ci.yml

name: CI

on:
  push:
    branches: [main, dev]
  pull_request:
    branches: [main, dev]

# ── Auto-scaling: cancel redundant runs on the same branch/PR ────────────────
# This is the primary cost-saving mechanism for CI: only the most recent
# push on a branch consumes runner minutes.
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

# ── Resource tags emitted on every run ───────────────────────────────────────
# Downstream tooling (cost-monitor, dashboards) can filter by these values.
env:
  SERVICE: agenticpay
  ENVIRONMENT: ${{ github.ref_name == 'main' && 'production' || 'staging' }}
  COMMIT_SHORT: ${{ github.sha }}

jobs:
  # ── Detect changed paths (avoids running unaffected jobs) ─────────────────
  changes:
    runs-on: ubuntu-latest
    timeout-minutes: 5
    outputs:
      backend:   ${{ steps.filter.outputs.backend }}
      frontend:  ${{ steps.filter.outputs.frontend }}
      contracts: ${{ steps.filter.outputs.contracts }}
    steps:
      - uses: actions/checkout@v4
      - uses: dorny/paths-filter@v3
        id: filter
        with:
          filters: |
            backend:
              - 'backend/**'
            frontend:
              - 'frontend/**'
            contracts:
              - 'contracts/**'

  # ── Backend ───────────────────────────────────────────────────────────────
  backend:
    needs: changes
    if: ${{ needs.changes.outputs.backend == 'true' }}
    name: Backend (Node.js ${{ matrix.node-version }})
    runs-on: ubuntu-latest
    # Auto-scaling: cap concurrent backend matrix jobs to avoid runner exhaustion.
    # With a 2-version matrix, max 2 jobs run simultaneously per branch.
    timeout-minutes: 15
    strategy:
      matrix:
        node-version: [20, 22]
      # Don't cancel the entire matrix on a single failure — let all versions report
      fail-fast: false
      # Auto-scale: limit simultaneous matrix jobs.
      # Raise to 2 (or remove) if faster turnaround is preferred over cost savings.
      max-parallel: 2
    defaults:
      run:
        working-directory: backend
    steps:
      - uses: actions/checkout@v4

      - name: Setup Node.js ${{ matrix.node-version }}
        uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node-version }}
          cache: npm
          cache-dependency-path: backend/package-lock.json

      # Cache the installed node_modules between runs with the same lock file.
      # This shaves ~30s off each run after the first on a given branch.
      - name: Cache node_modules
        uses: actions/cache@v4
        with:
          path: backend/node_modules
          key: ${{ runner.os }}-backend-modules-node${{ matrix.node-version }}-${{ hashFiles('backend/package-lock.json') }}
          restore-keys: |
            ${{ runner.os }}-backend-modules-node${{ matrix.node-version }}-

      - name: Install dependencies
        run: npm ci --prefer-offline

      - name: Lint changed files
        run: |
          if [ "${{ github.event_name }}" = "pull_request" ]; then
            CHANGED=$(git diff --name-only origin/${{ github.base_ref }}...HEAD -- backend/src/ | grep '\.ts$' | tr '\n' ' ')
          else
            CHANGED=$(git diff --name-only HEAD^ HEAD -- backend/src/ | grep '\.ts$' | tr '\n' ' ')
          fi
          if [ -n "$CHANGED" ]; then
            echo "Linting changed files: $CHANGED"
            npx eslint $CHANGED
          else
            echo "No backend source files changed — skipping lint"
          fi

      - name: Test changed files
        run: |
          if [ "${{ github.event_name }}" = "pull_request" ]; then
            CHANGED=$(git diff --name-only origin/${{ github.base_ref }}...HEAD -- backend/src/ | grep '\.test\.ts$' | tr '\n' ' ')
          else
            CHANGED=$(git diff --name-only HEAD^ HEAD -- backend/src/ | grep '\.test\.ts$' | tr '\n' ' ')
          fi
          if [ -n "$CHANGED" ]; then
            echo "Testing changed files: $CHANGED"
            npx vitest run $CHANGED
          else
            echo "No backend test files changed — skipping tests"
          fi

      - name: Build
        run: |
          if [ "${{ github.event_name }}" = "pull_request" ]; then
            CHANGED=$(git diff --name-only origin/${{ github.base_ref }}...HEAD -- backend/src/ | grep '\.ts$' | wc -l)
          else
            CHANGED=$(git diff --name-only HEAD^ HEAD -- backend/src/ | grep '\.ts$' | wc -l)
          fi
          if [ "$CHANGED" -gt 0 ]; then
            echo "Building — $CHANGED backend source files changed"
            npm run build
          else
            echo "No backend source files changed — skipping build"
          fi

