src/js/logic/linearize-pdf-page.ts

import { showAlert } from '../ui.js';
import { downloadFile, formatBytes, initializeQpdf, readFileAsArrayBuffer } from '../utils/helpers.js';
import { icons, createIcons } from 'lucide';
import JSZip from 'jszip';
import { LinearizePdfState } from '@/types';

const pageState: LinearizePdfState = {
    files: [],
};

function resetState() {
    pageState.files = [];

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

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

    const fileControls = document.getElementById('file-controls');
    if (fileControls) fileControls.classList.add('hidden');

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

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

    if (!fileDisplayArea) return;

    fileDisplayArea.innerHTML = '';

    if (pageState.files.length > 0) {
        pageState.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 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);

            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 () {
                pageState.files.splice(index, 1);
                updateUI();
            };

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

        createIcons({ icons });

        if (toolOptions) toolOptions.classList.remove('hidden');
        if (fileControls) fileControls.classList.remove('hidden');
    } else {
        if (toolOptions) toolOptions.classList.add('hidden');
        if (fileControls) fileControls.classList.add('hidden');
    }
}

function handleFileSelect(files: FileList | null) {
    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) {
            pageState.files.push(...pdfFiles);
            updateUI();
        }
    }
}

async function linearizePdf() {
    const pdfFiles = pageState.files.filter(
        (file: File) => file.type === 'application/pdf'
    );
    if (!pdfFiles || pdfFiles.length === 0) {
        showAlert('No PDF Files', 'Please upload at least one PDF file.');
        return;
    }

    const loaderModal = document.getElementById('loader-modal');
    const loaderText = document.getElementById('loader-text');
    if (loaderModal) loaderModal.classList.remove('hidden');
    if (loaderText) loaderText.textContent = 'Optimizing PDFs for web view (linearizing)...';

    const zip = new JSZip();
    let qpdf: any;
    let successCount = 0;
    let errorCount = 0;

    try {
        qpdf = await initializeQpdf();

        for (let i = 0; i < pdfFiles.length; i++) {
            const file = pdfFiles[i];
            const inputPath = `/input_${i}.pdf`;
            const outputPath = `/output_${i}.pdf`;

            if (loaderText) loaderText.textContent = `Optimizing ${file.name} (${i + 1}/${pdfFiles.length})...`;

            try {
                const fileBuffer = await readFileAsArrayBuffer(file);
                const uint8Array = new Uint8Array(fileBuffer as ArrayBuffer);

                qpdf.FS.writeFile(inputPath, uint8Array);

                const args = [inputPath, '--linearize', outputPath];

                qpdf.callMain(args);

                const outputFile = qpdf.FS.readFile(outputPath, { encoding: 'binary' });
                if (!outputFile || outputFile.length === 0) {
                    console.error(
                        `Linearization resulted in an empty file for ${file.name}.`
                    );
                    throw new Error(`Processing failed for ${file.name}.`);
                }

                zip.file(`linearized-${file.name}`, outputFile, { binary: true });
                successCount++;
            } catch (fileError: any) {
                errorCount++;
                console.error(`Failed to linearize ${file.name}:`, fileError);
            } finally {
                try {
                    if (qpdf?.FS) {
                        if (qpdf.FS.analyzePath(inputPath).exists) {
                            qpdf.FS.unlink(inputPath);
                        }
                        if (qpdf.FS.analyzePath(outputPath).exists) {
                            qpdf.FS.unlink(outputPath);
                        }
                    }
                } catch (cleanupError) {
                    console.warn(
                        `Failed to cleanup WASM FS for ${file.name}:`,
                        cleanupError
                    );
                }
            }
        }

        if (successCount === 0) {
            throw new Error('No PDF files could be linearized.');
        }

        if (loaderText) loaderText.textContent = 'Generating ZIP file...';
        const zipBlob = await zip.generateAsync({ type: 'blob' });
        downloadFile(zipBlob, 'linearized-pdfs.zip');

        let alertMessage = `${successCount} PDF(s) linearized successfully.`;
        if (errorCount > 0) {
            alertMessage += ` ${errorCount} file(s) failed.`;
        }
        showAlert('Processing Complete', alertMessage, 'success', () => { resetState(); });
    } catch (error: any) {
        console.error('Linearization process error:', error);
        showAlert(
            'Linearization Failed',
            `An error occurred: ${error.message || 'Unknown error'}.`
        );
    } finally {
        if (loaderModal) loaderModal.classList.add('hidden');
    }
}

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 addMoreBtn = document.getElementById('add-more-btn');
    const clearFilesBtn = document.getElementById('clear-files-btn');
    const backBtn = document.getElementById('back-to-tools');

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

    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');
            handleFileSelect(e.dataTransfer?.files);
        });

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

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

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

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