7 files changed, 483 insertions, 0 deletions
diff --git a/lib/email.ts b/lib/email.ts
new file mode 100644
index 0000000..38beb0c
--- /dev/null
+++ b/lib/email.ts
@@ -0,0 +1,200 @@
+import { ImapFlow, type FetchMessageObject, type FetchQueryObject, type MailboxLockObject } from 'imapflow';
+import { EmailSendInstruction, type Email, EmailRecvInstruction } from '@emprespresso/uptime';
+import { Either, ITraceable, LogLevel, Metric, Optional, ServerTrace, TraceUtil } from '@emprespresso/pengueno';
+import { createTransport } from 'nodemailer';
+
+interface IRecv {
+    connect: () => Promise<void>;
+    logout: () => Promise<void>;
+
+    getMailboxLock: (mailbox: string) => Promise<MailboxLockObject>;
+    mailboxClose: () => Promise<boolean>;
+
+    fetchAll: (range: string, options: FetchQueryObject) => Promise<FetchMessageObject[]>;
+    messageDelete: (uids: number[], opts: Record<string, any>) => Promise<boolean>;
+}
+
+interface ISend {
+    sendMail: (email: Email) => Promise<Email>;
+}
+
+export class Outbox {
+    public constructor(private readonly sender: ISend) {}
+
+    public async send(email: ITraceable<Email>) {
+        return email
+            .flatMap(TraceUtil.withMetricTrace(Outbox.Metrics.SEND))
+            .peek((res) => res.trace.traceScope(LogLevel.INFO).trace('Sending email'))
+            .map((email) => Either.fromFailableAsync<Error, Email>(() => this.sender.sendMail(email.get())))
+            .peek(TraceUtil.promiseify(TraceUtil.traceResultingEither(Outbox.Metrics.SEND)))
+            .get();
+    }
+
+    public static async from(instruction: ITraceable<EmailSendInstruction>) {
+        return instruction
+            .flatMap(TraceUtil.withMetricTrace(Outbox.Metrics.INIT))
+            .peek((res) => res.trace.traceScope(LogLevel.INFO).trace('Initializing outbox'))
+            .map((instruction) =>
+                createTransport({
+                    host: instruction.get().send_host,
+                    port: instruction.get().send_port,
+                    auth: {
+                        user: instruction.get().username,
+                        pass: instruction.get().password,
+                    },
+                    tls: {
+                        rejectUnauthorized: false,
+                    },
+                }),
+            )
+            .map(
+                (transport) =>
+                    new Outbox({
+                        sendMail: (email: Email) =>
+                            new Promise<Email>((resolve, reject) =>
+                                transport.get().sendMail(email, (error) => {
+                                    if (error) {
+                                        reject(error);
+                                    } else {
+                                        resolve(email);
+                                    }
+                                }),
+                            ),
+                    }),
+            )
+            .peek(TraceUtil.withMetricTrace(Outbox.Metrics.INIT))
+            .map((x) => Either.right<Error, Outbox>(x.get()))
+            .get();
+    }
+
+    private static Metrics = {
+        INIT: Metric.fromName('Outbox.Initialize').asResult(),
+        SEND: Metric.fromName('Outbox.Send').asResult(),
+    };
+}
+
+export class Inbox {
+    public constructor(
+        private readonly recv: IRecv,
+        private lock?: ITraceable<MailboxLockObject, ServerTrace>,
+    ) {}
+
+    public async deleteMessages(_uids: Array<number> | number) {
+        const uids = Array.isArray(_uids) ? _uids : [_uids];
+        return this.lock!.flatMap(TraceUtil.withMetricTrace(Inbox.Metrics.DELETE))
+            .peek((res) => res.trace.traceScope(LogLevel.INFO).trace(`Deleting messages ${uids}`))
