package handlers

import (
	"context"
	"fmt"
	"log/slog"
	"net"
	"strings"
	"time"

	"github.com/gin-gonic/gin"

	"git.netcell-it.de/projekte/edgeguard-native/internal/cluster"
	"git.netcell-it.de/projekte/edgeguard-native/internal/handlers/response"
	"git.netcell-it.de/projekte/edgeguard-native/internal/models"
	"git.netcell-it.de/projekte/edgeguard-native/internal/services/audit"
	"git.netcell-it.de/projekte/edgeguard-native/internal/services/clusterjoin"
	"git.netcell-it.de/projekte/edgeguard-native/internal/services/setup"
)

// SetupHandler exposes the first-run wizard endpoints. Both endpoints
// are mounted before SetupGate so they remain reachable while the API
// is in setup mode.
type SetupHandler struct {
	Store        *setup.Store
	Audit        *audit.Repo
	NodeID       string
	Version      string
	ClusterStore *cluster.Store
	PeerReloader PeerReloader
}

func NewSetupHandler(store *setup.Store) *SetupHandler {
	return &SetupHandler{Store: store}
}

// WithAudit injiziert Audit-Repo + Node-ID damit Mutationen (contact-emails)
// in audit_log landen. Optional — wenn Audit nil bleibt, läuft die
// Mutation, aber ohne Log-Eintrag.
func (h *SetupHandler) WithAudit(a *audit.Repo, nodeID string) *SetupHandler {
	h.Audit = a
	h.NodeID = nodeID
	return h
}

// WithVersion macht die laufende Version für auto-register verfügbar.
func (h *SetupHandler) WithVersion(v string) *SetupHandler {
	h.Version = v
	return h
}

// WithClusterSupport erlaubt dem JoinCluster-Handler nach dem Join den
// Primary in der lokalen ha_nodes zu registrieren + nftables neu zu laden,
// damit Port 8443 bidirektional offen ist.
func (h *SetupHandler) WithClusterSupport(store *cluster.Store, reloader PeerReloader) *SetupHandler {
	h.ClusterStore = store
	h.PeerReloader = reloader
	return h
}

func (h *SetupHandler) Register(rg *gin.RouterGroup) {
	g := rg.Group("/setup")
	g.GET("/status", h.Status)
	g.POST("/complete", h.Complete)
	g.POST("/complete-node", h.CompleteAsNode)
	g.POST("/join-cluster", h.JoinCluster)
	g.GET("/replication-status", h.ReplicationStatus)
}

// RegisterAuthed mountet die Endpoints die nach abgeschlossenem Setup
// den Admin-Modus brauchen — Aufrufer hat requireAuth schon dran.
func (h *SetupHandler) RegisterAuthed(rg *gin.RouterGroup) {
	g := rg.Group("/setup")
	g.POST("/contact-emails", h.SetContactEmails)
}

// Status returns just the public bits of the setup state: whether
// it's done and (if so) the configured admin_email + acme_email +
// fqdn. Never exposes the password hash.
func (h *SetupHandler) Status(c *gin.Context) {
	st, err := h.Store.Load()
	if err != nil {
		response.Internal(c, err)
		return
	}
	response.OK(c, gin.H{
		"completed":   st.Completed,
		"admin_email": st.AdminEmail,
		"acme_email":  st.ACMEEmail,
		"fqdn":        st.FQDN,
	})
}

// SetContactEmails: Admin-only Update der zwei E-Mail-Felder.
// Sessions bleiben aktiv (Cookie referenziert den alten Actor); auf
// nächstem Login zählt der neue Wert.
func (h *SetupHandler) SetContactEmails(c *gin.Context) {
	var req struct {
		AdminEmail string `json:"admin_email" binding:"required,email"`
		ACMEEmail  string `json:"acme_email"  binding:"required,email"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, err)
		return
	}
	if err := h.Store.SetContactEmails(req.AdminEmail, req.ACMEEmail); err != nil {
		response.BadRequest(c, err)
		return
	}
	st, err := h.Store.Load()
	if err != nil {
		response.Internal(c, err)
		return
	}
	if h.Audit != nil {
		_ = h.Audit.Log(c.Request.Context(), actorOf(c), "setup.contact_emails",
			st.AdminEmail, gin.H{
				"admin_email": st.AdminEmail,
				"acme_email":  st.ACMEEmail,
			}, h.NodeID)
	}
	response.OK(c, gin.H{
		"admin_email": st.AdminEmail,
		"acme_email":  st.ACMEEmail,
	})
}

func (h *SetupHandler) Complete(c *gin.Context) {
	var req setup.Request
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, err)
		return
	}
	st, err := h.Store.Complete(req)
	if err != nil {
		response.BadRequest(c, err)
		return
	}
	response.OK(c, gin.H{
		"completed":   st.Completed,
		"admin_email": st.AdminEmail,
		"fqdn":        st.FQDN,
	})
}

func (h *SetupHandler) CompleteAsNode(c *gin.Context) {
	var req setup.NodeRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, err)
		return
	}
	st, err := h.Store.CompleteAsNode(req)
	if err != nil {
		response.BadRequest(c, err)
		return
	}
	response.OK(c, gin.H{
		"completed":       st.Completed,
		"is_cluster_node": st.IsClusterNode,
		"fqdn":            st.FQDN,
	})
}

