package middleware

import (
	"encoding/json"
	"fmt"
	"go-api/static"
	"net/http"
	"net/textproto"
	"regexp"
	"strings"

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

type SwaggerOptions struct {
	Root string
}

var regex = regexp.MustCompile(`(src|href)="./`)
var specRegex = regexp.MustCompile(`url:.+`)

func SwaggerSpecServe() gin.HandlerFunc {
	return func(c *gin.Context) {
		b, err := static.GetSpec()
		if err != nil {
			c.String(http.StatusNotFound, "not found")
			return
		}

		var j map[string]interface{}
		if err := json.Unmarshal(b, &j); err != nil {
			c.String(http.StatusInternalServerError, "internal error")
			return
		}

		if _, ok := j["host"]; ok {
			j["host"] = c.Request.Host
		}
		if xfp := c.Request.Header.Get(textproto.CanonicalMIMEHeaderKey("X-Forwarded-Proto")); xfp != "" && xfp == "https" {
			j["schemes"] = []string{xfp}
		}

		c.JSON(http.StatusOK, j)
	}
}

func SwaggerServe(prefix string, opts *SwaggerOptions) gin.HandlerFunc {
	return func(c *gin.Context) {
		fp := c.Request.URL.Path

		if prefix != "" {
			if !strings.HasPrefix(fp, prefix) {
				c.Next()
				return
			}
			if fp = strings.Replace(fp, prefix, "", 1); fp == "" {
				fp = "/"
			}
		}

		// end of slash replace to index.html file
		if strings.HasSuffix(fp, "/") {
			fp += "index.html"
		}

		if b, mime, err := static.GetWebFile(fp); err == nil {
			// 如果是 index.html 要更新內部的連結 轉換成絕對路徑
			if fp == "/index.html" {
				replPrefix := prefix
				if !strings.HasSuffix(replPrefix, "/") {
					replPrefix += "/"
				}

				b = regex.ReplaceAll(b, []byte(fmt.Sprintf(`$1="%s`, replPrefix)))
				b = specRegex.ReplaceAll(b, []byte(fmt.Sprintf(`url: '%s.json',`, prefix)))
			}

			c.Writer.Header().Set(textproto.CanonicalMIMEHeaderKey("Content-Type"), mime)
			c.Status(http.StatusOK)
			c.Writer.Write(b)
			c.Abort()
		}

	}
}