package platform

import (
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"strings"
	"time"
)

func renderBenchmarkReport(result NvidiaBenchmarkResult) string {
	return renderBenchmarkReportWithCharts(result, nil)
}

type benchmarkReportChart struct {
	Title   string
	Content string
}

var ansiEscapePattern = regexp.MustCompile(`\x1b\[[0-9;]*m`)

func renderBenchmarkReportWithCharts(result NvidiaBenchmarkResult, charts []benchmarkReportChart) string {
	var b strings.Builder
	fmt.Fprintf(&b, "Bee NVIDIA Benchmark Report\n")
	fmt.Fprintf(&b, "===========================\n\n")
	fmt.Fprintf(&b, "Generated: %s\n", result.GeneratedAt.Format("2006-01-02 15:04:05 UTC"))
	fmt.Fprintf(&b, "Host: %s\n", result.Hostname)
	fmt.Fprintf(&b, "Profile: %s\n", result.BenchmarkProfile)
	fmt.Fprintf(&b, "Overall status: %s\n", result.OverallStatus)
	fmt.Fprintf(&b, "Selected GPUs: %s\n", joinIndexList(result.SelectedGPUIndices))
	fmt.Fprintf(&b, "Normalization: %s\n\n", result.Normalization.Status)

	if len(result.Findings) > 0 {
		fmt.Fprintf(&b, "Executive Summary\n")
		fmt.Fprintf(&b, "-----------------\n")
		for _, finding := range result.Findings {
			fmt.Fprintf(&b, "- %s\n", finding)
		}
		b.WriteString("\n")
	}

	if len(result.Warnings) > 0 {
		fmt.Fprintf(&b, "Warnings\n")
		fmt.Fprintf(&b, "--------\n")
		for _, warning := range result.Warnings {
			fmt.Fprintf(&b, "- %s\n", warning)
		}
		b.WriteString("\n")
	}

	fmt.Fprintf(&b, "Per GPU Scorecard\n")
	fmt.Fprintf(&b, "-----------------\n")
	for _, gpu := range result.GPUs {
		fmt.Fprintf(&b, "GPU %d  %s\n", gpu.Index, gpu.Name)
		fmt.Fprintf(&b, "  Status: %s\n", gpu.Status)
		fmt.Fprintf(&b, "  Composite score: %.2f\n", gpu.Scores.CompositeScore)
		fmt.Fprintf(&b, "  Compute score: %.2f\n", gpu.Scores.ComputeScore)
		if gpu.Scores.TOPSPerSMPerGHz > 0 {
			fmt.Fprintf(&b, "  Compute efficiency: %.3f TOPS/SM/GHz\n", gpu.Scores.TOPSPerSMPerGHz)
		}
		fmt.Fprintf(&b, "  Power sustain: %.1f\n", gpu.Scores.PowerSustainScore)
		fmt.Fprintf(&b, "  Thermal sustain: %.1f\n", gpu.Scores.ThermalSustainScore)
		fmt.Fprintf(&b, "  Stability: %.1f\n", gpu.Scores.StabilityScore)
		if gpu.Scores.InterconnectScore > 0 {
			fmt.Fprintf(&b, "  Interconnect: %.1f\n", gpu.Scores.InterconnectScore)
		}
		if len(gpu.DegradationReasons) > 0 {
			fmt.Fprintf(&b, "  Degradation reasons: %s\n", strings.Join(gpu.DegradationReasons, ", "))
		}
		fmt.Fprintf(&b, "  Avg power/temp/clock: %.1f W / %.1f C / %.0f MHz\n", gpu.Steady.AvgPowerW, gpu.Steady.AvgTempC, gpu.Steady.AvgGraphicsClockMHz)
		fmt.Fprintf(&b, "  P95 power/temp/clock: %.1f W / %.1f C / %.0f MHz\n", gpu.Steady.P95PowerW, gpu.Steady.P95TempC, gpu.Steady.P95GraphicsClockMHz)
		if len(gpu.PrecisionResults) > 0 {
			fmt.Fprintf(&b, "  Precision results:\n")
			for _, precision := range gpu.PrecisionResults {
				if precision.Supported {
					fmt.Fprintf(&b, "    - %s: %.2f TOPS lanes=%d iterations=%d\n", precision.Name, precision.TeraOpsPerSec, precision.Lanes, precision.Iterations)
				} else {
					fmt.Fprintf(&b, "    - %s: unsupported (%s)\n", precision.Name, precision.Notes)
				}
			}
		}
		fmt.Fprintf(&b, "  Throttle: %s\n", formatThrottleLine(gpu.Throttle, gpu.Steady.DurationSec))
		if len(gpu.Notes) > 0 {
			fmt.Fprintf(&b, "  Notes:\n")
			for _, note := range gpu.Notes {
				fmt.Fprintf(&b, "    - %s\n", note)
			}
		}
		b.WriteString("\n")
	}

