package handler

import (
	"bytes"
	"context"
	"encoding/base64"
	"encoding/json"
	"errors"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"
	"vctp/internal/auth"
	"vctp/internal/settings"
	"vctp/server/models"
)

type stubLDAPAuthenticator struct {
	identity auth.LDAPIdentity
	err      error
}

func (s *stubLDAPAuthenticator) AuthenticateAndFetchGroups(_ context.Context, _ string, _ string) (auth.LDAPIdentity, error) {
	return s.identity, s.err
}

type stubJWTService struct {
	token  string
	claims auth.Claims
	err    error
}

func (s *stubJWTService) IssueToken(_ string, _ []string, _ []string) (string, auth.Claims, error) {
	return s.token, s.claims, s.err
}

func TestAuthLoginAuthDisabled(t *testing.T) {
	h := &Handler{
		Logger:   newTestLogger(),
		Settings: &settings.Settings{Values: &settings.SettingsYML{}},
	}

	req := httptest.NewRequest(http.MethodPost, "/api/auth/login", bytes.NewBufferString(`{"username":"alice","password":"pw"}`))
	rr := httptest.NewRecorder()
	h.AuthLogin(rr, req)

	if rr.Code != http.StatusServiceUnavailable {
		t.Fatalf("expected status %d, got %d", http.StatusServiceUnavailable, rr.Code)
	}
}

func TestAuthLoginInvalidCredentials(t *testing.T) {
	restoreFactories := swapAuthFactoriesForTest(
		func(_ auth.LDAPConfig) (ldapAuthenticator, error) {
			return &stubLDAPAuthenticator{err: auth.ErrLDAPInvalidCredentials}, nil
		},
		func(_ auth.JWTConfig) (jwtService, error) {
			return &stubJWTService{}, nil
		},
	)
	defer restoreFactories()

	h := &Handler{
		Logger:   newTestLogger(),
		Settings: testAuthEnabledSettings(),
	}

	req := httptest.NewRequest(http.MethodPost, "/api/auth/login", bytes.NewBufferString(`{"username":"alice","password":"pw"}`))
	rr := httptest.NewRecorder()
	h.AuthLogin(rr, req)

	if rr.Code != http.StatusUnauthorized {
		t.Fatalf("expected status %d, got %d", http.StatusUnauthorized, rr.Code)
	}
	var payload models.ErrorResponse
	if err := json.Unmarshal(rr.Body.Bytes(), &payload); err != nil {
		t.Fatalf("failed to decode response: %v", err)
	}
	if payload.Message != authLoginFailureMessage {
		t.Fatalf("unexpected error message: %q", payload.Message)
	}
}

func TestAuthLoginRejectsUnmappedRoles(t *testing.T) {
	restoreFactories := swapAuthFactoriesForTest(
		func(_ auth.LDAPConfig) (ldapAuthenticator, error) {
			return &stubLDAPAuthenticator{
				identity: auth.LDAPIdentity{
					Username: "alice",
					Groups:   []string{"cn=other-group,ou=groups,dc=example,dc=com"},
				},
			}, nil
		},
		func(_ auth.JWTConfig) (jwtService, error) {
			return &stubJWTService{}, nil
		},
	)
	defer restoreFactories()

	h := &Handler{
		Logger:   newTestLogger(),
		Settings: testAuthEnabledSettings(),
	}

	req := httptest.NewRequest(http.MethodPost, "/api/auth/login", bytes.NewBufferString(`{"username":"alice","password":"pw"}`))
	rr := httptest.NewRecorder()
	h.AuthLogin(rr, req)

	if rr.Code != http.StatusUnauthorized {
		t.Fatalf("expected status %d, got %d", http.StatusUnauthorized, rr.Code)
	}
}

