package web

import (
	"crypto/sha256"
	"encoding/hex"
	"net/http"
	"time"

	"gitea.dooplex.hu/admin/felhom-hub/internal/configgen"
)

// selfbind_mint.go — the OPERATOR side of customer self-bind (v0.66.0, R-27 slice 1): the "Send
// self-bind link" button on the customer page mints a 7-day capability token and emails the customer
// a public bind link. The customer side (the public /bind/ page) lives in selfbind.go. No hub
// customer-login exists — the emailed link IS the auth model.

// selfBindTTL is the capability link's lifetime. After it, self-bind falls back to operator-bind
// unchanged (the token simply reads as expired; nothing else regresses).
const selfBindTTL = 7 * 24 * time.Hour

// selfBindBaseURL is the hub's public origin, matching the hardcoded origin used elsewhere
// (configgen). The link is https://hub.felhom.eu/bind/<token>.
const selfBindBaseURL = "https://hub.felhom.eu"

// SelfBindMailer delivers the self-bind capability link to the registered customer address. The
// notify.Dispatcher implements it (a sibling of the claim mailer — NOT routed through claim). The
// signature takes plain strings so the implementation needs no import of this package.
type SelfBindMailer interface {
	SendSelfBindEmail(customerID, email, link string) error
}

// SetSelfBindMailer wires the self-bind link sender (v0.66.0). Absent → the button returns 502.
func (s *Server) SetSelfBindMailer(m SelfBindMailer) { s.selfBindMailer = m }

func selfBindHash(token string) string {
	sum := sha256.Sum256([]byte(token))
	return hex.EncodeToString(sum[:])
}

// handleSelfBindLinkSend — POST /customers/{id}/selfbind-link. Mints a single-active capability token
// for the customer and emails the public bind link. Honesty rules:
//   - F1: no registered email → nothing is minted, LOUD flash (a link no one can receive is useless).
//   - F2: email send fails → the just-minted token is deleted (not left silently live), LOUD flash.
//
// The plaintext token exists only between minting and the send; it is never logged (only an 8-char
// hash prefix) and never persisted (only its sha256).
func (s *Server) handleSelfBindLinkSend(w http.ResponseWriter, r *http.Request, customerID string) {
	if s.selfBindMailer == nil {
		http.Error(w, "Self-bind mailer is not configured on this hub", http.StatusBadGateway)
		return
	}
	cfg, err := s.store.GetCustomerConfig(customerID)
	if err != nil || cfg == nil {
		http.NotFound(w, r)
		return
	}
	// F1: refuse to mint a link that cannot be delivered.
	if cfg.Email == "" {
		s.logger.Printf("[WARN] self-bind link for %s NOT sent: customer has no registered email", customerID)
		http.Redirect(w, r, "/customers/"+customerID+"?flash=selfbind-no-email#tab=setup", http.StatusSeeOther)
		return
	}

	token, err := configgen.RandomHex(32) // 256-bit capability token
	if err != nil {
		s.logger.Printf("[ERROR] self-bind link for %s: token generation: %v", customerID, err)
		http.Error(w, "Internal error", http.StatusInternalServerError)
		return
	}
	hash := selfBindHash(token)
	if err := s.store.MintSelfBindToken(customerID, hash, selfBindTTL); err != nil {
		s.logger.Printf("[ERROR] self-bind link for %s: minting token: %v", customerID, err)
		http.Error(w, "Internal error", http.StatusInternalServerError)
		return
	}

	link := selfBindBaseURL + "/bind/" + token
	if err := s.selfBindMailer.SendSelfBindEmail(customerID, cfg.Email, link); err != nil {
		// F2: delivery failed — do not leave a live capability token behind (the plaintext link is
		// already gone from memory, so nobody could ever use it; delete it and surface the failure).
		if derr := s.store.DeleteSelfBindTokens(customerID); derr != nil {
			s.logger.Printf("[ERROR] self-bind link for %s: send failed AND cleanup failed: send=%v cleanup=%v", customerID, err, derr)
		} else {
			s.logger.Printf("[ERROR] self-bind link for %s: email send failed, token invalidated (hash %s…): %v", customerID, hash[:8], err)
		}
		http.Redirect(w, r, "/customers/"+customerID+"?flash=selfbind-send-failed#tab=setup", http.StatusSeeOther)
		return
	}
	if err := s.store.MarkSelfBindEmailed(hash); err != nil {
		s.logger.Printf("[WARN] self-bind link sent to %s but emailed_at not recorded: %v", customerID, err)
	}
	s.logger.Printf("[INFO] self-bind link (hash %s…, valid 7 days) emailed to the registered address of %s", hash[:8], customerID)
	http.Redirect(w, r, "/customers/"+customerID+"?flash=selfbind-sent#tab=setup", http.StatusSeeOther)
}