+            .map(() => Either.fromFailableAsync<Error, boolean>(() => this.recv.messageDelete(uids, { uid: true })))
+            .peek(TraceUtil.promiseify(TraceUtil.traceResultingEither(Inbox.Metrics.DELETE)))
+            .get();
+    }
+
+    public async listMessages() {
+        return this.lock!.flatMap(TraceUtil.withMetricTrace(Inbox.Metrics.LIST))
+            .peek((res) => res.trace.traceScope(LogLevel.INFO).trace('Listing messages'))
+            .map(() =>
+                Either.fromFailableAsync<Error, Array<FetchMessageObject>>(() =>
+                    this.recv.fetchAll('*', {
+                        uid: true,
+                        envelope: true,
+                        headers: true,
+                        bodyParts: ['text'],
+                    }),
+                ),
+            )
+            .peek(TraceUtil.promiseify(TraceUtil.traceResultingEither(Inbox.Metrics.LIST)))
+            .peek(
+                TraceUtil.promiseify((res) =>
+                    res.trace.trace(
+                        res.get().fold(
+                            (err) => err.toString(),
+                            (ok) => `Found ${ok.length} messages`,
+                        ),
+                    ),
+                ),
+            )
+            .get();
+    }
+
+    public async close() {
+        await this.recv.mailboxClose().then(() => this.recv.logout());
+        this.lock!.peek((l) => l.get().release())
+            .peek(t => t.trace.trace(Inbox.Metrics.LOCK))
+            .peek((res) => res.trace.traceScope(LogLevel.INFO).trace('Released lock'))
+            .get();
+        delete this.lock;
+    }
+
+    public async find(email: ITraceable<Email>) {
+        return email
+            .flatMap(TraceUtil.withMetricTrace(Inbox.Metrics.FIND))
+            .map((e) =>
+                this.listMessages().then((eitherMessages) =>
+                    eitherMessages.flatMap((messages) =>
+                        Either.fromFailable(() =>
+                            Optional.from(messages.find((message) => this.equals(e.get(), message))).get(),
+                        ),
+                    ),
+                ),
+            )
+            .peek(TraceUtil.promiseify(TraceUtil.traceResultingEither(Inbox.Metrics.FIND)))
+            .get();
+    }
+
+    public static from(instruction: ITraceable<EmailRecvInstruction, ServerTrace>) {
+        const client = new ImapFlow({
+            logger: false,
+            host: instruction.get().read_host,
+            port: instruction.get().read_port,
+            secure: true,
+            auth: {
+                user: instruction.get().username,
+                pass: instruction.get().password,
+            },
+        });
+        return instruction
+            .move(client)
+            .flatMap(TraceUtil.withMetricTrace(Inbox.Metrics.INIT))
+            .peek((res) => res.trace.traceScope(LogLevel.INFO).trace('Initializing mailbox'))
+            .map((tClient) =>
+                Either.fromFailableAsync<Error, MailboxLockObject>(() =>
+                    tClient
+                        .get()
+                        .connect()
+                        .then(() => tClient.get().getMailboxLock('INBOX')),
+                ).then((eitherLock) =>
+                    eitherLock
+                        .mapRight((lock) => tClient.move(lock).flatMap(TraceUtil.withMetricTrace(Inbox.Metrics.LOCK)))
+                        .mapRight((traceableLock) => new Inbox(tClient.get(), traceableLock)),
+                ),
+            )
+            .peek(TraceUtil.promiseify(TraceUtil.traceResultingEither(Inbox.Metrics.INIT)))
+            .peek(
+                TraceUtil.promiseify((res) =>
+                    res.trace.trace(