      # Emit build size as a workflow annotation (picked up by cost-monitor)
      - name: Report build size
        if: always()
        run: |
          if [ -d dist ]; then
            SIZE=$(du -sh dist | cut -f1)
            echo "::notice title=Backend Build Size (Node ${{ matrix.node-version }})::${SIZE}"
          fi

  # ── Frontend ──────────────────────────────────────────────────────────────
  frontend:
    needs: changes
    if: ${{ needs.changes.outputs.frontend == 'true' }}
    name: Frontend (Node.js ${{ matrix.node-version }})
    runs-on: ubuntu-latest
    timeout-minutes: 20
    strategy:
      matrix:
        node-version: [20, 22]
      fail-fast: false
      max-parallel: 2
    defaults:
      run:
        working-directory: frontend
    steps:
      - uses: actions/checkout@v4

      - name: Setup Node.js ${{ matrix.node-version }}
        uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node-version }}
          cache: npm
          cache-dependency-path: frontend/package-lock.json

      - name: Cache node_modules
        uses: actions/cache@v4
        with:
          path: frontend/node_modules
          key: ${{ runner.os }}-frontend-modules-node${{ matrix.node-version }}-${{ hashFiles('frontend/package-lock.json') }}
          restore-keys: |
            ${{ runner.os }}-frontend-modules-node${{ matrix.node-version }}-

      # Next.js build cache (incremental compilation)
      - name: Cache Next.js build
        uses: actions/cache@v4
        with:
          path: ${{ github.workspace }}/frontend/.next/cache
          key: ${{ runner.os }}-nextjs-node${{ matrix.node-version }}-${{ hashFiles('frontend/package-lock.json') }}-${{ hashFiles('frontend/src/**') }}
          restore-keys: |
            ${{ runner.os }}-nextjs-node${{ matrix.node-version }}-${{ hashFiles('frontend/package-lock.json') }}-
            ${{ runner.os }}-nextjs-node${{ matrix.node-version }}-

      - name: Install dependencies
        run: npm ci --prefer-offline

      - name: Lint changed files
        run: |
          if [ "${{ github.event_name }}" = "pull_request" ]; then
            CHANGED=$(git diff --name-only origin/${{ github.base_ref }}...HEAD -- . | grep -E '\.(ts|tsx)$' | tr '\n' ' ')
          else
            CHANGED=$(git diff --name-only HEAD^ HEAD -- . | grep -E '\.(ts|tsx)$' | tr '\n' ' ')
          fi
          if [ -n "$CHANGED" ]; then
            echo "Linting changed files: $CHANGED"
            npx eslint $CHANGED
          else
            echo "No frontend source files changed — skipping lint"
          fi

      - name: Test changed files
        run: |
          if [ "${{ github.event_name }}" = "pull_request" ]; then
            CHANGED=$(git diff --name-only origin/${{ github.base_ref }}...HEAD -- . | grep '\.test\.(ts|tsx)$' | tr '\n' ' ')
          else
            CHANGED=$(git diff --name-only HEAD^ HEAD -- . | grep '\.test\.(ts|tsx)$' | tr '\n' ' ')
          fi
          if [ -n "$CHANGED" ]; then
            echo "Testing changed files: $CHANGED"
            npx vitest run $CHANGED
          else
            echo "No frontend test files changed — skipping tests"
          fi

      - name: Build
        run: |
          if [ "${{ github.event_name }}" = "pull_request" ]; then
            CHANGED=$(git diff --name-only origin/${{ github.base_ref }}...HEAD -- . | grep -E '\.(ts|tsx)$' | wc -l)
          else
            CHANGED=$(git diff --name-only HEAD^ HEAD -- . | grep -E '\.(ts|tsx)$' | wc -l)
          fi
          if [ "$CHANGED" -gt 0 ]; then
            echo "Building — $CHANGED frontend source files changed"
            npm run build
          else
            echo "No frontend source files changed — skipping build"
          fi

      - name: Report build size
        if: always()
        run: |
          if [ -d .next ]; then
            SIZE=$(du -sh --exclude=cache .next 2>/dev/null || du -sh .next | cut -f1)
            echo "::notice title=Frontend Build Size (Node ${{ matrix.node-version }})::${SIZE}"
          fi

  # ── Smart Contracts ───────────────────────────────────────────────────────
  contracts:
    needs: changes
    if: ${{ needs.changes.outputs.contracts == 'true' }}
    name: Smart Contracts (Rust)
    runs-on: ubuntu-latest
    timeout-minutes: 30
    steps:
      - uses: actions/checkout@v4

      - name: Install Rust toolchain
        uses: dtolnay/rust-toolchain@stable
        with:
          targets: wasm32-unknown-unknown

      - name: Rust Cache
        uses: Swatinem/rust-cache@v2
        with:
          workspaces: "contracts -> target"

      - name: Build & Check
        working-directory: contracts
        run: |
          cargo build --target wasm32-unknown-unknown --release
          cargo check