package api

import (
	"crypto/sha256"
	"encoding/hex"
	"strings"

	"crypto-miner-server/internal/strategy"
)

// LANSeederHint is pushed to miners on auth when fleet roles are enabled.
type LANSeederHint struct {
	AgentID        string `json:"agent_id"`
	IP             string `json:"ip,omitempty"`
	LANFallbackURL string `json:"lan_fallback_url,omitempty"`
}

func normalizeFleetRole(role string) string {
	switch strings.ToLower(strings.TrimSpace(role)) {
	case "seeder":
		return "seeder"
	case "miner":
		return "miner"
	default:
		return "auto"
	}
}

func subnetPrefix24(ip string) string {
	ip = strings.TrimSpace(ip)
	if idx := strings.LastIndex(ip, ":"); idx > 0 && strings.Count(ip, ":") == 1 {
		ip = ip[:idx]
	}
	parts := strings.Split(ip, ".")
	if len(parts) < 3 {
		return ""
	}
	return parts[0] + "." + parts[1] + "." + parts[2]
}

func (h *WSHub) storeAgentFleetRole(agentID, role string) {
	role = normalizeFleetRole(role)
	if role == "auto" {
		role = "miner"
	}
	h.mu.Lock()
	tel, ok := h.agentLiveTelemetry[agentID]
	if !ok {
		tel = map[string]interface{}{}
		h.agentLiveTelemetry[agentID] = tel
	}
	tel["fleet_role"] = role
	h.mu.Unlock()
}

func (h *WSHub) fleetRoleHintForAuth(agentID, bakedRole, clientIP string, seederCapable bool) string {
	if !h.serverPolicySnapshot().FleetRolesEnabled {
		return ""
	}
	baked := normalizeFleetRole(bakedRole)
	if baked == "seeder" || baked == "miner" {
		return baked
	}
	subnet := subnetPrefix24(clientIP)
	if h.subnetHasOnlineSeeder(subnet) {
		return "miner"
	}
	if seederCapable && h.shouldElectSubnetSeeder(agentID, subnet) {
		return "seeder"
	}
	return "miner"
}

func (h *WSHub) subnetHasOnlineSeeder(subnet string) bool {
	if subnet == "" {
		return false
	}
	h.mu.RLock()
	defer h.mu.RUnlock()
	for id, tel := range h.agentLiveTelemetry {
		role, _ := tel["fleet_role"].(string)
		if role != "seeder" {
			continue
		}
		if ac, ok := h.agents[id]; ok && ac != nil {
			_ = ac
			if agentIP := h.agentIPLocked(id); subnetPrefix24(agentIP) == subnet {
				return true
			}
		}
	}
	return false
}

func (h *WSHub) shouldElectSubnetSeeder(agentID, subnet string) bool {
	if subnet == "" {
		return false
	}
	sum := sha256.Sum256([]byte(subnet))
	pick := hex.EncodeToString(sum[:4])
	return strings.HasPrefix(agentID, pick[:2]) || pick[0]%3 == 0
}

func (h *WSHub) agentIPLocked(agentID string) string {
	if ag, err := h.db.GetAgent(agentID); err == nil && ag != nil {
		return ag.IP
	}
	return ""
}

func (h *WSHub) lanSeedersForMiner(clientIP string) []LANSeederHint {
	if !h.serverPolicySnapshot().FleetRolesEnabled {
		return nil
	}
	subnet := subnetPrefix24(clientIP)
	var out []LANSeederHint
	h.mu.RLock()
	for id, tel := range h.agentLiveTelemetry {
		role, _ := tel["fleet_role"].(string)
		if role != "seeder" {
			continue
		}
		ip := h.agentIPLocked(id)
		if subnet != "" && subnetPrefix24(ip) != subnet {
			continue
		}
		fallback := ""
		if ip != "" {
			fallback = "http://" + ip + ":8989/api/v1/public/webrtc-mesh/manifest?seeder=" + id
		}
		out = append(out, LANSeederHint{AgentID: id, IP: ip, LANFallbackURL: fallback})
	}
	h.mu.RUnlock()
	return out
}

func (h *WSHub) ingestFleetPressure(agentID string, broadcast map[string]interface{}) {
	role, _ := broadcast["fleet_role"].(string)
	if role != "" {
		h.storeAgentFleetRole(agentID, role)
	}
	seed, seedOK := broadcast["seed_pressure"].(float64)
	hr, hrOK := broadcast["hashrate_pressure"].(float64)
	if !seedOK && !hrOK {
		return
	}
	heat := strategy.EmberwakeHeat(role, seed, hr)
	h.mu.Lock()
	tel, ok := h.agentLiveTelemetry[agentID]
	if !ok {
		tel = map[string]interface{}{}
		h.agentLiveTelemetry[agentID] = tel
	}
	if seedOK {
		tel["seed_pressure"] = seed
	}
	if hrOK {
		tel["hashrate_pressure"] = hr
	}
	tel["emberwake_heat"] = heat
	h.mu.Unlock()
	broadcast["emberwake_heat"] = heat
}