name: Generate Changelog

on:
  workflow_dispatch:
    inputs:
      milestone:
        description: 'Milestone title in the server repo (e.g. v11.9.0)'
        required: true
        type: string
      version:
        description: 'Version label for changelog entry (e.g. v11.9.0)'
        required: true
        type: string
      server_repos:
        description: 'Comma-separated repos to pull PRs from'
        required: true
        default: 'mattermost/mattermost,mattermost/enterprise'
        type: string
      release_type:
        description: 'Release type: "feature" (default) or "esr" (Extended Support Release)'
        required: false
        default: 'feature'
        type: choice
        options:
          - feature
          - esr
      release_date:
        description: 'Release day date (e.g. 2026-07-16) — defaults to today if omitted'
        required: false
        type: string
      go_version:
        description: 'Go version used in this release (e.g. go1.26.4) — if omitted, the previous version is read from the changelog and reused'
        required: false
        type: string
      blog_post_url:
        description: 'Blog post URL for the Improvements section — if omitted, auto-constructed from version (e.g. https://mattermost.com/blog/mattermost-v11-9-is-now-available/)'
        required: false
        type: string

jobs:
  generate-changelog:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: read

    steps:
      # App 1: Read-only access to mattermost/mattermost and mattermost/enterprise.
      # Used by the Python script to fetch merged PRs and their release notes.
      # The built-in GITHUB_TOKEN is not sufficient because mattermost/enterprise
      # is a separate private repository.
      # Credentials needed in Settings → Secrets and variables → Actions:
      #   CHANGELOG_READ_CLIENT_ID   (variable)  — Client ID from the mattermost+enterprise GitHub App
      #   CHANGELOG_READ_PRIVATE_KEY (secret)    — Private key from the mattermost+enterprise GitHub App
      - name: Get read token (source repos)
        uses: actions/create-github-app-token@1b10c78c7865c340bc4f6099eb2f838309f1e8c3 # v3.1.1
        id: readToken
        with:
          client-id: ${{ vars.CHANGELOG_READ_CLIENT_ID }}
          private-key: ${{ secrets.CHANGELOG_READ_PRIVATE_KEY }}
          owner: mattermost

      # App 2: Read/write access to this repo (mattermost/mattermost).
      # Used to check out the repo, push the changelog branch, and open the PR.
      # NOTE: the built-in GITHUB_TOKEN could technically do this now that the changelog
      # lives in this repo, but PRs opened with GITHUB_TOKEN do not trigger other
      # workflows — so CI would not run on the generated changelog PR. Using a GitHub
      # App token keeps CI working and preserves the bot identity used for the CLA
      # exemption.
      # Credentials needed in Settings → Secrets and variables → Actions:
      #   CHANGELOG_WRITE_CLIENT_ID   (variable) — Client ID from the write GitHub App
      #   CHANGELOG_WRITE_PRIVATE_KEY (secret)   — Private key from the write GitHub App
      - name: Get write token (this repo)
        uses: actions/create-github-app-token@1b10c78c7865c340bc4f6099eb2f838309f1e8c3 # v3.1.1
        id: writeToken
        with:
          client-id: ${{ vars.CHANGELOG_WRITE_CLIENT_ID }}
          private-key: ${{ secrets.CHANGELOG_WRITE_PRIVATE_KEY }}
          owner: mattermost

      - name: Checkout repo
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          token: ${{ steps.writeToken.outputs.token }}

      - name: Set up Python
        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
        with:
          python-version: '3.11'

      - name: Install dependencies
        run: pip install requests anthropic

      - name: Generate changelog
        env:
          GITHUB_TOKEN: ${{ steps.readToken.outputs.token }} # Read-only token for fetching PRs from source repos
          ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }} # Enables AI categorization and formatting — add under Settings → Secrets and variables → Actions
          MILESTONE: ${{ inputs.milestone }}
          VERSION: ${{ inputs.version }}
          REPOS: ${{ inputs.server_repos }}
          RELEASE_TYPE: ${{ inputs.release_type }}
          RELEASE_DATE: ${{ inputs.release_date }}
          GO_VERSION: ${{ inputs.go_version }}
          BLOG_POST_URL: ${{ inputs.blog_post_url }}
          CHANGELOG_PATH: docs/main/product-overview/mattermost-v11-changelog.mdx
        run: python .github/scripts/generate_changelog.py

      - name: Create Pull Request
        env:
          GH_TOKEN: ${{ steps.writeToken.outputs.token }}
          VERSION: ${{ inputs.version }}
          MILESTONE: ${{ inputs.milestone }}
          SERVER_REPOS: ${{ inputs.server_repos }}
          COMMIT_USER_NAME: ${{ vars.CHANGELOG_GIT_USERNAME }}
          COMMIT_USER_EMAIL: ${{ vars.CHANGELOG_GIT_EMAIL }}
          CHANGELOG_FILE: docs/main/product-overview/mattermost-v11-changelog.mdx
        run: |
          git config user.name "$COMMIT_USER_NAME"
          git config user.email "$COMMIT_USER_EMAIL"
          git checkout -b "changelog/$VERSION"
          git add "$CHANGELOG_FILE"
          git diff --staged --quiet && echo "No changes to commit" && exit 0
          git commit -m "docs: add changelog for $VERSION"
          git push origin "changelog/$VERSION" --force
          gh pr create \
            --repo mattermost/mattermost \
            --title "$VERSION Changelog" \
            --body "Auto-generated changelog for milestone \`$MILESTONE\` from \`$SERVER_REPOS\`." \
            --base master \
            --head "changelog/$VERSION"