Google AdSense 支払いツール

You are an experienced full-stack web developer. Build a web tool called "Google AdSense の支払い" that meets the requirements below.

## Goal

Build a web tool that signs in with Google, reads finalised AdSense payments, splits them into AdSense and YouTube, applies exchange rates and exports an Excel report.

## Core features

- Google OAuth sign-in requesting only the adsense.readonly scope
- Read accounts and payments via the AdSense Management API
- Classify payments as AdSense or YouTube
- Apply payment-date exchange rates from a public FX API
- Choose a year range and export to Excel (.xlsx)

## Inputs

- Google sign-in
- Year range and target currency

## Outputs

- Payment table (date, amount, source, converted amount)
- Excel file

## Edge cases and handling rules

- Re-authenticate when tokens expire
- Handle zero or multiple AdSense accounts
- Retry and show a clear error when the FX API fails
- Use the previous business day's rate for weekend payments

## Implementation requirements

- Requires a server-side implementation (e.g. ASP.NET Core or Node.js). Keep the OAuth client secret on the server and never commit it.
- Describe Google user data use in the privacy policy and delete tokens immediately when the user disconnects.
- Make the UI responsive and easy to use on mobile; label every input and keep everything keyboard accessible.
- Add a Copy button for results and show clear, friendly error messages for invalid input.
- Keep the core logic in functions separate from the UI so it can be unit-tested.

## Definition of done (test cases)

- Unit-test classification: YouTube items are classified as YouTube
- Excel contains no rows outside the year range
- Rates are applied by payment date

First outline your implementation plan in at most five lines, then write the complete code, and finally explain how to check the test cases above.

---
name: build-google-adsense-earning
description: Use when building or changing a Google AdSense の支払い tool. Build a web tool that signs in with Google, reads finalised AdSense payments, splits them into AdSense and YouTube, applies exchange rates and exports an Excel report.
---

# Build: Google AdSense の支払い

## Goal

Build a web tool that signs in with Google, reads finalised AdSense payments, splits them into AdSense and YouTube, applies exchange rates and exports an Excel report.

## Workflow

1. Review the required features, inputs and outputs below and ask about anything missing first.
2. Implement the core logic as pure functions separate from the UI.
3. Check the logic against the test cases in the verification list.
4. Build a responsive UI with an input form, a result area and a Copy button.
5. Reproduce each edge case listed under Rules and refine the error messages.

## Core features

- Google OAuth sign-in requesting only the adsense.readonly scope
- Read accounts and payments via the AdSense Management API
- Classify payments as AdSense or YouTube
- Apply payment-date exchange rates from a public FX API
- Choose a year range and export to Excel (.xlsx)

## Inputs

- Google sign-in
- Year range and target currency

## Outputs

- Payment table (date, amount, source, converted amount)
- Excel file

## Rules

- Re-authenticate when tokens expire
- Handle zero or multiple AdSense accounts
- Retry and show a clear error when the FX API fails
- Use the previous business day's rate for weekend payments
- Requires a server-side implementation (e.g. ASP.NET Core or Node.js). Keep the OAuth client secret on the server and never commit it.
- Describe Google user data use in the privacy policy and delete tokens immediately when the user disconnects.

## Verification

- [ ] Unit-test classification: YouTube items are classified as YouTube
- [ ] Excel contains no rows outside the year range
- [ ] Rates are applied by payment date