name: CI

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

concurrency:
    group: ci-${{ github.event.pull_request.number || github.sha }}
    cancel-in-progress: true

permissions:
    contents: read

env:
    CARGO_TERM_COLOR: always

jobs:
    changes:
        name: Detect Change Scope
        runs-on: blacksmith-2vcpu-ubuntu-2404
        outputs:
            docs_only: ${{ steps.scope.outputs.docs_only }}
            docs_changed: ${{ steps.scope.outputs.docs_changed }}
            rust_changed: ${{ steps.scope.outputs.rust_changed }}
            docs_files: ${{ steps.scope.outputs.docs_files }}
        steps:
            - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
              with:
                  fetch-depth: 0

            - name: Detect docs-only changes
              id: scope
              shell: bash
              run: |
                  set -euo pipefail

                  write_empty_docs_files() {
                    {
                      echo "docs_files<<EOF"
                      echo "EOF"
                    } >> "$GITHUB_OUTPUT"
                  }

                  if [ "${{ github.event_name }}" = "pull_request" ]; then
                    BASE="${{ github.event.pull_request.base.sha }}"
                  else
                    BASE="${{ github.event.before }}"
                  fi

                  if [ -z "$BASE" ] || ! git cat-file -e "$BASE^{commit}" 2>/dev/null; then
                    {
                      echo "docs_only=false"
                      echo "docs_changed=false"
                      echo "rust_changed=true"
                    } >> "$GITHUB_OUTPUT"
                    write_empty_docs_files
                    exit 0
                  fi

                  CHANGED="$(git diff --name-only "$BASE" HEAD || true)"
                  if [ -z "$CHANGED" ]; then
                    {
                      echo "docs_only=false"
                      echo "docs_changed=false"
                      echo "rust_changed=false"
                    } >> "$GITHUB_OUTPUT"
                    write_empty_docs_files
                    exit 0
                  fi

                  docs_only=true
                  docs_changed=false
                  rust_changed=false
                  docs_files=()
                  while IFS= read -r file; do
                    [ -z "$file" ] && continue

                    if [[ "$file" == docs/* ]] \
                      || [[ "$file" == *.md ]] \
                      || [[ "$file" == *.mdx ]] \
                      || [[ "$file" == "LICENSE" ]] \
                      || [[ "$file" == ".markdownlint-cli2.yaml" ]] \
                      || [[ "$file" == .github/ISSUE_TEMPLATE/* ]] \
                      || [[ "$file" == .github/pull_request_template.md ]]; then
                      if [[ "$file" == *.md ]] \
                        || [[ "$file" == *.mdx ]] \
                        || [[ "$file" == "LICENSE" ]] \
                        || [[ "$file" == .github/pull_request_template.md ]]; then
                        docs_changed=true
                        docs_files+=("$file")
                      fi
                      continue
                    fi

                    docs_only=false

                    if [[ "$file" == src/* ]] \
                      || [[ "$file" == tests/* ]] \
                      || [[ "$file" == "Cargo.toml" ]] \
                      || [[ "$file" == "Cargo.lock" ]] \
                      || [[ "$file" == "deny.toml" ]]; then
                      rust_changed=true
                    fi
                  done <<< "$CHANGED"

                  {
                    echo "docs_only=$docs_only"
                    echo "docs_changed=$docs_changed"
                    echo "rust_changed=$rust_changed"
                    echo "docs_files<<EOF"
                    printf '%s\n' "${docs_files[@]}"
                    echo "EOF"
                  } >> "$GITHUB_OUTPUT"

    lint:
        name: Format & Lint
        needs: [changes]
        if: needs.changes.outputs.rust_changed == 'true'
        runs-on: blacksmith-2vcpu-ubuntu-2404
        timeout-minutes: 20
        steps:
            - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
              with:
                  fetch-depth: 0
            - uses: dtolnay/rust-toolchain@631a55b12751854ce901bb631d5902ceb48146f7 # stable
              with:
                  toolchain: 1.92
                  components: rustfmt, clippy
            - uses: Swatinem/rust-cache@779680da715d629ac1d338a641029a2f4372abb5 # v2
            - name: Run rustfmt
              run: cargo fmt --all -- --check
            - name: Run clippy
              run: cargo clippy --locked --all-targets -- -D clippy::correctness

