                }

                const zipBlob = await zip.generateAsync({ type: 'blob' });

                downloadFile(zipBlob, 'pdfa-converted.zip');

                hideLoader();

                showAlert(
                    'Conversion Complete',
                    `Successfully converted ${state.files.length} PDF(s) to ${level}.`,
                    'success',
                    () => resetState()
                );
            }
        } catch (e: any) {
            hideLoader();
            showAlert(
                'Error',
                `An error occurred during conversion. Error: ${e.message}`
            );
        }
    };

    const handleFileSelect = (files: FileList | null) => {
        if (files && files.length > 0) {
            state.files = [...state.files, ...Array.from(files)];
            updateUI();
        }
    };

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

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

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

        dropZone.addEventListener('drop', (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(f => f.type === 'application/pdf' || f.name.toLowerCase().endsWith('.pdf'));
                if (pdfFiles.length > 0) {
                    const dataTransfer = new DataTransfer();
                    pdfFiles.forEach(f => dataTransfer.items.add(f));
                    handleFileSelect(dataTransfer.files);
                }
            }
        });

        // Clear value on click to allow re-selecting the same file
        fileInput.addEventListener('click', () => {
            fileInput.value = '';
        });
    }

    if (addMoreBtn) {
        addMoreBtn.addEventListener('click', () => {
            fileInput.click();
        });
    }

    if (clearFilesBtn) {
        clearFilesBtn.addEventListener('click', () => {
            resetState();
        });
    }

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