package alertmanager

import (
	"sort"
	"time"

	"github.com/prymitive/karma/internal/config"
	"github.com/prymitive/karma/internal/models"
	"github.com/prymitive/karma/internal/slices"
	"github.com/prymitive/karma/internal/transform"
)

// DedupAlerts will collect alert groups from all defined Alertmanager
// upstreams and deduplicate them, so we only return unique alerts
func DedupAlerts() []models.AlertGroup {
	uniqueGroups := map[string][]models.AlertGroup{}

	upstreams := GetAlertmanagers()
	for _, am := range upstreams {
		groups := am.Alerts()
		for _, ag := range groups {
			if _, found := uniqueGroups[ag.ID]; !found {
				uniqueGroups[ag.ID] = []models.AlertGroup{}
			}
			uniqueGroups[ag.ID] = append(uniqueGroups[ag.ID], ag)
		}
	}

	dedupedGroups := []models.AlertGroup{}
	alertStates := map[string][]string{}
	for _, agList := range uniqueGroups {
		alerts := map[string]models.Alert{}
		for _, ag := range agList {
			for _, alert := range ag.Alerts {
				alert := alert // scopelint pin
				// remove all alerts for receiver(s) that the user doesn't
				// want to see in the UI
				if transform.StripReceivers(config.Config.Receivers.Keep, config.Config.Receivers.Strip, alert.Receiver) {
					continue
				}
				alertLFP := alert.LabelsFingerprint()
				a, found := alerts[alertLFP]
				if found {
					// if we already have an alert with the same fp then just append
					// alertmanager instances to it, this way we end up with all instances
					// for each unique alert merged into a single alert with all
					// alertmanager instances attached to it
					a.Alertmanager = append(a.Alertmanager, alert.Alertmanager...)
					// set startsAt to the earliest value we have
					if alert.StartsAt.Before(a.StartsAt) {
						a.StartsAt = alert.StartsAt
					}
					// update map
					alerts[alertLFP] = a
					// and append alert state to the slice
					alertStates[alertLFP] = append(alertStates[alertLFP], alert.State)
				} else {
					alerts[alertLFP] = models.Alert(alert)
					// seed alert state slice
					alertStates[alertLFP] = []string{alert.State}
				}
			}
		}
		// skip empty groups
		if len(alerts) == 0 {
			continue
		}
		ag := models.AlertGroup(agList[0])
		ag.Alerts = make(models.AlertList, 0, len(alerts))
		for _, alert := range alerts {
			alert := alert // scopelint pin
			// strip labels and annotations user doesn't want to see in the UI
			alert.Labels = transform.StripLables(config.Config.Labels.Keep, config.Config.Labels.Strip, alert.Labels)
			alert.Annotations = transform.StripAnnotations(config.Config.Annotations.Keep, config.Config.Annotations.Strip, alert.Annotations)
			// calculate final alert state based on the most important value found
			// in the list of states from all instances
			alertLFP := alert.LabelsFingerprint()
			if slices.StringInSlice(alertStates[alertLFP], models.AlertStateActive) {
				alert.State = models.AlertStateActive
			} else if slices.StringInSlice(alertStates[alertLFP], models.AlertStateSuppressed) {
				alert.State = models.AlertStateSuppressed
			} else {
				alert.State = models.AlertStateUnprocessed
			}
			// sort Alertmanager instances for every alert
			sort.Slice(alert.Alertmanager, func(i, j int) bool {
				return alert.Alertmanager[i].Name < alert.Alertmanager[j].Name
			})
			ag.Alerts = append(ag.Alerts, alert)
		}
		ag.Hash = ag.ContentFingerprint()
		dedupedGroups = append(dedupedGroups, ag)
	}

	return dedupedGroups
}

// DedupKnownLabels returns a deduplicated slice of all known label names
func DedupSilences() []models.ManagedSilence {
	silenceByCluster := map[string]map[string]models.Silence{}
	upstreams := GetAlertmanagers()

