package web

import (
	"encoding/json"
	"errors"
	"net/http"
	"net/url"
	"strings"
	"time"

	"gitea.dooplex.hu/admin/felhom-controller/internal/backup"
	"gitea.dooplex.hu/admin/felhom-controller/internal/i18n"
	"gitea.dooplex.hu/admin/felhom-controller/internal/notify"
)

// 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)
	if msg, ok := s.beginRestoreOp("restore", k.Source); !ok {
		http.Redirect(w, r, "/backups/restore?flash_error="+url.QueryEscape(msg), http.StatusFound)
		return
	}
	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)
}

// ── D62 (operator ruling 2026-10-29): restore copies in the same list ───────────────────────────────────────────────
//
// Each restore copy shows the app, the date of the restore it protects, its size and the day the box deletes it by
// itself (30 days after the restore). „Törlés most" deletes it earlier: a warning that names the app and the date,
// and the app's name typed. A copy a hold or a pending put-back needs shows why in one line and has no button — and
// the handler refuses it too. Pinned by TestD62_* (web).

// restoreCopyRow is one restore copy on the page.
type restoreCopyRow struct {
	App        string
	Stamp      string
	Name       string // the app's display name — what the household types
	Line       string // „visszaállítás: <date> · <size> · automatikusan törlődik: <date>"
	NeededText string // why it cannot be deleted; "" = the button is offered
	Warning    string // the confirm step's sentence (app and date)
	TypePrompt string
}

// restoreCopyAppName is the app's display name, or its slug when the app is gone.
func (s *Server) restoreCopyAppName(app string) string {
	if s.stackMgr != nil {
		if st, ok := s.stackMgr.GetStack(app); ok && st.Meta.DisplayName != "" {
			return st.Meta.DisplayName
		}
	}
	return app
}

func (s *Server) restoreCopyRows(lang string) []restoreCopyRow {
	if s.backupMgr == nil {
		return nil
	}
	var out []restoreCopyRow
	for _, c := range s.backupMgr.RestoreCopies() {
		name := s.restoreCopyAppName(c.App)
		at := c.At.In(getTimezone())
		line := s.msgLang(lang, "restore_copy.restored_on", fmtLocalTime(lang, c.At)) + " · " +
			i18n.LocalizeDecimals(lang, backup.HumanizeBytes(c.SizeBytes))
		row := restoreCopyRow{App: c.App, Stamp: c.Stamp, Name: name}
		if c.Needed == "" {
			line += " · " + s.msgLang(lang, "restore_copy.auto_delete", i18n.FormatDate(lang, c.DeleteOn.In(getTimezone())))
			row.Warning = s.msgLang(lang, "restore_copy.warning", name, strings.TrimSuffix(i18n.FormatDate(lang, at), "."))
			row.TypePrompt = s.msgLang(lang, "kept.delete.type", name)
		} else {
			row.NeededText = s.msgLang(lang, "restore_copy.needed."+c.Needed)
		}
		row.Line = line
		out = append(out, row)
	}
	return out
}

// restoreCopyJSON is the delete's answer: ok with the page to go to, or the refusal's sentence.
func restoreCopyJSON(w http.ResponseWriter, code int, ok bool, msg, redirect string) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(code)
	_ = json.NewEncoder(w).Encode(map[string]interface{}{"ok": ok, "error": msg, "redirect": redirect})
}