    test:
        name: Test
        needs: [changes]
        if: needs.changes.outputs.rust_changed == 'true'
        runs-on: blacksmith-2vcpu-ubuntu-240
        timeout-minutes: 30
        steps:
            - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
            - uses: dtolnay/rust-toolchain@631a55b12751854ce901bb631d5902ceb48146f7 # stable
              with:
                  toolchain: 1.92
            - uses: Swatinem/rust-cache@779680da715d629ac1d338a641029a2f4372abb5 # v2
            - name: Run tests
              run: cargo test --locked --verbose

    build:
        name: Build (Smoke)
        needs: [changes]
        if: needs.changes.outputs.rust_changed == 'true'
        runs-on: blacksmith-2vcpu-ubuntu-240
        timeout-minutes: 20

        steps:
            - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
            - uses: dtolnay/rust-toolchain@631a55b12751854ce901bb631d5902ceb48146f7 # stable
              with:
                  toolchain: 1.92
            - uses: Swatinem/rust-cache@779680da715d629ac1d338a641029a2f4372abb5 # v2
            - name: Build release binary
              run: cargo build --release --locked --verbose

    docs-only:
        name: Docs-Only Fast Path
        needs: [changes]
        if: needs.changes.outputs.docs_only == 'true'
        runs-on: blacksmith-2vcpu-ubuntu-2404
        steps:
            - name: Skip heavy jobs for docs-only change
              run: echo "Docs-only change detected. Rust lint/test/build skipped."

    non-rust:
        name: Non-Rust Fast Path
        needs: [changes]
        if: needs.changes.outputs.docs_only != 'true' && needs.changes.outputs.rust_changed != 'true'
        runs-on: blacksmith-2vcpu-ubuntu-2404
        steps:
            - name: Skip Rust jobs for non-Rust change scope
              run: echo "No Rust-impacting files changed. Rust lint/test/build skipped."

    docs-quality:
        name: Docs Quality
        needs: [changes]
        if: needs.changes.outputs.docs_changed == 'true'
        runs-on: blacksmith-2vcpu-ubuntu-240
        timeout-minutes: 15
        steps:
            - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4

            - name: Markdown lint
              uses: DavidAnson/markdownlint-cli2-action@07035fd053f7be764496c0f8d8f9f41f98305101 # v22
              with:
                  globs: ${{ needs.changes.outputs.docs_files }}

            - name: Link check (offline)
              uses: lycheeverse/lychee-action@a8c4c7cb88f0c7386610c35eb25108e448569cb0 # v2
              with:
                  fail: true
                  args: >-
                      --offline
                      --no-progress
                      --format detailed
                      ${{ needs.changes.outputs.docs_files }}
              env:
                  GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

    ci-required:
        name: CI Required Gate
        if: always()
        needs: [changes, lint, test, build, docs-only, non-rust, docs-quality]
        runs-on: blacksmith-2vcpu-ubuntu-2404
        steps:
            - name: Enforce required status
              shell: bash
              run: |
                  set -euo pipefail

                  docs_changed="${{ needs.changes.outputs.docs_changed }}"
                  rust_changed="${{ needs.changes.outputs.rust_changed }}"
                  docs_result="${{ needs.docs-quality.result }}"

                  if [ "${{ needs.changes.outputs.docs_only }}" = "true" ]; then
                    echo "docs=${docs_result}"
                    if [ "$docs_changed" = "true" ] && [ "$docs_result" != "success" ]; then
                      echo "Docs-only change touched markdown docs, but docs-quality did not pass."
                      exit 1
                    fi
                    echo "Docs-only fast path passed."
                    exit 0
                  fi

                  if [ "$rust_changed" != "true" ]; then
                    echo "rust_changed=false (non-rust fast path)"
                    echo "docs=${docs_result}"
                    if [ "$docs_changed" = "true" ] && [ "$docs_result" != "success" ]; then
                      echo "Docs changed but docs-quality did not pass."
                      exit 1
                    fi
                    echo "Non-rust fast path passed."
                    exit 0
                  fi

                  lint_result="${{ needs.lint.result }}"
                  test_result="${{ needs.test.result }}"
                  build_result="${{ needs.build.result }}"

                  echo "lint=${lint_result}"
                  echo "test=${test_result}"
                  echo "build=${build_result}"
                  echo "docs=${docs_result}"

                  if [ "$lint_result" != "success" ] || [ "$test_result" != "success" ] || [ "$build_result" != "success" ]; then
                    echo "Required CI jobs did not pass."
                    exit 1
                  fi

                  if [ "$docs_changed" = "true" ] && [ "$docs_result" != "success" ]; then
                    echo "Docs changed but docs-quality did not pass."
                    exit 1
                  fi

                  echo "All required CI jobs passed."