package httpapi

import (
	"net/http"

	"github.com/mitbringsl/backend/internal/config"
)

// ConfigHandler exposes the public server configuration that the Android app
// needs before logging in (e.g. which auth methods are available).
type ConfigHandler struct {
	cfg *config.Config
}

// NewConfigHandler creates a ConfigHandler.
func NewConfigHandler(cfg *config.Config) *ConfigHandler {
	return &ConfigHandler{cfg: cfg}
}

// serverConfigResponse is the public config payload returned to the app.
type serverConfigResponse struct {
	Auth authConfig `json:"auth"`
}

// authConfig describes which login methods the server offers.
type authConfig struct {
	PasswordEnabled bool            `json:"password_enabled"`
	OIDC            oidcProvidersDTO `json:"oidc"`
}

type oidcProvidersDTO struct {
	Google  oidcProviderDTO `json:"google"`
	Generic oidcProviderDTO `json:"generic"`
}

type oidcProviderDTO struct {
	Enabled    bool   `json:"enabled"`
	Issuer     string `json:"issuer,omitempty"`
	DisplayName string `json:"display_name,omitempty"`
}

// Config returns the public server configuration.
// GET /api/config  (public, no auth required)
func (h *ConfigHandler) Config(w http.ResponseWriter, r *http.Request) {
	renderJSON(w, http.StatusOK, serverConfigResponse{
		Auth: authConfig{
			PasswordEnabled: h.cfg.AuthPasswordEnabled,
			OIDC: oidcProvidersDTO{
				Google: oidcProviderDTO{
					Enabled:     h.cfg.GoogleOIDC.Enabled,
					Issuer:      h.cfg.GoogleOIDC.Issuer,
					DisplayName: "Google",
				},
				Generic: oidcProviderDTO{
					Enabled:     h.cfg.GenericOIDC.Enabled,
					Issuer:      h.cfg.GenericOIDC.Issuer,
					DisplayName: h.cfg.GenericOIDC.DisplayName,
				},
			},
		},
	})
}