// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
//
// This Source Code Form is subject to the terms of the MIT License.
// If a copy of the MIT was not distributed with this file,
// You can obtain one at https://github.com/gogf/gf.

package ghttp

import (
	"bytes"
	"fmt"
	"io"
	"mime"
	"mime/multipart"
	"net/http"
	"reflect"
	"strings"

	"github.com/gogf/gf/v2/container/gvar"
	"github.com/gogf/gf/v2/encoding/gjson"
	"github.com/gogf/gf/v2/encoding/gurl"
	"github.com/gogf/gf/v2/encoding/gxml"
	"github.com/gogf/gf/v2/errors/gcode"
	"github.com/gogf/gf/v2/errors/gerror"
	"github.com/gogf/gf/v2/internal/json"
	"github.com/gogf/gf/v2/internal/utils"
	"github.com/gogf/gf/v2/text/gregex"
	"github.com/gogf/gf/v2/text/gstr"
	"github.com/gogf/gf/v2/util/gconv"
	"github.com/gogf/gf/v2/util/gvalid"
)

const (
	parseTypeRequest = iota
	parseTypeQuery
	parseTypeForm
)

var (
	// xmlHeaderBytes is the most common XML format header.
	xmlHeaderBytes = []byte("<?xml")
)

// Parse is the most commonly used function, which converts request parameters to struct or struct
// slice. It also automatically validates the struct or every element of the struct slice according
// to the validation tag of the struct.
//
// The parameter `pointer` can be type of: *struct/**struct/*[]struct/*[]*struct.
//
// It supports single and multiple struct converting:
// 1. Single struct, post content like: {"id":1, "name":"john"} or ?id=1&name=john
// 2. Multiple struct, post content like: [{"id":1, "name":"john"}, {"id":, "name":"smith"}]
//
// TODO: Improve the performance by reducing duplicated reflect usage on the same variable across packages.
func (r *Request) Parse(pointer interface{}) error {
	return r.doParse(pointer, parseTypeRequest)
}

// ParseQuery performs like function Parse, but only parses the query parameters.
func (r *Request) ParseQuery(pointer interface{}) error {
	return r.doParse(pointer, parseTypeQuery)
}

// ParseForm performs like function Parse, but only parses the form parameters or the body content.
func (r *Request) ParseForm(pointer interface{}) error {
	return r.doParse(pointer, parseTypeForm)
}

// doParse parses the request data to struct/structs according to request type.
func (r *Request) doParse(pointer interface{}, requestType int) error {
	var (
		reflectVal1  = reflect.ValueOf(pointer)
		reflectKind1 = reflectVal1.Kind()
	)
	if reflectKind1 != reflect.Ptr {
		return gerror.NewCodef(
			gcode.CodeInvalidParameter,
			`invalid parameter type "%v", of which kind should be of *struct/**struct/*[]struct/*[]*struct, but got: "%v"`,
			reflectVal1.Type(),
			reflectKind1,
		)
	}
	var (
		reflectVal2  = reflectVal1.Elem()
		reflectKind2 = reflectVal2.Kind()
	)
	switch reflectKind2 {
	// Single struct, post content like:
	// 1. {"id":1, "name":"john"}
	// 2. ?id=1&name=john
	case reflect.Ptr, reflect.Struct:
		var (
			err  error
			data map[string]interface{}
		)
		// Converting.
		switch requestType {
		case parseTypeQuery:
			if data, err = r.doGetQueryStruct(pointer); err != nil {
				return err
			}
		case parseTypeForm:
			if data, err = r.doGetFormStruct(pointer); err != nil {
				return err
			}
		default:
			if data, err = r.doGetRequestStruct(pointer); err != nil {
				return err
			}
		}
		// Validation.
		if err = gvalid.New().
			Bail().
			Data(pointer).
			Assoc(data).
			Run(r.Context()); err != nil {
			return err
		}

	// Multiple struct, it only supports JSON type post content like:
	// [{"id":1, "name":"john"}, {"id":, "name":"smith"}]
	case reflect.Array, reflect.Slice:
		// If struct slice conversion, it might post JSON/XML/... content,
		// so it uses `gjson` for the conversion.
		j, err := gjson.LoadContent(r.GetBody())
		if err != nil {
			return err
		}
		if err = j.Var().Scan(pointer); err != nil {
			return err
		}
		for i := 0; i < reflectVal2.Len(); i++ {
			if err = gvalid.New().
				Bail().
				Data(reflectVal2.Index(i)).
				Assoc(j.Get(gconv.String(i)).Map()).
				Run(r.Context()); err != nil {
				return err
			}
		}
	}
	return nil
}

// Get is alias of GetRequest, which is one of the most commonly used functions for
// retrieving parameter.
// See r.GetRequest.
func (r *Request) Get(key string, def ...interface{}) *gvar.Var {
	return r.GetRequest(key, def...)
}

