// Copyright 2014 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package context

import (
	"fmt"
	"html"
	"html/template"
	"io"
	"net/http"
	"path"
	"strings"
	"time"

	"code.gitea.io/gitea/models"
	"code.gitea.io/gitea/modules/auth"
	"code.gitea.io/gitea/modules/base"
	"code.gitea.io/gitea/modules/log"
	"code.gitea.io/gitea/modules/setting"
	"github.com/Unknwon/com"
	"github.com/go-macaron/cache"
	"github.com/go-macaron/csrf"
	"github.com/go-macaron/i18n"
	"github.com/go-macaron/session"
	macaron "gopkg.in/macaron.v1"
)

// Context represents context of a request.
type Context struct {
	*macaron.Context
	Cache   cache.Cache
	csrf    csrf.CSRF
	Flash   *session.Flash
	Session session.Store

	Link        string // current request URL
	EscapedLink string
	User        *models.User
	IsSigned    bool
	IsBasicAuth bool

	Repo *Repository
	Org  *Organization
}

// HasAPIError returns true if error occurs in form validation.
func (ctx *Context) HasAPIError() bool {
	hasErr, ok := ctx.Data["HasError"]
	if !ok {
		return false
	}
	return hasErr.(bool)
}

// GetErrMsg returns error message
func (ctx *Context) GetErrMsg() string {
	return ctx.Data["ErrorMsg"].(string)
}

// HasError returns true if error occurs in form validation.
func (ctx *Context) HasError() bool {
	hasErr, ok := ctx.Data["HasError"]
	if !ok {
		return false
	}
	ctx.Flash.ErrorMsg = ctx.Data["ErrorMsg"].(string)
	ctx.Data["Flash"] = ctx.Flash
	return hasErr.(bool)
}

// HasValue returns true if value of given name exists.
func (ctx *Context) HasValue(name string) bool {
	_, ok := ctx.Data[name]
	return ok
}

// HTML calls Context.HTML and converts template name to string.
func (ctx *Context) HTML(status int, name base.TplName) {
	log.Debug("Template: %s", name)
	ctx.Context.HTML(status, string(name))
}

// RenderWithErr used for page has form validation but need to prompt error to users.
func (ctx *Context) RenderWithErr(msg string, tpl base.TplName, form interface{}) {
	if form != nil {
		auth.AssignForm(form, ctx.Data)
	}
	ctx.Flash.ErrorMsg = msg
	ctx.Data["Flash"] = ctx.Flash
	ctx.HTML(200, tpl)
}

// Handle handles and logs error by given status.
func (ctx *Context) Handle(status int, title string, err error) {
	if err != nil {
		log.Error(4, "%s: %v", title, err)
		if macaron.Env != macaron.PROD {
			ctx.Data["ErrorMsg"] = err
		}
	}

	switch status {
	case 404:
		ctx.Data["Title"] = "Page Not Found"
	case 500:
		ctx.Data["Title"] = "Internal Server Error"
	}
	ctx.HTML(status, base.TplName(fmt.Sprintf("status/%d", status)))
}

// NotFoundOrServerError use error check function to determine if the error
// is about not found. It responses with 404 status code for not found error,
// or error context description for logging purpose of 500 server error.
func (ctx *Context) NotFoundOrServerError(title string, errck func(error) bool, err error) {
	if errck(err) {
		ctx.Handle(404, title, err)
		return
	}

	ctx.Handle(500, title, err)
}

// HandleText handles HTTP status code
func (ctx *Context) HandleText(status int, title string) {
	if (status/100 == 4) || (status/100 == 5) {
		log.Error(4, "%s", title)
	}
	ctx.PlainText(status, []byte(title))
}

// ServeContent serves content to http request
func (ctx *Context) ServeContent(name string, r io.ReadSeeker, params ...interface{}) {
	modtime := time.Now()
	for _, p := range params {
		switch v := p.(type) {
		case time.Time:
			modtime = v
		}
	}
	ctx.Resp.Header().Set("Content-Description", "File Transfer")
	ctx.Resp.Header().Set("Content-Type", "application/octet-stream")
	ctx.Resp.Header().Set("Content-Disposition", "attachment; filename="+name)
	ctx.Resp.Header().Set("Content-Transfer-Encoding", "binary")
	ctx.Resp.Header().Set("Expires", "0")
	ctx.Resp.Header().Set("Cache-Control", "must-revalidate")
	ctx.Resp.Header().Set("Pragma", "public")
	http.ServeContent(ctx.Resp, ctx.Req.Request, name, modtime, r)
}

