#!/usr/bin/env bash

# Local Benchmark Runner
# Mimics the GitHub Actions workflow for local execution

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(dirname "$(dirname "$SCRIPT_DIR")")"
LOCAL_ARTIFACTS_DIR="$PROJECT_ROOT/.local-artifacts"
ARCHIVE_DIR="$LOCAL_ARTIFACTS_DIR/archive"
TIMESTAMP=$(date -u +"%Y%m%d_%H%M%S")
RUN_DIR="$LOCAL_ARTIFACTS_DIR/run_$TIMESTAMP"

# Create artifacts directory
mkdir -p "$RUN_DIR"

echo "=== Local Benchmark Runner ==="
echo "Run ID: $TIMESTAMP"
echo "Artifacts: $RUN_DIR"
echo ""

# Step 1: Run benchmarks
echo "Step 1: Running benchmarks..."
cd "$PROJECT_ROOT"
BENCHMARK_RESULTS_FILE="$RUN_DIR/benchmark_results.txt"
GO_TEST_EXIT_CODE=0
go test -bench=. -benchmem ./tests/benchmarks/... > "$BENCHMARK_RESULTS_FILE" 2>&1 || GO_TEST_EXIT_CODE=$?
if [ "$GO_TEST_EXIT_CODE" -ne 0 ]; then
  echo "Benchmark run exited non-zero (exit code: $GO_TEST_EXIT_CODE)." >&2
  echo "Continuing to generate metrics from available output: $BENCHMARK_RESULTS_FILE" >&2
  echo "--- tail (last 50 lines) ---" >&2
  tail -n 50 "$BENCHMARK_RESULTS_FILE" >&2 || true
fi

# Step 1b: Run native library benchmarks if available
NATIVE_RESULTS_FILE="$RUN_DIR/native_benchmark_results.txt"
NATIVE_EXIT_CODE=0
if [[ -f "native/build/libqueue_index.dylib" || -f "native/build/libqueue_index.so" ]]; then
  echo ""
  echo "Step 1b: Running native library benchmarks..."
  CGO_ENABLED=1 go test -tags native_libs -bench=. -benchmem ./tests/benchmarks/... > "$NATIVE_RESULTS_FILE" 2>&1 || NATIVE_EXIT_CODE=$?
  if [ "$NATIVE_EXIT_CODE" -ne 0 ]; then
    echo "Native benchmark run exited non-zero (exit code: $NATIVE_EXIT_CODE)." >&2
    echo "--- tail (last 50 lines) ---" >&2
    tail -n 50 "$NATIVE_RESULTS_FILE" >&2 || true
  fi
else
  echo ""
  echo "Step 1b: Native libraries not found, skipping native benchmarks"
  echo "       (Build with: make native-build)"
fi

# Extract benchmark results
grep "Benchmark.*-[0-9].*" "$BENCHMARK_RESULTS_FILE" > "$RUN_DIR/clean_benchmarks.txt" || true

# Step 2: Convert to Prometheus metrics
echo "Step 2: Converting to Prometheus metrics..."
cat > "$RUN_DIR/prometheus_metrics.txt" << EOF
# HELP benchmark_time_per_op Time per operation in nanoseconds
# TYPE benchmark_time_per_op gauge
# HELP benchmark_memory_per_op Memory per operation in bytes
# TYPE benchmark_memory_per_op gauge
# HELP benchmark_allocs_per_op Allocations per operation
# TYPE benchmark_allocs_per_op gauge
EOF

# Parse benchmark results and convert to Prometheus format
while IFS= read -r line; do
  if [[ -n "$line" ]]; then
    BENCHMARK_NAME=$(echo "$line" | awk '{print $1}' | sed 's/-[0-9]*$//')
    ITERATIONS=$(echo "$line" | awk '{print $2}')

