package handlers

import (
	"errors"
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"

	"git.netcell-it.de/projekte/edgeguard-native/internal/handlers/response"
	"git.netcell-it.de/projekte/edgeguard-native/internal/services/audit"
	"git.netcell-it.de/projekte/edgeguard-native/internal/services/backup"
)

// BackupHandler exposes:
//
//	GET    /api/v1/backups              — list
//	POST   /api/v1/backups              — trigger manual backup (sync)
//	GET    /api/v1/backups/:id          — single entry
//	GET    /api/v1/backups/:id/download — sendfile tar.gz
//	DELETE /api/v1/backups/:id          — delete tar.gz + row
type BackupHandler struct {
	Service *backup.Service
	Audit   *audit.Repo
	NodeID  string
	Version string
}

func NewBackupHandler(s *backup.Service, a *audit.Repo, nodeID, version string) *BackupHandler {
	return &BackupHandler{Service: s, Audit: a, NodeID: nodeID, Version: version}
}

func (h *BackupHandler) Register(rg *gin.RouterGroup) {
	g := rg.Group("/backups")
	g.GET("", h.List)
	g.POST("", h.Trigger)
	g.GET("/:id", h.Get)
	g.GET("/:id/download", h.Download)
	g.POST("/:id/restore", h.Restore)
	g.DELETE("/:id", h.Delete)
}

// Restore startet einen Restore aus einem vorhandenen Backup. Endpoint
// returnt sofort 202 Accepted — der eigentliche Restore läuft in einer
// transient systemd-Unit; die UI pollt /healthz für die Restart-
// Detection. Massive Audit-Trail, weil das ein destruktiver Eingriff
// in den live-DB-State ist.
func (h *BackupHandler) Restore(c *gin.Context) {
	id, ok := parseID(c)
	if !ok {
		return
	}
	e, err := h.Service.Restore(c.Request.Context(), id)
	if err != nil {
		response.Err(c, http.StatusInternalServerError, err)
		return
	}
	_ = h.Audit.Log(c.Request.Context(), actorOf(c), "backup.restore",
		e.File, gin.H{"id": id, "sha256": e.SHA256}, h.NodeID)
	c.JSON(http.StatusAccepted, response.Envelope{
		Data:    gin.H{"status": "restoring", "file": e.File, "id": id},
		Message: "Restore gestartet",
	})
}

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

func (h *BackupHandler) Trigger(c *gin.Context) {
	// Manual backup läuft synchron — der Operator wartet vor dem
	// Knopf. Bei echten Multi-GB-DBs wäre async besser, aber unsere
	// edgeguard-DB ist klein (<50 MB typisch).
	res, err := h.Service.Run(c.Request.Context(), backup.KindManual, h.Version)
	if err != nil {
		response.Err(c, http.StatusInternalServerError, err)
		return
	}
	_ = h.Audit.Log(c.Request.Context(), actorOf(c), "backup.create",
		res.File, gin.H{"size": res.SizeBytes, "sha256": res.SHA256}, h.NodeID)
	response.OK(c, gin.H{
		"id":            res.ID,
		"file":          res.File,
		"size_bytes":    res.SizeBytes,
		"sha256":        res.SHA256,
		"db_dump_bytes": res.DBDumpBytes,
		"files_bytes":   res.FilesBytes,
		"started_at":    res.StartedAt,
		"finished_at":   res.FinishedAt,
	})
}

func (h *BackupHandler) Get(c *gin.Context) {
	id, ok := parseID(c)
	if !ok {
		return
	}
	e, _, err := h.Service.Get(c.Request.Context(), id)
	if err != nil {
		response.NotFound(c, err)
		return
	}
	response.OK(c, e)
}

func (h *BackupHandler) Download(c *gin.Context) {
	id, ok := parseID(c)
	if !ok {
		return
	}
	e, path, err := h.Service.Get(c.Request.Context(), id)
	if err != nil {
		response.NotFound(c, err)
		return
	}
	// gin.FileAttachment setzt Content-Disposition + sendet stream.
	c.FileAttachment(path, e.File)
}

func (h *BackupHandler) Delete(c *gin.Context) {
	id, ok := parseID(c)
	if !ok {
		return
	}
	if err := h.Service.Delete(c.Request.Context(), id); err != nil {
		response.Err(c, http.StatusInternalServerError, err)
		return
	}
	_ = h.Audit.Log(c.Request.Context(), actorOf(c), "backup.delete",
		strconv.FormatInt(id, 10), gin.H{"id": id}, h.NodeID)
	response.NoContent(c)
}

// Defensive — falls jemand den Pool fehlerhaft injected.
var _ = errors.New