package service

import (
	edgenode "iop/apps/edge/internal/node"
	"iop/packages/go/config"
	iop "iop/proto/gen/iop"
)

// getSnapshotForNodeLocked builds provider snapshots for nodeID without
// acquiring m.mu. The caller must hold m.mu before invoking this variant so
// that runtime config and queue state are observed atomically under a single
// critical section. Used by the status path that linearizes the queue → service
// reader-writer boundary.
func (m *modelQueueManager) getSnapshotForNodeLocked(nodeID string, rec *edgenode.NodeRecord) []*iop.ProviderSnapshot {
	var snaps []*iop.ProviderSnapshot

	// Catalog-first: nodes with a providers[] catalog emit only catalog snapshots.
	// Adapter snapshots (sections 1-4) are omitted to prevent duplicate metrics
	// when a node has both adapter instances and provider-pool catalog entries.
	if len(rec.Providers) > 0 {
		// Precompute current-candidate pressure once so the catalog loop reads
		// live candidate universe without rescanning the full queue per provider.
		pressure := m.providerQueuePressureLocked()
		for _, prov := range rec.Providers {
			if prov.ID == "" {
				continue
			}

			servedModels := make([]string, len(prov.Models))
			copy(servedModels, prov.Models)
			lifecycleCaps := make([]string, len(prov.LifecycleCapabilities))
			copy(lifecycleCaps, prov.LifecycleCapabilities)

			// Disabled providers appear in the snapshot with status=disabled and
			// effective capacity 0 so operators can see the switch state.
			if !config.ProviderEnabled(prov) {
				snaps = append(snaps, &iop.ProviderSnapshot{
					Adapter:               prov.Adapter,
					Status:                "disabled",
					Capacity:              0,
					InFlight:              0,
					Queued:                0,
					Id:                    prov.ID,
					Type:                  prov.Type,
					Category:              string(prov.Category),
					ServedModels:          servedModels,
					Health:                "disabled",
					LoadRatio:             0,
					LifecycleCapabilities: lifecycleCaps,
					LongContextCapacity:   0,
					LongInFlight:          0,
					LongQueued:            0,
				})
				continue
			}

			capVal := prov.Capacity
			inflight, queued, longInflight, longQueued := m.providerSnapshotStatsLocked(nodeID, prov.ID, pressure)

			var loadRatio float32
			if capVal > 0 {
				loadRatio = float32(inflight) / float32(capVal)
			}

			snaps = append(snaps, &iop.ProviderSnapshot{
				Adapter:               prov.Adapter,
				Status:                "available",
				Capacity:              int32(capVal),
				InFlight:              int32(inflight),
				Queued:                int32(queued),
				Id:                    prov.ID,
				Type:                  prov.Type,
				Category:              string(prov.Category),
				ServedModels:          servedModels,
				Health:                prov.Health,
				LoadRatio:             loadRatio,
				LifecycleCapabilities: lifecycleCaps,
				LongContextCapacity:   int32(prov.LongContextCapacity),
				LongInFlight:          int32(longInflight),
				LongQueued:            int32(longQueued),
			})
		}
		return snaps
	}

	// Legacy adapter snapshots for nodes with no providers catalog.
	concurrencyFallback := 1
	if rec.Runtime.Concurrency > 0 {
		concurrencyFallback = rec.Runtime.Concurrency
	}

	// 1. CLI
	if rec.Adapters.CLI.Enabled {
		capVal := concurrencyFallback
		inflight, queued := m.getStatsForAdapterLocked(nodeID, rec, "cli")
		snaps = append(snaps, &iop.ProviderSnapshot{
			Adapter:  "cli",
			Status:   "available",
			Capacity: int32(capVal),
			InFlight: int32(inflight),
			Queued:   int32(queued),
		})
	}

	// 2. Ollama
	for _, inst := range rec.Adapters.OllamaInstances {
		if !inst.Enabled {
			continue
		}
		name := inst.Name
		if name == "" {
			name = "ollama"
		}
		capVal := inst.Capacity
		if capVal <= 0 {
			capVal = concurrencyFallback
		}
		inflight, queued := m.getStatsForAdapterLocked(nodeID, rec, name)
		snaps = append(snaps, &iop.ProviderSnapshot{
			Adapter:  name,
			Status:   "available",
			Capacity: int32(capVal),
			InFlight: int32(inflight),
			Queued:   int32(queued),
		})
	}

