name: Community PR Handler

on:
  pull_request_target:
    types: [opened, reopened, ready_for_review]

permissions:
  contents: read
  pull-requests: write

jobs:
  handle-community-pr:
    runs-on: ubuntu-latest
    if: github.event.pull_request.draft == false
    steps:
      - name: Check if community contributor
        id: check
        uses: actions/github-script@v9
        with:
          script: |
            const pr = context.payload.pull_request;
            const prAuthor = pr.user.login;
            const association = pr.author_association;
            
            console.log('========== PR Info ==========');
            console.log(`PR Number: #${pr.number}`);
            console.log(`PR Title: ${pr.title}`);
            console.log(`PR Author: ${prAuthor}`);
            console.log(`Author Association: ${association}`);
            console.log(`Base Branch: ${pr.base.ref}`);
            console.log(`Head Branch: ${pr.head.ref}`);
            console.log(`Head Repo: ${pr.head.repo?.full_name || 'same repo'}`);
            
            // OWNER, MEMBER, COLLABORATOR are maintainers; others are community contributors
            const maintainerRoles = ['OWNER', 'MEMBER', 'COLLABORATOR'];
            const isCommunity = !maintainerRoles.includes(association);
            
            console.log('========== Decision ==========');
            console.log(`Maintainer Roles: ${maintainerRoles.join(', ')}`);
            console.log(`Is Community Contributor: ${isCommunity}`);
            
            if (!isCommunity) {
              console.log('Skipping: PR author is a maintainer, no action needed.');
            }
            
            core.setOutput('is_community', isCommunity);

      - name: Checkout base branch for CODEOWNERS
        if: steps.check.outputs.is_community == 'true'
        uses: actions/checkout@v7
        with:
          ref: ${{ github.event.pull_request.base.ref }}
          sparse-checkout: .github/CODEOWNERS
          sparse-checkout-cone-mode: false

      - name: Assign reviewer as assignee
        if: steps.check.outputs.is_community == 'true'
        uses: actions/github-script@v9
        with:
          script: |
            const fs = require('fs');
            const prNumber = context.payload.pull_request.number;
            
            console.log('========== Fetching Changed Files ==========');
            // Get changed files
            const { data: files } = await github.rest.pulls.listFiles({
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: prNumber
            });
            const changedFiles = files.map(f => f.filename);
            console.log(`Total changed files: ${changedFiles.length}`);
            changedFiles.forEach((f, i) => console.log(`  [${i + 1}] ${f}`));
            
            console.log('========== Parsing CODEOWNERS ==========');
            // Parse CODEOWNERS
            let codeowners = [];
            try {
              const content = fs.readFileSync('.github/CODEOWNERS', 'utf8');
              const lines = content.split('\n').filter(l => l.trim() && !l.trim().startsWith('#'));
              console.log(`Found ${lines.length} rules in CODEOWNERS`);
              for (const line of lines) {
                const parts = line.trim().split(/\s+/);
                if (parts.length >= 2) {
                  const pattern = parts[0];
                  const owners = parts.slice(1).map(o => o.replace('@', ''));
                  codeowners.push({ pattern, owners });
                  console.log(`  Rule: "${pattern}" -> [${owners.join(', ')}]`);
                }
              }
            } catch (e) {
              console.log('ERROR: Could not read CODEOWNERS:', e.message);
              return;
            }
            
            console.log('========== Matching Files to Owners ==========');
            // Find matching owners for changed files
            const matchedOwners = new Set();
            for (const file of changedFiles) {
              let matchedOwner = null;
              let matchedPattern = null;
              for (const rule of codeowners) {
                const pattern = rule.pattern;
                if (pattern === '*') {
                  matchedOwner = rule.owners[0];
                  matchedPattern = pattern;
                } else if (pattern.endsWith('/')) {
                  const dir = pattern.replace(/^\//, '').replace(/\/$/, '');
                  if (file.startsWith(dir + '/') || file.startsWith(dir)) {
                    matchedOwner = rule.owners[0];
                    matchedPattern = pattern;
                  }
                } else if (file === pattern || file === pattern.replace(/^\//, '')) {
                  matchedOwner = rule.owners[0];
                  matchedPattern = pattern;
                }
              }
              if (matchedOwner) {
                matchedOwners.add(matchedOwner);
                console.log(`  "${file}" -> matched "${matchedPattern}" -> @${matchedOwner}`);
              } else {
                console.log(`  "${file}" -> NO MATCH`);
              }
            }
            
            console.log('========== Setting Assignees ==========');
            // Set assignees
            const assignees = Array.from(matchedOwners);
            console.log(`Assignees to set: [${assignees.join(', ')}]`);
            
            if (assignees.length > 0) {
              try {
                await github.rest.issues.addAssignees({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: prNumber,
                  assignees: assignees
                });
                console.log('SUCCESS: Assignees set successfully!');
              } catch (e) {
                console.log('ERROR: Failed to set assignees:', e.message);
                console.log('Error details:', JSON.stringify(e, null, 2));
              }
            } else {
              console.log('WARNING: No assignees to set - no matching owners found.');
            }
            
            console.log('========== Done ==========');