// Contexter initializes a classic context for a request.
func Contexter() macaron.Handler {
	return func(c *macaron.Context, l i18n.Locale, cache cache.Cache, sess session.Store, f *session.Flash, x csrf.CSRF) {
		ctx := &Context{
			Context: c,
			Cache:   cache,
			csrf:    x,
			Flash:   f,
			Session: sess,
			Link:    setting.AppSubURL + strings.TrimSuffix(c.Req.URL.EscapedPath(), "/"),
			Repo: &Repository{
				PullRequest: &PullRequest{},
			},
			Org: &Organization{},
		}
		c.Data["Link"] = ctx.Link
		ctx.Data["PageStartTime"] = time.Now()
		// Quick responses appropriate go-get meta with status 200
		// regardless of if user have access to the repository,
		// or the repository does not exist at all.
		// This is particular a workaround for "go get" command which does not respect
		// .netrc file.
		if ctx.Query("go-get") == "1" {
			ownerName := c.Params(":username")
			repoName := c.Params(":reponame")
			branchName := "master"

			owner, err := models.GetUserByName(ownerName)
			if err == nil {
				repo, err := models.GetRepositoryByName(owner.ID, repoName)
				if err == nil && len(repo.DefaultBranch) > 0 {
					branchName = repo.DefaultBranch
				}
			}
			prefix := setting.AppURL + path.Join(ownerName, repoName, "src", "branch", branchName)
			c.PlainText(http.StatusOK, []byte(com.Expand(`
<html>
	<head>
		<meta name="go-import" content="{GoGetImport} git {CloneLink}">
		<meta name="go-source" content="{GoGetImport} _ {GoDocDirectory} {GoDocFile}">
	</head>
	<body>
		go get {GoGetImport}
	</body>
</html>
`, map[string]string{
				"GoGetImport":    ComposeGoGetImport(ownerName, strings.TrimSuffix(repoName, ".git")),
				"CloneLink":      models.ComposeHTTPSCloneURL(ownerName, repoName),
				"GoDocDirectory": prefix + "{/dir}",
				"GoDocFile":      prefix + "{/dir}/{file}#L{line}",
			})))
			return
		}

		// Get user from session if logged in.
		ctx.User, ctx.IsBasicAuth = auth.SignedInUser(ctx.Context, ctx.Session)

		if ctx.User != nil {
			ctx.IsSigned = true
			ctx.Data["IsSigned"] = ctx.IsSigned
			ctx.Data["SignedUser"] = ctx.User
			ctx.Data["SignedUserID"] = ctx.User.ID
			ctx.Data["SignedUserName"] = ctx.User.Name
			ctx.Data["IsAdmin"] = ctx.User.IsAdmin
		} else {
			ctx.Data["SignedUserID"] = 0
			ctx.Data["SignedUserName"] = ""
		}

		// If request sends files, parse them here otherwise the Query() can't be parsed and the CsrfToken will be invalid.
		if ctx.Req.Method == "POST" && strings.Contains(ctx.Req.Header.Get("Content-Type"), "multipart/form-data") {
			if err := ctx.Req.ParseMultipartForm(setting.AttachmentMaxSize << 20); err != nil && !strings.Contains(err.Error(), "EOF") { // 32MB max size
				ctx.Handle(500, "ParseMultipartForm", err)
				return
			}
		}

		ctx.Resp.Header().Set(`X-Frame-Options`, `SAMEORIGIN`)

		ctx.Data["CsrfToken"] = html.EscapeString(x.GetToken())
		ctx.Data["CsrfTokenHtml"] = template.HTML(`<input type="hidden" name="_csrf" value="` + ctx.Data["CsrfToken"].(string) + `">`)
		log.Debug("Session ID: %s", sess.ID())
		log.Debug("CSRF Token: %v", ctx.Data["CsrfToken"])

		ctx.Data["ShowRegistrationButton"] = setting.Service.ShowRegistrationButton
		ctx.Data["ShowFooterBranding"] = setting.ShowFooterBranding
		ctx.Data["ShowFooterVersion"] = setting.ShowFooterVersion
		ctx.Data["EnableOpenIDSignIn"] = setting.Service.EnableOpenIDSignIn

		c.Map(ctx)
	}
}