	// 3. vLLM
	for _, inst := range rec.Adapters.VllmInstances {
		if !inst.Enabled {
			continue
		}
		name := inst.Name
		if name == "" {
			name = "vllm"
		}
		capVal := inst.Capacity
		if capVal <= 0 {
			capVal = concurrencyFallback
		}
		inflight, queued := m.getStatsForAdapterLocked(nodeID, rec, name)
		snaps = append(snaps, &iop.ProviderSnapshot{
			Adapter:  name,
			Status:   "available",
			Capacity: int32(capVal),
			InFlight: int32(inflight),
			Queued:   int32(queued),
		})
	}

	// 4. OpenAI Compat
	for _, inst := range rec.Adapters.OpenAICompatInstances {
		if !inst.Enabled {
			continue
		}
		name := inst.Name
		if name == "" {
			name = "openai_compat"
		}
		capVal := inst.Capacity
		if capVal <= 0 {
			capVal = concurrencyFallback
		}
		inflight, queued := m.getStatsForAdapterLocked(nodeID, rec, name)
		snaps = append(snaps, &iop.ProviderSnapshot{
			Adapter:  name,
			Status:   "available",
			Capacity: int32(capVal),
			InFlight: int32(inflight),
			Queued:   int32(queued),
		})
	}

	return snaps
}

func (m *modelQueueManager) getSnapshotForNode(nodeID string, rec *edgenode.NodeRecord) []*iop.ProviderSnapshot {
	m.mu.Lock()
	defer m.mu.Unlock()
	return m.getSnapshotForNodeLocked(nodeID, rec)
}

// providerPressure accumulates queued and long-queued candidate counts for
// a single (nodeID, providerID) pair across all model groups. Built once per
// snapshot so the catalog loop can read both dimensions without rescanning
// the full queue.
type providerPressure struct {
	queued     int
	longQueued int
}

// providerPressureMap is a nested map keyed by (nodeID, providerID) that
// holds queued/longQueued candidate counts for every provider referenced by
// pending items. Built once per snapshot via providerQueuePressureLocked.
type providerPressureMap map[string]map[string]*providerPressure

// providerQueuePressureLocked aggregates candidate pressure across all model
// groups using the live candidate resolver for each pending item. One item's
// (nodeID, providerID) pair is counted at most once regardless of how many
// times it appears in that item's candidate slice. Resolver error or an empty
// result excludes the item from the aggregation (no stale snapshot fallback).
// Must be called with m.mu held.
func (m *modelQueueManager) providerQueuePressureLocked() providerPressureMap {
	pm := make(providerPressureMap)
	for _, group := range m.groups {
		for _, item := range group.queue {
			candidates, ok := m.resolveQueuedCandidatesLocked(item)
			if !ok {
				continue
			}
			seen := make(map[nodeProvKey]bool, len(candidates))
			for i := range candidates {
				c := &candidates[i]
				if c.entry == nil {
					continue
				}
				key := nodeProvKey{nodeID: c.entry.NodeID, providerID: c.providerID}
				if seen[key] {
					continue
				}
				seen[key] = true
				if pm[key.nodeID] == nil {
					pm[key.nodeID] = make(map[string]*providerPressure)
				}
				pp := pm[key.nodeID][key.providerID]
				if pp == nil {
					pp = &providerPressure{}
					pm[key.nodeID][key.providerID] = pp
				}
				pp.queued++
				if item.long {
					pp.longQueued++
				}
			}
		}
	}
	return pm
}

// providerSnapshotStatsLocked returns lease-backed inflight counts and the
// pre-aggregated candidate pressure for (nodeID, providerID). The pressure
// map is built once per snapshot by providerQueuePressureLocked. Must be
// called with m.mu held.
func (m *modelQueueManager) providerSnapshotStatsLocked(nodeID, providerID string, pressure providerPressureMap) (inFlight, queued, longInFlight, longQueued int) {
	key := providerResourceKey{nodeID: nodeID, providerID: providerID}
	if res, ok := m.resources[key]; ok {
		inFlight = res.inFlight
		longInFlight = res.longInFlight
	}
	if nodeMap, ok := pressure[nodeID]; ok {
		if pp, ok := nodeMap[providerID]; ok {
			queued = pp.queued
			longQueued = pp.longQueued
		}
	}
	return
}

// nodeProvKey is a local dedup key inside providerQueuePressureLocked.
type nodeProvKey struct {
	nodeID     string
	providerID string
}