    # Go benchmark output can include optional columns (e.g. MB/s) and units are
    # usually separate tokens: "123 ns/op 456 B/op 7 allocs/op".
    TIME_VALUE=$(echo "$line" | awk '{for (i=1;i<=NF;i++) if ($i=="ns/op") {print $(i-1); exit}}')
    MEMORY_VALUE=$(echo "$line" | awk '{for (i=1;i<=NF;i++) if ($i=="B/op") {print $(i-1); exit}}')
    ALLOCS_VALUE=$(echo "$line" | awk '{for (i=1;i<=NF;i++) if ($i=="allocs/op") {print $(i-1); exit}}')
    
    # Clean benchmark name for Prometheus
    CLEAN_NAME=$(echo "$BENCHMARK_NAME" | sed 's/[^a-zA-Z0-9_]/_/g')
    
    # Only add metrics if we have valid numeric values
    if [[ "$TIME_VALUE" =~ ^[0-9.]+$ ]]; then
      echo "benchmark_time_per_op{benchmark=\"$CLEAN_NAME\"} ${TIME_VALUE}" >> "$RUN_DIR/prometheus_metrics.txt"
    fi
    if [[ "$MEMORY_VALUE" =~ ^[0-9.]+$ ]]; then
      echo "benchmark_memory_per_op{benchmark=\"$CLEAN_NAME\"} ${MEMORY_VALUE}" >> "$RUN_DIR/prometheus_metrics.txt"
    fi
    if [[ "$ALLOCS_VALUE" =~ ^[0-9.]+$ ]]; then
      echo "benchmark_allocs_per_op{benchmark=\"$CLEAN_NAME\"} ${ALLOCS_VALUE}" >> "$RUN_DIR/prometheus_metrics.txt"
    fi
  fi
done < "$RUN_DIR/clean_benchmarks.txt"

# Step 3: Push to local Pushgateway (if running)
echo "Step 3: Pushing to Prometheus..."
if command -v curl >/dev/null 2>&1; then
  if curl -s http://localhost:9091 >/dev/null 2>&1; then
    echo "Pushgateway detected, pushing metrics..."
    curl --data-binary @"$RUN_DIR/prometheus_metrics.txt" \
      "http://localhost:9091/metrics/job/benchmark/instance/local_$TIMESTAMP"
  else
    echo "Pushgateway not running at http://localhost:9091"
    echo "Start it with: make monitoring-performance"
  fi
else
  echo "curl not available, skipping push to Pushgateway"
fi

# Step 4: Display results
echo ""
echo "=== Results Summary ==="
echo "Benchmark results saved to: $RUN_DIR/benchmark_results.txt"
echo "Prometheus metrics saved to: $RUN_DIR/prometheus_metrics.txt"
if [ "${GO_TEST_EXIT_CODE:-0}" -ne 0 ]; then
  echo "WARNING: go test exited with code: $GO_TEST_EXIT_CODE"
fi
echo ""

# Show top 10 results
echo "Top 10 Go benchmark times:"
cat "$RUN_DIR/prometheus_metrics.txt" | grep "benchmark_time_per_op" | head -10

# Show native comparison if available
if [[ -f "$NATIVE_RESULTS_FILE" && "$NATIVE_EXIT_CODE" -eq 0 ]]; then
  echo ""
  echo "Native library benchmarks available at: $NATIVE_RESULTS_FILE"
  echo "To compare Go vs Native:"
  echo "  make benchmark-compare"
fi

# Step 5: Generate HTML report
echo "Step 5: Generating HTML report..."
cat > "$RUN_DIR/report.html" << EOF
<!DOCTYPE html>
<html>
<head>
    <title>Benchmark Report - $TIMESTAMP</title>
    <style>
        body { font-family: Arial, sans-serif; margin: 20px; }
        table { border-collapse: collapse; width: 100%; }
        th, td { border: 1px solid #ddd; padding: 8px; text-align: left; }
        th { background-color: #f2f2f2; }
        .metric { font-family: monospace; }
    </style>
</head>
<body>
    <h1>Benchmark Report</h1>
    <p><strong>Run ID:</strong> $TIMESTAMP</p>
    <p><strong>Date:</strong> $(date)</p>
    
