/**
 * Converts a Uint8Array buffer to a usable image URL
 * @param imageBuffer The Uint8Array containing image data
 * @param mimeType The MIME type of the image (default: 'image/png')
 * @returns A data URL or Blob URL that can be used as an image source
 */
export function bufferToImageUrl(imageBuffer: Uint8Array, mimeType: string = 'image/png'): string {
    if(imageBuffer.length == 1) {
        throw new Error("This is the default logo.")
    }
    // Method 1: Create a data URL
    const base64String = arrayBufferToBase64(imageBuffer);
    return `data:${mimeType};base64,${base64String}`;
    
    // Alternative Method 2: Create a Blob URL
    // const blob = new Blob([imageBuffer], { type: mimeType });
    // return URL.createObjectURL(blob);
}

/**
 * Helper function to convert ArrayBuffer to base64 string
 * @param buffer The ArrayBuffer to convert
 * @returns Base64 encoded string
 */
export function arrayBufferToBase64(buffer: Uint8Array): string {
    let binary = '';
    const bytes = new Uint8Array(buffer);
    const len = bytes.byteLength;
    
    for (let i = 0; i < len; i++) {
        binary += String.fromCharCode(bytes[i]);
    }
    
    return btoa(binary);
}

export async function convertImageToUint8Array(file: File): Promise<Uint8Array> {
    return new Promise((resolve, reject) => {
        // Create a FileReader to read the file
        const reader = new FileReader();
        
        // Set up the onload event handler
        reader.onload = function() {
            // Create an image element to load the file data
            const img = new Image();
            
            img.onload = function() {
                // Create a canvas to draw the image
                const canvas = document.createElement('canvas');
                const ctx = canvas.getContext('2d');
                
                if (!ctx) {
                    reject(new Error('Failed to get canvas context'));
                    return;
                }
                
                // Set canvas dimensions to match image
                canvas.width = img.width;
                canvas.height = img.height;
                
                // Draw the image on the canvas
                ctx.drawImage(img, 0, 0);
                
                // Convert the canvas to a JPEG blob
                canvas.toBlob((blob) => {
                    if (!blob) {
                        reject(new Error('Failed to create blob'));
                        return;
                    }
                    
                    // Convert blob to ArrayBuffer
                    const blobReader = new FileReader();
                    blobReader.onload = function() {
                        if (!blobReader.result || typeof blobReader.result === 'string') {
                            reject(new Error('Failed to read blob data'));
                            return;
                        }
                        
                        // Convert ArrayBuffer to Uint8Array
                        const uint8Array = new Uint8Array(blobReader.result);
                        resolve(uint8Array);
                    };
                    
                    blobReader.onerror = function() {
                        reject(new Error('Failed to read blob'));
                    };
                    
                    blobReader.readAsArrayBuffer(blob);
                }, 'image/jpeg', 0.85); // 0.85 is the quality level (0-1)
            };
            
            img.onerror = function() {
                reject(new Error('Failed to load image'));
            };
            
            // Load the image with the file data
            img.src = reader.result as string;
        };
        
        reader.onerror = function() {
            reject(new Error('Failed to read file'));
        };
        
        // Read the file as a data URL
        reader.readAsDataURL(file);
    });
}

/**
 * Converts a link (data URL or HTTP/HTTPS URL) to a Uint8Array
 * @param link The image link (data URL or HTTP/HTTPS URL)
 * @returns Promise resolving to a Uint8Array containing the image data
 */
export async function linkToUint8Array(link: string): Promise<Uint8Array> {
    // Check if the link is a data URL
    if (link.startsWith('data:')) {
        // Extract the base64 part of the data URL
        const matches = link.match(/^data:([^;]+);base64,(.+)$/);
        if (!matches || matches.length !== 3) {
            throw new Error('Invalid data URL format');
        }
        
        // Convert base64 to Uint8Array
        const base64Data = matches[2];
        const binaryString = atob(base64Data);
        const length = binaryString.length;
        const bytes = new Uint8Array(length);
        
        for (let i = 0; i < length; i++) {
            bytes[i] = binaryString.charCodeAt(i);
        }
        
        return bytes;
    } 
    // Handle HTTP/HTTPS URLs
    else if (link.startsWith('http://') || link.startsWith('https://')) {
        try {
            // Fetch the image
            const response = await fetch(link);
            
            if (!response.ok) {
                throw new Error(`HTTP error! Status: ${response.status}`);
            }
            
            // Get the array buffer from the response
            const arrayBuffer = await response.arrayBuffer();
            
            // Convert to Uint8Array
            return new Uint8Array(arrayBuffer);
        } catch (error) {
            throw new Error(`Failed to fetch image: ${error instanceof Error ? error.message : String(error)}`);
        }
    } else {
        throw new Error('Unsupported link format. Must be a data URL or HTTP/HTTPS URL');
    }
}