core.rs

use time;

use db_conn::MedalConnection;
use db_objects::{Grade, Group, Submission, Taskgroup};
use helpers;
use oauth_provider::OauthProvider;
use webfw_iron::{json_val, to_json};

#[derive(Serialize, Deserialize)]
pub struct SubTaskInfo {
    pub id: i32,
    pub linktext: String,
    pub active: bool,
    pub greyout: bool,
}

#[derive(Serialize, Deserialize)]
pub struct TaskInfo {
    pub name: String,
    pub subtasks: Vec<SubTaskInfo>,
}

#[derive(Serialize, Deserialize)]
pub struct ContestInfo {
    pub id: i32,
    pub location: String,
    pub filename: String,
    pub name: String,
    pub duration: i32,
    pub public: bool,
    pub tasks: Vec<TaskInfo>,
}

#[derive(Clone)]
pub enum MedalError {
    NotLoggedIn,
    AccessDenied,
    CsrfCheckFailed,
    SessionTimeout,
    DatabaseError,
    PasswordHashingError,
    UnmatchedPasswords,
}

type MedalValue = (String, json_val::Map<String, json_val::Value>);
type MedalResult<T> = Result<T, MedalError>;
type MedalValueResult = MedalResult<MedalValue>;

pub fn index<T: MedalConnection>(conn: &T, session_token: Option<String>,
                                 (self_url, oauth_providers): (Option<String>, Option<Vec<OauthProvider>>))
                                 -> (String, json_val::Map<String, json_val::Value>)
{
    let mut data = json_val::Map::new();

    //let mut contests = Vec::new();

    if let Some(token) = session_token {
        if let Some(session) = conn.get_session(&token) {
            if session.is_logged_in() {
                data.insert("logged_in".to_string(), to_json(&true));
                data.insert("username".to_string(), to_json(&session.username));
                data.insert("firstname".to_string(), to_json(&session.firstname));
                data.insert("lastname".to_string(), to_json(&session.lastname));
                data.insert("teacher".to_string(), to_json(&session.is_teacher));
            }
        }
    }

    let mut oauth_links: Vec<(String, String, String)> = Vec::new();
    if let Some(oauth_providers) = oauth_providers {
        for oauth_provider in oauth_providers {
            oauth_links.push((oauth_provider.provider_id.to_owned(),
                              oauth_provider.login_link_text.to_owned(),
                              oauth_provider.url.to_owned()));
        }
    }

    data.insert("self_url".to_string(), to_json(&self_url));
    data.insert("oauth_links".to_string(), to_json(&oauth_links));

    ("index".to_owned(), data)
}

pub fn debug<T: MedalConnection>(conn: &T, session_token: Option<String>)
                                 -> (String, json_val::Map<String, json_val::Value>) {
    let mut data = json_val::Map::new();

    if let Some(token) = session_token {
        if let Some(session) = conn.get_session(&token) {
            data.insert("known_session".to_string(), to_json(&true));
            data.insert("now_timestamp".to_string(), to_json(&time::get_time().sec));
            if let Some(last_activity) = session.last_activity {
                data.insert("session_timestamp".to_string(), to_json(&last_activity.sec));
                data.insert("timediff".to_string(), to_json(&(time::get_time() - last_activity).num_seconds()));
            }
            if session.is_alive() {
                data.insert("alive_session".to_string(), to_json(&true));
                if session.is_logged_in() {
                    data.insert("logged_in".to_string(), to_json(&true));
                    data.insert("username".to_string(), to_json(&session.username));
                    data.insert("firstname".to_string(), to_json(&session.firstname));
                    data.insert("lastname".to_string(), to_json(&session.lastname));
                    data.insert("teacher".to_string(), to_json(&session.is_teacher));
                }
            }
        }
        data.insert("session".to_string(), to_json(&token));
        println!("etwas session?!");
    } else {
        data.insert("session".to_string(), to_json(&"No session token given"));
        println!("warum nix session?!");
    }