// GetBody retrieves and returns request body content as bytes.
// It can be called multiple times retrieving the same body content.
func (r *Request) GetBody() []byte {
	if r.bodyContent == nil {
		r.bodyContent = r.MakeBodyRepeatableRead(true)
	}
	return r.bodyContent
}

// MakeBodyRepeatableRead marks the request body could be repeatedly readable or not.
// It also returns the current content of the request body.
func (r *Request) MakeBodyRepeatableRead(repeatableRead bool) []byte {
	if r.bodyContent == nil {
		var err error
		if r.bodyContent, err = io.ReadAll(r.Body); err != nil {
			errMsg := `Read from request Body failed`
			if gerror.Is(err, io.EOF) {
				errMsg += `, the Body might be closed or read manually from middleware/hook/other package previously`
			}
			panic(gerror.WrapCode(gcode.CodeInternalError, err, errMsg))
		}
	}
	r.Body = utils.NewReadCloser(r.bodyContent, repeatableRead)
	return r.bodyContent
}

// GetBodyString retrieves and returns request body content as string.
// It can be called multiple times retrieving the same body content.
func (r *Request) GetBodyString() string {
	return string(r.GetBody())
}

// GetJson parses current request content as JSON format, and returns the JSON object.
// Note that the request content is read from request BODY, not from any field of FORM.
func (r *Request) GetJson() (*gjson.Json, error) {
	return gjson.LoadWithOptions(r.GetBody(), gjson.Options{
		Type:      gjson.ContentTypeJson,
		StrNumber: true,
	})
}

// GetMap is an alias and convenient function for GetRequestMap.
// See GetRequestMap.
func (r *Request) GetMap(def ...map[string]interface{}) map[string]interface{} {
	return r.GetRequestMap(def...)
}

// GetMapStrStr is an alias and convenient function for GetRequestMapStrStr.
// See GetRequestMapStrStr.
func (r *Request) GetMapStrStr(def ...map[string]interface{}) map[string]string {
	return r.GetRequestMapStrStr(def...)
}

// GetStruct is an alias and convenient function for GetRequestStruct.
// See GetRequestStruct.
func (r *Request) GetStruct(pointer interface{}, mapping ...map[string]string) error {
	return r.GetRequestStruct(pointer, mapping...)
}

// parseQuery parses query string into r.queryMap.
func (r *Request) parseQuery() {
	if r.parsedQuery {
		return
	}
	r.parsedQuery = true
	if r.URL.RawQuery != "" {
		var err error
		r.queryMap, err = gstr.Parse(r.URL.RawQuery)
		if err != nil {
			panic(gerror.WrapCode(gcode.CodeInvalidParameter, err, "Parse Query failed"))
		}
	}
}

// parseBody parses the request raw data into r.rawMap.
// Note that it also supports JSON data from client request.
func (r *Request) parseBody() {
	if r.parsedBody {
		return
	}
	r.parsedBody = true
	// There's no data posted.
	if r.ContentLength == 0 {
		return
	}
	// If it's a multipart request, it does not parse the body content.
	contentType := r.Header.Get("Content-Type")
	if gstr.Contains(contentType, "multipart/") {
		return
	}

	// Skip binary content types, which should not be parsed.
	if r.isBinaryContentType(contentType) {
		return
	}

	if body := r.GetBody(); len(body) > 0 {
		// Trim space/new line characters.
		body = bytes.TrimSpace(body)

		// json/xml content type checks.
		if gstr.Contains(contentType, "/json") {
			_ = json.UnmarshalUseNumber(body, &r.bodyMap)
			return
		}
		if gstr.Contains(contentType, "/xml") {
			r.bodyMap, _ = gxml.DecodeWithoutRoot(body)
			return
		}
		// Auto decoding body content.
		if r.Server.config.AutoDecodingBody {
			// JSON format checks.
			if body[0] == '{' && body[len(body)-1] == '}' {
				_ = json.UnmarshalUseNumber(body, &r.bodyMap)
			}
			// XML format checks.
			if len(body) > 5 && bytes.EqualFold(body[:5], xmlHeaderBytes) {
				r.bodyMap, _ = gxml.DecodeWithoutRoot(body)
			}
			if body[0] == '<' && body[len(body)-1] == '>' {
				r.bodyMap, _ = gxml.DecodeWithoutRoot(body)
			}
		}
		// Default parameters decoding.
		if r.bodyMap == nil {
			r.bodyMap, _ = gstr.Parse(r.GetBodyString())
		}
	}
}

