ycf.ts

import type { APIGatewayProxyEvent, APIGatewayProxyResult } from 'aws-lambda'
import { readFileSync } from 'node:fs'
import { resolve } from 'node:path'
import { render } from './entry-server'
import { getFormState, initYDB, NotFoundError } from './ydb'
import { configureStore } from '@reduxjs/toolkit'
import { AppMode, appReceived, formReceived, reducer } from './store'

initYDB().catch(console.error)

interface QueryParams {
    target?: AppMode
    channel_id?: string
    contact_id?: string
    form_id?: string
    token?: string
}

// noinspection JSUnusedGlobalSymbols
export async function handler(event: APIGatewayProxyEvent): Promise<APIGatewayProxyResult> {
    const { target, contact_id, form_id, token } = (event.queryStringParameters || {}) as QueryParams

    if (!contact_id) {
        return {
            statusCode: 400,
            body: '400 Bad Request: missing required query parameter: contact_id',
        }
    }

    if (!form_id) {
        return {
            statusCode: 400,
            body: '400 Bad Request: missing required query parameter: form_id',
        }
    }

    const scripts: string[] = []
    if (target === 'webview') {
        scripts.push('<script src="https://telegram.org/js/telegram-web-app.js"></script>')
        scripts.push('<script>html.classList.add(window.Telegram.WebApp.colorScheme)</script>')
    }

    const store = configureStore({ reducer: reducer })
    await store.dispatch(appReceived({ mode: target || 'web', contactID: contact_id, formID: form_id }))

    try {
        const form = await getFormState(form_id, contact_id)
        await store.dispatch(formReceived(form))

        const template = readFileSync(resolve(__dirname, '../client/index.html'), 'utf-8')
        const html = template
            .replace(`<!--ssr-csrf-token-->`, token || '')
            .replace(`<!--ssr-scripts-->`, scripts.join('\n'))
            .replace(`<!--ssr-html-->`, await render(store.getState()))
            .replace(`<!--ssr-state-->`, JSON.stringify(store.getState()).replace(/</g, '\\u003c'))

        return {
            statusCode: 200,
            headers: {
                'Content-Type': 'text/html',
            },
            body: html,
        }
    } catch (err) {
        console.error(err)
        // TODO: report to Sentry or similar

        if (err instanceof NotFoundError) {
            return {
                statusCode: 404,
                body: err.message,
            }
        }

        return {
            statusCode: 500,
            body: err instanceof Error ? err.message : '500 Internal Server Error',
        }
    }
}