    ("debug".to_owned(), data)
}

pub fn debug_create_session<T: MedalConnection>(conn: &T, session_token: Option<String>) {
    if let Some(token) = session_token {
        conn.get_session_or_new(&token);
    }
}

pub fn show_contests<T: MedalConnection>(conn: &T) -> MedalValue {
    let mut data = json_val::Map::new();

    let v: Vec<ContestInfo> = conn.get_contest_list()
                                  .iter()
                                  .map(|c| ContestInfo { id: c.id.unwrap(),
                                                         location: c.location.clone(),
                                                         filename: c.filename.clone(),
                                                         name: c.name.clone(),
                                                         duration: c.duration,
                                                         public: c.public,
                                                         tasks: Vec::new() })
                                  .collect();
    data.insert("contest".to_string(), to_json(&v));

    ("contests".to_owned(), data)
}

fn generate_subtaskstars(tg: &Taskgroup, grade: &Grade, ast: Option<i32>) -> Vec<SubTaskInfo> {
    let mut subtaskinfos = Vec::new();
    let mut not_print_yet = true;
    for st in &tg.tasks {
        let mut blackstars: usize = 0;
        if not_print_yet && st.stars >= grade.grade.unwrap_or(0) {
            blackstars = grade.grade.unwrap_or(0) as usize;
            not_print_yet = false;
        }

        let greyout = not_print_yet && st.stars < grade.grade.unwrap_or(0);
        let active = ast.is_some() && st.id == ast;
        let linktext = format!("{}{}",
                               str::repeat("★", blackstars as usize),
                               str::repeat("☆", st.stars as usize - blackstars as usize));
        let si = SubTaskInfo { id: st.id.unwrap(), linktext: linktext, active, greyout };

        subtaskinfos.push(si);
    }
    subtaskinfos
}

pub fn show_contest<T: MedalConnection>(conn: &T, contest_id: i32, session_token: &str) -> MedalValueResult {
    let c = conn.get_contest_by_id_complete(contest_id);
    let grades = conn.get_contest_user_grades(&session_token, contest_id);

    let mut totalgrade = 0;
    let mut max_totalgrade = 0;

    let mut tasks = Vec::new();
    for (taskgroup, grade) in c.taskgroups.into_iter().zip(grades) {
        let subtaskstars = generate_subtaskstars(&taskgroup, &grade, None);
        let ti = TaskInfo { name: taskgroup.name, subtasks: subtaskstars };
        tasks.push(ti);

        totalgrade += grade.grade.unwrap_or(0);
        max_totalgrade += taskgroup.tasks.iter().map(|x| x.stars).max().unwrap_or(0);
    }

    let ci = ContestInfo { id: c.id.unwrap(),
                           location: c.location.clone(),
                           filename: c.filename.clone(),
                           name: c.name.clone(),
                           duration: c.duration,
                           public: c.public,
                           tasks: tasks };

    let mut data = json_val::Map::new();
    data.insert("contest".to_string(), to_json(&ci));

    data.insert("logged_in".to_string(), to_json(&false));
    data.insert("can_start".to_string(), to_json(&false));
    if let Some(session) = conn.get_session(&session_token) {
        data.insert("logged_in".to_string(), to_json(&true));
        data.insert("can_start".to_string(), to_json(&true));
        data.insert("username".to_string(), to_json(&session.username));
        data.insert("firstname".to_string(), to_json(&session.firstname));
        data.insert("lastname".to_string(), to_json(&session.lastname));
        data.insert("teacher".to_string(), to_json(&session.is_teacher));
        data.insert("csrf_token".to_string(), to_json(&session.csrf_token));
    }
    if c.duration == 0 {
        data.insert("can_start".to_string(), to_json(&true));
    }

    match conn.get_participation(&session_token, contest_id) {
        None => Ok(("contest".to_owned(), data)),
        Some(participation) => {
            let now = time::get_time();
            let passed_secs = now.sec - participation.start.sec;
            if passed_secs < 0 {
                // behandle inkonsistente Serverzeit
            }

            data.insert("participation_start_date".to_string(), to_json(&format!("{}", passed_secs)));
            data.insert("total_points".to_string(), to_json(&totalgrade));
            data.insert("max_total_points".to_string(), to_json(&max_totalgrade));
            data.insert("relative_points".to_string(), to_json(&((totalgrade * 100) / max_totalgrade)));

            let left_secs = i64::from(ci.duration) * 60 - passed_secs;
            if left_secs < 0 {
                // Contest over
                data.insert("is_time_left".to_string(), to_json(&false));
            } else {
                data.insert("is_time_left".to_string(), to_json(&true));
                let left_min = left_secs / 60;
                let left_sec = left_secs % 60;
                if left_sec < 10 {
                    data.insert("time_left".to_string(), to_json(&format!("{}:0{}", left_min, left_sec)));
                } else {
                    data.insert("time_left".to_string(), to_json(&format!("{}:{}", left_min, left_sec)));
                }
            }

