feat(sub2api): add host adapter client and tests

internal/host/sub2api/capability_probe.go

@@ -0,0 +1,92 @@
+package sub2api
+
+import (
+	"bytes"
+	"context"
+	"net/http"
+	"strings"
+)
+
+func (c *Client) ProbeCapabilities(ctx context.Context) (HostCapabilities, error) {
+	groups, err := c.probeEndpoint(ctx, http.MethodPost, "/api/v1/admin/groups", map[string]any{})
+	if err != nil {
+		return HostCapabilities{}, err
+	}
+
+	channels, err := c.probeEndpoint(ctx, http.MethodPost, "/api/v1/admin/channels", map[string]any{})
+	if err != nil {
+		return HostCapabilities{}, err
+	}
+
+	plans, err := c.probeEndpoint(ctx, http.MethodPost, "/api/v1/admin/payment/plans", map[string]any{})
+	if err != nil {
+		return HostCapabilities{}, err
+	}
+
+	accounts, err := c.probeEndpoint(ctx, http.MethodPost, "/api/v1/admin/accounts", map[string]any{})
+	if err != nil {
+		return HostCapabilities{}, err
+	}
+
+	accountTest, err := c.probeEndpoint(ctx, http.MethodPost, "/api/v1/admin/accounts/__probe__/test", map[string]any{})
+	if err != nil {
+		return HostCapabilities{}, err
+	}
+
+	accountModels, err := c.probeEndpoint(ctx, http.MethodGet, "/api/v1/admin/accounts/__probe__/models", nil)
+	if err != nil {
+		return HostCapabilities{}, err
+	}
+
+	subscriptions, err := c.probeEndpoint(ctx, http.MethodPost, "/api/v1/admin/subscriptions/assign", map[string]any{})
+	if err != nil {
+		return HostCapabilities{}, err
+	}
+
+	return HostCapabilities{
+		Groups:        groups,
+		Channels:      channels,
+		Plans:         plans,
+		Accounts:      accounts,
+		AccountTest:   accountTest,
+		AccountModels: accountModels,
+		Subscriptions: subscriptions,
+	}, nil
+}
+
+func (c *Client) probeEndpoint(ctx context.Context, method, path string, requestBody any) (bool, error) {
+	statusCode, headers, body, err := c.perform(ctx, method, path, requestBody)
+	if err != nil {
+		return false, err
+	}
+
+	switch {
+	case statusCode >= http.StatusOK && statusCode < http.StatusMultipleChoices:
+		return true, nil
+	case statusCode == http.StatusUnauthorized || statusCode == http.StatusForbidden:
+		return false, newHTTPError(method, path, statusCode, body)
+	case statusCode == http.StatusNotFound || statusCode == http.StatusMethodNotAllowed:
+		return looksLikeExistingEndpoint(headers, body), nil
+	case statusCode >= http.StatusBadRequest && statusCode < http.StatusInternalServerError:
+		return true, nil
+	default:
+		return false, newHTTPError(method, path, statusCode, body)
+	}
+}
+
+func looksLikeExistingEndpoint(headers http.Header, body []byte) bool {
+	contentType := strings.ToLower(headers.Get("Content-Type"))
+	trimmedBody := bytes.TrimSpace(body)
+
+	if strings.Contains(contentType, "application/json") || strings.Contains(contentType, "text/event-stream") {
+		return true
+	}
+	if len(trimmedBody) == 0 {
+		return false
+	}
+	if trimmedBody[0] == '{' || trimmedBody[0] == '[' {
+		return true
+	}
+
+	return false
+}