package swaggerui

import (
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"
	swaggerFiles "github.com/swaggo/files"
	ginSwagger "github.com/swaggo/gin-swagger"
)

const initializerJS = `window.onload = function() {
  const ui = SwaggerUIBundle({
    url: "doc.json",
    dom_id: '#swagger-ui',
    validatorUrl: null,
    persistAuthorization: true,
    presets: [
      SwaggerUIBundle.presets.apis,
      SwaggerUIStandalonePreset
    ],
    plugins: [
      SwaggerUIBundle.plugins.DownloadUrl
    ],
    layout: "StandaloneLayout",
    docExpansion: "list",
    deepLinking: true,
    defaultModelsExpandDepth: 1,
    requestInterceptor: function(request) {
      const auth = request.headers.Authorization || request.headers.authorization

      if (typeof auth === 'string') {
        const trimmed = auth.trim()

        if (trimmed !== '' && !/^Bearer\s+/i.test(trimmed)) {
          request.headers.Authorization = 'Bearer ' + trimmed
        }
      }

      return request
    }
  })

  window.ui = ui
}
`

// Handler serves Swagger UI and overrides the initializer script to prefix raw tokens with Bearer.
func Handler() gin.HandlerFunc {
	defaultHandler := ginSwagger.WrapHandler(swaggerFiles.Handler, ginSwagger.PersistAuthorization(true))

	return func(c *gin.Context) {
		if strings.HasSuffix(c.Request.URL.Path, "/swagger-initializer.js") {
			c.Data(http.StatusOK, "application/javascript", []byte(initializerJS))
			return
		}

		defaultHandler(c)
	}
}