            Ok(("contest".to_owned(), data))
        }
    }
}

pub fn show_contest_results<T: MedalConnection>(conn: &T, contest_id: i32, session_token: &str) -> MedalValueResult {
    let session = conn.get_session(&session_token)
                      .ok_or(MedalError::AccessDenied)?
                      .ensure_alive()
                      .ok_or(MedalError::AccessDenied)?; // TODO SessionTimeout?
    let (tasknames, resultdata) = conn.get_contest_groups_grades(session.id, contest_id);

    let mut results: Vec<(String, Vec<(String, Vec<String>)>)> = Vec::new();

    for (group, groupdata) in resultdata {
        let mut groupresults: Vec<(String, Vec<String>)> = Vec::new();

        //TODO: use user
        for (_user, userdata) in groupdata {
            let mut userresults: Vec<String> = Vec::new();

            userresults.push(String::new());
            let mut summe = 0;

            for grade in userdata {
                if let Some(g) = grade.grade {
                    userresults.push(format!("{}", g));
                    summe += g;
                } else {
                    userresults.push(format!("–"));
                }
            }

            userresults[0] = format!("{}", summe);

            groupresults.push((format!("Name"), userresults))
        }

        results.push((format!("{}", group.name), groupresults));
    }

    let mut data = json_val::Map::new();
    data.insert("taskname".to_string(), to_json(&tasknames));
    data.insert("result".to_string(), to_json(&results));

    let c = conn.get_contest_by_id(contest_id);
    let ci = ContestInfo { id: c.id.unwrap(),
                           location: c.location.clone(),
                           filename: c.filename.clone(),
                           name: c.name.clone(),
                           duration: c.duration,
                           public: c.public,
                           tasks: Vec::new() };
    data.insert("contest".to_string(), to_json(&ci));

    Ok(("contestresults".to_owned(), data))
}

//TODO: use csrf_token
pub fn start_contest<T: MedalConnection>(conn: &T, contest_id: i32, session_token: &str, csrf_token: &str)
                                         -> MedalResult<()> {
    // TODO: Should check if logged in or anonymous!
    // TODO: Is _or_new the right semantic?
    let session = conn.get_session_or_new(&session_token);
    //.ensure_logged_in()
    //.ok_or(MedalError::AccessDenied)?;

    if session.is_logged_in() && session.csrf_token != csrf_token {
        return Err(MedalError::CsrfCheckFailed);
    }

    match conn.new_participation(&session_token, contest_id) {
        Ok(_) => Ok(()),
        _ => Err(MedalError::AccessDenied), // Contest already started TODO: Maybe redirect to page with hint
    }
}

pub fn login<T: MedalConnection>(conn: &T, login_data: (String, String)) -> Result<String, MedalValue> {
    let (username, password) = login_data;

    match conn.login(None, &username, &password) {
        Ok(session_token) => Ok(session_token),
        Err(()) => {
            let mut data = json_val::Map::new();
            data.insert("reason".to_string(), to_json(&"Login fehlgeschlagen. Bitte erneut versuchen.".to_string()));
            data.insert("username".to_string(), to_json(&username));
            Err(("login".to_owned(), data))
        }
    }
}

pub fn login_with_code<T: MedalConnection>(
    conn: &T, code: &str)
    -> Result<Result<String, String>, (String, json_val::Map<String, json_val::Value>)> {
    match conn.login_with_code(None, &code) {
        Ok(session_token) => Ok(Ok(session_token)),
        Err(()) => match conn.create_user_with_groupcode(None, &code) {
            Ok(session_token) => Ok(Err(session_token)),
            Err(()) => {
                let mut data = json_val::Map::new();
                data.insert("reason".to_string(), to_json(&"Kein gültiger Code. Bitte erneut versuchen.".to_string()));
                data.insert("code".to_string(), to_json(&code));
                Err(("login".to_owned(), data))
            }
        },
    }
}