+                        res.get().fold(
+                            (err) => `Could not initialize mailbox: ${err.stack}`,
+                            (ok) => `Initialized mailbox`,
+                        ),
+                    ),
+                ),
+            )
+            .get();
+    }
+
+    private equals(email: Email, message: FetchMessageObject) {
+        const subjectMatches = email.subject === message.envelope?.subject;
+        const bodyMatches = message.bodyParts?.get('text')?.toString().trim() === email.text.trim();
+        const headers = message.headers?.toLocaleString();
+        const fromMatches = headers?.includes(`Return-Path: <${email.from}>`);
+        const toMatches = headers?.includes(`Delivered-To: ${email.to}`);
+        return subjectMatches && bodyMatches && fromMatches && toMatches;
+    }
+
+    private static Metrics = {
+        INIT: Metric.fromName('Inbox.Initialize').asResult(),
+        FIND: Metric.fromName('Inbox.FindMessage').asResult(),
+        LOCK: Metric.fromName('Inbox.Lock').asResult(),
+        LIST: Metric.fromName('Inbox.List').asResult(),
+        DELETE: Metric.fromName('Inbox.Delete').asResult(),
+    };
+}
diff --git a/lib/email_activity.ts b/lib/email_activity.ts
new file mode 100644
index 0000000..9abdb1f
--- /dev/null
+++ b/lib/email_activity.ts
@@ -0,0 +1,130 @@
+import {
+    Either,
+    type IActivity,
+    type IEither,
+    type ITraceable,
+    jsonModel,
+    JsonResponse,
+    LogLevel,
+    Metric,
+    PenguenoError,
+    type PenguenoRequest,
+    type ServerTrace,
+    TraceUtil,
+} from '@emprespresso/pengueno';
+import {
+    Email,
+    EmailJob,
+    isEmailJob,
+    Inbox,
+    Outbox,
+    EmailSendInstruction,
+    EmailRecvInstruction,
+} from '@emprespresso/uptime';
+
+const wellFormedJobMetric = Metric.fromName('Email.WellFormed').asResult();
+
+const jobJsonTransformer = (j: ITraceable<unknown, ServerTrace>): IEither<PenguenoError, EmailJob> =>
+    j
+        .flatMap(TraceUtil.withMetricTrace(wellFormedJobMetric))
+        .map((tJson): IEither<PenguenoError, EmailJob> => {
+            const tJob = tJson.get();
+            if (!isEmailJob(tJob)) {
+                const err = 'seems like a pwetty mawfomed job (-.-)';
+                tJson.trace.traceScope(LogLevel.WARN).trace(err);
+                return Either.left(new PenguenoError(err, 400));
+            }
+            return Either.right(tJob);
+        })
+        .peek(TraceUtil.traceResultingEither(wellFormedJobMetric))
+        .get();
+
+export interface IEmailActivity {
+    runMail: IActivity;
+}
+
+const emailJobRequestMetric = Metric.fromName('JobHook.process').asResult();
+export class EmailActivityImpl implements IEmailActivity {
+    constructor(
+        private readonly outboxFactory: (
+            instruction: ITraceable<EmailSendInstruction, ServerTrace>,
+        ) => Promise<IEither<Error, Outbox>>,
+        private readonly inboxFactory: (
+            instruction: ITraceable<EmailRecvInstruction, ServerTrace>,
+        ) => Promise<IEither<Error, Inbox>>,
+    ) {}
+
+    private trace(r: ITraceable<PenguenoRequest, ServerTrace>) {
+        return r.flatMap(TraceUtil.withClassTrace(this)).flatMap(TraceUtil.withMetricTrace(emailJobRequestMetric));
+    }
+
+    private async runJob(_tJob: ITraceable<EmailJob, ServerTrace>) {
+        const { from, to, readRetry } = _tJob.get();
+        const emailToTest: Email = {
+            from: from.email,
+            to: to.email,
+            subject: [new Date().toISOString(), crypto.randomUUID()].join(' | '),
+            text: crypto.randomUUID(),
+        };
+        const tJob = _tJob.traceScope(() => `Subject = ${emailToTest.subject}`);