	if result.Interconnect != nil {
		fmt.Fprintf(&b, "Interconnect\n")
		fmt.Fprintf(&b, "------------\n")
		fmt.Fprintf(&b, "Status: %s\n", result.Interconnect.Status)
		if result.Interconnect.Supported {
			fmt.Fprintf(&b, "Avg algbw / busbw: %.1f / %.1f GB/s\n", result.Interconnect.AvgAlgBWGBps, result.Interconnect.AvgBusBWGBps)
			fmt.Fprintf(&b, "Max algbw / busbw: %.1f / %.1f GB/s\n", result.Interconnect.MaxAlgBWGBps, result.Interconnect.MaxBusBWGBps)
		}
		for _, note := range result.Interconnect.Notes {
			fmt.Fprintf(&b, "- %s\n", note)
		}
		b.WriteString("\n")
	}

	if len(charts) > 0 {
		fmt.Fprintf(&b, "Terminal Charts\n")
		fmt.Fprintf(&b, "---------------\n")
		for _, chart := range charts {
			content := strings.TrimSpace(stripANSIEscapeSequences(chart.Content))
			if content == "" {
				continue
			}
			fmt.Fprintf(&b, "%s\n", chart.Title)
			fmt.Fprintf(&b, "%s\n", strings.Repeat("~", len(chart.Title)))
			fmt.Fprintf(&b, "%s\n\n", content)
		}
	}

	if sp := result.ServerPower; sp != nil {
		fmt.Fprintf(&b, "Server Power (IPMI)\n")
		fmt.Fprintf(&b, "-------------------\n")
		if !sp.Available {
			fmt.Fprintf(&b, "Unavailable\n")
		} else {
			fmt.Fprintf(&b, "  Server idle:         %.0f W\n", sp.IdleW)
			fmt.Fprintf(&b, "  Server under load:   %.0f W\n", sp.LoadedW)
			fmt.Fprintf(&b, "  Server delta:        %.0f W\n", sp.DeltaW)
			fmt.Fprintf(&b, "  GPU reported (sum):  %.0f W\n", sp.GPUReportedSumW)
			if sp.ReportingRatio > 0 {
				fmt.Fprintf(&b, "  Reporting ratio:     %.2f  (1.0 = accurate, <0.75 = GPU over-reports)\n", sp.ReportingRatio)
			}
		}
		for _, note := range sp.Notes {
			fmt.Fprintf(&b, "  Note: %s\n", note)
		}
		b.WriteString("\n")
	}

	fmt.Fprintf(&b, "Methodology\n")
	fmt.Fprintf(&b, "-----------\n")
	fmt.Fprintf(&b, "- Profile %s uses standardized baseline, warmup, steady-state, interconnect, and cooldown phases.\n", result.BenchmarkProfile)
	fmt.Fprintf(&b, "- Single-GPU compute score comes from bee-gpu-burn cuBLASLt output when available.\n")
	fmt.Fprintf(&b, "- Thermal and power limitations are inferred from NVIDIA clock event reason counters and sustained telemetry.\n")
	fmt.Fprintf(&b, "- result.json is the canonical machine-readable source for this benchmark run.\n\n")