pub fn logout<T: MedalConnection>(conn: &T, session_token: Option<String>) {
    session_token.map(|token| conn.logout(&token));
}

pub fn load_submission<T: MedalConnection>(conn: &T, task_id: i32, session_token: &str, subtask: Option<String>)
                                           -> MedalResult<String> {
    let session = conn.get_session(&session_token)
                      .ok_or(MedalError::AccessDenied)?
                      .ensure_alive()
                      .ok_or(MedalError::AccessDenied)?; // TODO SessionTimeout

    match match subtask {
              Some(s) => conn.load_submission(&session, task_id, Some(&s)),
              None => conn.load_submission(&session, task_id, None),
          } {
        Some(submission) => Ok(submission.value),
        None => Ok("{}".to_string()),
    }
}

pub fn save_submission<T: MedalConnection>(conn: &T, task_id: i32, session_token: &str, csrf_token: &str,
                                           data: String, grade: i32, subtask: Option<String>)
                                           -> MedalResult<String>
{
    let session = conn.get_session(&session_token)
                      .ok_or(MedalError::AccessDenied)?
                      .ensure_alive()
                      .ok_or(MedalError::AccessDenied)?; // TODO SessionTimeout

    if session.csrf_token != csrf_token {
        return Err(MedalError::CsrfCheckFailed);
    }

    let submission = Submission { id: None,
                                  session_user: session.id,
                                  task: task_id,
                                  grade: grade,
                                  validated: false,
                                  nonvalidated_grade: grade,
                                  needs_validation: true,
                                  subtask_identifier: subtask,
                                  value: data,
                                  date: time::get_time() };

    conn.submit_submission(submission);

    Ok("{}".to_string())
}

pub fn show_task<T: MedalConnection>(conn: &T, task_id: i32, session_token: &str) -> MedalValueResult {
    let session = conn.get_session_or_new(&session_token).ensure_alive().ok_or(MedalError::AccessDenied)?; // TODO SessionTimeout

    let (t, tg, c) = conn.get_task_by_id_complete(task_id);
    let grade = conn.get_taskgroup_user_grade(&session_token, tg.id.unwrap()); // TODO: Unwrap?
    let tasklist = conn.get_contest_by_id_complete(c.id.unwrap()); // TODO: Unwrap?

    let mut prevtaskgroup: Option<Taskgroup> = None;
    let mut nexttaskgroup: Option<Taskgroup> = None;
    let mut current_found = false;

    let mut subtaskstars = Vec::new();

    for taskgroup in tasklist.taskgroups {
        if current_found {
            nexttaskgroup = Some(taskgroup);
            break;
        }

        if taskgroup.id == tg.id {
            current_found = true;
            subtaskstars = generate_subtaskstars(&taskgroup, &grade, Some(task_id));
        } else {
            prevtaskgroup = Some(taskgroup);
        }
    }

    match conn.get_participation(&session_token, c.id.expect("Value from database")) {
        None => Err(MedalError::AccessDenied),
        Some(participation) => {
            let now = time::get_time();
            let passed_secs = now.sec - participation.start.sec;
            if passed_secs < 0 {
                // behandle inkonsistente Serverzeit
            }

            let mut data = json_val::Map::new();
            data.insert("participation_start_date".to_string(), to_json(&format!("{}", passed_secs)));
            data.insert("subtasks".to_string(), to_json(&subtaskstars));
            data.insert("prevtask".to_string(), to_json(&prevtaskgroup.map(|tg| tg.tasks[0].id)));
            data.insert("nexttask".to_string(), to_json(&nexttaskgroup.map(|tg| tg.tasks[0].id))); // TODO: fail better

            let left_secs = i64::from(c.duration) * 60 - passed_secs;
            if c.duration > 0 && left_secs < 0 {
                Err(MedalError::AccessDenied)
            // Contest over
            // TODO: Nicer message!
            } else {
                let (hour, min, sec) = (left_secs / 3600, left_secs / 60 % 60, left_secs % 60);