+        const tEmail = tJob.move(emailToTest);
+
+        const inNOut = await (
+            await this.outboxFactory(tJob.move(from))
+        ).joinRightAsync(
+            () => this.inboxFactory(tJob.move(to)),
+            (inbox, outbox) => ({ inbox, outbox }),
+        );
+        const sent = await inNOut.joinRightAsync(
+            () => inNOut.flatMapAsync(({ outbox }) => outbox.send(tEmail)),
+            (prev, n) => prev,
+        );
+        const recvd = await Either.retrying(
+            async () =>
+                sent.joinRightAsync(
+                    () =>
+                        inNOut.flatMapAsync(({ inbox }) =>
+                            inbox.find(tEmail.peek((t) => t.trace.trace('Looking for message'))),
+                        ),
+                    (prev, n) => prev,
+                ),
+            readRetry.attempts,
+            (_attempt) => new Promise((res) => setTimeout(res, readRetry.interval * 1000)),
+        );
+        const deleted = await recvd
+            .joinRight(inNOut, ({ inbox }, recvd) => inbox.deleteMessages(recvd.uid))
+            .flatMapAsync((x) => x);
+        return inNOut.flatMapAsync(async ({ inbox }) => {
+            await inbox.close();
+            return deleted;
+        });
+    }
+
+    public runMail(r: ITraceable<PenguenoRequest, ServerTrace>) {
+        return this.trace(r)
+            .map(jsonModel(jobJsonTransformer))
+            .map(async (tJob) => {
+                const eitherJob = await tJob.get();
+                return eitherJob.flatMapAsync((job) =>
+                    this.runJob(tJob.move(job)).then((res) =>
+                        res.mapLeft((err) => {
+                            tJob.trace.traceScope(LogLevel.ERROR).trace(err);
+                            return new PenguenoError('Failed running job ' + err.toString(), 500);
+                        }),
+                    ),
+                );
+            })
+            .map(
+                TraceUtil.promiseify(
+                    (tEitherEmail) =>
+                        new JsonResponse(r, tEitherEmail.get(), {
+                            status: tEitherEmail.get().fold(
+                                ({ status }) => status,
+                                () => 200,
+                            ),
+                        }),
+                ),
+            )
+            .get();
+    }
+}
diff --git a/lib/healthcheck.ts b/lib/healthcheck.ts
new file mode 100644
index 0000000..3ecc0eb
--- /dev/null
+++ b/lib/healthcheck.ts
@@ -0,0 +1,18 @@
+import {
+    TraceUtil,
+    IEither,
+    ITraceable,
+    HealthChecker,
+    HealthCheckInput,
+    HealthCheckOutput,
+    ServerTrace,
+    Either,
+} from '@emprespresso/pengueno';
+
+export const healthCheck: HealthChecker = (
+    input: ITraceable<HealthCheckInput, ServerTrace>,
+): Promise<IEither<Error, HealthCheckOutput>> =>
+    input
+        .flatMap(TraceUtil.withFunctionTrace(healthCheck))
+        .move(Promise.resolve(Either.right<Error, HealthCheckOutput>(HealthCheckOutput.YAASSSLAYQUEEN)))
+        .get();
diff --git a/lib/index.ts b/lib/index.ts
new file mode 100644
index 0000000..9194b03
--- /dev/null
+++ b/lib/index.ts
@@ -0,0 +1,6 @@
+export * from './model';
+export * from './email';
+export * from './email_activity';
+export * from './healthcheck';
+export * from './server';
+export * from './run';
diff --git a/lib/model.ts b/lib/model.ts
new file mode 100644
index 0000000..7896d70
--- /dev/null
+++ b/lib/model.ts
@@ -0,0 +1,87 @@
+import { isObject } from '@emprespresso/pengueno';
+
+export interface Email {
+    from: string;
+    to: string;
+    subject: string;
+    text: string;
+}
+
+export interface EmailCredentials {
+    email: string;
+    username: string;
