package assets

import (
	"net/url"
	"strings"
	"testing"
	"time"

	"infinite-canvas/backend/internal/kernel"
	"infinite-canvas/backend/internal/model"
	"infinite-canvas/backend/internal/storage"
)

func testReadyResource(provider string) *model.Resource {
	return &model.Resource{
		ID: "resource-1", UserID: "user-1", Provider: provider, ObjectKey: "users/user-1/image/test.png",
		Status: model.ResourceStatusReady, MimeType: "image/png", ETag: "etag-1",
	}
}

func testPlatformURL(variants *[]ResourceVariant) func(ResourceVariant, time.Time) (string, error) {
	return func(variant ResourceVariant, _ time.Time) (string, error) {
		*variants = append(*variants, variant)
		return "https://canvas.example/api/resources/resource-1/file", nil
	}
}

func TestResolveAccessPolicyMatrix(t *testing.T) {
	now := time.Date(2026, time.January, 2, 3, 4, 5, 0, time.UTC)
	tests := []struct {
		name       string
		resource   *model.Resource
		setting    storage.Settings
		options    AccessOptions
		wantMode   DeliveryMode
		wantReason string
		wantURL    string
		wantErr    string
	}{
		{
			name:     "local uses platform controlled URL",
			resource: testReadyResource("local"),
			options:  AccessOptions{Purpose: PurposeDisplay},
			wantMode: DeliveryLocal,
			wantURL:  "https://canvas.example/api/resources/resource-1/file",
		},
		{
			name:     "public CDN uses CDN URL",
			resource: testReadyResource("aliyun"),
			setting:  storage.Settings{Provider: "aliyun", CDNBaseURL: "https://media.example.com", Delivery: storage.DeliverySettings{CDNAuthMode: "public"}},
			options:  AccessOptions{Purpose: PurposeCopy},
			wantMode: DeliveryCDN,
			wantURL:  "https://media.example.com/users/user-1/image/test.png",
		},
		{
			name:     "CDN without supported auth falls back to public origin",
			resource: testReadyResource("aliyun"),
			setting:  storage.Settings{Provider: "aliyun", Endpoint: "https://s3.amazonaws.com", CDNBaseURL: "https://media.example.com", AccessKeyID: "id", AccessKeySecret: "secret"},
			options:  AccessOptions{Purpose: PurposeDisplay},
			wantMode: DeliveryOrigin, wantReason: "cdn_auth_unconfigured",
		},
		{
			name:     "require CDN rejects incomplete CDN auth",
			resource: testReadyResource("aliyun"),
			setting:  storage.Settings{Provider: "aliyun", Endpoint: "https://s3.amazonaws.com", CDNBaseURL: "https://media.example.com", AccessKeyID: "id", AccessKeySecret: "secret", Delivery: storage.DeliverySettings{RequireCDN: true}},
			options:  AccessOptions{Purpose: PurposeDisplay},
			wantErr:  "resource_cdn_unconfigured",
		},
		{
			name:     "browser access never proxies a private OSS origin",
			resource: testReadyResource("aliyun"),
			setting:  storage.Settings{Provider: "aliyun", Endpoint: "http://storage.internal", Delivery: storage.DeliverySettings{AllowPrivateProxy: true}},
			options:  AccessOptions{Purpose: PurposeDisplay},
			wantErr:  "resource_origin_private",
		},
		{
			name:     "provider input may use an explicitly enabled private proxy",
			resource: testReadyResource("aliyun"),
			setting:  storage.Settings{Provider: "aliyun", Endpoint: "http://storage.internal", Delivery: storage.DeliverySettings{AllowPrivateProxy: true}},
			options:  AccessOptions{Purpose: PurposeProvider},
			wantMode: DeliveryProxy, wantReason: "private_origin",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			var variants []ResourceVariant
			access, err := ResolveAccess(tt.resource, tt.setting, tt.options, now, testPlatformURL(&variants))
			if tt.wantErr != "" {
				if err == nil || !strings.Contains(string(errorReason(err)), tt.wantErr) {
					t.Fatalf("ResolveAccess() error = %v, want reason %q", err, tt.wantErr)
				}
				return
			}
			if err != nil {
				t.Fatalf("ResolveAccess() error = %v", err)
			}
			if access.Delivery != tt.wantMode || access.FallbackReason != tt.wantReason {
				t.Fatalf("ResolveAccess() = %#v, want mode=%q reason=%q", access, tt.wantMode, tt.wantReason)
			}
			if tt.wantURL != "" && access.URL != tt.wantURL {
				t.Fatalf("ResolveAccess().URL = %q, want %q", access.URL, tt.wantURL)
			}
		})
	}
}

