name: Auto-assign Copilot Coding Agent

# copilot ラベルが付いた Issue に GitHub Copilot Coding Agent を GraphQL でアサインする。
# 正しい API: GraphQL replaceActorsForAssignable + agentAssignment フィールド
# (REST API の assignees や @github-copilot コメントは Coding Agent を起動しない)
on:
  issues:
    types: [labeled, opened]

jobs:
  assign:
    name: Assign Copilot Coding Agent
    runs-on: ubuntu-latest
    # copilot ラベルが付いている Issue のみ対象
    if: contains(github.event.issue.labels.*.name, 'copilot')
    permissions:
      issues: write
    steps:
      - name: Check if Copilot already assigned
        id: check
        uses: actions/github-script@v7
        with:
          result-encoding: string
          script: |
            const timeline = await github.rest.issues.listEventsForTimeline({
              owner:        context.repo.owner,
              repo:         context.repo.repo,
              issue_number: context.issue.number,
              per_page:     100,
              mediaType:    { previews: ['mockingbird'] },
            });
            // "assigned" イベントで assignee.login === "Copilot" が存在すれば既に割り当て済み
            const already = timeline.data.some(
              e => e.event === 'assigned' && e.assignee?.login === 'Copilot'
            );
            return already ? 'yes' : 'no';

      - name: Assign Copilot via GraphQL
        if: steps.check.outputs.result == 'no'
        uses: actions/github-script@v7
        with:
          # GITHUB_TOKEN で動作（PAT 不要）
          # 修正: agentAssignment.targetRepositoryId が必須。ないと silent fail する。
          script: |
            const issueNodeId = context.payload.issue.node_id;

            // リポジトリの Node ID を取得（agentAssignment に必須）
            const repoData = await github.graphql(`
              query GetRepoId($owner: String!, $name: String!) {
                repository(owner: $owner, name: $name) { id }
              }
            `, {
              owner: context.repo.owner,
              name: context.repo.repo,
            });
            const repoId = repoData.repository.id;

            await github.graphql(`
              mutation AssignCopilot($input: ReplaceActorsForAssignableInput!) {
                replaceActorsForAssignable(input: $input) {
                  assignable {
                    ... on Issue { number title }
                  }
                }
              }
            `, {
              input: {
                assignableId: issueNodeId,
                actorLogins: [],
                agentAssignment: {
                  targetRepositoryId: repoId,   // 必須: これがないと Copilot が起動しない
                  baseRef: 'master',
                  customInstructions: 'IMPORTANT: Every PR MUST contain at least one executable code file (.js .ts .py .sh .go .rs etc). Do NOT create PRs with only .md documentation files — that is not acceptable. Implement exactly what the Issue acceptance criteria require. Write tests for new functions. Keep the PR title concise and never include [WIP]. Make small focused commits. If the Issue is unclear, implement the minimal working version that satisfies the stated acceptance criteria.',
                },
              },
            });

            console.log(`✅ Copilot Coding Agent assigned to #${context.issue.number}`);