// Parses log/bmc/diagnose/OtrdDiagnoseComponent.json, an HGX BMC structural
// snapshot of PCIe topology (present GPUs/NICs/NVMe, negotiated link state).
// This is a direct point-in-time source for GPU presence and PCIe link
// degradation, independent of SEL/IDL alarm history.
package inspur

import (
	"encoding/json"
	"fmt"
	"strings"

	"git.mchus.pro/mchus/logpile/internal/models"
	"git.mchus.pro/mchus/logpile/internal/parser/vendors/pciids"
)

// otrdDiagnosePCIeEntry mirrors the relevant fields of "Pcie Device Info"
// entries in OtrdDiagnoseComponent.json.
type otrdDiagnosePCIeEntry struct {
	LocString        string `json:"LocString"`
	PcieSlot         int    `json:"PcieSlot"`
	PresentStatus    int    `json:"PresentStatus"`
	VendorId         int    `json:"VendorId"`
	DeviceId         int    `json:"DeviceId"`
	BusNumber        int    `json:"BusNumber"`
	DeviceNumber     int    `json:"DeviceNumber"`
	FunctionNumber   int    `json:"FunctionNumber"`
	CurrentLinkSpeed int    `json:"CurrentLinkSpeed"`
	MaxLinkSpeed     int    `json:"MaxLinkSpeed"`
	NegotiatedLinkWidth int `json:"NegotiatedLinkWidth"`
	MaxLinkWidth     int    `json:"MaxLinkWidth"`
	SerialNumber     *string `json:"SerialNumber"`
	PartNumber       *string `json:"PartNumber"`
}

type otrdDiagnoseComponent struct {
	PcieDeviceInfo []otrdDiagnosePCIeEntry `json:"Pcie Device Info"`
}

// ParseOtrdDiagnosePCIe parses the "Pcie Device Info" array from
// OtrdDiagnoseComponent.json into PCIe device inventory entries.
func ParseOtrdDiagnosePCIe(content []byte) []models.PCIeDevice {
	var doc otrdDiagnoseComponent
	if err := json.Unmarshal(content, &doc); err != nil {
		return nil
	}

	devices := make([]models.PCIeDevice, 0, len(doc.PcieDeviceInfo))
	for _, e := range doc.PcieDeviceInfo {
		present := e.PresentStatus == 1
		_, deviceName := pciids.DeviceInfo(e.VendorId, e.DeviceId)
		deviceClass := normalizeModelLabel(deviceName)
		if strings.Contains(strings.ToUpper(deviceName), "NVIDIA") {
			deviceClass = "GPU (" + deviceName + ")"
		}

		serial := ""
		if e.SerialNumber != nil {
			serial = strings.TrimSpace(*e.SerialNumber)
		}
		partNum := ""
		if e.PartNumber != nil {
			partNum = strings.TrimSpace(*e.PartNumber)
		}

		status := ""
		if present && isLinkDegraded(e) {
			status = "Link Degraded"
		}

		devices = append(devices, models.PCIeDevice{
			Slot:         e.LocString,
			VendorID:     e.VendorId,
			DeviceID:     e.DeviceId,
			BDF:          formatBDF(e.BusNumber, e.DeviceNumber, e.FunctionNumber),
			DeviceClass:  deviceClass,
			Manufacturer: normalizeModelLabel(pciids.VendorName(e.VendorId)),
			LinkWidth:    e.NegotiatedLinkWidth,
			LinkSpeed:    fmt.Sprintf("GEN%d", e.CurrentLinkSpeed),
			MaxLinkWidth: e.MaxLinkWidth,
			MaxLinkSpeed: fmt.Sprintf("GEN%d", e.MaxLinkSpeed),
			PartNumber:   partNum,
			SerialNumber: serial,
			Present:      &present,
			Status:       status,
		})
	}

	return devices
}

func isLinkDegraded(e otrdDiagnosePCIeEntry) bool {
	if e.MaxLinkSpeed > 0 && e.CurrentLinkSpeed < e.MaxLinkSpeed {
		return true
	}
	if e.MaxLinkWidth > 0 && e.NegotiatedLinkWidth < e.MaxLinkWidth {
		return true
	}
	return false
}

// BuildPCIeLinkDegradationEvents emits a Warning event for every PCIe device
// present in OtrdDiagnoseComponent.json but running below its negotiated max
// link speed/width (e.g. a GPU baseboard degrading from Gen5 x16 to a lower
// state), so the log viewer surfaces the same signal the IDL alarms would.
func BuildPCIeLinkDegradationEvents(devices []models.PCIeDevice) []models.Event {
	var events []models.Event
	for _, d := range devices {
		if d.Present == nil || !*d.Present || d.Status != "Link Degraded" {
			continue
		}
		events = append(events, models.Event{
			ID:          fmt.Sprintf("pcie_link_degraded_%s", strings.TrimPrefix(d.Slot, "#")),
			Source:      "PCIe Diagnose",
			SensorType:  "pcie_link",
			EventType:   "Link Degraded",
			Severity:    models.SeverityWarning,
			Description: fmt.Sprintf("%s: link degraded to %s x%d (max %s x%d)", d.Slot, d.LinkSpeed, d.LinkWidth, d.MaxLinkSpeed, d.MaxLinkWidth),
		})
	}
	return events
}