package main

import (
	"github.com/gorilla/mux"
	"github.com/gorilla/sessions"
	"net/http"
	"github.com/dballard/transmet/user"
	"fmt"
	"time"
	"io/ioutil"
	"regexp"
	"strings"
	"strconv"
	"github.com/dballard/transmet/categories"
	"github.com/dballard/transmet/news"
	"bytes"
	txtTemplate "text/template"
	"path"
)

func GetFlashes(session *sessions.Session) map[string]interface{} {
	var flashes = make(map[string]interface{})
	flashes["error"] = session.Flashes(flash_err)
	flashes["info"] = session.Flashes(flash_info)
	return flashes
}

func sessionWipe(session *sessions.Session) {
	session.Values = make(map[interface{}]interface{})
}

func initSessionUser(r *http.Request) (*user.User, *sessions.Session) {
	session, _ := store.Get(r, "c_user")
	if session.Values["username"] == nil {
		return nil, session
	}

	return user.NewUserFromUsername(db, session.Values["username"].(string)), session
}

// wrapper for handlers requiring a User
func userHandler(next func(http.ResponseWriter, *http.Request, *user.User, *sessions.Session)) func(http.ResponseWriter, *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		user, session := initSessionUser(r)
		if user == nil {
			http.Redirect(w, r, "/login", http.StatusFound)
		} else {
			next(w, r, user, session)
		}
	}
}

// wrapper for handlers forking on GET and POST
//   r.HandleFunc("/login", getPostHandler(LoginFormHandler, LoginPostHandler))
func getPostHandler(getFn, postFn func(http.ResponseWriter, *http.Request)) func(http.ResponseWriter, *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method == "GET" {
			getFn(w, r)
		} else { // POST
			postFn(w, r)
		}
	}
}

// Log in page handler
func LoginFormHandler(w http.ResponseWriter, r *http.Request) {
	session, _ := store.Get(r, "c_user")
	flashes := GetFlashes(session)
	session.Save(r, w)
	
	ShowTemplate("login", w, map[string]interface{}{"flashes": flashes})
}

// handler for login POST
//  TODO: proper per account and client flood control rate limiting
//    currently weak per call slow down is by-passable at scale
func LoginPostHandler(w http.ResponseWriter, r *http.Request) {
	time.Sleep(500 * time.Millisecond) // WEAK poor mans rate limiting for logins
	r.ParseForm()
	username := r.PostFormValue("username")
	// lookup user
	password := r.PostFormValue("password")
	user := user.NewUserFromAuth(db, username, password)
	if user != nil {
		session, _ := store.Get(r, "c_user")
		session.Values["username"] = user.Username
		session.Save(r, w)
		if r.URL.Query().Get("url") != "" {
		    http.Redirect(w, r, "/add?" + r.URL.RawQuery, http.StatusFound)
		}
		http.Redirect(w, r, "/", http.StatusFound)
	} else {
		time.Sleep(500 * time.Millisecond) // WEAK bypassable poor mans rate limiting for failed logins
		session, _ := store.Get(r, "c_user")
		session.AddFlash("Username or password", flash_err)
		session.Save(r, w)
		http.Redirect(w, r, "/login?"+r.URL.RawQuery, http.StatusFound)
	}
}

// logout POST handler
func LogoutHandler(w http.ResponseWriter, r *http.Request, user *user.User, session *sessions.Session) {
	//session.Options = &sessions.Options{MaxAge: -1}
	sessionWipe(session)
	session.Save(r, w)
	http.Redirect(w, r, "/", http.StatusFound)
}

func getUrlTitle(url string) string {
    resp, err := http.Get(url)
    if err != nil {
        fmt.Println("Error looking up link", url, ":", err)
    } else {
        body, err := ioutil.ReadAll(resp.Body)
        if err != nil {
            fmt.Println("Error reading link", url, ":", err)
        } else {
            re := regexp.MustCompile("< *[Tt][Ii][Tt][Ll][Ee] *>(.*)</ *[Tt][Ii][Tt][Ll][Ee] *>")
            title := re.FindStringSubmatch(string(body))
            if title != nil {
                return strings.TrimSpace(title[1])
            }
        }
    }
    return ""
}