	for _, am := range upstreams {
		for id, silence := range am.Silences() {
			cluster := am.ClusterName()

			if _, found := silenceByCluster[cluster]; !found {
				silenceByCluster[cluster] = map[string]models.Silence{}
			}

			if _, ok := silenceByCluster[cluster][id]; !ok {
				silenceByCluster[cluster][id] = silence
			}
		}
	}

	now := time.Now()
	dedupedSilences := []models.ManagedSilence{}
	for cluster, silenceMap := range silenceByCluster {
		s := make([]models.ManagedSilence, 0, len(silenceMap))
		for _, silence := range silenceMap {
			managedSilence := models.ManagedSilence{
				Cluster:   cluster,
				IsExpired: silence.EndsAt.Before(now),
				Silence:   silence,
			}
			s = append(s, managedSilence)
		}
		dedupedSilences = append(dedupedSilences, s...)
	}
	return dedupedSilences
}

// DedupColors returns a color map merged from all Alertmanager upstream color
// maps
func DedupColors() models.LabelsColorMap {
	dedupedColors := models.LabelsColorMap{}

	upstreams := GetAlertmanagers()

	for _, am := range upstreams {
		colors := am.Colors()
		// map[string]map[string]LabelColors
		for labelName, valueMap := range colors {
			if _, found := dedupedColors[labelName]; !found {
				dedupedColors[labelName] = make(map[string]models.LabelColors, len(valueMap))
			}
			for labelVal, labelColors := range valueMap {
				if _, found := dedupedColors[labelName][labelVal]; !found {
					dedupedColors[labelName][labelVal] = labelColors
				}
			}
		}
	}

	return dedupedColors
}

// DedupAutocomplete returns a list of autocomplete hints merged from all
// Alertmanager upstreams
func DedupAutocomplete() []models.Autocomplete {
	uniqueAutocomplete := map[string]*models.Autocomplete{}

	upstreams := GetAlertmanagers()

	for _, am := range upstreams {
		ac := am.Autocomplete()
		for _, hint := range ac {
			h, found := uniqueAutocomplete[hint.Value]
			if found {
				for _, token := range hint.Tokens {
					if !slices.StringInSlice(h.Tokens, token) {
						h.Tokens = append(h.Tokens, token)
					}
				}
			} else {
				uniqueAutocomplete[hint.Value] = &models.Autocomplete{
					Value:  hint.Value,
					Tokens: hint.Tokens,
				}
			}
		}
	}

	dedupedAutocomplete := make([]models.Autocomplete, 0, len(uniqueAutocomplete))
	for _, hint := range uniqueAutocomplete {
		dedupedAutocomplete = append(dedupedAutocomplete, *hint)
	}

	return dedupedAutocomplete
}

// DedupKnownLabels returns a deduplicated slice of all known label names
func DedupKnownLabels() []string {
	dedupedLabels := map[string]bool{}
	upstreams := GetAlertmanagers()

	for _, am := range upstreams {
		for _, key := range am.KnownLabels() {
			dedupedLabels[key] = true
		}
	}

	flatLabels := make([]string, 0, len(dedupedLabels))
	for key := range dedupedLabels {
		flatLabels = append(flatLabels, key)
	}
	return flatLabels
}

// DedupKnownLabelValues returns a list of all known values for label $name
func DedupKnownLabelValues(name string) []string {
	dedupedValues := map[string]bool{}
	upstreams := GetAlertmanagers()

	for _, am := range upstreams {
		for _, ag := range am.Alerts() {
			for _, alert := range ag.Alerts {
				if val, found := alert.Labels[name]; found {
					dedupedValues[val] = true
				}
			}
		}
	}

	flatValues := make([]string, 0, len(dedupedValues))
	for key := range dedupedValues {
		flatValues = append(flatValues, key)
	}
	return flatValues
}