                data.insert("time_left".to_string(), to_json(&format!("{}:{:02}", hour, min)));
                data.insert("time_left_sec".to_string(), to_json(&format!(":{:02}", sec)));

                let taskpath = format!("{}{}", c.location, t.location);

                data.insert("contestname".to_string(), to_json(&c.name));
                data.insert("name".to_string(), to_json(&tg.name));
                data.insert("taskid".to_string(), to_json(&task_id));
                data.insert("csrf_token".to_string(), to_json(&session.csrf_token));
                data.insert("taskpath".to_string(), to_json(&taskpath));
                data.insert("contestid".to_string(), to_json(&c.id));
                data.insert("seconds_left".to_string(), to_json(&left_secs));

                Ok(("task".to_owned(), data))
            }
        }
    }
}

#[derive(Serialize, Deserialize)]
pub struct GroupInfo {
    pub id: i32,
    pub name: String,
    pub tag: String,
    pub code: String,
}

pub fn show_groups<T: MedalConnection>(conn: &T, session_token: &str) -> MedalValueResult {
    let session = conn.get_session_or_new(&session_token).ensure_logged_in().ok_or(MedalError::NotLoggedIn)?;

    //    let groupvec = conn.get_group(session_token);

    let mut data = json_val::Map::new();

    let v: Vec<GroupInfo> =
        conn.get_groups(session.id)
            .iter()
            .map(|g| GroupInfo { id: g.id.unwrap(),
                                 name: g.name.clone(),
                                 tag: g.tag.clone(),
                                 code: g.groupcode.clone() })
            .collect();
    data.insert("group".to_string(), to_json(&v));
    data.insert("csrf_token".to_string(), to_json(&session.csrf_token));

    Ok(("groups".to_string(), data))
}

#[derive(Serialize, Deserialize)]
pub struct MemberInfo {
    pub id: i32,
    pub firstname: String,
    pub lastname: String,
    pub grade: i32,
    pub logincode: String,
}

pub fn show_group<T: MedalConnection>(conn: &T, group_id: i32, session_token: &str) -> MedalValueResult {
    let session = conn.get_session_or_new(&session_token).ensure_logged_in().ok_or(MedalError::NotLoggedIn)?;
    let group = conn.get_group_complete(group_id).unwrap(); // TODO handle error

    let mut data = json_val::Map::new();

    if group.admin != session.id {
        return Err(MedalError::AccessDenied);
    }

    let gi = GroupInfo { id: group.id.unwrap(),
                         name: group.name.clone(),
                         tag: group.tag.clone(),
                         code: group.groupcode.clone() };

    let v: Vec<MemberInfo> =
        group.members
             .iter()
             .map(|m| MemberInfo { id: m.id,
                                   firstname: m.firstname.clone().unwrap_or_else(|| "".to_string()),
                                   lastname: m.lastname.clone().unwrap_or_else(|| "".to_string()),
                                   grade: m.grade,
                                   logincode: m.logincode.clone().unwrap_or_else(|| "".to_string()) })
             .collect();

    data.insert("group".to_string(), to_json(&gi));
    data.insert("member".to_string(), to_json(&v));

    Ok(("group".to_string(), data))
}

pub fn modify_group<T: MedalConnection>(_conn: &T, _group_id: i32, _session_token: &str) -> MedalResult<()> {
    unimplemented!()
}

pub fn add_group<T: MedalConnection>(conn: &T, session_token: &str, csrf_token: &str, name: String, tag: String)
                                     -> MedalResult<i32> {
    let session = conn.get_session(&session_token)
                      .ok_or(MedalError::AccessDenied)?
                      .ensure_logged_in()
                      .ok_or(MedalError::AccessDenied)?;

    if session.csrf_token != csrf_token {
        return Err(MedalError::CsrfCheckFailed);
    }

    let group_code = helpers::make_group_code();
    // TODO: check for collisions

    let mut group =
        Group { id: None, name: name, groupcode: group_code, tag: tag, admin: session.id, members: Vec::new() };

    conn.add_group(&mut group);

