name: Profiling Changes

on:
  pull_request:
    paths:
      - 'node-graph/**'
      - 'Cargo.toml'
      - 'Cargo.lock'

env:
  CARGO_TERM_COLOR: always

jobs:
  profile:
    runs-on: ubuntu-latest
    continue-on-error: true
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Install Rust
        uses: dtolnay/rust-toolchain@stable

      - name: Install Valgrind
        run: |
          sudo apt update
          sudo apt install -y valgrind

      - name: Cache Rust dependencies
        uses: Swatinem/rust-cache@v2
        with:
          # Cache on Cargo.lock file
          cache-on-failure: true

      - name: Cache iai-callgrind binary
        id: cache-iai
        uses: actions/cache@v4
        with:
          path: ~/.cargo/bin/iai-callgrind-runner
          key: ${{ runner.os }}-iai-callgrind-runner-0.16.1

      - name: Install iai-callgrind
        if: steps.cache-iai.outputs.cache-hit != 'true'
        run: |
          cargo install iai-callgrind-runner@0.16.1

      - name: Checkout master branch
        run: |
          git fetch origin master:master
          git checkout master

      - name: Get master commit SHA
        id: master-sha
        run: echo "sha=$(git rev-parse HEAD)" >> $GITHUB_OUTPUT

      - name: Get CPU info
        id: cpu-info
        run: |
          # Get CPU model and create a short hash for cache key
          CPU_MODEL=$(cat /proc/cpuinfo | grep "model name" | head -1 | cut -d: -f2 | xargs)
          CPU_HASH=$(echo "$CPU_MODEL" | sha256sum | cut -c1-8)
          echo "cpu-hash=$CPU_HASH" >> $GITHUB_OUTPUT
          echo "CPU: $CPU_MODEL (hash: $CPU_HASH)"

      - name: Cache benchmark baselines
        id: cache-benchmark-baselines
        uses: actions/cache@v4
        with:
          path: target/iai
          key: ${{ runner.os }}-${{ runner.arch }}-${{ steps.cpu-info.outputs.cpu-hash }}-benchmark-baselines-master-${{ steps.master-sha.outputs.sha }}
          restore-keys: |
            ${{ runner.os }}-${{ runner.arch }}-${{ steps.cpu-info.outputs.cpu-hash }}-benchmark-baselines-master-

      - name: Run baseline benchmarks
        if: steps.cache-benchmark-baselines.outputs.cache-hit != 'true'
        run: |
          # Compile benchmarks
          cargo bench --bench compile_demo_art_iai -- --save-baseline=master

          # Runtime benchmarks
          cargo bench --bench update_executor_iai -- --save-baseline=master
          cargo bench --bench run_once_iai -- --save-baseline=master
          cargo bench --bench run_cached_iai -- --save-baseline=master

      - name: Checkout PR branch
        run: |
          git checkout ${{ github.event.pull_request.head.sha }}

      - name: Run PR benchmarks
        run: |
          # Compile benchmarks
          cargo bench --bench compile_demo_art_iai -- --baseline=master --output-format=json | jq -sc | sed 's/\\"//g' > /tmp/compile_output.json

          # Runtime benchmarks  
          cargo bench --bench update_executor_iai -- --baseline=master --output-format=json | jq -sc | sed 's/\\"//g' > /tmp/update_output.json
          cargo bench --bench run_once_iai -- --baseline=master --output-format=json | jq -sc | sed 's/\\"//g' > /tmp/run_once_output.json
          cargo bench --bench run_cached_iai -- --baseline=master --output-format=json | jq -sc | sed 's/\\"//g' > /tmp/run_cached_output.json

      - name: Make old comments collapsed by default
        # Only run if we have write permissions (not a fork)
        if: github.event.pull_request.head.repo.full_name == github.repository
        uses: actions/github-script@v7
        with:
          github-token: ${{secrets.GITHUB_TOKEN}}
          script: |
            const { data: comments } = await github.rest.issues.listComments({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
            });

            const botComments = comments.filter((comment) =>
              comment.user.type === 'Bot' && comment.body.includes('Performance Benchmark Results') && comment.body.includes('<details open>')
            );

            for (const comment of botComments) {
              // Edit the comment to remove the "open" attribute from the <details> tag
              await github.rest.issues.updateComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: comment.id,
                body: comment.body.replace('<details open>', '<details>')
              });
            }

