package web

import (
	"errors"
	"net/http"
	"net/url"
	"strings"

	"gitea.dooplex.hu/admin/felhom-controller/internal/backup"
)

// D25 (operator ruling 2026-10-21; R-1175 + R-1181): the restore page lists the second-drive copies whose source is
// gone and lets the household release one with „Eltávolítás". Nothing else removes them.

// keptCopyRow is one line of the „Megőrzött másolatok" list.
type keptCopyRow struct {
	ID        string
	Source    string
	Line      string // „a(z) <drive> meghajtóról megőrzött másolat · <why>"
	SizeHuman string
	Since     string
	// Restorable (D47): a set-aside recovery unit of an earlier install — the row offers „Visszaállítás" too.
	Restorable bool
}

func (s *Server) keptCopyRows(lang string) []keptCopyRow {
	if s.backupMgr == nil {
		return nil
	}
	var out []keptCopyRow
	for _, k := range s.backupMgr.KeptCopies() {
		why := s.msgLang(lang, "kept.reason."+k.Reason)
		out = append(out, keptCopyRow{
			ID:         k.ID,
			Source:     k.Source,
			Line:       s.msgLang(lang, "kept.from_drive", k.Drive) + " · " + why,
			SizeHuman:  backup.HumanizeBytes(k.SizeBytes),
			Since:      k.Since,
			Restorable: k.Kind == backup.KeptKindUnit,
		})
	}
	return out
}

// keptCopyRemoveHandler is „Eltávolítás": POST /backup/kept/remove (id, confirm=1). It removes ONE kept copy by its
// record (backup.RemoveKeptCopy: the recorded path, inside its copy tree, same device + inode) and nothing else.
func (s *Server) keptCopyRemoveHandler(w http.ResponseWriter, r *http.Request) {
	if s.backupMgr == nil {
		offboxRedirectTo(w, r, "/backups/restore", "flash.offbox.mgr_unreachable", true)
		return
	}
	_ = r.ParseForm()
	id := strings.TrimSpace(r.FormValue("id"))
	if r.FormValue("confirm") != "1" {
		offboxRedirectTo(w, r, "/backups/restore", "flash.kept.needs_confirmation", true)
		return
	}
	if msg, blocked := s.restoreOpBlocked(); blocked {
		s.logger.Printf("[WARN] [web] kept-copy removal refused (%s): a backup/restore op is running", id)
		offboxRedirectTo(w, r, "/backups/restore", msg, true)
		return
	}
	switch err := s.backupMgr.RemoveKeptCopy(id); {
	case err == nil:
		offboxRedirectTo(w, r, "/backups/restore", "flash.kept.removed", false)
	case errors.Is(err, backup.ErrKeptCopyNotFound):
		offboxRedirectTo(w, r, "/backups/restore", "flash.kept.not_found", true)
	case errors.Is(err, backup.ErrKeptCopyChanged):
		offboxRedirectTo(w, r, "/backups/restore", "flash.kept.changed", true)
	default:
		s.logger.Printf("[WARN] [web] kept-copy removal %s failed: %v", id, err)
		offboxRedirectTo(w, r, "/backups/restore", "flash.kept.remove_failed", true, err.Error())
	}
}

// keptUnitRestoreHandler is „Visszaállítás" on a set-aside unit (D47): POST /backup/kept/restore (id, confirm=1). The
// unit is named only by its record (backup.SetAsideUnitFor: the recorded folder, inside its set-aside tree, same device
// + inode), and restored through the one unit-restore body, in the background like every restore.
func (s *Server) keptUnitRestoreHandler(w http.ResponseWriter, r *http.Request) {
	if s.backupMgr == nil {
		offboxRedirectTo(w, r, "/backups/restore", "flash.offbox.mgr_unreachable", true)
		return
	}
	_ = r.ParseForm()
	id := strings.TrimSpace(r.FormValue("id"))
	if r.FormValue("confirm") != "1" {
		offboxRedirectTo(w, r, "/backups/restore", "flash.kept.restore_needs_confirmation", true)
		return
	}
	if msg, blocked := s.restoreOpBlocked(); blocked {
		http.Redirect(w, r, "/backups/restore?flash_error="+url.QueryEscape(msg), http.StatusFound)
		return
	}
	k, err := s.backupMgr.SetAsideUnitFor(id)
	switch {
	case errors.Is(err, backup.ErrKeptCopyNotFound):
		offboxRedirectTo(w, r, "/backups/restore", "flash.kept.not_found", true)
		return
	case err != nil:
		offboxRedirectTo(w, r, "/backups/restore", "flash.kept.changed", true)
		return
	}
	if legs := s.backupMgr.DeclaredDriveFileLegs(k.Source); len(legs) > 0 {
		msg := s.missingFileLegsRefusal(r.Context(), s.langFor(r), k.Source)
		http.Redirect(w, r, "/backups/restore?flash_error="+url.QueryEscape(msg), http.StatusFound)
		return
	}
	s.logger.Printf("[WARN] [web] Restore of %s from a set-aside unit requested (async): %s from %s", k.Source, k.Path, r.RemoteAddr)
	s.backupMgr.BeginRestoreOp("restore", k.Source)
	go func() {
		app, res, err := s.backupMgr.RestoreSetAsideUnit(id)
		if err != nil {
			s.logger.Printf("[ERROR] [web] Restore from the set-aside unit failed (async): stack=%s: %v", app, err)
			s.endRestoreFailed("note.restore.unit_failed", err, "")
			return
		}
		s.backupMgr.EndRestoreOp(true, s.restoredVersionPrefix(app, res.VersionChanged, res.DataPins, res.DataAt)+s.unitRestoreOutcomeMsg(app, res))
	}()
	http.Redirect(w, r, "/backups/restore?"+flashQuery("flash", "flash.restore.started"), http.StatusFound)
}