package auth

import (
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"
)

func bearerHeader(token string) string {
	return "Bearer " + token
}

func claimsHandler(t *testing.T) http.Handler {
	t.Helper()
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		claims, ok := ClaimsFromContext(r.Context())
		if !ok {
			http.Error(w, "no claims in context", http.StatusInternalServerError)
			return
		}
		w.Header().Set("X-Claims-Sub", claims.Sub)
		w.Header().Set("X-Claims-Role", string(claims.Role))
		w.WriteHeader(http.StatusOK)
	})
}

func doAuth(h http.Handler, tok string) *httptest.ResponseRecorder {
	req := httptest.NewRequest(http.MethodGet, "/", nil)
	if tok != "" {
		req.Header.Set("Authorization", bearerHeader(tok))
	}
	rr := httptest.NewRecorder()
	h.ServeHTTP(rr, req)
	return rr
}

func responseCode(t *testing.T, rr *httptest.ResponseRecorder, want int) {
	t.Helper()
	if rr.Code != want {
		t.Fatalf("status = %d, want %d (body: %s)", rr.Code, want, rr.Body.String())
	}
}

func assertErrorCode(t *testing.T, rr *httptest.ResponseRecorder, want string) {
	t.Helper()
	var body struct {
		Error struct {
			Code    string `json:"code"`
			Message string `json:"message"`
		} `json:"error"`
	}
	if err := json.NewDecoder(strings.NewReader(rr.Body.String())).Decode(&body); err != nil {
		t.Fatalf("decode error body: %v", err)
	}
	if body.Error.Code != want {
		t.Errorf("error.code = %q, want %q", body.Error.Code, want)
	}
}

func TestAuthorize_NoBearer(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	rr := doAuth(svc.Authorize(RoleViewer)(claimsHandler(t)), "")
	responseCode(t, rr, http.StatusUnauthorized)
	assertErrorCode(t, rr, "unauthorized")
}

func TestAuthorize_InvalidToken(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	rr := doAuth(svc.Authorize(RoleViewer)(claimsHandler(t)), "not-a-jwt")
	responseCode(t, rr, http.StatusUnauthorized)
	assertErrorCode(t, rr, "unauthorized")
}

func TestAuthorize_ExpiredToken(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleViewer, -time.Minute)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(svc.Authorize(RoleViewer)(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusUnauthorized)
	assertErrorCode(t, rr, "unauthorized")
}

func TestAuthorize_OwnerSatisfiesAdminAndViewer(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleOwner, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(svc.Authorize(RoleAdmin, RoleViewer)(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusOK)
	if rr.Header().Get("X-Claims-Sub") != "u" {
		t.Errorf("X-Claims-Sub = %q, want u", rr.Header().Get("X-Claims-Sub"))
	}
	if rr.Header().Get("X-Claims-Role") != "owner" {
		t.Errorf("X-Claims-Role = %q, want owner", rr.Header().Get("X-Claims-Role"))
	}
}

func TestAuthorize_AdminSatisfiesViewer(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleAdmin, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(svc.Authorize(RoleViewer)(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusOK)
}

func TestAuthorize_AdminFailsOwner(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleAdmin, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(svc.Authorize(RoleOwner)(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusForbidden)
	assertErrorCode(t, rr, "forbidden")
}

func TestAuthorize_ViewerFailsAdmin(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleViewer, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(svc.Authorize(RoleAdmin)(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusForbidden)
	assertErrorCode(t, rr, "forbidden")
}

func TestAuthorize_AnyAuthenticated(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleViewer, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(svc.Authorize()(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusOK)
}

func TestAuthorize_BearerPrefixRequired(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleViewer, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	req := httptest.NewRequest(http.MethodGet, "/", nil)
	req.Header.Set("Authorization", tok) // no "Bearer " prefix
	rr := httptest.NewRecorder()
	svc.Authorize(RoleViewer)(claimsHandler(t)).ServeHTTP(rr, req)
	responseCode(t, rr, http.StatusUnauthorized)
}

func TestClaimsFromContext_Missing(t *testing.T) {
	t.Parallel()
	if _, ok := ClaimsFromContext(context.Background()); ok {
		t.Fatal("ClaimsFromContext on empty ctx should return ok=false")
	}
}