package web

import (
	"context"
	"net/http"
	"time"

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

// R-193 — THE RECOVERY SCREEN. A customer whose machine was rebuilt has everything they need to get
// their data back and, until this page, no way to find out: the only route was a command line.
//
// IT UNLOCKS, AND ONLY UNLOCKS (operator ruling, 2026-08-05). It explains the situation, takes the
// recovery code, opens the repository, and shows what is in there. It does NOT restore anything.
// Restoring is already per-app and already lives in the backups area; putting files back is a
// separate item. A screen that unlocks and then offers to overwrite is two decisions wearing one
// button.
//
// THREE WAYS OUT, and none of them is a dismiss button:
//   - RECOVER  — the main path (/recovery/unlock).
//   - MOST NEM — the full page stops interrupting; the backups-area entry point stays PERMANENTLY,
//     because the data is still there whether or not anyone clicked (/recovery/postpone).
//   - I DO NOT WANT THE OLD DATA — deliberate, explained, confirmed TWICE, and it reaches the
//     SHIPPED move-aside (`/backup/offbox/reset`), which sets the store aside and never deletes.
//
// THE RECOVERY CODE IS HANDLED NO MORE LOOSELY THAN ON THE COMMAND LINE (§8.3): POST body only, never
// a query string, never logged at any level, never persisted, never echoed back, cleared on every
// path, and the page is served no-store with autocomplete off.

// recoveryOffer reports whether this box is in the situation the screen exists for. The predicate and
// its two shapes live in backup.OffsiteRecoveryOffer — read its header before changing anything here.
func (s *Server) recoveryOffer() bool {
	// CLAIMED AND BEHIND THE PASSWORD (§8.1). Before claiming there is no customer, and this page
	// states metadata about the household's own backups — accepted as metadata rather than content
	// (operator ruling 2026-08-05), which is only true while it sits behind the household password.
	// A legacy-open box (no password anywhere) reaches ServeHTTP through RequireAuth's pass-through,
	// so WITHOUT this line the interception would fire on an unauthenticated visitor. Caught by
	// TestRecovery_B_DoesNotAppearForAnyoneElse/not_claimed, which failed before it was added.
	if !s.authEnabled() {
		return false
	}
	return s.backupMgr != nil && s.backupMgr.OffsiteRecoveryOffer()
}

// recoveryInterrupts reports whether the FULL PAGE should take over the landing pages. "Most nem"
// suppresses this and nothing else — recoveryOffer stays true, so the backups-area entry point
// survives. That asymmetry is the whole of Scenario E.
func (s *Server) recoveryInterrupts() bool {
	if !s.recoveryOffer() {
		return false
	}
	return s.settings == nil || !s.settings.GetRecoveryNoticePostponed()
}

// recoveryNoStore stamps the page uncacheable. The rendered page carries no secret, but it does carry
// the form the code is typed into, and a cached copy of a recovery form is a form served from disk.
func recoveryNoStore(w http.ResponseWriter) {
	w.Header().Set("Cache-Control", "no-store, no-cache, must-revalidate, private")
	w.Header().Set("Pragma", "no-cache")
}

// recoveryPageHandler renders the screen (GET /recovery). Reachable whenever the situation holds —
// including after "most nem", which is how the backups-area entry point can point at it forever.
func (s *Server) recoveryPageHandler(w http.ResponseWriter, r *http.Request) {
	s.renderRecovery(w, r, "", "", nil)
}

