package auth

import (
	"testing"
	"time"

	"github.com/bluesky-social/indigo/atproto/atcrypto"
	"github.com/golang-jwt/jwt/v5"
)

// TestCreateAppviewServiceToken_Claims locks the claim shape so we can detect
// regressions when swapping the underlying signer.
func TestCreateAppviewServiceToken_Claims(t *testing.T) {
	priv, err := atcrypto.GeneratePrivateKeyP256()
	if err != nil {
		t.Fatalf("generate key: %v", err)
	}

	const (
		appviewDID = "did:web:atcr.io"
		holdDID    = "did:web:hold01.atcr.io"
		userDID    = "did:plc:pddp4xt5lgnv2qsegbzzs4xg"
	)

	before := time.Now()
	tokenStr, err := CreateAppviewServiceToken(priv, appviewDID, holdDID, userDID)
	if err != nil {
		t.Fatalf("CreateAppviewServiceToken: %v", err)
	}
	after := time.Now()

	parser := jwt.NewParser(jwt.WithoutClaimsValidation())
	parsed, _, err := parser.ParseUnverified(tokenStr, jwt.MapClaims{})
	if err != nil {
		t.Fatalf("parse token: %v", err)
	}

	if parsed.Method.Alg() != "ES256" {
		t.Errorf("alg = %q, want ES256", parsed.Method.Alg())
	}

	claims, ok := parsed.Claims.(jwt.MapClaims)
	if !ok {
		t.Fatalf("claims type %T", parsed.Claims)
	}

	if got, _ := claims["iss"].(string); got != appviewDID {
		t.Errorf("iss = %q, want %q", got, appviewDID)
	}
	aud := claims["aud"]
	switch a := aud.(type) {
	case string:
		if a != holdDID {
			t.Errorf("aud = %q, want %q", a, holdDID)
		}
	case []any:
		if len(a) != 1 || a[0] != holdDID {
			t.Errorf("aud = %v, want [%q]", a, holdDID)
		}
	default:
		t.Errorf("aud unexpected type %T = %v", aud, aud)
	}

	exp, err := claims.GetExpirationTime()
	if err != nil || exp == nil {
		t.Fatalf("exp missing: %v", err)
	}
	delta := exp.Sub(before)
	if delta < 55*time.Second || delta > 65*time.Second {
		t.Errorf("exp delta from sign time = %v, want ~60s", delta)
	}

	iat, err := claims.GetIssuedAt()
	if err != nil || iat == nil {
		t.Fatalf("iat missing: %v", err)
	}
	if iat.Before(before.Add(-1*time.Second)) || iat.After(after.Add(1*time.Second)) {
		t.Errorf("iat = %v, outside sign window [%v, %v]", iat.Time, before, after)
	}

	if got, _ := claims["sub"].(string); got != userDID {
		t.Errorf("sub = %q, want %q", got, userDID)
	}
	if got, _ := claims["lxm"].(string); got != AppviewLxm.String() {
		t.Errorf("lxm = %q, want %q", got, AppviewLxm.String())
	}
	if got, _ := claims["jti"].(string); got == "" {
		t.Error("jti claim missing — required for replay protection")
	}
}

// TestCreateAppviewServiceToken_K256UsesES256K — when given a secp256k1 key,
// the token must be signed with ES256K so K-256-only appviews (legacy ATProto
// PDS keys) can still authenticate to hold.
func TestCreateAppviewServiceToken_K256UsesES256K(t *testing.T) {
	priv, err := atcrypto.GeneratePrivateKeyK256()
	if err != nil {
		t.Fatalf("generate K-256: %v", err)
	}
	tok, err := CreateAppviewServiceToken(priv, "did:web:atcr.io", "did:web:hold01.atcr.io", "did:plc:pddp4xt5lgnv2qsegbzzs4xg")
	if err != nil {
		t.Fatalf("sign: %v", err)
	}
	parser := jwt.NewParser(jwt.WithoutClaimsValidation())
	parsed, _, err := parser.ParseUnverified(tok, jwt.MapClaims{})
	if err != nil {
		t.Fatalf("parse: %v", err)
	}
	if parsed.Method.Alg() != "ES256K" {
		t.Errorf("alg = %q, want ES256K", parsed.Method.Alg())
	}
}

// TestCreateAppviewServiceToken_HasJTI — after the swap to indigo's
// SignServiceAuth, every token carries a non-empty `jti` (random nonce) so
// hold can reject replays. Two consecutive tokens get distinct jtis.
func TestCreateAppviewServiceToken_HasJTI(t *testing.T) {
	priv, err := atcrypto.GeneratePrivateKeyP256()
	if err != nil {
		t.Fatalf("generate key: %v", err)
	}
	const (
		appviewDID = "did:web:atcr.io"
		holdDID    = "did:web:hold01.atcr.io"
		userDID    = "did:plc:pddp4xt5lgnv2qsegbzzs4xg"
	)
	parser := jwt.NewParser(jwt.WithoutClaimsValidation())

	jti := func(t *testing.T) string {
		t.Helper()
		s, err := CreateAppviewServiceToken(priv, appviewDID, holdDID, userDID)
		if err != nil {
			t.Fatalf("sign: %v", err)
		}
		tok, _, err := parser.ParseUnverified(s, jwt.MapClaims{})
		if err != nil {
			t.Fatalf("parse: %v", err)
		}
		claims, _ := tok.Claims.(jwt.MapClaims)
		val, _ := claims["jti"].(string)
		return val
	}
	a := jti(t)
	if a == "" {
		t.Fatal("jti claim missing or empty — needed for replay prevention")
	}
	b := jti(t)
	if a == b {
		t.Errorf("two tokens share jti %q; expected distinct nonces", a)
	}
}