    Ok(group.id.unwrap())
}

pub fn group_csv<T: MedalConnection>(conn: &T, session_token: &str) -> MedalValueResult {
    let session = conn.get_session_or_new(&session_token).ensure_logged_in().ok_or(MedalError::NotLoggedIn)?;

    let mut data = json_val::Map::new();
    data.insert("csrf_token".to_string(), to_json(&session.csrf_token));

    Ok(("groupcsv".to_string(), data))
}

pub fn upload_groups<T: MedalConnection>(conn: &T, session_token: &str, csrf_token: &str, group_data: &str) -> MedalResult<()> {
    let session = conn.get_session(&session_token)
                      .ok_or(MedalError::AccessDenied)?
                      .ensure_logged_in()
                      .ok_or(MedalError::AccessDenied)?;

    if session.csrf_token != csrf_token {
        return Err(MedalError::CsrfCheckFailed);
    }

    Ok(())
}

#[allow(dead_code)]
pub fn show_groups_results<T: MedalConnection>(conn: &T, contest_id: i32, session_token: &str) -> MedalValueResult {
    let session = conn.get_session_or_new(&session_token).ensure_logged_in().ok_or(MedalError::NotLoggedIn)?;
    //TODO: use g
    let _g = conn.get_contest_groups_grades(session.id, contest_id);

    let data = json_val::Map::new();

    Ok(("groupresults".into(), data))
}

pub fn show_profile<T: MedalConnection>(conn: &T, session_token: &str, user_id: Option<i32>,
                                        query_string: Option<String>)
                                        -> MedalValueResult
{
    let session = conn.get_session_or_new(&session_token).ensure_alive().ok_or(MedalError::AccessDenied)?; // TODO SessionTimeout

    let mut data = json_val::Map::new();

    match user_id {
        None => {
            data.insert("firstname".to_string(), to_json(&session.firstname));
            data.insert("lastname".to_string(), to_json(&session.lastname));
            data.insert("street".to_string(), to_json(&session.street));
            data.insert("zip".to_string(), to_json(&session.zip));
            data.insert("city".to_string(), to_json(&session.city));
            data.insert(format!("sel{}", session.grade), to_json(&"selected"));

            data.insert("logincode".to_string(), to_json(&session.logincode));
            if session.password.is_some() {
                data.insert("username".to_string(), to_json(&session.username));
                data.insert("not_in_group".into(), to_json(&true));
            }
            data.insert("ownprofile".into(), to_json(&true));

            data.insert("csrf_token".to_string(), to_json(&session.csrf_token));

            if let Some(query) = query_string {
                if query.starts_with("status=") {
                    let status: &str = &query[7..];
                    if ["NothingChanged", "DataChanged", "PasswordChanged", "PasswordMissmatch"].contains(&status) {
                        data.insert((status).to_string(), to_json(&true));
                    }
                }
            }
        }
        Some(user_id) => {
            // TODO: Add test to check if this access restriction works
            let (user, opt_group) = conn.get_user_and_group_by_id(user_id).ok_or(MedalError::AccessDenied)?;
            let group = opt_group.ok_or(MedalError::AccessDenied)?;
            if group.admin != session.id {
                return Err(MedalError::AccessDenied);
            }

            data.insert("firstname".to_string(), to_json(&user.firstname));
            data.insert("lastname".to_string(), to_json(&user.lastname));
            data.insert("street".to_string(), to_json(&session.street));
            data.insert("zip".to_string(), to_json(&session.zip));
            data.insert("city".to_string(), to_json(&session.city));
            data.insert(format!("sel{}", user.grade), to_json(&"selected"));

            data.insert("logincode".to_string(), to_json(&user.logincode));
            if user.password.is_some() {
                data.insert("username".to_string(), to_json(&user.username));
                data.insert("not_in_group".into(), to_json(&true));
            }

            data.insert("ownprofile".into(), to_json(&false));

            data.insert("csrf_token".to_string(), to_json(&session.csrf_token));

            if let Some(query) = query_string {
                if query.starts_with("status=") {
                    let status: &str = &query[7..];
                    if ["NothingChanged", "DataChanged", "PasswordChanged", "PasswordMissmatch"].contains(&status) {
                        data.insert((status).to_string(), to_json(&true));
                    }
                }
            }
        }
    }