// renderRecovery is the one render path: pre-unlock (explanation + code form), or post-unlock (the
// read-only listing). errorMsg/flash are already-customer-facing Hungarian; NEITHER EVER CONTAINS THE
// CODE — see unlockHandler.
func (s *Server) renderRecovery(w http.ResponseWriter, r *http.Request, errorMsg, flash string, inv *backup.OffsiteInventory) {
	recoveryNoStore(w)
	data := s.baseData("recovery", "Adatok visszaszerzése")
	data["CSRFField"] = s.csrfField(r)
	data["Offer"] = s.recoveryOffer()
	data["Postponed"] = s.settings != nil && s.settings.GetRecoveryNoticePostponed()
	data["Error"] = errorMsg
	data["Flash"] = flash
	data["SealedAt"] = s.recoverySealedAt()
	// The set-aside choice is offered ONLY when the shipped move-aside can actually run — it refuses
	// unless the tier is orphaned. Showing a button that is guaranteed to refuse would be worse than
	// not showing it, and rewriting the move-aside is explicitly out of scope.
	data["CanSetAside"] = s.backupMgr != nil && s.backupMgr.OffboxOrphaned()
	data["ConfirmSetAside"] = r.URL.Query().Get("setaside") == "1"
	if inv != nil {
		data["Unlocked"] = true
		data["InvApps"] = inv.Apps
		data["InvEmpty"] = inv.Empty
		data["InvUntagged"] = !inv.Empty && len(inv.Apps) == 0
	}
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	if err := s.tmpl.ExecuteTemplate(w, "recovery", data); err != nil {
		s.logger.Printf("[ERROR] [web] Template error (recovery): %v", err)
		http.Error(w, "Internal error", http.StatusInternalServerError)
	}
}

// recoverySealedAt returns the human date the hub says the sealed package was created (""
// when unknown). Non-secret: a timestamp, and the page must not pretend to know more than that
// before a code is entered.
func (s *Server) recoverySealedAt() string {
	if s.escrowSealedAtFn == nil {
		return ""
	}
	return s.escrowSealedAtFn()
}

// SetEscrowSealedAt wires the ACK's escrow created_at (report.EscrowAutoConfirmer). INIT-ONLY.
func (s *Server) SetEscrowSealedAt(fn func() string) { s.escrowSealedAtFn = fn }

// recoveryRecoverer returns the agent seam that unseals the package. nil → the shared agentClient(),
// the same channel the CLI uses; tests inject. The seam exists so the HANDLER can be driven in a test
// — a helper-level test would not observe a mutation that lives in the handler (§10).
func (s *Server) recoveryRecoverer() (backup.OffsiteKeyRecoverer, error) {
	if s.recoveryRecovererFn != nil {
		return s.recoveryRecovererFn()
	}
	return s.agentClient()
}

// SetRecoveryRecoverer overrides the agent seam (tests).
func (s *Server) SetRecoveryRecoverer(fn func() (backup.OffsiteKeyRecoverer, error)) {
	s.recoveryRecovererFn = fn
}