	fmt.Fprintf(&b, "Raw Files\n")
	fmt.Fprintf(&b, "---------\n")
	fmt.Fprintf(&b, "- result.json\n")
	fmt.Fprintf(&b, "- report.txt\n")
	fmt.Fprintf(&b, "- summary.txt\n")
	fmt.Fprintf(&b, "- verbose.log\n")
	fmt.Fprintf(&b, "- gpu-*-baseline-metrics.csv/html/term.txt\n")
	fmt.Fprintf(&b, "- gpu-*-warmup.log\n")
	fmt.Fprintf(&b, "- gpu-*-steady.log\n")
	fmt.Fprintf(&b, "- gpu-*-steady-metrics.csv/html/term.txt\n")
	fmt.Fprintf(&b, "- gpu-*-cooldown-metrics.csv/html/term.txt\n")
	if result.Interconnect != nil {
		fmt.Fprintf(&b, "- nccl-all-reduce.log\n")
	}
	return b.String()
}

func loadBenchmarkReportCharts(runDir string, gpuIndices []int) []benchmarkReportChart {
	phases := []struct {
		name  string
		label string
	}{
		{name: "baseline", label: "Baseline"},
		{name: "steady", label: "Steady State"},
		{name: "cooldown", label: "Cooldown"},
	}
	var charts []benchmarkReportChart
	for _, idx := range gpuIndices {
		for _, phase := range phases {
			path := filepath.Join(runDir, fmt.Sprintf("gpu-%d-%s-metrics-term.txt", idx, phase.name))
			raw, err := os.ReadFile(path)
			if err != nil || len(raw) == 0 {
				continue
			}
			charts = append(charts, benchmarkReportChart{
				Title:   fmt.Sprintf("GPU %d %s", idx, phase.label),
				Content: string(raw),
			})
		}
	}
	return charts
}

func stripANSIEscapeSequences(raw string) string {
	return ansiEscapePattern.ReplaceAllString(raw, "")
}

// formatThrottleLine renders throttle counters as human-readable percentages of
// the steady-state window.  Only non-zero counters are shown.  When the steady
// duration is unknown (0), raw seconds are shown instead.
func formatThrottleLine(t BenchmarkThrottleCounters, steadyDurationSec float64) string {
	type counter struct {
		label string
		us    uint64
	}
	counters := []counter{
		{"sw_power", t.SWPowerCapUS},
		{"sw_thermal", t.SWThermalSlowdownUS},
		{"sync_boost", t.SyncBoostUS},
		{"hw_thermal", t.HWThermalSlowdownUS},
		{"hw_power_brake", t.HWPowerBrakeSlowdownUS},
	}
	var parts []string
	for _, c := range counters {
		if c.us == 0 {
			continue
		}
		sec := float64(c.us) / 1e6
		if steadyDurationSec > 0 {
			pct := sec / steadyDurationSec * 100
			parts = append(parts, fmt.Sprintf("%s=%.1f%% (%.0fs)", c.label, pct, sec))
		} else if sec < 1 {
			parts = append(parts, fmt.Sprintf("%s=%.0fms", c.label, sec*1000))
		} else {
			parts = append(parts, fmt.Sprintf("%s=%.1fs", c.label, sec))
		}
	}
	if len(parts) == 0 {
		return "none"
	}
	return strings.Join(parts, "  ")
}

func renderBenchmarkSummary(result NvidiaBenchmarkResult) string {
	var b strings.Builder
	fmt.Fprintf(&b, "run_at_utc=%s\n", result.GeneratedAt.Format(time.RFC3339))
	fmt.Fprintf(&b, "benchmark_profile=%s\n", result.BenchmarkProfile)
	fmt.Fprintf(&b, "overall_status=%s\n", result.OverallStatus)
	fmt.Fprintf(&b, "gpu_count=%d\n", len(result.GPUs))
	fmt.Fprintf(&b, "normalization_status=%s\n", result.Normalization.Status)
	var best float64
	for i, gpu := range result.GPUs {
		fmt.Fprintf(&b, "gpu_%d_status=%s\n", gpu.Index, gpu.Status)
		fmt.Fprintf(&b, "gpu_%d_composite_score=%.2f\n", gpu.Index, gpu.Scores.CompositeScore)
		if i == 0 || gpu.Scores.CompositeScore > best {
			best = gpu.Scores.CompositeScore
		}
	}
	fmt.Fprintf(&b, "best_composite_score=%.2f\n", best)
	if result.Interconnect != nil {
		fmt.Fprintf(&b, "interconnect_status=%s\n", result.Interconnect.Status)
		fmt.Fprintf(&b, "interconnect_max_busbw_gbps=%.1f\n", result.Interconnect.MaxBusBWGBps)
	}
	return b.String()
}