+    password: string;
+}
+
+export const isCreds = (u: unknown): u is EmailCredentials =>
+    !!(
+        isObject(u) &&
+        ['email', 'username', 'password'].every((key) => key in u && typeof u[key as keyof typeof u] === 'string')
+    );
+
+export interface EmailSendInstruction extends EmailCredentials {
+    send_host: string;
+    send_port: number;
+}
+
+export const isSend = (u: unknown): u is EmailSendInstruction =>
+    !!(
+        isCreds(u) &&
+        'send_host' in u &&
+        typeof u.send_host === 'string' &&
+        'send_port' in u &&
+        typeof u.send_port === 'number'
+    );
+
+export interface EmailRecvInstruction extends EmailCredentials {
+    read_host: string;
+    read_port: number;
+}
+
+export const isRecv = (u: unknown): u is EmailSendInstruction =>
+    !!(
+        isCreds(u) &&
+        'read_host' in u &&
+        typeof u.read_host === 'string' &&
+        'read_port' in u &&
+        typeof u.read_port === 'number'
+    );
+
+export interface EmailJob {
+    from: EmailSendInstruction;
+    to: EmailRecvInstruction;
+    readRetry: Retry;
+}
+
+export const isEmailJob = (u: unknown): u is EmailJob =>
+    !!(
+        isObject(u) &&
+        'from' in u &&
+        isSend(u.from) &&
+        'to' in u &&
+        isRecv(u.to) &&
+        'readRetry' in u &&
+        isRetry(u.readRetry)
+    );
+
+export interface Retry {
+    attempts: number;
+    interval: number;
+}
+
+export const isRetry = (u: unknown): u is Retry =>
+    !!(
+        isObject(u) && ['attempts', 'interval'].every((key) => key in u && typeof u[key as keyof typeof u] === 'number')
+    );
+
+export const redact = <T extends EmailCredentials>(instruction: T): T => ({
+    ...instruction,
+    password: 'REDACTED',
+    username: 'REDACTED',
+});
+
+export const redactJob = (job: EmailJob): EmailJob => ({
+    ...job,
+    from: redact(job.from),
+    to: redact(job.to),
+});
diff --git a/lib/run.ts b/lib/run.ts
new file mode 100644
index 0000000..b16fd53
--- /dev/null
+++ b/lib/run.ts
@@ -0,0 +1,7 @@
+import { HonoProxy } from '@emprespresso/pengueno';
+import { UptimeServer } from '@emprespresso/uptime';
+
+const server = new UptimeServer();
+const hono = new HonoProxy(server);
+
+export const runServer = (port: number, hostname: string) => hono.serve(port, hostname);
diff --git a/lib/server.ts b/lib/server.ts
new file mode 100644
index 0000000..9885bf3
--- /dev/null
+++ b/lib/server.ts
@@ -0,0 +1,35 @@
+import {
+    FourOhFourActivityImpl,
+    HealthCheckActivityImpl,
+    type HealthChecker,
+    type IFourOhFourActivity,
+    type IHealthCheckActivity,
+    type ITraceable,
+    PenguenoRequest,
+    Server,
+    type ServerTrace,
+} from '@emprespresso/pengueno';
+import { healthCheck as _healthCheck, EmailActivityImpl, IEmailActivity, Inbox, Outbox } from './index';
+
+export class UptimeServer implements Server {
+    constructor(
+        healthCheck: HealthChecker = _healthCheck,
+        private readonly healthCheckActivity: IHealthCheckActivity = new HealthCheckActivityImpl(healthCheck),
+        private readonly emailActivity: IEmailActivity = new EmailActivityImpl(
+            (a) => Outbox.from(a),
+            (b) => Inbox.from(b),
+        ),
+        private readonly fourOhFourActivity: IFourOhFourActivity = new FourOhFourActivityImpl(),
+    ) {}
+
+    public serve(req: ITraceable<PenguenoRequest, ServerTrace>) {
+        const url = new URL(req.get().req.url);
+        if (url.pathname === '/health') {
+            return this.healthCheckActivity.checkHealth(req);
+        }
+        if (url.pathname === '/email') {
+            return this.emailActivity.runMail(req);
+        }
+        return this.fourOhFourActivity.fourOhFour(req);
+    }
+}