func TestResolveAccessVariantAndExpiryContract(t *testing.T) {
	now := time.Date(2026, time.January, 2, 3, 4, 5, 0, time.UTC)
	resource := testReadyResource("local")
	resource.Kind = "video"
	resource.PlaybackStatus = model.PlaybackStatusReady
	resource.PlaybackObjectKey = "playback/resource-1.mp4"
	var variants []ResourceVariant
	access, err := ResolveAccess(resource, storage.Settings{}, AccessOptions{Purpose: PurposeProcess, Variant: VariantPlayback, ExpiresAt: now.Add(90 * time.Second)}, now, testPlatformURL(&variants))
	if err != nil {
		t.Fatal(err)
	}
	if access.ActualVariant != VariantPlayback || access.ExpiresAt == nil || !access.ExpiresAt.Equal(now.Add(90*time.Second)) {
		t.Fatalf("playback access = %#v", access)
	}
	if len(variants) != 1 || variants[0] != VariantPlayback {
		t.Fatalf("platform URL variants = %#v, want playback", variants)
	}

	provider, err := ResolveAccess(resource, storage.Settings{}, AccessOptions{Purpose: PurposeProvider}, now, testPlatformURL(&variants))
	if err != nil {
		t.Fatal(err)
	}
	if provider.ExpiresAt == nil || !provider.ExpiresAt.Equal(now.Add(4*time.Hour)) {
		t.Fatalf("provider access expiry = %v, want %v", provider.ExpiresAt, now.Add(4*time.Hour))
	}
}

func TestResolveDownloadUsesObjectOriginAttachmentInsteadOfCDNOrProxy(t *testing.T) {
	now := time.Date(2026, time.January, 2, 3, 4, 5, 0, time.UTC)
	resource := testReadyResource("aliyun")
	setting := storage.Settings{
		// A public IP keeps the test deterministic: PublicOrigin intentionally
		// resolves hostnames to reject private DNS answers, so a made-up OSS host
		// would depend on the machine's DNS configuration.
		Provider: "aliyun", Endpoint: "https://1.1.1.1", Bucket: "private-bucket",
		AccessKeyID: "access-id", AccessKeySecret: "secret-value", CDNBaseURL: "https://media.example.com",
		Delivery: storage.DeliverySettings{CDNAuthMode: "public"},
	}
	access, err := ResolveAccess(resource, setting, AccessOptions{Purpose: PurposeDownload, DownloadName: "画布_镜头01.mp4"}, now, testPlatformURL(&[]ResourceVariant{}))
	if err != nil {
		t.Fatal(err)
	}
	parsed, err := url.Parse(access.URL)
	if err != nil {
		t.Fatal(err)
	}
	disposition := parsed.Query().Get("response-content-disposition")
	if access.Delivery != DeliveryOrigin || parsed.Host != "1.1.1.1" || !strings.HasPrefix(disposition, "attachment") || !strings.Contains(strings.ToLower(disposition), "utf-8''") {
		t.Fatalf("download access = %#v, disposition=%q", access, disposition)
	}
}

func TestResolveDownloadRejectsPrivateOriginInsteadOfProxyingMediaBytes(t *testing.T) {
	setting := storage.Settings{
		Provider: "aliyun", Endpoint: "http://storage.internal", Bucket: "private-bucket",
		Delivery: storage.DeliverySettings{AllowPrivateProxy: true},
	}
	_, err := ResolveAccess(testReadyResource("aliyun"), setting, AccessOptions{Purpose: PurposeDownload}, time.Now(), testPlatformURL(&[]ResourceVariant{}))
	if err == nil || errorReason(err) != "resource_origin_private" {
		t.Fatalf("ResolveAccess() error = %v, want resource_origin_private", err)
	}
}

func TestResolveAccessRejectsPendingResource(t *testing.T) {
	resource := testReadyResource("local")
	resource.Status = model.ResourceStatusPending
	_, err := ResolveAccess(resource, storage.Settings{}, AccessOptions{Purpose: PurposeDisplay}, time.Now(), func(ResourceVariant, time.Time) (string, error) {
		return "", nil
	})
	if err == nil || !strings.Contains(string(errorReason(err)), "resource_not_ready") {
		t.Fatalf("ResolveAccess() error = %v, want resource_not_ready", err)
	}
}

func errorReason(err error) string {
	if appErr, ok := err.(*kernel.AppError); ok {
		return string(appErr.Reason)
	}
	return err.Error()
}