// restoreCopyDeleteHandler is „Törlés most": POST /backup/restore-copy/delete (app, stamp, confirm). JSON answer:
// 200 deleted; 400 the typed name does not match; 404 no such copy; 409 the copy is needed, or an operation runs on
// the box or the app; 500 the removal failed. CSRF as every state-changing form (CsrfProtect).
func (s *Server) restoreCopyDeleteHandler(w http.ResponseWriter, r *http.Request) {
	lang := s.langFor(r)
	if s.backupMgr == nil {
		restoreCopyJSON(w, http.StatusServiceUnavailable, false, s.msgLang(lang, "flash.offbox.mgr_unreachable"), "")
		return
	}
	_ = r.ParseForm()
	app, stamp := strings.TrimSpace(r.FormValue("app")), strings.TrimSpace(r.FormValue("stamp"))
	var found *backup.RestoreCopy
	for _, c := range s.backupMgr.RestoreCopies() {
		if c.App == app && c.Stamp == stamp {
			c := c
			found = &c
			break
		}
	}
	if found == nil {
		s.logger.Printf("[WARN] [web] restore-copy delete REFUSED: %q/%q is not a listed copy (from %s)", app, stamp, clientIP(r))
		restoreCopyJSON(w, http.StatusNotFound, false, s.msgLang(lang, "restore_copy.not_found"), "")
		return
	}
	if found.Needed != "" {
		s.logger.Printf("[WARN] [web] restore-copy delete REFUSED for %s: the copy is needed (%s)", found.Path, found.Needed)
		restoreCopyJSON(w, http.StatusConflict, false, s.msgLang(lang, "restore_copy.needed."+found.Needed), "")
		return
	}
	name := s.restoreCopyAppName(app)
	if strings.TrimSpace(r.FormValue("confirm")) != name {
		s.logger.Printf("[WARN] [web] restore-copy delete REFUSED for %s: the typed confirmation did not match", found.Path)
		restoreCopyJSON(w, http.StatusBadRequest, false, s.msgLang(lang, "kept.delete.mismatch", name), "")
		return
	}
	if s.stackMgr != nil && s.stackMgr.IsUpdating(app) {
		s.logger.Printf("[WARN] [web] restore-copy delete REFUSED for %s: an update of %s runs", found.Path, app)
		restoreCopyJSON(w, http.StatusConflict, false, s.msgLang(lang, "restore_copy.app_busy"), "")
		return
	}
	who := "the household (dashboard sign-in) from " + clientIP(r)
	c, err := s.backupMgr.DeleteRestoreCopy(app, stamp)
	switch {
	case errors.Is(err, backup.ErrRestoreCopyBusy):
		busy, mirror := s.backupMgr.RestoreBusy()
		msg, blocked := s.restoreBusyMessage(busy, mirror)
		if !blocked {
			msg = s.msgLang(lang, "restore_copy.app_busy")
		}
		s.logger.Printf("[WARN] [web] restore-copy delete REFUSED for %s: a backup or restore operation runs", found.Path)
		restoreCopyJSON(w, http.StatusConflict, false, msg, "")
		return
	case errors.Is(err, backup.ErrRestoreCopyNeeded):
		restoreCopyJSON(w, http.StatusConflict, false, s.msgLang(lang, "restore_copy.needed."+c.Needed), "")
		return
	case errors.Is(err, backup.ErrRestoreCopyNotFound):
		restoreCopyJSON(w, http.StatusNotFound, false, s.msgLang(lang, "restore_copy.not_found"), "")
		return
	case err != nil:
		s.logger.Printf("[ERROR] [web] restore-copy delete of %s failed: %v", found.Path, err)
		restoreCopyJSON(w, http.StatusInternalServerError, false, s.msgLang(lang, "restore_copy.failed", err.Error()), "")
		return
	}
	restoreAt := c.At.UTC().Format(time.RFC3339)
	s.logger.Printf("[WARN] [web] restore copy DELETED by hand (D62): app=%s restore_at=%s size=%d path=%s who=%s",
		app, restoreAt, c.SizeBytes, c.Path, who)
	if s.notifier != nil {
		s.notifier.NotifyRestoreCopyDeleted(notify.RestoreCopyDeletedDetails{App: app, RestoreAt: restoreAt, SizeBytes: c.SizeBytes, Who: who, Path: c.Path})
	}
	restoreCopyJSON(w, http.StatusOK, true, "", "/backups/restore?"+flashQuery("flash", "flash.restore_copy.deleted", name))
}