package inspur

import (
	"regexp"
	"sort"
	"strconv"
	"strings"

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

var (
	reNVMeEventIndex = regexp.MustCompile(`(?i)\bNvmeIndex\s*:\s*(\d+)\b`)
	reNVMeLabelIndex = regexp.MustCompile(`(?i)\bNVME(\d+)\b`)
	reOBStorageSlot  = regexp.MustCompile(`(?i)^OB(\d+)$`)
)

// applyStorageStatusFromEvents projects source-backed NVMe fault state onto
// the physical storage inventory. Healthy-looking presence data is not enough
// to claim OK, so unaffected drives keep their existing (usually Unknown)
// status. dev_status.log, when available, is the authoritative active-fault
// snapshot; IDL supplies transition history.
func applyStorageStatusFromEvents(hw *models.HardwareConfig, events, currentDeviceEvents []models.Event, currentSnapshotAvailable bool) {
	if hw == nil || len(hw.Storage) == 0 {
		return
	}

	storageByIndex := make(map[int]*models.Storage)
	for i := range hw.Storage {
		if idx, ok := storageIndexFromSlot(hw.Storage[i].Slot); ok {
			storageByIndex[idx] = &hw.Storage[i]
		}
	}

	relevant := relevantStorageFaultEvents(events)
	sort.SliceStable(relevant, func(i, j int) bool {
		return relevant[i].Timestamp.Before(relevant[j].Timestamp)
	})
	touched := make(map[int]bool)
	for _, event := range relevant {
		idx, ok := storageFaultIndex(event)
		storage := storageByIndex[idx]
		if !ok || storage == nil {
			continue
		}
		touched[idx] = true
		applyStorageFaultTransition(storage, event)
	}

	if !currentSnapshotAvailable {
		return
	}

	active := make(map[int]models.Event)
	for _, event := range relevantStorageFaultEvents(currentDeviceEvents) {
		idx, ok := storageFaultIndex(event)
		if !ok || eventIsDeassert(event) {
			continue
		}
		active[idx] = event
	}
	for idx := range touched {
		if _, ok := active[idx]; ok {
			continue
		}
		storage := storageByIndex[idx]
		storage.Status = "Unknown"
		storage.ErrorDescription = ""
	}
	for idx, event := range active {
		if storage := storageByIndex[idx]; storage != nil {
			applyStorageFaultTransition(storage, event)
		}
	}
}

func relevantStorageFaultEvents(events []models.Event) []models.Event {
	out := make([]models.Event, 0)
	for _, event := range events {
		if _, ok := storageFaultIndex(event); ok {
			out = append(out, event)
		}
	}
	return out
}

func storageFaultIndex(event models.Event) (int, bool) {
	description := strings.TrimSpace(event.Description)
	lower := strings.ToLower(description)
	if !strings.Contains(lower, "drive fault") && !strings.EqualFold(strings.TrimSpace(event.ID), "0DFF0702") {
		return 0, false
	}
	for _, re := range []*regexp.Regexp{reNVMeEventIndex, reNVMeLabelIndex} {
		match := re.FindStringSubmatch(description)
		if len(match) != 2 {
			continue
		}
		idx, err := strconv.Atoi(match[1])
		if err == nil && idx >= 0 {
			return idx, true
		}
	}
	return 0, false
}

func storageIndexFromSlot(slot string) (int, bool) {
	match := reOBStorageSlot.FindStringSubmatch(strings.TrimSpace(slot))
	if len(match) != 2 {
		return 0, false
	}
	oneBased, err := strconv.Atoi(match[1])
	if err != nil || oneBased < 1 {
		return 0, false
	}
	return oneBased - 1, true
}

func applyStorageFaultTransition(storage *models.Storage, event models.Event) {
	status := "Critical"
	description := strings.TrimSpace(event.Description)
	if eventIsDeassert(event) {
		status = "Unknown"
		description = ""
	}
	if storage.Status != status && !event.Timestamp.IsZero() {
		storage.StatusHistory = append(storage.StatusHistory, models.StatusHistoryEntry{
			Status:    status,
			ChangedAt: event.Timestamp,
			Details:   strings.TrimSpace(event.Description),
		})
		ts := event.Timestamp
		storage.StatusChangedAt = &ts
	}
	storage.Status = status
	storage.ErrorDescription = description
	if !event.Timestamp.IsZero() {
		ts := event.Timestamp
		storage.StatusCheckedAt = &ts
	}
}

func eventIsDeassert(event models.Event) bool {
	return strings.Contains(strings.ToLower(event.EventType+" "+event.RawData), "deassert")
}