/**
 * @Author: aesoper
 * @Description: 请求方法重写中间件
 * @File:  method_override
 * @Version: 1.0.0
 * @Date: 2020/5/19 19:01
 */

package gin_middleware

import (
	"gitee.com/gin-ecosystem/gin-middleware/consts"
	"github.com/gin-gonic/gin"
	"net/http"
	"strings"
)

type (
	MethodOverrideConfig struct {
		Skipper Skipper
		Getter  MethodOverrideGetter
	}

	MethodOverrideGetter func(ctx *gin.Context) string
)

var (
	DefaultMethodOverrideConfig = MethodOverrideConfig{
		Skipper: DefaultSkipper,
		Getter:  MethodFromHeader(consts.HeaderXHTTPMethodOverride),
	}
)

func DefaultMethodOverride() gin.HandlerFunc {
	return NewMethodOverride(DefaultMethodOverrideConfig)
}

func NewMethodOverride(config MethodOverrideConfig) gin.HandlerFunc {
	// Defaults
	if config.Skipper == nil {
		config.Skipper = DefaultMethodOverrideConfig.Skipper
	}
	if config.Getter == nil {
		config.Getter = DefaultMethodOverrideConfig.Getter
	}

	return func(ctx *gin.Context) {
		if config.Skipper(ctx) {
			ctx.Next()
			return
		}

		req := ctx.Request
		if req.Method == http.MethodPost {
			m := config.Getter(ctx)
			if m != "" {
				req.Method = strings.ToUpper(m)
			}
		}
		ctx.Next()
	}
}

func MethodFromHeader(header string) MethodOverrideGetter {
	return func(c *gin.Context) string {
		return c.Request.Header.Get(header)
	}
}

func MethodFromForm(param string) MethodOverrideGetter {
	return func(c *gin.Context) string {
		return c.PostForm(param)
	}
}

func MethodFromQuery(param string) MethodOverrideGetter {
	return func(c *gin.Context) string {
		return c.Query(param)
	}
}