// ?url=
func addFormHandler(w http.ResponseWriter, r *http.Request, user *user.User, session *sessions.Session) {
    categories.LoadCategories(db)
    
    flashes := GetFlashes(session)
    popup := session.Values["popup"]
    delete(session.Values, "popup")
	title := session.Values["title"]
	delete(session.Values, "title")
	link := session.Values["link"]
	delete(session.Values, "link")
	description := session.Values["description"]
	delete(session.Values, "description")
	session.Save(r, w)
	
	if link != nil {
	    //TODO category_id
		ShowTemplate("add", w, map[string]interface{}{"user": user, "flashes": flashes, "categories": categories.CategoriesTree, "link": link, "title": title, "description": description, "popup": popup})
		return
	}
    
    var url = r.URL.Query().Get("url")
    reHttp := regexp.MustCompile("^https?://")
    if url != "" && ! reHttp.Match([]byte(url)) {
        url = "http://" + url
    } 
    
    title = r.URL.Query().Get("title")
    if title == "" && url != "" {
        title = getUrlTitle(url)
    }
    
    popup = r.URL.Query().Get("popup")
    
	ShowTemplate("add", w, map[string]interface{}{"user": user, "flashes": flashes, "link": url, "categories": categories.CategoriesTree, "title": title, "popup": popup})
}

func addPostHandler(w http.ResponseWriter, r *http.Request, user *user.User, session *sessions.Session) {
	var news news.News
	
	news.Title = r.FormValue("title")
	news.Notes = r.FormValue("notes")
	news.Url = r.FormValue("link")
	popup := r.FormValue("popup")
	category_id, err := strconv.Atoi(r.FormValue("category"))
	if err != nil {
	    category_id = -1
	}
	news.Category_id = category_id
	
	err = (&news).Insert(db)
	if err != nil {
	    session.AddFlash("Error saving news: " + err.Error(), flash_err)
	    session.Values["title"] = news.Title
	    session.Values["link"] = news.Url
	    session.Values["notes"] = news.Notes
	    session.Values["popup"] = popup
		session.Save(r, w)
	    http.Redirect(w, r, "/add", http.StatusFound)
	} else {
	    // TODO auto close? redirect
	    session.AddFlash("Added news \""+news.Title+"\"", flash_info)
		session.Save(r, w)
		if popup == "1" {
		    http.Redirect(w, r, "/added", http.StatusFound)
		} else {
	    	http.Redirect(w, r, "/", http.StatusFound)
	    }
	}
}

func templateFormHandler(w http.ResponseWriter, r *http.Request, user *user.User, session *sessions.Session) {
    flashes := GetFlashes(session)
    session.Save(r, w)
    
    news, count, err := news.Unexported(db)
	if err != nil {
	    return
	}
	
	var templateBuf bytes.Buffer
	template, err := txtTemplate.ParseFiles("templates/html_template.txt")
	if err != nil {
	    fmt.Println("Error processing html_tempalte:" , err)
	}
	err = template.Execute(&templateBuf, map[string]interface{}{"news": news})
	if err != nil {
		fmt.Println("Exec err: ", err)
	}
    
	ShowTemplate("export", w, map[string]interface{}{"user": user, "flashes": flashes, "template": &templateBuf, "count": count, "url": config.Url})
}

func exportHandler(w http.ResponseWriter, r *http.Request, user *user.User, session *sessions.Session) {
	err := news.MarkExported(db)
	
	if err != nil {
	    session.AddFlash("Error marking last batch of news exported", flash_err)
	} else {
		session.AddFlash("Last batch of news marked exported", flash_info)
	}
	session.Save(r, w)
    http.Redirect(w, r, "/", http.StatusFound)
}

func addedHandler(w http.ResponseWriter, r *http.Request, user *user.User, session *sessions.Session) {
    flashes := GetFlashes(session)
    session.Save(r, w)
    ShowTemplate("added", w, map[string]interface{}{"user": user, "flashes": flashes})
}


func categoriesFormHandler(w http.ResponseWriter, r *http.Request, user *user.User, session *sessions.Session) {
    flashes := GetFlashes(session)
    session.Save(r, w)
    categories.LoadCategories(db)