// JoinCluster performs the full cluster-join flow from the setup wizard:
// fetches certs from the primary, writes them to disk, then marks setup
// as completed. No CLI required.
func (h *SetupHandler) JoinCluster(c *gin.Context) {
	var body struct {
		FQDN        string `json:"fqdn"         binding:"required"`
		ACMEEmail   string `json:"acme_email"   binding:"required,email"`
		PrimaryFQDN string `json:"primary_fqdn" binding:"required"`
		Token       string `json:"token"        binding:"required"`
	}
	if err := c.ShouldBindJSON(&body); err != nil {
		response.BadRequest(c, err)
		return
	}

	fqdn := strings.ToLower(strings.TrimSpace(body.FQDN))

	if err := clusterjoin.Join(clusterjoin.Request{
		PrimaryFQDN: body.PrimaryFQDN,
		Token:       strings.TrimSpace(body.Token),
		CommonName:  fqdn,
		Insecure:    true, // security comes from the HMAC token, not TLS cert trust
		Force:       true, // bootstrap self-signed cert must be replaced
		Version:     h.Version,
		NodeID:      h.NodeID,
	}); err != nil {
		response.BadRequest(c, err)
		return
	}

	st, err := h.Store.CompleteAsNode(setup.NodeRequest{
		FQDN:        fqdn,
		ACMEEmail:   body.ACMEEmail,
		PrimaryFQDN: strings.ToLower(strings.TrimSpace(body.PrimaryFQDN)),
	})
	if err != nil {
		response.Internal(c, err)
		return
	}

	// Pre-register the primary in our local ha_nodes so its IP lands in
	// @peer_ipv4 and port 8443 is open bidirectionally.
	if h.ClusterStore != nil && h.PeerReloader != nil {
		go h.preRegisterPrimary(body.PrimaryFQDN)
	}

	// Logical Replication automatisch einrichten. Ohne diesen Schritt waere
	// der Node zwar im Cluster registriert, wuerde aber keinerlei geteilte
	// Config (Domains, Backends, Firewall-Rules, WireGuard, …) bekommen —
	// was frueher erst beim Failover auffiel. Laeuft detached, der Wizard
	// pollt /setup/replication-status.
	h.startReplicationSetup(body.PrimaryFQDN)

	response.OK(c, gin.H{
		"completed":       st.Completed,
		"is_cluster_node": st.IsClusterNode,
		"fqdn":            st.FQDN,
	})
}

// StartupPeerSync is called once after the DB pool and ClusterStore are
// ready. On cluster nodes it re-registers the primary in the local ha_nodes
// and reloads nftables so @peer_ipv4 is correct after a package update or
// reboot — without requiring a new join.
func (h *SetupHandler) StartupPeerSync() {
	if h.ClusterStore == nil || h.PeerReloader == nil {
		return
	}
	st, err := h.Store.Load()
	if err != nil || st == nil || !st.IsClusterNode || st.PrimaryFQDN == "" {
		return
	}
	h.preRegisterPrimary(st.PrimaryFQDN)
}

// preRegisterPrimary inserts the primary node into the local ha_nodes with
// its resolved IP so nftables @peer_ipv4 allows port 8443 from the primary.
// Uses a stable ID derived from the FQDN so repeated calls are idempotent.
func (h *SetupHandler) preRegisterPrimary(primaryFQDN string) {
	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer cancel()

	primaryFQDN = strings.ToLower(strings.TrimSpace(primaryFQDN))

	addrs, err := net.DefaultResolver.LookupHost(ctx, primaryFQDN)
	if err != nil || len(addrs) == 0 {
		slog.Warn("setup: could not resolve primary FQDN for pre-registration",
			"fqdn", primaryFQDN, "error", err)
		return
	}
	ip := addrs[0]

	// Sobald der Primary sich selbst gemeldet hat (Heartbeat-Push), steht
	// hier bereits eine Zeile mit seiner ECHTEN Node-ID. Dann ist nur die
	// IP frisch zu halten — mehr will diese Funktion gar nicht.
	//
	// Vorher lief in dem Fall unbedingt der Platzhalter-Upsert unten, der
	// am fqdn-Unique-Index scheiterte: UpsertSelf nutzt ON CONFLICT (id),
	// und die Synthetik-ID "prenode-<fqdn>" trifft die echte Zeile nicht.
	// Ergebnis war ein "duplicate key value violates unique constraint
	// ha_nodes_fqdn_unique" bei JEDEM API-Start auf dem Standby — folgenlos
	// (die echte Zeile stimmt ja), aber es sah nach einem Defekt aus und
	// verdeckte echte Warnungen.
	tag, err := h.ClusterStore.Pool.Exec(ctx,
		`UPDATE ha_nodes SET public_ip = $1, updated_at = NOW() WHERE fqdn = $2`,
		ip, primaryFQDN)
	if err != nil {
		slog.Warn("setup: refreshing primary IP in ha_nodes failed",
			"fqdn", primaryFQDN, "error", err)
		return
	}
	if tag.RowsAffected() == 0 {
		// Noch keine Zeile: Platzhalter anlegen, damit @peer_ipv4 den
		// Primary schon kennt, bevor er sich das erste Mal meldet.
		// Stabile ID, damit wiederholte Aufrufe (Join + Start) keine
		// Zeilen anhaeufen.
		nodeID := fmt.Sprintf("prenode-%s", strings.ReplaceAll(primaryFQDN, ".", "-"))
		n := models.HANode{
			ID:     nodeID,
			Name:   primaryFQDN,
			FQDN:   primaryFQDN,
			APIURL: "https://" + primaryFQDN + ":3443",
			Role:   "primary",
			Status: "online",
		}
		n.PublicIP = &ip
		if _, err := h.ClusterStore.UpsertSelf(ctx, n); err != nil {
			slog.Warn("setup: pre-register primary in ha_nodes failed",
				"fqdn", primaryFQDN, "error", err)
			return
		}
	}
	if err := h.PeerReloader(ctx); err != nil {
		slog.Warn("setup: PeerReloader failed after primary pre-register", "error", err)
		return
	}
	slog.Info("setup: primary pre-registered locally, firewall updated",
		"fqdn", primaryFQDN, "ip", ip)
}