      - name: Analyze profiling changes
        id: analyze
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');

            function isSignificantChange(diffPct, absoluteChange, benchmarkType) {
              const meetsPercentageThreshold = Math.abs(diffPct) > 5;
              const meetsAbsoluteThreshold = absoluteChange > 200000;
              const isCachedExecution = benchmarkType === 'run_cached' ||
                                        benchmarkType.includes('Cached Execution');

              return isCachedExecution
                ? (meetsPercentageThreshold && meetsAbsoluteThreshold)
                : meetsPercentageThreshold;
            }

            const allOutputs = [
              JSON.parse(fs.readFileSync('/tmp/compile_output.json', 'utf8')),
              JSON.parse(fs.readFileSync('/tmp/update_output.json', 'utf8')),
              JSON.parse(fs.readFileSync('/tmp/run_once_output.json', 'utf8')),
              JSON.parse(fs.readFileSync('/tmp/run_cached_output.json', 'utf8'))
            ];
            const outputNames = ['compile', 'update', 'run_once', 'run_cached'];
            const sectionTitles = ['Compilation', 'Update', 'Run Once', 'Cached Execution'];

            let hasSignificantChanges = false;
            let regressionDetails = [];

            for (let i = 0; i < allOutputs.length; i++) {
              const benchmarkOutput = allOutputs[i];
              const outputName = outputNames[i];
              const sectionTitle = sectionTitles[i];

              for (const benchmark of benchmarkOutput) {
                if (benchmark.profiles?.[0]?.summaries?.parts?.[0]?.metrics_summary?.Callgrind?.Ir?.diffs?.diff_pct) {
                  const diffPct = parseFloat(benchmark.profiles[0].summaries.parts[0].metrics_summary.Callgrind.Ir.diffs.diff_pct);
                  const oldValue = benchmark.profiles[0].summaries.parts[0].metrics_summary.Callgrind.Ir.metrics.Both[1].Int;
                  const newValue = benchmark.profiles[0].summaries.parts[0].metrics_summary.Callgrind.Ir.metrics.Both[0].Int;
                  const absoluteChange = Math.abs(newValue - oldValue);

                  if (isSignificantChange(diffPct, absoluteChange, outputName)) {
                    hasSignificantChanges = true;
                    regressionDetails.push({
                      module_path: benchmark.module_path,
                      id: benchmark.id,
                      diffPct,
                      absoluteChange,
                      sectionTitle
                    });
                  }
                }
              }
            }

            core.setOutput('has-significant-changes', hasSignificantChanges);
            core.setOutput('regression-details', JSON.stringify(regressionDetails));

      - name: Comment PR
        if: github.event.pull_request.head.repo.full_name == github.repository
        uses: actions/github-script@v7
        with:
          github-token: ${{secrets.GITHUB_TOKEN}}
          script: |
            const fs = require('fs');

            const compileOutput = JSON.parse(fs.readFileSync('/tmp/compile_output.json', 'utf8'));
            const updateOutput = JSON.parse(fs.readFileSync('/tmp/update_output.json', 'utf8'));  
            const runOnceOutput = JSON.parse(fs.readFileSync('/tmp/run_once_output.json', 'utf8'));
            const runCachedOutput = JSON.parse(fs.readFileSync('/tmp/run_cached_output.json', 'utf8'));

            const hasSignificantChanges = '${{ steps.analyze.outputs.has-significant-changes }}' === 'true';
            let commentBody = "";

            function formatNumber(num) {
              return num.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
            }

            function formatPercentage(pct) {
              const sign = pct >= 0 ? '+' : '';
              return `${sign}${pct.toFixed(2)}%`;
            }

            function padRight(str, len) {
              return str.padEnd(len);
            }

            function padLeft(str, len) {
              return str.padStart(len);
            }

            function processBenchmarkOutput(benchmarkOutput, sectionTitle, isLast = false) {
              let sectionBody = "";
              let hasResults = false;
              let hasSignificantChanges = false;

              function isSignificantChange(diffPct, absoluteChange, benchmarkType) {
                const meetsPercentageThreshold = Math.abs(diffPct) > 5;
                const meetsAbsoluteThreshold = absoluteChange > 200000;
                const isCachedExecution = benchmarkType === 'run_cached' ||
                                          benchmarkType.includes('Cached Execution');

                return isCachedExecution
                  ? (meetsPercentageThreshold && meetsAbsoluteThreshold)
                  : meetsPercentageThreshold;
              }
              
