package store

import (
	"encoding/json"
	"net"
	"net/url"
	"strings"
)

// SpeakerMeta holds well-known keys from bgp_speaker.meta_json.
type SpeakerMeta struct {
	AgentDomain                 string `json:"agent_domain,omitempty"`
	AgentSecret                 string `json:"agent_secret,omitempty"`
	AgentPort                   int    `json:"agent_port,omitempty"`
	NodeIPv4                    string `json:"node_ipv4,omitempty"`
	BirdBgpSourceIPv4           string `json:"bird_bgp_source_ipv4,omitempty"`
	BirdBgpSourceIPv6           string `json:"bird_bgp_source_ipv6,omitempty"`
	NodeEnrolledAt              string `json:"node_enrolled_at,omitempty"`
	LastDispatchAt              string `json:"last_dispatch_at,omitempty"`
	LastDispatchError           string `json:"last_dispatch_error,omitempty"`
	LastDispatchStatus          string `json:"last_dispatch_status,omitempty"`
	SyncStatus                  string `json:"sync_status,omitempty"`
	FirewallFailover            bool   `json:"firewall_failover,omitempty"`
	LastFirewallReplicateAt     string `json:"last_firewall_replicate_at,omitempty"`
	LastFirewallReplicateStatus string `json:"last_firewall_replicate_status,omitempty"`
	LastFirewallReplicateError  string `json:"last_firewall_replicate_error,omitempty"`
}

// ParseSpeakerMeta decodes meta_json object; unknown keys are ignored.
func ParseSpeakerMeta(metaJSON string) SpeakerMeta {
	raw := strings.TrimSpace(metaJSON)
	if raw == "" || raw == "{}" {
		return SpeakerMeta{}
	}
	var m SpeakerMeta
	_ = json.Unmarshal([]byte(raw), &m)
	if m.AgentPort == 0 {
		m.AgentPort = 8443
	}
	return m
}

// SpeakerMetaJSON marshals SpeakerMeta to a JSON object string.
func SpeakerMetaJSON(m SpeakerMeta) string {
	b, err := json.Marshal(m)
	if err != nil {
		return "{}"
	}
	return string(b)
}

// MergeSpeakerMetaJSON merges patch into existing meta_json string.
func MergeSpeakerMetaJSON(existing string, patch SpeakerMeta) string {
	cur := ParseSpeakerMeta(existing)
	if patch.AgentDomain != "" {
		cur.AgentDomain = patch.AgentDomain
	}
	if patch.AgentSecret != "" {
		cur.AgentSecret = patch.AgentSecret
	}
	if patch.AgentPort != 0 {
		cur.AgentPort = patch.AgentPort
	}
	if patch.NodeIPv4 != "" {
		cur.NodeIPv4 = patch.NodeIPv4
	}
	if patch.BirdBgpSourceIPv4 != "" {
		cur.BirdBgpSourceIPv4 = patch.BirdBgpSourceIPv4
	}
	if patch.BirdBgpSourceIPv6 != "" {
		cur.BirdBgpSourceIPv6 = patch.BirdBgpSourceIPv6
	}
	if patch.NodeEnrolledAt != "" {
		cur.NodeEnrolledAt = patch.NodeEnrolledAt
	}
	if patch.LastDispatchAt != "" {
		cur.LastDispatchAt = patch.LastDispatchAt
	}
	if patch.LastDispatchStatus == "ok" {
		cur.LastDispatchError = ""
	} else if patch.LastDispatchError != "" {
		cur.LastDispatchError = patch.LastDispatchError
	}
	if patch.LastDispatchStatus != "" {
		cur.LastDispatchStatus = patch.LastDispatchStatus
	}
	if patch.SyncStatus != "" {
		cur.SyncStatus = patch.SyncStatus
	}
	if patch.FirewallFailover {
		cur.FirewallFailover = true
	}
	if patch.LastFirewallReplicateAt != "" {
		cur.LastFirewallReplicateAt = patch.LastFirewallReplicateAt
	}
	if patch.LastFirewallReplicateStatus == "ok" {
		cur.LastFirewallReplicateError = ""
	} else if patch.LastFirewallReplicateError != "" {
		cur.LastFirewallReplicateError = patch.LastFirewallReplicateError
	}
	if patch.LastFirewallReplicateStatus != "" {
		cur.LastFirewallReplicateStatus = patch.LastFirewallReplicateStatus
	}
	return SpeakerMetaJSON(cur)
}

// IPv4FromEndpoint extracts an IPv4 from endpoint URL host when present.
func IPv4FromEndpoint(endpoint string) string {
	ep := strings.TrimSpace(endpoint)
	if ep == "" {
		return ""
	}
	if !strings.Contains(ep, "://") {
		ep = "https://" + ep
	}
	u, err := url.Parse(ep)
	if err != nil {
		return ""
	}
	host := strings.TrimSpace(u.Hostname())
	if host == "" {
		return ""
	}
	if ip := net.ParseIP(host); ip != nil && ip.To4() != nil {
		return ip.String()
	}
	return ""
}

// ValidIPv4 reports whether s is a dotted-quad IPv4 address.
func ValidIPv4(s string) bool {
	ip := net.ParseIP(strings.TrimSpace(s))
	return ip != nil && ip.To4() != nil
}

// AgentSyncURL returns HTTPS sync URL for a speaker with agent_domain configured.
func AgentSyncURL(meta SpeakerMeta) string {
	domain := strings.TrimSpace(meta.AgentDomain)
	if domain == "" {
		return ""
	}
	return "https://" + strings.TrimSuffix(domain, "/") + "/v1/agent/sync"
}

// AgentHealthURL returns HTTPS health URL for agent_domain.
func AgentHealthURL(meta SpeakerMeta) string {
	return agentHTTPSURL(meta, "/v1/agent/health")
}

// AgentBirdProtocolsURL returns HTTPS bird protocols URL for agent_domain.
func AgentBirdProtocolsURL(meta SpeakerMeta) string {
	return agentHTTPSURL(meta, "/v1/agent/bird/protocols")
}

func agentHTTPSURL(meta SpeakerMeta, path string) string {
	domain := strings.TrimSpace(meta.AgentDomain)
	if domain == "" {
		return ""
	}
	return "https://" + strings.TrimSuffix(domain, "/") + path
}

// SpeakerNeedsRemoteDispatch reports whether deploy_apply should wake this speaker via agent HTTP.
func SpeakerNeedsRemoteDispatch(role string, meta SpeakerMeta) bool {
	r := strings.ToLower(strings.TrimSpace(role))
	if r == "master" {
		return false
	}
	return strings.TrimSpace(meta.AgentDomain) != "" && strings.TrimSpace(meta.AgentSecret) != ""
}