import { showLoader, hideLoader, showAlert } from '../ui.js';
import { downloadFile, formatBytes, readFileAsArrayBuffer } from '../utils/helpers.js';
import { createIcons, icons } from 'lucide';
import { PDFDocument as PDFLibDocument } from 'pdf-lib';
import { decode } from 'tiff';

let files: File[] = [];

const updateUI = () => {
    const fileDisplayArea = document.getElementById('file-display-area');
    const fileControls = document.getElementById('file-controls');
    const processBtn = document.getElementById('process-btn');

    if (!fileDisplayArea || !fileControls || !processBtn) return;

    fileDisplayArea.innerHTML = '';

    if (files.length > 0) {
        fileControls.classList.remove('hidden');
        processBtn.classList.remove('hidden');

        files.forEach((file, 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 items-center gap-2 overflow-hidden';

            const nameSpan = document.createElement('span');
            nameSpan.className = 'truncate font-medium text-gray-200';
            nameSpan.textContent = file.name;

            const sizeSpan = document.createElement('span');
            sizeSpan.className = 'flex-shrink-0 text-gray-400 text-xs';
            sizeSpan.textContent = `(${formatBytes(file.size)})`;

            infoContainer.append(nameSpan, sizeSpan);

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

            fileDiv.append(infoContainer, removeBtn);
            fileDisplayArea.appendChild(fileDiv);
        });
        createIcons({ icons });
    } else {
        fileControls.classList.add('hidden');
        processBtn.classList.add('hidden');
    }
};

const resetState = () => {
    files = [];
    updateUI();
};

async function convert() {
    if (files.length === 0) {
        showAlert('No Files', 'Please select at least one TIFF file.');
        return;
    }
    showLoader('Converting TIFF to PDF...');
    try {
        const pdfDoc = await PDFLibDocument.create();
        for (const file of files) {
            const tiffBytes = await readFileAsArrayBuffer(file);
            const ifds = decode(tiffBytes as ArrayBuffer);

            for (const ifd of ifds) {
                const width = ifd.width;
                const height = ifd.height;
                const rgba = ifd.data;

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

                const imageData = ctx.createImageData(width, height);
                for (let i = 0; i < rgba.length; i++) {
                    imageData.data[i] = rgba[i];
                }
                ctx.putImageData(imageData, 0, 0);

                const pngBlob = await new Promise<Blob | null>((res) =>
                    canvas.toBlob(res, 'image/png')
                );
                if (!pngBlob) continue;

                const pngBytes = await pngBlob.arrayBuffer();
                const pngImage = await pdfDoc.embedPng(pngBytes);
                const page = pdfDoc.addPage([pngImage.width, pngImage.height]);
                page.drawImage(pngImage, {
                    x: 0,
                    y: 0,
                    width: pngImage.width,
                    height: pngImage.height,
                });
            }
        }
        const pdfBytes = await pdfDoc.save();
        downloadFile(
            new Blob([new Uint8Array(pdfBytes)], { type: 'application/pdf' }),
            'from_tiff.pdf'
        );
        showAlert('Success', 'PDF created successfully!', 'success', () => {
            resetState();
        });
    } catch (e) {
        console.error(e);
        showAlert(
            'Error',
            'Failed to convert TIFF to PDF. One of the files may be invalid.'
        );
    } finally {
        hideLoader();
    }
}

document.addEventListener('DOMContentLoaded', () => {
    const fileInput = document.getElementById('file-input') as HTMLInputElement;
    const dropZone = document.getElementById('drop-zone');
    const addMoreBtn = document.getElementById('add-more-btn');
    const clearFilesBtn = document.getElementById('clear-files-btn');
    const processBtn = document.getElementById('process-btn');
    const backBtn = document.getElementById('back-to-tools');

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

    const handleFileSelect = (newFiles: FileList | null) => {
        if (!newFiles || newFiles.length === 0) return;
        const validFiles = Array.from(newFiles).filter(
            (file) =>
                file.type === 'image/tiff' ||
                file.name.toLowerCase().endsWith('.tiff') ||
                file.name.toLowerCase().endsWith('.tif')
        );

        if (validFiles.length < newFiles.length) {
            showAlert('Invalid Files', 'Some files were skipped. Only TIFF files are allowed.');
        }

        if (validFiles.length > 0) {
            files = [...files, ...validFiles];
            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');
            handleFileSelect(e.dataTransfer?.files ?? null);
        });

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

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

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

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