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| 1 | +import { Injectable, Logger } from '@nestjs/common'; |
| 2 | +import { ConfigService } from '@nestjs/config'; |
| 3 | +import * as nodemailer from 'nodemailer'; |
| 4 | + |
| 5 | +export type MailTemplate = |
| 6 | + | 'welcome' |
| 7 | + | 'transfer-decision' |
| 8 | + | 'warranty-expiring'; |
| 9 | + |
| 10 | +/** Renders a template + context into a subject and HTML body. */ |
| 11 | +function renderTemplate( |
| 12 | + template: MailTemplate, |
| 13 | + context: Record<string, unknown>, |
| 14 | +): { subject: string; html: string } { |
| 15 | + const layout = (title: string, body: string) => |
| 16 | + `<div style="font-family:sans-serif"><h2>${title}</h2>${body}<hr/><small>AssetsUp</small></div>`; |
| 17 | + |
| 18 | + switch (template) { |
| 19 | + case 'welcome': |
| 20 | + return { |
| 21 | + subject: 'Welcome to AssetsUp', |
| 22 | + html: layout('Welcome', `<p>Hi ${context.name ?? 'there'}, your account is ready.</p>`), |
| 23 | + }; |
| 24 | + case 'transfer-decision': |
| 25 | + return { |
| 26 | + subject: `Asset transfer ${context.decision ?? 'update'}`, |
| 27 | + html: layout( |
| 28 | + 'Transfer decision', |
| 29 | + `<p>Your transfer request for <b>${context.assetName ?? 'an asset'}</b> was <b>${context.decision ?? 'updated'}</b>.</p>`, |
| 30 | + ), |
| 31 | + }; |
| 32 | + case 'warranty-expiring': |
| 33 | + return { |
| 34 | + subject: 'Warranty expiring soon', |
| 35 | + html: layout( |
| 36 | + 'Warranty expiring', |
| 37 | + `<p>The warranty for <b>${context.assetName ?? 'an asset'}</b> expires on ${context.expiresOn ?? 'soon'}.</p>`, |
| 38 | + ), |
| 39 | + }; |
| 40 | + } |
| 41 | +} |
| 42 | + |
| 43 | +/** |
| 44 | + * Sends transactional email via SMTP (config from env). When SMTP is not |
| 45 | + * configured (e.g. local dev) it falls back to logging the message instead of |
| 46 | + * failing, so features that send mail work without a mail server. |
| 47 | + */ |
| 48 | +@Injectable() |
| 49 | +export class MailService { |
| 50 | + private readonly logger = new Logger(MailService.name); |
| 51 | + private readonly transporter: nodemailer.Transporter | null; |
| 52 | + |
| 53 | + constructor(private readonly config: ConfigService) { |
| 54 | + const host = this.config.get<string>('SMTP_HOST'); |
| 55 | + this.transporter = host |
| 56 | + ? nodemailer.createTransport({ |
| 57 | + host, |
| 58 | + port: Number(this.config.get<string>('SMTP_PORT') ?? 587), |
| 59 | + auth: this.config.get<string>('SMTP_USER') |
| 60 | + ? { |
| 61 | + user: this.config.get<string>('SMTP_USER'), |
| 62 | + pass: this.config.get<string>('SMTP_PASS'), |
| 63 | + } |
| 64 | + : undefined, |
| 65 | + }) |
| 66 | + : null; |
| 67 | + } |
| 68 | + |
| 69 | + async send( |
| 70 | + to: string, |
| 71 | + template: MailTemplate, |
| 72 | + context: Record<string, unknown> = {}, |
| 73 | + ): Promise<void> { |
| 74 | + const { subject, html } = renderTemplate(template, context); |
| 75 | + |
| 76 | + if (!this.transporter) { |
| 77 | + this.logger.log(`[mail:dev] to=${to} template=${template} subject="${subject}"`); |
| 78 | + return; |
| 79 | + } |
| 80 | + |
| 81 | + await this.transporter.sendMail({ |
| 82 | + from: this.config.get<string>('MAIL_FROM') ?? 'no-reply@assetsup.local', |
| 83 | + to, |
| 84 | + subject, |
| 85 | + html, |
| 86 | + }); |
| 87 | + } |
| 88 | +} |
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