package httpapi

import (
	"context"
	"encoding/json"
	"errors"
	"io"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"testing"

	"github.com/easyai/easyai-ai-gateway/apps/api/internal/auth"
	"github.com/easyai/easyai-ai-gateway/apps/api/internal/config"
	"github.com/easyai/easyai-ai-gateway/apps/api/internal/store"
)

type fakeOIDCUserResolver struct {
	result store.ResolveOrProvisionOIDCUserResult
	err    error
	calls  int
	input  store.ResolveOrProvisionOIDCUserInput
}

func (f *fakeOIDCUserResolver) ResolveOrProvisionOIDCUser(_ context.Context, input store.ResolveOrProvisionOIDCUserInput) (store.ResolveOrProvisionOIDCUserResult, error) {
	f.calls++
	f.input = input
	return f.result, f.err
}

func TestResolveGatewayUserAddsLocalOIDCContext(t *testing.T) {
	resolver := &fakeOIDCUserResolver{result: store.ResolveOrProvisionOIDCUserResult{User: &auth.User{
		ID:              "platform-user",
		Username:        "alice",
		Roles:           []string{"basic"},
		TenantID:        "external-tenant",
		Source:          "oidc",
		GatewayUserID:   "21dd9ccb-3793-4023-ab31-4d04982ca4d3",
		GatewayTenantID: "8f17f3ac-136e-4d0f-b097-655e2a6240a3",
		TenantKey:       "default",
		UserGroupID:     "6dcf86f2-8eaf-4b43-8e69-181315db24f0",
	}}}
	server := &Server{
		cfg: config.Config{
			OIDCIssuer:                 "https://auth.test.example/realms/easyai",
			OIDCGatewayTenantKey:       "default",
			OIDCJITProvisioningEnabled: true,
		},
		oidcUserResolver: resolver,
		logger:           slog.New(slog.NewTextHandler(io.Discard, nil)),
	}

	next := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		user, ok := auth.UserFromContext(r.Context())
		if !ok || user.GatewayUserID == "" || user.GatewayTenantID == "" || user.UserGroupID == "" {
			t.Fatalf("resolved Gateway context missing: %+v", user)
		}
		writeJSON(w, http.StatusOK, user)
	})
	request := httptest.NewRequest(http.MethodGet, "/api/v1/me", nil)
	request = request.WithContext(auth.WithUser(request.Context(), &auth.User{
		ID:       "platform-user",
		Username: "alice",
		Roles:    []string{"basic"},
		TenantID: "external-tenant",
		Source:   "oidc",
	}))
	recorder := httptest.NewRecorder()

	server.resolveGatewayUser(next).ServeHTTP(recorder, request)
	if recorder.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", recorder.Code)
	}
	if resolver.calls != 1 || resolver.input.Subject != "platform-user" || resolver.input.GatewayTenantKey != "default" || !resolver.input.ProvisioningEnabled {
		t.Fatalf("unexpected resolver call: calls=%d input=%+v", resolver.calls, resolver.input)
	}
}

func TestResolveGatewayUserLeavesNonOIDCIdentityChainsUnchanged(t *testing.T) {
	for _, source := range []string{"gateway", "api_key", "server-main"} {
		t.Run(source, func(t *testing.T) {
			resolver := &fakeOIDCUserResolver{}
			server := &Server{oidcUserResolver: resolver, logger: slog.New(slog.NewTextHandler(io.Discard, nil))}
			request := httptest.NewRequest(http.MethodGet, "/api/v1/me", nil)
			original := &auth.User{ID: "local-user", Source: source, GatewayUserID: "local-user"}
			request = request.WithContext(auth.WithUser(request.Context(), original))
			recorder := httptest.NewRecorder()

			server.resolveGatewayUser(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				resolved, _ := auth.UserFromContext(r.Context())
				if resolved != original {
					t.Fatalf("non-OIDC identity context was replaced: %+v", resolved)
				}
				w.WriteHeader(http.StatusNoContent)
			})).ServeHTTP(recorder, request)

			if recorder.Code != http.StatusNoContent || resolver.calls != 0 {
				t.Fatalf("status=%d resolver calls=%d", recorder.Code, resolver.calls)
			}
		})
	}
}

func TestResolveGatewayUserReturnsStructuredErrors(t *testing.T) {
	tests := []struct {
		name   string
		err    error
		status int
		code   string
	}{
		{name: "not provisioned", err: store.ErrOIDCUserNotProvisioned, status: http.StatusForbidden, code: "GATEWAY_USER_NOT_PROVISIONED"},
		{name: "disabled", err: store.ErrOIDCUserDisabled, status: http.StatusForbidden, code: "GATEWAY_USER_DISABLED"},
		{name: "tenant unavailable", err: store.ErrOIDCTenantUnavailable, status: http.StatusServiceUnavailable, code: "GATEWAY_TENANT_UNAVAILABLE"},
		{name: "storage failure", err: errors.New("database unavailable"), status: http.StatusServiceUnavailable, code: "GATEWAY_USER_PROVISIONING_FAILED"},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			server := &Server{
				cfg:              config.Config{OIDCIssuer: "https://auth.test.example", OIDCGatewayTenantKey: "default"},
				oidcUserResolver: &fakeOIDCUserResolver{err: test.err},
				logger:           slog.New(slog.NewTextHandler(io.Discard, nil)),
			}
			request := httptest.NewRequest(http.MethodGet, "/api/v1/me", nil)
			request = request.WithContext(auth.WithUser(request.Context(), &auth.User{
				ID: "platform-user", Source: "oidc", TenantID: "external-tenant",
			}))
			recorder := httptest.NewRecorder()
			server.resolveGatewayUser(http.HandlerFunc(func(http.ResponseWriter, *http.Request) {
				t.Fatal("next handler must not run")
			})).ServeHTTP(recorder, request)

			if recorder.Code != test.status {
				t.Fatalf("status = %d, want %d", recorder.Code, test.status)
			}
			var envelope struct {
				Error struct {
					Code    string `json:"code"`
					Message string `json:"message"`
					Status  int    `json:"status"`
				} `json:"error"`
			}
			if err := json.Unmarshal(recorder.Body.Bytes(), &envelope); err != nil {
				t.Fatalf("decode error envelope: %v", err)
			}
			if envelope.Error.Code != test.code || envelope.Error.Status != test.status || envelope.Error.Message == "" {
				t.Fatalf("unexpected error envelope: %+v", envelope)
			}
			if envelope.Error.Message == test.err.Error() {
				t.Fatalf("internal error leaked to response: %q", envelope.Error.Message)
			}
		})
	}
}