/*
   Copyright (c) 2016 VMware, Inc. All Rights Reserved.
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package api

import (
	"encoding/json"
	"fmt"
	"net/http"
	"os"
	"strconv"

	"github.com/astaxie/beego/validation"
	"github.com/vmware/harbor/auth"
	"github.com/vmware/harbor/dao"
	"github.com/vmware/harbor/models"
	"github.com/vmware/harbor/utils/log"

	"github.com/astaxie/beego"
)

const (
	defaultPageSize int64 = 500
	maxPageSize     int64 = 500
)

// BaseAPI wraps common methods for controllers to host API
type BaseAPI struct {
	beego.Controller
}

// Render returns nil as it won't render template
func (b *BaseAPI) Render() error {
	return nil
}

// RenderError provides shortcut to render http error
func (b *BaseAPI) RenderError(code int, text string) {
	http.Error(b.Ctx.ResponseWriter, text, code)
}

// DecodeJSONReq decodes a json request
func (b *BaseAPI) DecodeJSONReq(v interface{}) {
	err := json.Unmarshal(b.Ctx.Input.CopyBody(1<<32), v)
	if err != nil {
		log.Errorf("Error while decoding the json request, error: %v", err)
		b.CustomAbort(http.StatusBadRequest, "Invalid json request")
	}
}

// Validate validates v if it implements interface validation.ValidFormer
func (b *BaseAPI) Validate(v interface{}) {
	validator := validation.Validation{}
	isValid, err := validator.Valid(v)
	if err != nil {
		log.Errorf("failed to validate: %v", err)
		b.CustomAbort(http.StatusInternalServerError, http.StatusText(http.StatusInternalServerError))
	}

	if !isValid {
		message := ""
		for _, e := range validator.Errors {
			message += fmt.Sprintf("%s %s \n", e.Field, e.Message)
		}
		b.CustomAbort(http.StatusBadRequest, message)
	}
}

// DecodeJSONReqAndValidate does both decoding and validation
func (b *BaseAPI) DecodeJSONReqAndValidate(v interface{}) {
	b.DecodeJSONReq(v)
	b.Validate(v)
}

// ValidateUser checks if the request triggered by a valid user
func (b *BaseAPI) ValidateUser() int {
	userID, needsCheck, ok := b.GetUserIDForRequest()
	if !ok {
		log.Warning("No user id in session, canceling request")
		b.CustomAbort(http.StatusUnauthorized, "")
	}
	if needsCheck {
		u, err := dao.GetUser(models.User{UserID: userID})
		if err != nil {
			log.Errorf("Error occurred in GetUser, error: %v", err)
			b.CustomAbort(http.StatusInternalServerError, "Internal error.")
		}
		if u == nil {
			log.Warningf("User was deleted already, user id: %d, canceling request.", userID)
			b.CustomAbort(http.StatusUnauthorized, "")
		}
	}
	return userID
}

// GetUserIDForRequest tries to get user ID from basic auth header and session.
// It returns the user ID, whether need further verification(when the id is from session) and if the action is successful
func (b *BaseAPI) GetUserIDForRequest() (int, bool, bool) {
	username, password, ok := b.Ctx.Request.BasicAuth()
	if ok {
		log.Infof("Requst with Basic Authentication header, username: %s", username)
		user, err := auth.Login(models.AuthModel{
			Principal: username,
			Password:  password,
		})
		if err != nil {
			log.Errorf("Error while trying to login, username: %s, error: %v", username, err)
			user = nil
		}
		if user != nil {
			// User login successfully no further check required.
			return user.UserID, false, true
		}
	}
	sessionUserID, ok := b.GetSession("userId").(int)
	if ok {
		// The ID is from session
		return sessionUserID, true, true
	}
	log.Debug("No valid user id in session.")
	return 0, false, false
}

// Redirect does redirection to resource URI with http header status code.
func (b *BaseAPI) Redirect(statusCode int, resouceID string) {
	requestURI := b.Ctx.Request.RequestURI
	resoucreURI := requestURI + "/" + resouceID

	b.Ctx.Redirect(statusCode, resoucreURI)
}

// GetIDFromURL checks the ID in request URL
func (b *BaseAPI) GetIDFromURL() int64 {
	idStr := b.Ctx.Input.Param(":id")
	if len(idStr) == 0 {
		b.CustomAbort(http.StatusBadRequest, "invalid ID in URL")
	}

	id, err := strconv.ParseInt(idStr, 10, 64)
	if err != nil || id <= 0 {
		b.CustomAbort(http.StatusBadRequest, "invalid ID in URL")
	}

	return id
}

// set "Link" and "X-Total-Count" header for pagination request
func (b *BaseAPI) setPaginationHeader(total, page, pageSize int64) {
	b.Ctx.ResponseWriter.Header().Set("X-Total-Count", strconv.FormatInt(total, 10))

	link := ""

	// set previous link
	if page > 1 && (page-1)*pageSize <= total {
		u := *(b.Ctx.Request.URL)
		q := u.Query()
		q.Set("page", strconv.FormatInt(page-1, 10))
		u.RawQuery = q.Encode()
		if len(link) != 0 {
			link += ", "
		}
		link += fmt.Sprintf("<%s>; rel=\"prev\"", u.String())
	}

	// set next link
	if pageSize*page < total {
		u := *(b.Ctx.Request.URL)
		q := u.Query()
		q.Set("page", strconv.FormatInt(page+1, 10))
		u.RawQuery = q.Encode()
		if len(link) != 0 {
			link += ", "
		}
		link += fmt.Sprintf("<%s>; rel=\"next\"", u.String())
	}

	if len(link) != 0 {
		b.Ctx.ResponseWriter.Header().Set("Link", link)
	}
}

func (b *BaseAPI) getPaginationParams() (page, pageSize int64) {
	page, err := b.GetInt64("page", 1)
	if err != nil || page <= 0 {
		b.CustomAbort(http.StatusBadRequest, "invalid page")
	}

	pageSize, err = b.GetInt64("page_size", defaultPageSize)
	if err != nil || pageSize <= 0 {
		b.CustomAbort(http.StatusBadRequest, "invalid page_size")
	}

	if pageSize > maxPageSize {
		pageSize = maxPageSize
		log.Debugf("the parameter page_size %d exceeds the max %d, set it to max", pageSize, maxPageSize)
	}

	return page, pageSize
}

func getIsInsecure() bool {
	insecure := false

	verifyRemoteCert := os.Getenv("VERIFY_REMOTE_CERT")
	if verifyRemoteCert == "off" {
		insecure = true
	}

	return insecure
}