# GitHub Actions Setup Guide

This guide explains how to set up the GitHub Actions workflow for automated APK builds with proper signing.

## Overview

The workflow in `.github/workflows/build-production-apk.yml` automatically:
- Builds signed APKs on every push to `main`
- Generates version numbers using `YYYY.MM.DD` + build number
- Creates 3 APK variants (universal, arm64-v8a, armeabi-v7a)
- Creates GitHub releases with all APKs attached

## Prerequisites

- GitHub CLI (`gh`) installed
- Java 17+ installed (for keytool)
- Git repository initialized with GitHub remote

## Step 1: Generate Signing Keystore

⚠️ **IMPORTANT**: Store the keystore securely! Without it, you cannot publish updates to your app.

```bash
# Navigate to project root
cd /path/to/simple-notes-sync

# Generate keystore (replace values as needed)
keytool -genkey -v \
  -keystore android/app/simple-notes-release.jks \
  -keyalg RSA \
  -keysize 2048 \
  -validity 10000 \
  -alias simple-notes

# You will be prompted for:
# - Keystore password (remember this!)
# - Key password (remember this!)
# - Your name, organization, etc.
```

**Store these securely:**
- Keystore password
- Key password
- Alias: `simple-notes`
- Keystore file: `android/app/simple-notes-release.jks`

⚠️ **BACKUP**: Make a backup of the keystore file in a secure location (NOT in the repository).

## Step 2: Base64 Encode Keystore

```bash
# Create base64 encoded version
base64 android/app/simple-notes-release.jks > simple-notes-release.jks.b64

# Or on macOS:
base64 -i android/app/simple-notes-release.jks -o simple-notes-release.jks.b64
```

## Step 3: Set GitHub Secrets

Using GitHub CLI (recommended):

```bash
# Set KEYSTORE_BASE64 secret
gh secret set KEYSTORE_BASE64 < simple-notes-release.jks.b64

# Set KEYSTORE_PASSWORD (will prompt for input)
gh secret set KEYSTORE_PASSWORD

# Set KEY_PASSWORD (will prompt for input)
gh secret set KEY_PASSWORD

# Set KEY_ALIAS (value: simple-notes)
printf "simple-notes" | gh secret set KEY_ALIAS
```

Or manually via GitHub web interface:
1. Go to repository Settings → Secrets and variables → Actions
2. Click "New repository secret"
3. Add these secrets:
   - `KEYSTORE_BASE64`: Paste content of `simple-notes-release.jks.b64`
   - `KEYSTORE_PASSWORD`: Your keystore password
   - `KEY_PASSWORD`: Your key password
   - `KEY_ALIAS`: `simple-notes`

## Step 4: Verify Setup

```bash
# Check secrets are set
gh secret list

# Expected output:
# KEYSTORE_BASE64  Updated YYYY-MM-DD
# KEYSTORE_PASSWORD  Updated YYYY-MM-DD
# KEY_PASSWORD  Updated YYYY-MM-DD
# KEY_ALIAS  Updated YYYY-MM-DD
```

## Step 5: Cleanup

```bash
# Remove sensitive files (they're in .gitignore, but double-check)
rm simple-notes-release.jks.b64
rm -f android/key.properties  # Generated by workflow

# Verify keystore is NOT tracked by git
git status | grep -i jks
# Should return nothing
```

## Step 6: Trigger First Build

```bash
# Commit and push to main
git add .
git commit -m "🚀 feat: Add GitHub Actions deployment workflow"
git push origin main

# Or manually trigger workflow
gh workflow run build-production-apk.yml
```

## Verification

1. Go to GitHub repository → Actions tab
2. Check workflow run status
3. Once complete, go to Releases tab
4. Verify release was created with 3 APK variants
5. Download and test one of the APKs

## Troubleshooting

### Build fails with "Keystore not found"
- Check `KEYSTORE_BASE64` secret is set correctly
- Verify base64 encoding was done without line breaks

### Build fails with "Incorrect password"
- Verify `KEYSTORE_PASSWORD` and `KEY_PASSWORD` are correct
- Re-set secrets if needed

### APK files not found
- Check build logs for errors in assembleRelease step
- Verify APK output paths match workflow expectations

### Updates don't work
- Ensure you're using the same keystore for all builds
- Verify `applicationId` in build.gradle.kts matches

## Security Notes

- ✅ Keystore is base64-encoded in GitHub secrets (secure)
- ✅ Passwords are stored in GitHub secrets (encrypted)
- ✅ `key.properties` and `.jks` files are in `.gitignore`
- ⚠️ Never commit keystore files to repository
- ⚠️ Keep backup of keystore in secure location
- ⚠️ Don't share keystore passwords

## Versioning

Versions follow this pattern:
- **Version Name**: `YYYY.MM.DD` (e.g., `2025.01.15`)
- **Version Code**: GitHub run number (e.g., `42`)
- **Release Tag**: `vYYYY.MM.DD-prod.BUILD` (e.g., `v2025.01.15-prod.42`)

This ensures:
- Semantic versioning based on release date
- Incremental version codes for Play Store compatibility
- Clear distinction between builds

## APK Variants

The workflow generates 3 APK variants:

1. **Universal APK** (~5 MB)
   - Works on all devices
   - Larger file size
   - Recommended for most users

2. **arm64-v8a APK** (~3 MB)
   - For modern devices (2018+)
   - Smaller, faster
   - 64-bit ARM processors

3. **armeabi-v7a APK** (~3 MB)
   - For older devices
   - 32-bit ARM processors

Users can choose based on their device - Obtanium auto-updates work with all variants.