    <h2>Results</h2>
    <table>
        <tr>
            <th>Benchmark</th>
            <th>Time (ns/op)</th>
            <th>Memory (B/op)</th>
            <th>Allocs (allocs/op)</th>
        </tr>
$(cat "$RUN_DIR/clean_benchmarks.txt" | while IFS= read -r line; do
  if [[ -n "$line" ]]; then
    BENCHMARK_NAME=$(echo "$line" | awk '{print $1}')

    TIME_PER_OP=$(echo "$line" | awk '{for (i=1;i<=NF;i++) if ($i=="ns/op") {print $(i-1)" " $i; exit}}')
    MEMORY_PER_OP=$(echo "$line" | awk '{for (i=1;i<=NF;i++) if ($i=="B/op") {print $(i-1)" " $i; exit}}')
    ALLOCS_PER_OP=$(echo "$line" | awk '{for (i=1;i<=NF;i++) if ($i=="allocs/op") {print $(i-1)" " $i; exit}}')
    echo "        <tr>"
    echo "            <td class=\"metric\">$BENCHMARK_NAME</td>"
    echo "            <td>$TIME_PER_OP</td>"
    echo "            <td>$MEMORY_PER_OP</td>"
    echo "            <td>$ALLOCS_PER_OP</td>"
    echo "        </tr>"
  fi
done)
    </table>
    
    <h2>Raw Output</h2>
    <pre>$(cat "$RUN_DIR/benchmark_results.txt")</pre>
</body>
</html>
EOF

echo "HTML report saved to: $RUN_DIR/report.html"
echo "Open with: open $RUN_DIR/report.html"

# Step 6: Artifact management
echo ""
echo "=== Artifact Management ==="
echo "All artifacts saved in: $RUN_DIR"
echo "Total runs: $(ls -1d "$LOCAL_ARTIFACTS_DIR"/run_* 2>/dev/null | wc -l)"
echo ""

# Show recent runs
echo "Recent runs:"
ls -lt "$LOCAL_ARTIFACTS_DIR"/run_* 2>/dev/null | head -5 || echo "No previous runs found"

# Step 7: Comprehensive cleanup
echo ""
echo "=== Cleanup Procedures ==="

# Use the dedicated cleanup script
if [ -f "$SCRIPT_DIR/cleanup-benchmarks.sh" ]; then
    echo "Running standard benchmark cleanup..."
    "$SCRIPT_DIR/cleanup-benchmarks.sh" benchmarks
else
    # Fallback cleanup if script not available
    echo "Archiving old benchmark runs (keeping last 10)..."
    stamp=$(date -u +%Y%m%d-%H%M%S)
    mkdir -p "$ARCHIVE_DIR/$stamp"
    cd "$LOCAL_ARTIFACTS_DIR"
    ls -1t run_* 2>/dev/null | tail -n +11 | while read -r run; do
        [ -n "$run" ] || continue
        mv "$run" "$ARCHIVE_DIR/$stamp/" 2>/dev/null || true
    done
    
    # Clean temporary files
    echo "Archiving temporary files..."
    tmp_archive_dir="$LOCAL_ARTIFACTS_DIR/tmp-archive/$stamp"
    mkdir -p "$tmp_archive_dir"
    find /tmp -name "benchmark_*" -type f -mmin +60 -print0 2>/dev/null | while IFS= read -r -d '' f; do
        mv "$f" "$tmp_archive_dir/" 2>/dev/null || true
    done
    find /var/tmp -name "benchmark_*" -type f -mmin +60 -print0 2>/dev/null | while IFS= read -r -d '' f; do
        mv "$f" "$tmp_archive_dir/" 2>/dev/null || true
    done
    
    # Clean Go build cache
    echo "Cleaning Go build cache..."
    go clean -testcache 2>/dev/null || true
fi

# Show final status
echo ""
echo "=== Final Status ==="
echo "Active runs remaining: $(ls -1d "$LOCAL_ARTIFACTS_DIR"/run_* 2>/dev/null | wc -l)"
echo "Disk usage: $(du -sh "$LOCAL_ARTIFACTS_DIR" 2>/dev/null | cut -f1 || echo "N/A")"

echo ""
echo "=== Complete! ==="
echo "View results: open $RUN_DIR/report.html"
echo "Push metrics: Available at http://localhost:9091 (if running)"