    ShowTemplate("categories", w, map[string]interface{}{"user": user, "flashes": flashes, "categories": categories.CategoriesTree})
}

func categoriesPostHandler(w http.ResponseWriter, r *http.Request, user *user.User, session *sessions.Session) {
    http.Redirect(w, r, "/categories", http.StatusFound)
}

func categoryFromReqArg(arg string) *categories.Category {
    if cid, err := strconv.Atoi(arg); err != nil {
        return nil
    } else if category, ok := categories.CategoriesFlat[cid]; !ok {
        return nil
    } else {
        return category
    }
}

func categoryChangeParentHandler(w http.ResponseWriter, r *http.Request, user *user.User, session *sessions.Session) {
	categories.LoadCategories(db)
	category := categoryFromReqArg(r.FormValue("cid"))
	parent := categoryFromReqArg(r.FormValue("parent"))
	
	if category == nil {
		session.AddFlash("Invalid category", flash_err)	
	} else if parent != nil && category.Id == parent.Id { 
		session.AddFlash("Cannot set category parent to itself", flash_err)
	} else {
	    err := category.ChangeParent(db, parent)
	    if err != nil {
	        session.AddFlash("Error commiting to Database", flash_err)
	    } else {
	    	session.AddFlash("Changed category parent", flash_info)
	    }	
    }
	
    session.Save(r, w)
    http.Redirect(w, r, "/categories", http.StatusFound)
}

func categoryAddHandler(w http.ResponseWriter, r *http.Request, user *user.User, session *sessions.Session) {
	name := r.FormValue("name")
	parent, perr := strconv.Atoi(r.FormValue("parent"))
	
	if perr != nil {
	    parent = -1
	}
	if name == "" {
		session.AddFlash("Invalid category name", flash_err)	
	} else {
	    err := categories.Add(db, name, parent)
	    if err != nil {
	        session.AddFlash("Error commiting to Database", flash_err)
	    } else {
	    	session.AddFlash("Added category", flash_info)
	    }	
    }
	
    session.Save(r, w)
    http.Redirect(w, r, "/categories", http.StatusFound)
}

func categoryDeleteHandler(w http.ResponseWriter, r *http.Request, user *user.User, session *sessions.Session) {
	id, idErr := strconv.Atoi(r.FormValue("id"))
	
	if idErr != nil {
		session.AddFlash("Invalid category to delete", flash_err)	
	} else {
	    err := categories.Delete(db, id)
	    if err != nil {
	        session.AddFlash("Error commiting to Database", flash_err)
	    } else {
	    	session.AddFlash("Deleted category", flash_info)
	    }	
    }
	
    session.Save(r, w)
    http.Redirect(w, r, "/categories", http.StatusFound)
}

func newsFormHandler(w http.ResponseWriter, r *http.Request, user *user.User, session *sessions.Session) {
    flashes := GetFlashes(session)
    session.Save(r, w)
    var offset = 0
    var amount = 100
    
    argOffset, eOffset := strconv.Atoi(r.FormValue("offset"))
    if eOffset == nil {
        offset = amount * argOffset 
    }
    
    news, count, err := news.LoadPage(db, offset, amount)
	if err != nil {
	    session.AddFlash("Error loading news", flash_err)
	}
    
    ShowTemplate("news", w, map[string]interface{}{"user": user, "flashes": flashes, "news": news, "count": count, "categories": categories.CategoriesFlat})
   	
}

func ServeFileHandler(res http.ResponseWriter, req *http.Request) {  
      fname := path.Base(req.URL.Path)  
      http.ServeFile(res, req, "./"+fname)  
 }  

func init_route_handlers() {
    http.Handle("/js/", http.StripPrefix("/js/", http.FileServer(http.Dir("js/"))))
	http.Handle("/css/", http.StripPrefix("/css/", http.FileServer(http.Dir("css/"))))
	http.Handle("/fonts/", http.StripPrefix("/fonts", http.FileServer(http.Dir("fonts/"))))
	http.HandleFunc("/favicon.ico", ServeFileHandler)

	r := mux.NewRouter()
	
	r.HandleFunc("/login", getPostHandler(LoginFormHandler, LoginPostHandler))
	r.HandleFunc("/logout", userHandler(LogoutHandler))

	r.HandleFunc("/add", getPostHandler(userHandler(addFormHandler), userHandler(addPostHandler)))
	r.HandleFunc("/", userHandler(newsFormHandler))
	r.HandleFunc("/news", userHandler(newsFormHandler))
	r.HandleFunc("/export", userHandler(templateFormHandler))
	r.HandleFunc("/export-commit", userHandler(exportHandler))
	r.HandleFunc("/added", userHandler(addedHandler))
	
	r.HandleFunc("/categories", getPostHandler(userHandler(categoriesFormHandler), userHandler(categoriesPostHandler)))
	r.HandleFunc("/categories/change-parent", userHandler(categoryChangeParentHandler))
	r.HandleFunc("/categories/add", userHandler(categoryAddHandler))
	r.HandleFunc("/categories/delete", userHandler(categoryDeleteHandler))
	
	http.Handle("/", r)
}