func TestAuthLoginSuccess(t *testing.T) {
	restoreFactories := swapAuthFactoriesForTest(
		func(_ auth.LDAPConfig) (ldapAuthenticator, error) {
			return &stubLDAPAuthenticator{
				identity: auth.LDAPIdentity{
					Username: "alice",
					UserDN:   "cn=alice,ou=users,dc=example,dc=com",
					Groups:   []string{"cn=vctp-admins,ou=groups,dc=example,dc=com"},
				},
			}, nil
		},
		func(_ auth.JWTConfig) (jwtService, error) {
			return &stubJWTService{
				token: "issued-token",
				claims: auth.Claims{
					ExpiresAt: time.Unix(1_700_000_000, 0).Unix(),
				},
			}, nil
		},
	)
	defer restoreFactories()

	h := &Handler{
		Logger:   newTestLogger(),
		Settings: testAuthEnabledSettings(),
	}

	req := httptest.NewRequest(http.MethodPost, "/api/auth/login", bytes.NewBufferString(`{"username":"alice","password":"pw"}`))
	rr := httptest.NewRecorder()
	h.AuthLogin(rr, req)

	if rr.Code != http.StatusOK {
		t.Fatalf("expected status %d, got %d: %s", http.StatusOK, rr.Code, rr.Body.String())
	}
	var payload models.AuthLoginResponse
	if err := json.Unmarshal(rr.Body.Bytes(), &payload); err != nil {
		t.Fatalf("failed to decode response: %v", err)
	}
	if payload.AccessToken != "issued-token" {
		t.Fatalf("unexpected token: %q", payload.AccessToken)
	}
	if payload.TokenType != "Bearer" {
		t.Fatalf("unexpected token type: %q", payload.TokenType)
	}
}

func TestAuthLoginJWTFactoryFailure(t *testing.T) {
	restoreFactories := swapAuthFactoriesForTest(
		func(_ auth.LDAPConfig) (ldapAuthenticator, error) {
			return &stubLDAPAuthenticator{
				identity: auth.LDAPIdentity{
					Username: "alice",
					Groups:   []string{"cn=vctp-admins,ou=groups,dc=example,dc=com"},
				},
			}, nil
		},
		func(_ auth.JWTConfig) (jwtService, error) {
			return nil, errors.New("jwt init failed")
		},
	)
	defer restoreFactories()

	h := &Handler{
		Logger:   newTestLogger(),
		Settings: testAuthEnabledSettings(),
	}

	req := httptest.NewRequest(http.MethodPost, "/api/auth/login", bytes.NewBufferString(`{"username":"alice","password":"pw"}`))
	rr := httptest.NewRecorder()
	h.AuthLogin(rr, req)

	if rr.Code != http.StatusInternalServerError {
		t.Fatalf("expected status %d, got %d", http.StatusInternalServerError, rr.Code)
	}
}

func testAuthEnabledSettings() *settings.Settings {
	cfg := &settings.Settings{Values: &settings.SettingsYML{}}
	cfg.Values.Settings.AuthEnabled = true
	cfg.Values.Settings.AuthMode = "required"
	cfg.Values.Settings.AuthJWTSigningKey = base64.StdEncoding.EncodeToString([]byte("test-signing-key"))
	cfg.Values.Settings.AuthTokenLifespanMinutes = 120
	cfg.Values.Settings.AuthJWTIssuer = "vctp"
	cfg.Values.Settings.AuthJWTAudience = "vctp-api"
	cfg.Values.Settings.AuthClockSkewSeconds = 60
	cfg.Values.Settings.LDAPBindAddress = "ldaps://ldap.example.com:636"
	cfg.Values.Settings.LDAPBaseDN = "dc=example,dc=com"
	cfg.Values.Settings.AuthGroupRoleMappings = map[string]string{
		"cn=vctp-admins,ou=groups,dc=example,dc=com": "admin",
	}
	return cfg
}

func swapAuthFactoriesForTest(
	ldapFactory func(auth.LDAPConfig) (ldapAuthenticator, error),
	jwtFactory func(auth.JWTConfig) (jwtService, error),
) func() {
	origLDAPFactory := newLDAPAuthenticator
	origJWTFactory := newJWTService
	newLDAPAuthenticator = ldapFactory
	newJWTService = jwtFactory
	return func() {
		newLDAPAuthenticator = origLDAPFactory
		newJWTService = origJWTFactory
	}
}