package handlers

import (
	"errors"
	"html/template"
	"log"
	"net/http"
	"time"

	"code.revolvingcow.com/revolvingcow/loop/account"
	"code.revolvingcow.com/revolvingcow/loop/environment"
	"code.revolvingcow.com/revolvingcow/loop/markdown"
	"code.revolvingcow.com/revolvingcow/loop/security"

	"github.com/gorilla/mux"
	"github.com/gorilla/sessions"
)

var (
	templateWorkspace = template.Must(template.ParseFiles(
		"html/loop.html",
		"html/workspace.html",
	))
	store = sessions.NewCookieStore([]byte(environment.Salt()))
)

// WorkspaceModel passes information to the template engine providing context to the web page.
type WorkspaceModel struct {
	Username    string
	Directories []string
	Title       string
	Content     string
}

// ContentHandler is the default handler used for user content.
func ContentHandler(w http.ResponseWriter, r *http.Request) {
	log.Println("Serving template for the content handler")

	session, _ := store.Get(r, "session-account")
	account, err := validateCredentials(session)
	if err != nil {
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	directories, _ := account.Content()
	model := WorkspaceModel{
		Username:    account.Username,
		Directories: directories,
	}

	if err := templateWorkspace.Execute(w, model); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
}

// ContentCreateHandler creates new content in the user context.
func ContentCreateHandler(w http.ResponseWriter, r *http.Request) {
	log.Println("Creating new document")

	session, _ := store.Get(r, "session-account")
	account, err := validateCredentials(session)
	if err != nil {
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	vars := mux.Vars(r)
	title := vars["title"]
	if title != "" {
		account.Add(title, "document.md", []byte{})
	} else {
		http.Redirect(w, r, account.Username, http.StatusSeeOther)
	}

	http.Redirect(w, r, "/"+account.Username+"/edit/"+title, http.StatusSeeOther)
}

// ContentReadHandler reads a document in the user context.
func ContentReadHandler(w http.ResponseWriter, r *http.Request) {
	log.Println("Reading document")

	session, _ := store.Get(r, "session-account")
	account, err := validateCredentials(session)
	if err != nil {
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	vars := mux.Vars(r)
	title := vars["title"]
	if title == "" {
		http.Error(w, "No title given", http.StatusInternalServerError)
		return
	}

	contents, err := account.Read(title)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	directories, _ := account.Content()
	model := WorkspaceModel{
		Username:    account.Username,
		Directories: directories,
		Title:       title,
		Content:     contents,
	}

	if err := templateWorkspace.Execute(w, model); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
}

// ContentPreviewHandler displays a Markdown document in HTML format.
func ContentPreviewHandler(w http.ResponseWriter, r *http.Request) {
	log.Println("Previewing document")

	session, _ := store.Get(r, "session-account")
	account, err := validateCredentials(session)
	if err != nil {
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	vars := mux.Vars(r)
	title := vars["title"]
	contents := r.FormValue("contents")
	if contents == "" {
		contents, _ = account.Read(title)
	}
	md := template.HTML(string(markdown.MarkdownToHtml([]byte(contents))))
	model := PageBlog{
		Title:     title,
		Published: time.Now().Format("2006-01-02 15:04"),
		Body:      md,
	}

	if err := templateArticle.Execute(w, model); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
}

// ContentUpdateHandler updates content in the user context.
func ContentUpdateHandler(w http.ResponseWriter, r *http.Request) {
	log.Println("Updating document")

	session, _ := store.Get(r, "session-account")
	account, err := validateCredentials(session)
	if err != nil {
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	vars := mux.Vars(r)
	title := vars["title"]
	if title == "" {
		http.Error(w, "No title given", http.StatusInternalServerError)
		return
	}

	contents := r.FormValue("contents")
	if contents == "" {
		http.Error(w, "No content given", http.StatusInternalServerError)
		return
	}

	account.Add(title, "document.md", []byte(contents))
}

// ContentUploadHandler allows for multiple document uploads in the user context.
func ContentUploadHandler(w http.ResponseWriter, r *http.Request) {
	log.Println("Uploading attachment")
}

// ContentDeleteHandler deletes content in the user context.
func ContentDeleteHandler(w http.ResponseWriter, r *http.Request) {
	log.Println("Deleting document")

	session, _ := store.Get(r, "session-account")
	account, err := validateCredentials(session)
	if err != nil {
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	vars := mux.Vars(r)
	title := vars["title"]
	if title == "" {
		http.Error(w, "No title given", http.StatusInternalServerError)
		return
	}

	account.Remove(title)
	http.Redirect(w, r, "/"+account.Username, http.StatusSeeOther)
}

// validateCredentials attempts to validate session information.
func validateCredentials(session *sessions.Session) (account.Account, error) {
	user := session.Values["username"]
	pass := session.Values["passphrase"]
	if user == nil || pass == nil {
		return account.Account{}, errors.New("No session state")
	}

	account := account.Account{
		Username:   user.(string),
		Passphrase: security.GeneratePassphrase(user.(string), pass.(string)),
	}
	valid, err := account.Validate()
	if err != nil || !valid {
		return account, errors.New("Invalid credentials")
	}

	return account, nil
}