    Ok(("profile".to_string(), data))
}

#[derive(Debug)]
pub enum ProfileStatus {
    NothingChanged,
    DataChanged,
    PasswordChanged,
    PasswordMissmatch,
}
impl std::convert::Into<String> for ProfileStatus {
    fn into(self) -> String { format!("{:?}", self) }
}

pub fn edit_profile<T: MedalConnection>(conn: &T, session_token: &str, user_id: Option<i32>, csrf_token: &str,
                                        (firstname, lastname, street, zip, city, password, password_repeat, grade): (String, String,Option<String>,Option<String>,Option<String>,Option<String>,Option<String>,i32))
                                        -> MedalResult<ProfileStatus>
{
    let mut session = conn.get_session(&session_token)
                          .ok_or(MedalError::AccessDenied)?
                          .ensure_alive()
                          .ok_or(MedalError::AccessDenied)?; // TODO SessionTimeout

    if session.csrf_token != csrf_token {
        return Err(MedalError::AccessDenied); // CsrfError
    }

    if session.firstname.as_ref() == Some(&firstname)
       && session.lastname.as_ref() == Some(&lastname)
       && session.street == street
       && session.zip == zip
       && session.city == city
       && session.grade == grade
    {
        return Ok(ProfileStatus::NothingChanged);
    }

    let mut result = ProfileStatus::DataChanged;

    let mut password_and_salt = None;

    if let (Some(password), Some(password_repeat)) = (password, password_repeat) {
        if password != "" || password_repeat != "" {
            if password == password_repeat {
                let salt = helpers::make_salt();
                let hash = helpers::hash_password(&password, &salt)?;

                password_and_salt = Some((hash, salt));
                result = ProfileStatus::PasswordChanged;
            } else {
                result = ProfileStatus::PasswordMissmatch;
            }
        } else {
            return Ok(ProfileStatus::NothingChanged);
        }
    }

    match user_id {
        None => {
            session.firstname = Some(firstname);
            session.lastname = Some(lastname);
            session.grade = grade;

            if street.is_some() {
                session.street = street;
            }
            if zip.is_some() {
                session.zip = zip;
            }
            if city.is_some() {
                session.city = city;
            }

            if let Some((password, salt)) = password_and_salt {
                session.password = Some(password);
                session.salt = Some(salt);
            }

            conn.save_session(session);
        }
        Some(user_id) => {
            // TODO: Add test to check if this access restriction works
            let (mut user, opt_group) = conn.get_user_and_group_by_id(user_id).ok_or(MedalError::AccessDenied)?;
            let group = opt_group.ok_or(MedalError::AccessDenied)?;
            if group.admin != session.id {
                return Err(MedalError::AccessDenied);
            }

            user.firstname = Some(firstname);
            user.lastname = Some(lastname);
            user.grade = grade;

            if street.is_some() {
                user.street = street;
            }
            if zip.is_some() {
                user.zip = zip;
            }
            if city.is_some() {
                user.city = city;
            }

            if let Some((password, salt)) = password_and_salt {
                user.password = Some(password);
                user.salt = Some(salt);
            }

            conn.save_session(user);
        }
    }

    Ok(result)
}

#[derive(PartialEq)]
pub enum UserType {
    User,
    Teacher,
    Admin,
}

pub enum UserGender {
    Female,
    Male,
    Unknown,
}

pub struct ForeignUserData {
    pub foreign_id: String,
    pub foreign_type: UserType,
    pub gender: UserGender,
    pub firstname: String,
    pub lastname: String,
}

pub fn login_oauth<T: MedalConnection>(conn: &T, user_data: ForeignUserData)
                                       -> Result<String, (String, json_val::Map<String, json_val::Value>)> {
    match conn.login_foreign(None,
                             &user_data.foreign_id,
                             user_data.foreign_type != UserType::User,
                             &user_data.firstname,
                             &user_data.lastname)
    {
        Ok(session_token) => Ok(session_token),
        Err(()) => {
            let mut data = json_val::Map::new();
            data.insert("reason".to_string(), to_json(&"OAuth-Login failed.".to_string()));
            Err(("login".to_owned(), data))
        }
    }
}