package handlers

import (
	"errors"
	"strconv"

	"github.com/gin-gonic/gin"

	"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/ipaddresses"
	"git.netcell-it.de/projekte/edgeguard-native/internal/services/networkifs"
)

type NetworksHandler struct {
	Repo     *networkifs.Repo
	IPs      *ipaddresses.Repo
	Audit    *audit.Repo
	NodeID   string
}

func NewNetworksHandler(repo *networkifs.Repo, ips *ipaddresses.Repo, a *audit.Repo, nodeID string) *NetworksHandler {
	return &NetworksHandler{Repo: repo, IPs: ips, Audit: a, NodeID: nodeID}
}

func (h *NetworksHandler) Register(rg *gin.RouterGroup) {
	g := rg.Group("/network-interfaces")
	g.GET("", h.List)
	g.POST("", h.Create)
	g.GET("/:id", h.Get)
	g.PUT("/:id", h.Update)
	g.DELETE("/:id", h.Delete)
	g.GET("/:id/ip-addresses", h.ListIPs)
}

func (h *NetworksHandler) List(c *gin.Context) {
	out, err := h.Repo.List(c.Request.Context())
	if err != nil {
		response.Internal(c, err)
		return
	}
	response.OK(c, gin.H{"interfaces": out})
}

func (h *NetworksHandler) Get(c *gin.Context) {
	id, ok := parseID(c)
	if !ok {
		return
	}
	x, err := h.Repo.Get(c.Request.Context(), id)
	if err != nil {
		if errors.Is(err, networkifs.ErrNotFound) {
			response.NotFound(c, err)
			return
		}
		response.Internal(c, err)
		return
	}
	response.OK(c, x)
}

func (h *NetworksHandler) Create(c *gin.Context) {
	var req models.NetworkInterface
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, err)
		return
	}
	if err := validateInterface(&req); err != nil {
		response.BadRequest(c, err)
		return
	}
	out, err := h.Repo.Create(c.Request.Context(), req)
	if err != nil {
		response.Internal(c, err)
		return
	}
	_ = h.Audit.Log(c.Request.Context(), actorOf(c), "network_interface.create", req.Name, out, h.NodeID)
	response.Created(c, out)
}

func (h *NetworksHandler) Update(c *gin.Context) {
	id, ok := parseID(c)
	if !ok {
		return
	}
	var req models.NetworkInterface
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, err)
		return
	}
	if err := validateInterface(&req); err != nil {
		response.BadRequest(c, err)
		return
	}
	out, err := h.Repo.Update(c.Request.Context(), id, req)
	if err != nil {
		if errors.Is(err, networkifs.ErrNotFound) {
			response.NotFound(c, err)
			return
		}
		response.Internal(c, err)
		return
	}
	_ = h.Audit.Log(c.Request.Context(), actorOf(c), "network_interface.update", out.Name, out, h.NodeID)
	response.OK(c, out)
}

func (h *NetworksHandler) Delete(c *gin.Context) {
	id, ok := parseID(c)
	if !ok {
		return
	}
	if err := h.Repo.Delete(c.Request.Context(), id); err != nil {
		if errors.Is(err, networkifs.ErrNotFound) {
			response.NotFound(c, err)
			return
		}
		response.Internal(c, err)
		return
	}
	_ = h.Audit.Log(c.Request.Context(), actorOf(c), "network_interface.delete",
		strconv.FormatInt(id, 10), gin.H{"id": id}, h.NodeID)
	response.NoContent(c)
}

// validateInterface enforces the per-type rules that the SQL CHECK
// constraints alone can't express in a friendly way:
//   - vlan: parent + vlan_id required
//   - bridge / bond: ≥ 1 member required, vlan_id forbidden
//   - ethernet / wireguard: parent + members + vlan_id ignored
//
// The caller normalises empty members to nil before calling so the
// repo always receives [] (NOT NULL).
func validateInterface(i *models.NetworkInterface) error {
	switch i.Type {
	case "vlan":
		if i.Parent == nil || *i.Parent == "" {
			return errors.New("vlan requires parent")
		}
		if i.VLANID == nil {
			return errors.New("vlan requires vlan_id")
		}
		i.Members = nil
	case "bridge", "bond":
		if len(i.Members) == 0 {
			return errors.New(i.Type + " requires at least one member interface")
		}
		i.Parent = nil
		i.VLANID = nil
	case "ethernet", "wireguard":
		i.Parent = nil
		i.VLANID = nil
		i.Members = nil
	default:
		return errors.New("unknown interface type")
	}
	return nil
}

// ListIPs surfaces the addresses bound to a single interface — UI
// uses this for the per-interface IP-list tab.
func (h *NetworksHandler) ListIPs(c *gin.Context) {
	id, ok := parseID(c)
	if !ok {
		return
	}
	out, err := h.IPs.ListForInterface(c.Request.Context(), id)
	if err != nil {
		response.Internal(c, err)
		return
	}
	response.OK(c, gin.H{"ip_addresses": out})
}