import {
    APIGatewayProxyEvent,
    APIGatewayProxyResult,
    Context
} from 'aws-lambda';
import {
    SendEmailCommand,
    SESClient,
    SESClientConfig
} from '@aws-sdk/client-ses';

interface ContactRequest {
    name: string;
    email: string;
    institution: string;
    message: string;
}

interface ValidationError {
    field: keyof ContactRequest;
    message: string;
}

interface ValidationErrorsResponse {
    errors: ValidationError[];
}

const sesClient = new SESClient({
    region: 'us-east-2'
} satisfies SESClientConfig);

export async function handler(
    event: APIGatewayProxyEvent,
    context: Context
): Promise<APIGatewayProxyResult> {
    if (event.body === null) {
        return {
            statusCode: 400,
            body: JSON.stringify({
                message: 'ContactRequest body required.'
            })
        };
    }

    const { name, email, institution, message } = JSON.parse(
        event.body
    ) as ContactRequest;
    const errors: ValidationError[] = [];

    // name
    if (!name) {
        errors.push({
            field: 'name',
            message: 'Name is required.'
        });
    } else if (name.trim().length === 0) {
        errors.push({
            field: 'name',
            message: 'Name may not be blank.'
        });
    }

    // email
    if (!email) {
        errors.push({
            field: 'email',
            message: 'Email is required.'
        });
    } else if (email.trim().length === 0) {
        errors.push({
            field: 'email',
            message: 'Email may not be blank.'
        });
    }

    // message
    if (!message) {
        errors.push({
            field: 'message',
            message: 'Message is required.'
        });
    } else if (message.trim().length === 0) {
        errors.push({
            field: 'message',
            message: 'Message may not be blank.'
        });
    }

    if (errors.length) {
        return {
            statusCode: 400,
            headers: {
                'Content-type': 'application/json'
            },
            body: JSON.stringify({ errors } satisfies ValidationErrorsResponse)
        };
    } else {
        const sendEmailCommand = new SendEmailCommand({
            Source: 'noreply@api.jessebrault.com',
            Destination: {
                ToAddresses: ['jesse@jessebrault.com']
            },
            Message: {
                Subject: {
                    Charset: 'UTF-8',
                    Data: 'Contact request'
                },
                Body: {
                    Text: {
                        Charset: 'utf-8',
                        Data: `
Contact Request from jessebrault.com
From ${name}
Email ${email}
Institution ${institution ?? '<none>'}
--- Message ---

${message}
                            `.trim()
                    }
                }
            }
        });
        await sesClient.send(sendEmailCommand);
        return {
            statusCode: 200,
            body: JSON.stringify({
                message: 'Success'
            })
        };
    }
}