// parseForm parses the request form for HTTP method PUT, POST, PATCH.
// The form data is pared into r.formMap.
//
// Note that if the form was parsed firstly, the request body would be cleared and empty.
func (r *Request) parseForm() {
	if r.parsedForm {
		return
	}
	r.parsedForm = true
	// There's no data posted.
	if r.ContentLength == 0 {
		return
	}

	if contentType := r.Header.Get("Content-Type"); contentType != "" {
		var isMultiPartRequest = gstr.Contains(contentType, "multipart/")
		var isFormRequest = gstr.Contains(contentType, "form")
		var err error

		if !isMultiPartRequest {
			// To avoid big memory consuming.
			// The `multipart/` type form always contains binary data, which is not necessary read twice.
			r.MakeBodyRepeatableRead(true)
		}
		if isMultiPartRequest {
			// multipart/form-data, multipart/mixed
			if err = r.ParseMultipartForm(r.Server.config.FormParsingMemory); err != nil {
				panic(gerror.WrapCode(gcode.CodeInvalidRequest, err, "r.ParseMultipartForm failed"))
			}
		} else if isFormRequest {
			// application/x-www-form-urlencoded
			if err = r.Request.ParseForm(); err != nil {
				panic(gerror.WrapCode(gcode.CodeInvalidRequest, err, "r.Request.ParseForm failed"))
			}
		}
		if len(r.PostForm) > 0 {
			// Parse the form data using united parsing way.
			params := ""
			for name, values := range r.PostForm {
				// Invalid parameter name.
				// Only allow chars of: '\w', '[', ']', '-'.
				if !gregex.IsMatchString(`^[\w\-\[\]]+$`, name) && len(r.PostForm) == 1 {
					// It might be JSON/XML content.
					if s := gstr.Trim(name + strings.Join(values, " ")); len(s) > 0 {
						if s[0] == '{' && s[len(s)-1] == '}' || s[0] == '<' && s[len(s)-1] == '>' {
							r.bodyContent = []byte(s)
							params = ""
							break
						}
					}
				}
				if len(values) == 1 {
					if len(params) > 0 {
						params += "&"
					}
					params += name + "=" + gurl.Encode(values[0])
				} else {
					if len(name) > 2 && name[len(name)-2:] == "[]" {
						name = name[:len(name)-2]
						for _, v := range values {
							if len(params) > 0 {
								params += "&"
							}
							params += name + "[]=" + gurl.Encode(v)
						}
					} else {
						if len(params) > 0 {
							params += "&"
						}
						params += name + "=" + gurl.Encode(values[len(values)-1])
					}
				}
			}
			if params != "" {
				if r.formMap, err = gstr.Parse(params); err != nil {
					panic(gerror.WrapCode(gcode.CodeInvalidParameter, err, "Parse request parameters failed"))
				}
			}
		}
	}
	// It parses the request body without checking the Content-Type.
	if r.formMap == nil {
		if r.Method != http.MethodGet {
			r.parseBody()
		}
		if len(r.bodyMap) > 0 {
			r.formMap = r.bodyMap
		}
	}
}

// GetMultipartForm parses and returns the form as multipart forms.
func (r *Request) GetMultipartForm() *multipart.Form {
	r.parseForm()
	return r.MultipartForm
}

// GetMultipartFiles parses and returns the post files array.
// Note that the request form should be type of multipart.
func (r *Request) GetMultipartFiles(name string) []*multipart.FileHeader {
	form := r.GetMultipartForm()
	if form == nil {
		return nil
	}
	if v := form.File[name]; len(v) > 0 {
		return v
	}
	// Support "name[]" as array parameter.
	if v := form.File[name+"[]"]; len(v) > 0 {
		return v
	}
	// Support "name[0]","name[1]","name[2]", etc. as array parameter.
	var (
		key   string
		files = make([]*multipart.FileHeader, 0)
	)
	for i := 0; ; i++ {
		key = fmt.Sprintf(`%s[%d]`, name, i)
		if v := form.File[key]; len(v) > 0 {
			files = append(files, v[0])
		} else {
			break
		}
	}
	if len(files) > 0 {
		return files
	}
	return nil
}

// isBinaryContentType check the content type is binary or not.
func (r *Request) isBinaryContentType(contentType string) bool {
	// parseMediaType
	mimeType, _, err := mime.ParseMediaType(contentType)
	// If the content type is invalid, it's treated as binary.
	if err != nil {
		return true
	}

	// Lowercase the MIME type for easier comparison
	mimeType = strings.ToLower(mimeType)

	// if the MIME type is text, then it's definitely not binary
	if strings.HasPrefix(mimeType, "text/") {
		return false
	}

	// defined non-binary MIME types
	nonBinaryTypes := map[string]struct{}{
		"application/json":                  {},
		"application/xml":                   {},
		"application/x-www-form-urlencoded": {},
		"application/javascript":            {},
		"application/xhtml+xml":             {},
	}
	if _, ok := nonBinaryTypes[mimeType]; ok {
		return false
	}

	// if the MIME type is JSON or XML, it's definitely not binary
	if strings.HasSuffix(mimeType, "+json") || strings.HasSuffix(mimeType, "+xml") {
		return false
	}

	// otherwise, it's binary
	// (this includes application/octet-stream、image/*、video/*、audio/*)
	return true
}