040-personal-flight-club/docs/business-case.md

Business Case

Metadata

Key	Value
ID	BC-001
CrossReference	SA-001
Language	en
Domain	it

Version History

Date	Status	Author	Reviewer	Change	Commit
2026-10-24	Accepted	Jens Tirsvad Nielsen	AI as stand-in for S01	Initial version	c5a6ed5

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Executive Summary

Day 40 of Udemy's "100 Days of Code: The Complete Python Pro Bootcamp" turns the Day 39 flight-deal finder into a small flight club. The program now searches direct flights first and falls back to flights with stopovers, reads a customer list from a second Google Sheet ("users"), and sends every customer an email with the deal through SMTP. This project delivers that program as a tested, documented Python 3.13+ repository, built on the code of the 039-personal-flight-club repository, for the course participant and for other participants who compare solutions.

Methodological and Standards Foundation

The work follows the SQA and QC framework mounted at framework/: artifacts are reviewed against QC checklists tagged with ISO/IEC 25010:2023 characteristics, and code follows the coding-conventions and clean-architecture skills. Source code carries Doxygen comments and is tested with pytest.

Problem Statement

The Day 39 program reports only the cheapest flight found, and says nothing about stopovers. Many popular destinations have no direct flight, so they are reported as "N/A". The deals reach only the participant, by WhatsApp; the club's customers, who sign up in a Google Form, get nothing. The starter files of the lesson use Twilio, which this participant replaced in Day 39 and does not want to bring back.

Business Opportunity

A club that mails every member the best deal, direct or with stops, is a complete small product and a portfolio piece. Other participants (S02) and GitHub visitors (S03) get readable code with the assignment's function names and clear run instructions.

Objectives

1. Search direct flights first (check_flights(..., is_direct=True)); when none is found, search again with stopovers, and record the number of stops in FlightData.stops.
2. Read the customer emails from the "users" sheet with DataManager.get_customer_emails(); all environment variables, including both sheet endpoints, are read in DataManager.__init__().
3. Send every customer an email through SMTP with NotificationManager.send_emails(), with a different message for a direct flight and for a flight with a stopover; the text uses "GBP" and is encoded as UTF-8.
4. Keep every secret in .env and never in the repository; keep the Day 39 response cache so free-tier quotas last.
5. Publish a documented repository: README with screenshots, wiki in English, Danish and Bahasa Malaysia with screenshots, Doxygen configuration, CI workflows, description and topics.

Scope

In Scope

• A Python 3.13+ project with src/ and tests/, pyproject.toml, a local .venv, pytest, constants.py, a Doxyfile and a Python .gitignore, starting from the Day 39 code.
• The assignment's classes and names: DataManager with get_customer_emails(), FlightSearch.check_flights() with is_direct, FlightData with stops, NotificationManager.send_emails(), and main.py.
• The WhatsApp message of Day 39 stays; the email is added next to it.
• README from the framework template, a three-language wiki, screenshots, CI workflows from the TirSystem workflow repository, repository description and topics.

Out of Scope

• Twilio SMS or WhatsApp, which the Day 39 project replaced.
• A sign-up form or website (the Google Form is outside the repository) and email address validation beyond a basic format check.
• Automated tests that call the real Sheety, SerpAPI, mock-flight, SMTP or WhatsApp services, or that read the real .env.
• A database, scheduling of the daily run, unsubscribe handling and booking of flights.

Expected Benefits

Tangible Benefits

• A working, runnable lesson solution with automated tests.
• A repository other participants can clone and run from the README alone.

Intangible Benefits

• Practice with smtplib, environment secrets, API fallbacks and a second data source.
• A reusable template for later course days.

Strategic Alignment

The project supports the participant's learning goal (completing the bootcamp) and the shared goal of publishing readable solutions that others can learn from.

Success Criteria

#	Criterion	Target	Measure
1	Unit tests pass	100% of tests pass, no network or .env access	pytest exit code 0
2	Indirect fallback	When the direct search finds nothing, a search with stops runs and stops is set	Unit test on main and check_flights
3	Customer emails	get_customer_emails() returns the list of addresses from the users sheet	Unit test with a fake HTTP response
4	Email content	Direct and stopover messages differ; text holds price, origin, destination, dates, stops and no "£"	Unit test on the message text
5	Run instructions work	A fresh clone runs by following the README steps only	Manual run of the README steps
6	Repository metadata and wiki	Description and at least 5 topics set; en, da and ms wiki pages with screenshots	Check on the git host and file review
7	Runtime dependencies	Only packages the assignment needs; none added over Day 39	pyproject.toml review

Risks

Risk	Impact	Mitigation
Free-tier quotas run out (SerpAPI 100/month, Sheety 200/month)	Development stops	Keep the response cache; use the mock flight service; keep 3 to 5 destinations; the extra indirect search runs only when no direct flight exists
Secrets committed by mistake	Credential leak	.env and cache files in .gitignore; only .env.example committed; secret scan before each PR
SMTP credentials are not yet in the local .env	Real mails cannot be sent	SMTP is isolated in NotificationManager; tests use a fake smtplib; the missing values are an open issue in the Project Plan
Mails sent to real customers by mistake during development	Spam to real people	Tests never send; README tells the participant to use a test sheet first
CI workflows from the TirSystem repository do not fit this project	Red pipeline	Install only the needed workflows; stop and report after three failed fixes

Assumptions

• The Day 39 code is the base. Its WhatsApp delivery (pywhatkit, optional and lazy) and the mock flight service remain; Twilio is not restored.
• The Sheety project exposes a prices sheet (city, iataCode, lowestPrice, id) and a users sheet filled by a Google Form (firstName, lastName, email); both use Bearer authentication.
• The participant (S01) is Product Owner, developer and reviewer; in autonomous mode the AI acts as stand-in reviewer and every such review says so.
• The origin airport is LHR and the currency is GBP, both constants, as in the assignment.
• Real tokens exist only in the participant's local .env, are used by the participant's own runs and by the repository setup on the git host, and never by tests. The AI uses only the git host token, to set the description and topics.

Constraints

• Python 3.13 or newer; venv; pytest; a constants.py for constants; pyproject.toml for configuration.
• Doxygen comments in source and a Doxyfile.
• Hosted at https://git.tirsystem.com/Tirsvad-Udemy-100-days-of-code (this project is the 040-personal-flight-club repository); one branch and pull request per step.
• No more runtime dependencies than needed; smtplib is part of the standard library.

Cost–Benefit Assessment

Costs	Benefits
The participant's spare time; free-tier API accounts; AI assistance	A finished lesson solution, a portfolio repository and a reusable template. Qualitative assessment: the project is small and the cost is time only.

Stakeholders

Stakeholder ID (SA)	Interest in this project
S01	Finish the lesson, own the product and review it
S02	Compare solutions; runnable code with the assignment's names
S03	Browse for ideas; clear description, topics and README

Recommendation

Proceed — the scope is small, builds on working Day 39 code, the risks are mitigated, and the result serves all three stakeholders.

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