name: Issue Auto Assign

on:
  issues:
    types: [opened]

jobs:
  auto-assign:
    runs-on: ubuntu-latest
    permissions:
      issues: write

    steps:
      - name: Parse issue and assign
        uses: actions/github-script@v9
        with:
          script: |
            const issue = context.payload.issue;
            const issueBody = issue.body || '';
            const issueLabels = (issue.labels || []).map(l => l.name);

            // Default assignees per template type (based on labels)
            const defaultAssignees = {
              'bug': 'zhourrr',
              'feature': 'feihongxu0824',
              'benchmark': 'egolearner',
              'enhancement': 'feihongxu0824',
              'integration': 'chinaux',
              'profile': 'richyreachy'
            };

            // Global fallback assignee
            const fallbackAssignee = 'feihongxu0824';

            // Parse user-selected assignee from issue body
            // The input field renders as: "### Preferred Assignee\n\n<entered_value>"
            let selectedAssignee = null;
            const assigneeMatch = issueBody.match(/### Preferred Assignee\s*\n+([^\n#]+)/);
            if (assigneeMatch) {
              const selection = assigneeMatch[1].trim();
              console.log(`Parsed assignee input: "${selection}"`);
              // If user entered a valid GitHub username (not empty, not placeholder text)
              if (selection && 
                  selection !== '_No response_' &&
                  selection !== 'None' &&
                  !selection.toLowerCase().includes('leave empty') &&
                  !selection.startsWith('e.g.,')) {
                // Clean up the username (remove @ if present)
                selectedAssignee = selection.replace(/^@/, '').trim();
              }
            }

            // Determine final assignee
            let finalAssignee = selectedAssignee;

            // If no user selection, use default based on label
            if (!finalAssignee && issueLabels.length > 0) {
              for (const [label, assignee] of Object.entries(defaultAssignees)) {
                if (issueLabels.includes(label)) {
                  finalAssignee = assignee;
                  console.log(`Matched label "${label}" -> assignee "${assignee}"`);
                  break;
                }
              }
            }

            // Fallback to default assignee if no match
            if (!finalAssignee) {
              finalAssignee = fallbackAssignee;
              console.log(`No match found, using fallback assignee: ${fallbackAssignee}`);
            }

            console.log(`Issue #${issue.number}: Labels = [${issueLabels.join(', ')}]`);
            console.log(`User selected assignee: ${selectedAssignee || 'None (Auto)'}`);
            console.log(`Final assignee: ${finalAssignee}`);

            // Assign the issue
            try {
              await github.rest.issues.addAssignees({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: issue.number,
                assignees: [finalAssignee]
              });
              console.log(`Successfully assigned issue #${issue.number} to ${finalAssignee}`);
            } catch (error) {
              console.error(`Failed to assign issue: ${error.message}`);
              // If assignment fails (user may not have permission), add a comment
              try {
                await github.rest.issues.createComment({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: issue.number,
                  body: `⚠️ Auto-assignment to \`${finalAssignee}\` failed. Please assign manually.`
                });
              } catch (commentError) {
                console.error(`Failed to create comment: ${commentError.message}`);
              }
            }