package httpx

import (
	"io/fs"
	"net/http"
	"path"
	"strings"

	"github.com/gin-gonic/gin"
)

func registerDocs(r *gin.Engine) {
	r.GET("/openapi.yaml", func(c *gin.Context) {
		c.Data(http.StatusOK, "application/yaml; charset=utf-8", openAPISpec)
	})
	serve := func(c *gin.Context) {
		c.Data(http.StatusOK, "text/html; charset=utf-8", docsHTML)
	}
	r.GET("/docs", serve)
	r.GET("/docs/enums", serve)
	r.GET("/docs/errors", serve)
	r.GET("/docs/", func(c *gin.Context) {
		c.Redirect(http.StatusFound, "/docs")
	})

	staticRoot, err := fs.Sub(docsStatic, "docs/static")
	if err != nil {
		panic("docs static embed: " + err.Error())
	}
	serveStaticFile := func(name, contentType string) gin.HandlerFunc {
		return func(c *gin.Context) {
			b, err := fs.ReadFile(staticRoot, name)
			if err != nil {
				c.Status(http.StatusNotFound)
				return
			}
			c.Header("Cache-Control", "public, max-age=604800")
			c.Data(http.StatusOK, contentType, b)
		}
	}
	r.GET("/favicon.ico", serveStaticFile("favicon.ico", "image/x-icon"))
	r.GET("/apple-touch-icon.png", serveStaticFile("apple-touch-icon.png", "image/png"))
	r.GET("/docs/static/*filepath", func(c *gin.Context) {
		rel := strings.TrimPrefix(c.Param("filepath"), "/")
		rel = path.Clean("/" + rel)
		rel = strings.TrimPrefix(rel, "/")
		if rel == "" || strings.Contains(rel, "..") {
			c.Status(http.StatusNotFound)
			return
		}
		b, err := fs.ReadFile(staticRoot, rel)
		if err != nil {
			c.Status(http.StatusNotFound)
			return
		}
		ct := contentTypeFor(rel)
		c.Header("Cache-Control", "public, max-age=604800")
		c.Data(http.StatusOK, ct, b)
	})
}

func contentTypeFor(name string) string {
	switch strings.ToLower(path.Ext(name)) {
	case ".png":
		return "image/png"
	case ".ico":
		return "image/x-icon"
	case ".svg":
		return "image/svg+xml"
	default:
		return "application/octet-stream"
	}
}