package backup

import (
	"fmt"
	"os"
	"strings"

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

// Offsite capture-set resolution (Task 3a, architecture doc §2/§6). Turns an app's Task-3-core
// TierOffsite capture set (recovery unit + MANDATORY userdata only) into the extra absolute paths
// appended to the app's restic snapshot, plus the Hungarian customer warnings for LOUD capture gaps.
//
// SP-3.4 is law here: restic 0.14.0 does NOT error on a missing source path — it skips with a warning,
// exits 0, and silently writes a partial snapshot. So a skipped/missing MANDATORY path is detected in
// THIS function (the structural-guard Skipped list + an os.Stat filter) and surfaced in BOTH the
// English log and the Hungarian LastWarning. A restic exit code proves nothing about a missing path.

// offboxBlocked records an app whose enlarged (userdata-carrying) push was refused by the pre-push
// quota gate. The unit-only push still proceeds (never a protection regression). estBytes is the
// mandatory-set size estimate that would have been added.
type offboxBlocked struct {
	stack    string
	estBytes int64
}

// offboxCaptureSet computes an app's OFFSITE mandatory capture paths to add to its recovery-unit
// snapshot, plus any Hungarian warnings for capture gaps. It never returns optional/excluded paths
// (the TierOffsite filter drops them — §2). Returns (nil, nil) for the legacy / no-provider / no-block
// world: offsite stays UNIT-ONLY, byte-identical to pre-v0.134.0 (the SQ5 cost-regression guard).
func (m *Manager) offboxCaptureSet(stack string) (extra []string, warns []string) {
	if m.stackProvider == nil {
		return nil, nil // no provider wired → legacy world → unit only
	}
	binds, has := m.stackProvider.GetStackClassifiedBinds(stack)
	if !has {
		return nil, nil // no backup block → legacy → unit only
	}
	// Resolve against the app's LIVE HDD_PATH (raw — NOT GetAppDrivePath, whose systemDataPath fallback
	// would resolve userdata onto the wrong drive). Empty ⇒ undeployed / no HDD (decision §2.4):
	// mandatory-path resolution needs the live HDD_PATH, so push unit-only + a loud WARN.
	hdd := strings.TrimSpace(m.stackProvider.GetStackHDDPath(stack))
	if hdd == "" {
		m.logger.Printf("[WARN] [offbox] %s: not deployed — offsite push is unit-only (mandatory userdata not resolvable)", stack)
		return nil, []string{fmt.Sprintf("Figyelmeztetés: a(z) %s nincs telepítve — csak a mentési egység került a távoli mentésbe.", stack)}
	}
	nsRoot := m.namespaceRoot(hdd)
	cs := appbackup.ComputeCaptureSet(binds, has, appbackup.TierOffsite, nsRoot)

	var gaps []string
	// Structurally-refused MANDATORY paths (traversal / bare drive-root / reserved backups/ zone) are
	// loud ERROR gaps — the path the customer thinks is protected is not in the snapshot.
	for _, sk := range cs.Skipped {
		if sk.Class == appbackup.ClassMandatory {
			m.logger.Printf("[ERROR] [offbox] %s: mandatory path refused by a structural guard (%s): %s/%s — NOT in the offsite snapshot",
				stack, sk.Reason, sk.Root, sk.RelPath)
			gaps = append(gaps, sk.RelPath)
		}
	}
	// Stat-filter (§2.5): a declared mandatory path absent on disk. restic would skip it SILENTLY
	// (SP-3.4), so drop it from argv AND warn — never a silent "looks backed up but isn't".
	for _, p := range cs.Paths {
		if _, err := os.Stat(p.Abs); err != nil {
			m.logger.Printf("[WARN] [offbox] %s: mandatory data path missing on disk, skipped from offsite: %s", stack, p.Abs)
			gaps = append(gaps, p.RelPath)
			continue
		}
		extra = append(extra, p.Abs)
	}
	if len(gaps) > 0 {
		warns = append(warns, fmt.Sprintf("Figyelmeztetés: a(z) %s alkalmazás egyes adatmappái nem kerültek a távoli mentésbe: %s.",
			stack, strings.Join(gaps, ", ")))
	}
	return extra, warns
}