              for (const benchmark of benchmarkOutput) {
                if (benchmark.profiles && benchmark.profiles.length > 0) {
                  const profile = benchmark.profiles[0];
                  if (profile.summaries && profile.summaries.parts && profile.summaries.parts.length > 0) {
                    const part = profile.summaries.parts[0];
                    if (part.metrics_summary && part.metrics_summary.Callgrind && part.metrics_summary.Callgrind.Ir) {
                      const irData = part.metrics_summary.Callgrind.Ir;
                      if (irData.diffs && irData.diffs.diff_pct !== null) {
                        const irDiff = {
                          diff_pct: parseFloat(irData.diffs.diff_pct),
                          old: irData.metrics.Both[1].Int,
                          new: irData.metrics.Both[0].Int
                        };
                    hasResults = true;
                    const changePercentage = formatPercentage(irDiff.diff_pct);
                    const color = irDiff.diff_pct > 0 ? "red" : "lime";
                    
                    sectionBody += `**${benchmark.module_path} ${benchmark.id}:${benchmark.details}**\n`;
                    sectionBody += `Instructions: \`${formatNumber(irDiff.old)}\` (master) → \`${formatNumber(irDiff.new)}\` (HEAD) : `;
                    sectionBody += `$$\\color{${color}}${changePercentage.replace("%", "\\\\%")}$$\n\n`;
                    
                    sectionBody += "<details>\n<summary>Detailed metrics</summary>\n\n```\n";
                    sectionBody += `Baselines:                master|       HEAD\n`;
                    
                    for (const [metricName, metricData] of Object.entries(part.metrics_summary.Callgrind)) {
                      if (metricData.diffs && metricData.diffs.diff_pct !== null) {
                        const changePercentage = formatPercentage(parseFloat(metricData.diffs.diff_pct));
                        const oldValue = metricData.metrics.Both[1].Int || metricData.metrics.Both[1].Float;
                        const newValue = metricData.metrics.Both[0].Int || metricData.metrics.Both[0].Float;
                        const line = `${padRight(metricName, 20)} ${padLeft(formatNumber(Math.round(oldValue)), 11)}|${padLeft(formatNumber(Math.round(newValue)), 11)} ${padLeft(changePercentage, 15)}`;
                        sectionBody += `${line}\n`;
                      }
                    }
                    
                    sectionBody += "```\n</details>\n\n";

                        if (isSignificantChange(irDiff.diff_pct, Math.abs(irDiff.new - irDiff.old), sectionTitle)) {
                          significantChanges = true;
                          hasSignificantChanges = true;
                        }
                      }
                    }
                  }
                }
              }
              
              if (hasResults) {
                // Wrap section in collapsible details, open only if there are significant changes
                const openAttribute = hasSignificantChanges ? " open" : "";
                const ruler = isLast ? "" : "\n\n---";
                return `<details${openAttribute}>\n<summary><h2>${sectionTitle}</h2></summary>\n\n${sectionBody}${ruler}\n</details>`;
              }
              return "";
            }

            // Process each benchmark category
            const sections = [
              { output: compileOutput, title: "🔧 Graph Compilation" },
              { output: updateOutput, title: "🔄 Executor Update" },
              { output: runOnceOutput, title: "🚀 Render: Cold Execution" },
              { output: runCachedOutput, title: "⚡ Render: Cached Execution" }
            ];

            // Generate sections and determine which ones have results
            const generatedSections = sections.map(({ output, title }) => 
              processBenchmarkOutput(output, title, true) // temporarily mark all as last
            ).filter(section => section.length > 0);

            // Re-generate with correct isLast flags
            let sectionIndex = 0;
            const finalSections = sections.map(({ output, title }) => {
              const section = processBenchmarkOutput(output, title, true); // check if it has results
              if (section.length > 0) {
                const isLast = sectionIndex === generatedSections.length - 1;
                sectionIndex++;
                return processBenchmarkOutput(output, title, isLast);
              }
              return "";
            }).filter(section => section.length > 0);

            // Combine all sections
            commentBody = finalSections.join("\n\n");

            if (commentBody.length > 0) {
              const output = `<details open>\n<summary>Performance Benchmark Results</summary>\n\n${commentBody}\n</details>`;

              if (hasSignificantChanges) {
                github.rest.issues.createComment({
                  issue_number: context.issue.number,
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  body: output
                });
              } else {
                console.log("No significant performance changes detected. Skipping comment.");
                console.log(output);
              }
            } else {
              console.log("No benchmark results to display.");
            }

      - name: Fail on significant regressions
        if: steps.analyze.outputs.has-significant-changes == 'true'
        uses: actions/github-script@v7
        with:
          script: |
            const regressionDetails = JSON.parse('${{ steps.analyze.outputs.regression-details }}');
            const firstRegression = regressionDetails[0];

            core.setFailed(`Significant performance regression detected: ${firstRegression.module_path} ${firstRegression.id} increased by ${firstRegression.absoluteChange.toLocaleString()} instructions (${firstRegression.diffPct.toFixed(2)}%)`);