package inspur

import (
	"fmt"
	"regexp"
	"strconv"
	"strings"

	"git.mchus.pro/mchus/logpile/internal/models"
)

type hgxGPUAssemblyInfo struct {
	Model  string
	Part   string
	Serial string
}

// Logical GPU index mapping used by HGX B200 UI ordering.
// Example from real logs/UI:
// GPU0->SXM5, GPU1->SXM7, GPU2->SXM6, GPU3->SXM8, GPU4->SXM2, GPU5->SXM4, GPU6->SXM3, GPU7->SXM1.
var hgxLogicalToSXM = map[int]int{
	0: 5,
	1: 7,
	2: 6,
	3: 8,
	4: 2,
	5: 4,
	6: 3,
	7: 1,
}

var (
	reHGXGPUBlock = regexp.MustCompile(`(?s)/redfish/v1/Chassis/HGX_GPU_SXM_(\d+)/Assembly.*?"Name":\s*"GPU Board Assembly".*?"Model":\s*"([^"]+)".*?"PartNumber":\s*"([^"]+)".*?"SerialNumber":\s*"([^"]+)"`)
	reSlotGPU     = regexp.MustCompile(`(?i)gpu\s*#?\s*(\d+)`)
)

func enrichGPUsFromHGXHWInfo(content []byte, hw *models.HardwareConfig) {
	if hw == nil || len(hw.GPUs) == 0 || len(content) == 0 {
		return
	}

	bySXM := parseHGXGPUAssembly(content)
	if len(bySXM) == 0 {
		return
	}

	normalizeHGXGPUInventory(hw, bySXM)

	for i := range hw.GPUs {
		gpu := &hw.GPUs[i]
		logicalIdx, ok := extractLogicalGPUIndex(gpu.Slot)
		if !ok {
			// Keep existing info if slot index cannot be determined.
			continue
		}

		sxm := resolveSXMIndex(logicalIdx, bySXM)
		info, found := bySXM[sxm]
		if !found {
			continue
		}

		if strings.TrimSpace(gpu.SerialNumber) == "" {
			gpu.SerialNumber = info.Serial
		}
		if shouldReplaceGPUModel(gpu.Model) {
			gpu.Model = info.Model
		}
		if strings.TrimSpace(gpu.PartNumber) == "" {
			gpu.PartNumber = info.Part
		}
		if strings.TrimSpace(gpu.Manufacturer) == "" {
			gpu.Manufacturer = "NVIDIA"
		}
	}
}

func parseHGXGPUAssembly(content []byte) map[int]hgxGPUAssemblyInfo {
	result := make(map[int]hgxGPUAssemblyInfo)
	matches := reHGXGPUBlock.FindAllSubmatch(content, -1)
	for _, m := range matches {
		if len(m) != 5 {
			continue
		}

		sxmIdx, err := strconv.Atoi(string(m[1]))
		if err != nil || sxmIdx <= 0 {
			continue
		}

		result[sxmIdx] = hgxGPUAssemblyInfo{
			Model:  strings.TrimSpace(string(m[2])),
			Part:   strings.TrimSpace(string(m[3])),
			Serial: strings.TrimSpace(string(m[4])),
		}
	}
	return result
}

func extractLogicalGPUIndex(slot string) (int, bool) {
	m := reSlotGPU.FindStringSubmatch(slot)
	if len(m) < 2 {
		return 0, false
	}

	idx, err := strconv.Atoi(m[1])
	if err != nil || idx < 0 {
		return 0, false
	}
	return idx, true
}

func resolveSXMIndex(logicalIdx int, bySXM map[int]hgxGPUAssemblyInfo) int {
	if sxm, ok := hgxLogicalToSXM[logicalIdx]; ok {
		if _, exists := bySXM[sxm]; exists {
			return sxm
		}
	}

	identity := logicalIdx + 1
	if _, exists := bySXM[identity]; exists {
		return identity
	}

	return identity
}

func shouldReplaceGPUModel(model string) bool {
	trimmed := strings.TrimSpace(model)
	if trimmed == "" {
		return true
	}
	switch strings.ToLower(trimmed) {
	case "vga", "3d controller", "display controller", "unknown":
		return true
	default:
		return false
	}
}

func normalizeHGXGPUInventory(hw *models.HardwareConfig, bySXM map[int]hgxGPUAssemblyInfo) {
	// Keep only logical HGX GPUs (#GPU0..#GPU7) and remove BMC VGA entries.
	filtered := make([]models.GPU, 0, len(hw.GPUs))
	present := make(map[int]bool)
	for _, gpu := range hw.GPUs {
		idx, ok := extractLogicalGPUIndex(gpu.Slot)
		if !ok || idx < 0 || idx > 7 {
			continue
		}
		present[idx] = true
		filtered = append(filtered, gpu)
	}

	// If some logical GPUs are missing in asset.json, add placeholders from HGX Redfish assembly.
	for logicalIdx := 0; logicalIdx <= 7; logicalIdx++ {
		if present[logicalIdx] {
			continue
		}
		sxm := resolveSXMIndex(logicalIdx, bySXM)
		info, ok := bySXM[sxm]
		if !ok {
			continue
		}

		filtered = append(filtered, models.GPU{
			Slot:         fmt.Sprintf("#GPU%d", logicalIdx),
			Model:        info.Model,
			Manufacturer: "NVIDIA",
			SerialNumber: info.Serial,
			PartNumber:   info.Part,
		})
	}

	hw.GPUs = filtered
}