upload.lambda

const AWS = require('aws-sdk');
const { v4: uuidv4 } = require('uuid');

// Configure AWS SDK
AWS.config.update({ region: process.env.AWS_REGION || 'eu-north-1' });

const s3 = new AWS.S3();
const dynamodb = new AWS.DynamoDB.DocumentClient();

exports.handler = async (event) => {
    console.log('Event:', JSON.stringify(event, null, 2));
    
    // Comprehensive CORS headers
    const headers = {
            'Access-Control-Allow-Origin' : '*',
            'Access-Control-Allow-Headers':'Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token',
            'Access-Control-Allow-Credentials' : true,
    };

    // Handle preflight OPTIONS request
    if (event.httpMethod === 'OPTIONS') {
        return { 
            statusCode: 200, 
            headers, 
            body: '' 
        };
    }

    try {
        console.log('Environment:', {
            bucket: process.env.BUCKET_NAME,
            table: process.env.TABLE_NAME,
            region: process.env.AWS_REGION
        });

        const body = JSON.parse(event.body);
        const { fileName, fileType, fileSize } = body;
        
        console.log('Request body:', { fileName, fileType, fileSize });
        
        if (!fileName || !fileType || !fileSize) {
            throw new Error('Missing required fields');
        }

        if (fileSize > 100 * 1024 * 1024) {
            throw new Error('File too large');
        }

        const fileId = uuidv4();
        const s3Key = `${fileId}.${fileName.split('.').pop() || 'bin'}`;
        
        console.log('Generated:', { fileId, s3Key });

        // Generate presigned URL (FIXED - removed invalid Conditions parameter)
        const presignedUrl = s3.getSignedUrl('putObject', {
            Bucket: process.env.BUCKET_NAME,
            Key: s3Key,
            ContentType: fileType,
            Expires: 300
        });

        console.log('Generated presigned URL successfully');

        // Save to DynamoDB
        await dynamodb.put({
            TableName: process.env.TABLE_NAME,
            Item: {
                fileId,
                originalName: fileName,
                s3Key,
                contentType: fileType,
                fileSize: Number(fileSize),
                uploadDate: new Date().toISOString(),
                downloadCount: 0,
                status: 'pending'
            }
        }).promise();

        console.log('Saved to DynamoDB successfully');

        const shareUrl = `https://${event.requestContext.domainName}/f/${fileId}`;

        console.log('Success response:', { fileId, shareUrl });

        return {
            statusCode: 200,
            headers,
            body: JSON.stringify({
                success: true,
                fileId,
                presignedUrl,
                shareUrl
            })
        };

    } catch (error) {
        console.error('Error details:', {
            message: error.message,
            stack: error.stack,
            name: error.name
        });
        return {
            statusCode: 500,
            headers,
            body: JSON.stringify({ 
                error: error.message || 'Internal server error',
                errorType: error.name || 'Unknown'
            })
        };
    }
};