package handlers

import (
	"context"
	"errors"
	"log/slog"
	"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/backendservers"
)

// BackendServersHandler exposes:
//   GET    /api/v1/backends/:id/servers
//   POST   /api/v1/backends/:id/servers
//   PUT    /api/v1/backend-servers/:id
//   DELETE /api/v1/backend-servers/:id
type BackendServersHandler struct {
	Repo     *backendservers.Repo
	Audit    *audit.Repo
	NodeID   string
	Reloader func(ctx context.Context) error
}

func NewBackendServersHandler(repo *backendservers.Repo, a *audit.Repo,
	nodeID string, reloader func(context.Context) error) *BackendServersHandler {
	return &BackendServersHandler{Repo: repo, Audit: a, NodeID: nodeID, Reloader: reloader}
}

func (h *BackendServersHandler) reload(ctx context.Context, op string) {
	if h.Reloader == nil {
		return
	}
	if err := h.Reloader(ctx); err != nil {
		slog.Warn("haproxy: reload after server mutation failed", "op", op, "error", err)
	}
}

func (h *BackendServersHandler) Register(rg *gin.RouterGroup) {
	rg.GET("/backends/:id/servers", h.ListForBackend)
	rg.POST("/backends/:id/servers", h.Create)
	g := rg.Group("/backend-servers")
	g.PUT("/:id", h.Update)
	g.DELETE("/:id", h.Delete)
}

func (h *BackendServersHandler) ListForBackend(c *gin.Context) {
	backendID, ok := parseID(c)
	if !ok {
		return
	}
	out, err := h.Repo.ListByBackend(c.Request.Context(), backendID)
	if err != nil {
		response.Internal(c, err)
		return
	}
	response.OK(c, gin.H{"servers": out})
}

func (h *BackendServersHandler) Create(c *gin.Context) {
	backendID, ok := parseID(c)
	if !ok {
		return
	}
	var req models.BackendServer
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, err)
		return
	}
	req.BackendID = backendID
	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), "backend.server.create", req.Name, out, h.NodeID)
	response.Created(c, out)
	h.reload(c.Request.Context(), "create")
}

func (h *BackendServersHandler) Update(c *gin.Context) {
	id, ok := parseID(c)
	if !ok {
		return
	}
	var req models.BackendServer
	if err := c.ShouldBindJSON(&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, backendservers.ErrNotFound) {
			response.NotFound(c, err)
			return
		}
		response.Internal(c, err)
		return
	}
	_ = h.Audit.Log(c.Request.Context(), actorOf(c), "backend.server.update", out.Name, out, h.NodeID)
	response.OK(c, out)
	h.reload(c.Request.Context(), "update")
}

func (h *BackendServersHandler) 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, backendservers.ErrNotFound) {
			response.NotFound(c, err)
			return
		}
		response.Internal(c, err)
		return
	}
	_ = h.Audit.Log(c.Request.Context(), actorOf(c), "backend.server.delete",
		strconv.FormatInt(id, 10), gin.H{"id": id}, h.NodeID)
	response.NoContent(c)
	h.reload(c.Request.Context(), "delete")
}