name: "Issue Assignment"

on:
  issue_comment:
    types: [created]

permissions:
  issues: write

jobs:
  handle-command:
    if: github.event_name == 'issue_comment' && !github.event.issue.pull_request
    runs-on: ubuntu-latest
    steps:
      - uses: actions/github-script@v7
        with:
          script: |
            const comment = context.payload.comment;
            const issue = context.payload.issue;
            const commenter = comment.user.login;
            const body = comment.body.trim();

            // /assign command
            if (/^\/assign\s*$/.test(body)) {
              const assignees = issue.assignees.map(a => a.login);

              if (assignees.length === 0) {
                // No assignee — assign commenter
                await github.rest.issues.addAssignees({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: issue.number,
                  assignees: [commenter]
                });
                await github.rest.issues.createComment({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: issue.number,
                  body: `@${commenter} has been assigned to this issue / 已被分配到此 Issue.`
                });
              } else if (assignees.includes(commenter)) {
                // Already assigned to commenter — ignore silently
              } else {
                // Assigned to someone else — reject
                const currentAssignee = assignees[0];
                await github.rest.issues.createComment({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: issue.number,
                  body: `This issue is currently assigned to @${currentAssignee} / 此 Issue 当前已分配给 @${currentAssignee}. Please wait or discuss in the comments / 请等待其释放或在评论中沟通。`
                });
              }
              return;
            }

            // /unassign command
            if (/^\/unassign\s*$/.test(body)) {
              const assignees = issue.assignees.map(a => a.login);

              if (assignees.includes(commenter)) {
                await github.rest.issues.removeAssignees({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: issue.number,
                  assignees: [commenter]
                });

                await github.rest.issues.createComment({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: issue.number,
                  body: `@${commenter} has been unassigned from this issue / 已取消认领此 Issue. It is now available for others / 现在可供其他人认领。`
                });
              }
              // If commenter is not assignee — ignore
              return;
            }