// recoveryUnlockHandler takes the recovery code and drives the SHARED core (POST /recovery/unlock).
//
// R HANDLING, and it must not drift from the CLI's:
//   - POST body only. A GET with a query string would put R in the access log, the browser history
//     and any Referer header the page later emits.
//   - never logged. Not at any level, not truncated, not hashed-and-logged.
//   - never persisted — not in the session, not in a cookie, not in a file.
//   - cleared on every path below, success and failure alike.
//   - never echoed. No message built here contains it; the agent's errors name the step, not the code.
//
// NO LOCKOUT (§8.4). The code is a 10-word EFF phrase — guessing is not the risk — and locking a
// customer out of their own data because they mistyped is a worse failure than anything it prevents.
// Failures ARE logged locally (without the code) so a box being probed is visible in the debug ring.
func (s *Server) recoveryUnlockHandler(w http.ResponseWriter, r *http.Request) {
	if !s.recoveryOffer() {
		http.Redirect(w, r, "/backups/remote", http.StatusFound)
		return
	}
	_ = r.ParseForm()
	code := r.PostFormValue("recovery_code") // PostFormValue: body only, never the query string
	if code == "" {
		s.renderRecovery(w, r, "Add meg a helyreállítási kódot.", "", nil)
		return
	}
	rec, err := s.recoveryRecoverer()
	if err != nil {
		code = ""
		s.logger.Printf("[ERROR] [web] recovery: agent channel unavailable: %v", err)
		s.renderRecovery(w, r, "A gép házon belüli kapcsolata most nem elérhető — próbáld újra néhány perc múlva.", "", nil)
		return
	}
	ctx, cancel := context.WithTimeout(context.Background(), 90*time.Second)
	defer cancel()
	// THE SHARED CORE — the same function the command line drives. There is no second recovery
	// implementation in this codebase (R-193 §8.5).
	res, rerr := backup.RecoverInstallCore(ctx, s.backupMgr, rec, code, true)
	code = "" // cleared here, before any branch below, on success and failure alike
	if rerr != nil {
		// The agent's error names the STEP (fetch / unseal / place) and carries no secret. It is not
		// shown raw: a customer needs to know what to check, not what age's KDF returned.
		s.logger.Printf("[WARN] [web] recovery: unlock failed: %v", rerr)
		s.renderRecovery(w, r, "A megadott helyreállítási kódot nem fogadtuk el. Ellenőrizd, hogy mind a tíz szót pontosan, szóközökkel elválasztva írtad be — a kis- és nagybetűk nem számítanak. Semmi nem változott, nyugodtan próbáld újra.", "", nil)
		return
	}
	switch res.Outcome {
	case backup.RecoverRefused:
		s.logger.Printf("[WARN] [web] recovery: refused — a different repository password is already present")
		s.renderRecovery(w, r, "Ezen a gépen már van egy másik mentési kulcs. A régi előzmény visszanyitása felülírná azt, ezért nem hajtottuk végre. Vedd fel a kapcsolatot a Felhom ügyfélszolgálatával.", "", nil)
		return
	}
	s.logger.Printf("[INFO] [web] recovery: the offsite repository key was recovered and placed (outcome=%s)", res.Outcome)
	// Unlocked. Now show what is in there — read-only.
	ictx, icancel := context.WithTimeout(context.Background(), 2*time.Minute)
	defer icancel()
	inv, ierr := s.backupMgr.OffsiteInventoryList(ictx)
	if ierr != nil {
		s.logger.Printf("[WARN] [web] recovery: unlocked but the inventory could not be read: %v", ierr)
		empty := backup.OffsiteInventory{}
		msg := "A kulcs visszakerült, de a mentések listáját most nem sikerült beolvasni. Nézd meg a Biztonsági mentés oldalt néhány perc múlva."
		if backup.ErrNoOffsiteTarget(ierr) {
			// The pristine rebuilt shape: the key is in place but the box has no off-site coordinates
			// yet. It resolves by itself once the tier is re-applied, so say that rather than showing a
			// failure the customer cannot act on.
			msg = "A kulcs visszakerült. A gép még most kapcsolódik újra a házon kívüli tárhelyhez — a mentéseid listája néhány perc múlva jelenik meg a Biztonsági mentés oldalon."
		}
		s.renderRecovery(w, r, msg, "", &empty)
		return
	}
	s.renderRecovery(w, r, "", "A mentéseid zárolása feloldva. Az alábbiakat találtuk a tárolóban — semmit nem állítottunk vissza.", &inv)
}

// recoveryPostponeHandler records "most nem" (POST /recovery/postpone). It suppresses the FULL-PAGE
// interruption ONLY: recoveryOffer stays true, so the backups-area entry point survives permanently.
func (s *Server) recoveryPostponeHandler(w http.ResponseWriter, r *http.Request) {
	if s.settings != nil {
		if err := s.settings.SetRecoveryNoticePostponed(true); err != nil {
			s.logger.Printf("[WARN] [web] recovery: recording the postpone failed: %v", err)
		}
	}
	s.logger.Printf("[INFO] [web] recovery: the customer chose to postpone; the backups-area entry point stays")
	http.Redirect(w, r, "/launcher", http.StatusFound)
}