// getStatsForProviderLocked returns lease-backed in-flight and candidate
// pressure for a provider-pool provider identified by (nodeID, providerID).
// queued is not a provider-owned queue depth: one Edge pending request is
// counted once for every provider candidate it includes, so queued values
// across provider snapshots are not additive. Must be called with m.mu held.
//
// Deprecated: prefer providerQueuePressureLocked + providerSnapshotStatsLocked
// for snapshot path. Kept for direct test usage that does not build a pressure
// map.
func (m *modelQueueManager) getStatsForProviderLocked(nodeID, providerID string) (inFlight, queued int) {
	key := providerResourceKey{nodeID: nodeID, providerID: providerID}
	if res, ok := m.resources[key]; ok {
		inFlight = res.inFlight
	}
	for _, group := range m.groups {
		for _, item := range group.queue {
			for _, c := range item.candidates {
				if c.entry.NodeID == nodeID && c.providerID == providerID {
					queued++
					break
				}
			}
		}
	}
	return
}

// getLongStatsForProviderLocked returns lease-backed long-context in-flight and
// long-request candidate pressure for a provider-pool provider identified by
// (nodeID, providerID). As with queued, one multi-candidate request may contribute
// to more than one provider snapshot. Must be called with m.mu held.
func (m *modelQueueManager) getLongStatsForProviderLocked(nodeID, providerID string) (longInFlight, longQueued int) {
	key := providerResourceKey{nodeID: nodeID, providerID: providerID}
	if res, ok := m.resources[key]; ok {
		longInFlight = res.longInFlight
	}
	for _, group := range m.groups {
		for _, item := range group.queue {
			if item.long {
				for _, c := range item.candidates {
					if c.entry.NodeID == nodeID && c.providerID == providerID {
						longQueued++
						break
					}
				}
			}
		}
	}
	return
}

// longInFlightForProvider returns the long-context in-flight count for a provider,
// acquiring the manager lock. Exposed for status/snapshot reporting and tests.
func (m *modelQueueManager) longInFlightForProvider(nodeID, providerID string) int {
	m.mu.Lock()
	defer m.mu.Unlock()
	longInFlight, _ := m.getLongStatsForProviderLocked(nodeID, providerID)
	return longInFlight
}

func (m *modelQueueManager) getStatsForAdapterLocked(nodeID string, rec *edgenode.NodeRecord, adapterName string) (inFlight, queued int) {
	for _, group := range m.groups {
		canonical, ok := resolveSnapshotAdapterName(rec, group.adapter, group.target)
		if ok && canonical == adapterName {
			if val, ok := group.inflight[nodeID]; ok {
				inFlight += val
			}
			for _, item := range group.queue {
				for _, c := range item.candidates {
					if c.entry.NodeID == nodeID {
						queued++
						break
					}
				}
			}
		}
	}
	return
}

// resolveSnapshotAdapterName returns the adapter/instance key used to match
// queue state for a provider snapshot.
// When adapterType is empty it falls back to the provider id (target) so that
// queue stats are still resolved instead of being dropped on an empty key.
func resolveSnapshotAdapterName(rec *edgenode.NodeRecord, adapterType, target string) (string, bool) {
	// Fallback to provider id when adapter is not set.
	if adapterType == "" {
		adapterType = target
	}
	if rec == nil {
		return adapterType, true
	}

	// 1. Exact instance Name match (highest priority).
	for _, inst := range rec.Adapters.OllamaInstances {
		if inst.Name == adapterType {
			return adapterType, true
		}
	}
	for _, inst := range rec.Adapters.VllmInstances {
		if inst.Name == adapterType {
			return adapterType, true
		}
	}
	for _, inst := range rec.Adapters.OpenAICompatInstances {
		if inst.Name == adapterType {
			return adapterType, true
		}
	}

	// 2. Type-name route.
	switch adapterType {
	case "ollama":
		var enabled []string
		for _, inst := range rec.Adapters.OllamaInstances {
			if inst.Enabled {
				name := inst.Name
				if name == "" {
					name = "ollama"
				}
				enabled = append(enabled, name)
			}
		}
		switch len(enabled) {
		case 0:
			return "ollama", true
		case 1:
			return enabled[0], true
		default:
			return "", false
		}

	case "vllm":
		var enabled []string
		for _, inst := range rec.Adapters.VllmInstances {
			if inst.Enabled {
				name := inst.Name
				if name == "" {
					name = "vllm"
				}
				enabled = append(enabled, name)
			}
		}
		switch len(enabled) {
		case 0:
			return "vllm", true
		case 1:
			return enabled[0], true
		default:
			return "", false
		}

	case "openai_compat":
		var enabled []string
		for _, inst := range rec.Adapters.OpenAICompatInstances {
			if inst.Enabled {
				name := inst.Name
				if name == "" {
					name = "openai_compat"
				}
				enabled = append(enabled, name)
			}
		}
		switch len(enabled) {
		case 0:
			return "openai_compat", true
		case 1:
			return enabled[0], true
		default:
			return "", false
		}

	case "cli":
		return "cli", true

	default:
		return adapterType, true
	}
}