package common

import (
	"database/sql"
	"errors"
	"strconv"

	qgen "git.tuxpa.in/a/gosora/query_gen"
	"golang.org/x/crypto/bcrypt"
)

// TODO: Add the watchdog goroutine
// TODO: Add some sort of update method
var Users UserStore
var ErrAccountExists = errors.New("this username is already in use")
var ErrLongUsername = errors.New("this username is too long")
var ErrSomeUsersNotFound = errors.New("Unable to find some users")

type UserStore interface {
    DirtyGet(id int) *User
    Get(id int) (*User, error)
    Getn(id int) *User
    GetByName(name string) (*User, error)
    BulkGetByName(names []string) (list []*User, err error)
    RawBulkGetByNameForConvo(f func(int, string, int, bool, int, int) error, names []string) error
    Exists(id int) bool
    SearchOffset(name, email string, gid, offset, perPage int) (users []*User, err error)
    GetOffset(offset, perPage int) ([]*User, error)
    Each(f func(*User) error) error
    //BulkGet(ids []int) ([]*User, error)
    BulkGetMap(ids []int) (map[int]*User, error)
    BypassGet(id int) (*User, error)
    ClearLastIPs() error
    Create(name, password, email string, group int, active bool) (int, error)
    Reload(id int) error
    Count() int
    CountSearch(name, email string, gid int) int

    SetCache(cache UserCache)
    GetCache() UserCache
}

type DefaultUserStore struct {
    cache UserCache

    get          *sql.Stmt
    getByName    *sql.Stmt
    searchOffset *sql.Stmt
    getOffset    *sql.Stmt
    getAll       *sql.Stmt
    exists       *sql.Stmt
    register     *sql.Stmt
    nameExists   *sql.Stmt

    count       *sql.Stmt
    countSearch *sql.Stmt

    clearIPs *sql.Stmt
}

// NewDefaultUserStore gives you a new instance of DefaultUserStore
func NewDefaultUserStore(cache UserCache) (*DefaultUserStore, error) {
    acc := qgen.NewAcc()
    if cache == nil {
        cache = NewNullUserCache()
    }
    u := "users"
    allCols := "uid,name,group,active,is_super_admin,session,email,avatar,message,level,score,posts,liked,last_ip,temp_group,createdAt,enable_embeds,profile_comments,who_can_convo"
    // TODO: Add an admin version of registerStmt with more flexibility?
    return &DefaultUserStore{
        cache: cache,

        get:          acc.Select(u).Columns("name,group,active,is_super_admin,session,email,avatar,message,level,score,posts,liked,last_ip,temp_group,createdAt,enable_embeds,profile_comments,who_can_convo").Where("uid=?").Prepare(),
        getByName:    acc.Select(u).Columns(allCols).Where("name=?").Prepare(),
        searchOffset: acc.Select(u).Columns(allCols).Where("(name=? OR ?='') AND (email=? OR ?='') AND (group=? OR ?=0)").Orderby("uid ASC").Limit("?,?").Prepare(),
        getOffset:    acc.Select(u).Columns(allCols).Orderby("uid ASC").Limit("?,?").Prepare(),
        getAll:       acc.Select(u).Columns(allCols).Prepare(),

        exists:     acc.Exists(u, "uid").Prepare(),
        register:   acc.Insert(u).Columns("name,email,password,salt,group,is_super_admin,session,active,message,createdAt,lastActiveAt,lastLiked,oldestItemLikedCreatedAt").Fields("?,?,?,?,?,0,'',?,'',UTC_TIMESTAMP(),UTC_TIMESTAMP(),UTC_TIMESTAMP(),UTC_TIMESTAMP()").Prepare(), // TODO: Implement user_count on users_groups here
        nameExists: acc.Exists(u, "name").Prepare(),

        count:       acc.Count(u).Prepare(),
        countSearch: acc.Count(u).Where("(name=? OR ?='') AND (email=? OR ?='') AND (group=? OR ?=0)").Prepare(),

        clearIPs: acc.Update(u).Set("last_ip=''").Where("last_ip!=''").Prepare(),
    }, acc.FirstError()
}

func (s *DefaultUserStore) DirtyGet(id int) *User {
    user, err := s.Get(id)
    if err == nil {
        return user
    }
    /*if s.OutOfBounds(id) {
        return BlankUser()
    }*/
    return BlankUser()
}

func (s *DefaultUserStore) scanUser(r *sql.Row, u *User) (embeds int, err error) {
    e := r.Scan(&u.Name, &u.Group, &u.Active, &u.IsSuperAdmin, &u.Session, &u.Email, &u.RawAvatar, &u.Message, &u.Level, &u.Score, &u.Posts, &u.Liked, &u.LastIP, &u.TempGroup, &u.CreatedAt, &embeds, &u.Privacy.ShowComments, &u.Privacy.AllowMessage)
    return embeds, e
}

// TODO: Log weird cache errors? Not just here but in every *Cache?
func (s *DefaultUserStore) Get(id int) (*User, error) {
    u, err := s.cache.Get(id)
    if err == nil {
        //log.Print("cached user")
        //log.Print(string(debug.Stack()))
        //log.Println("")
        return u, nil
    }
    //log.Print("uncached user")

    u = &User{ID: id, Loggedin: true}
    embeds, err := s.scanUser(s.get.QueryRow(id), u)
    if err == nil {
        if embeds != -1 {
            u.ParseSettings = DefaultParseSettings.CopyPtr()
            u.ParseSettings.NoEmbed = embeds == 0
        }
        u.Init()
        s.cache.Set(u)
    }
    return u, err
}

func (s *DefaultUserStore) Getn(id int) *User {
    u := s.cache.Getn(id)
    if u != nil {
        return u
    }

    u = &User{ID: id, Loggedin: true}
    embeds, err := s.scanUser(s.get.QueryRow(id), u)
    if err != nil {
        return nil
    }
    if embeds != -1 {
        u.ParseSettings = DefaultParseSettings.CopyPtr()
        u.ParseSettings.NoEmbed = embeds == 0
    }
    u.Init()
    s.cache.Set(u)
    return u
}

// TODO: Log weird cache errors? Not just here but in every *Cache?
// ! This bypasses the cache, use frugally
func (s *DefaultUserStore) GetByName(name string) (*User, error) {
    u := &User{Loggedin: true}
    var embeds int
    err := s.getByName.QueryRow(name).Scan(&u.ID, &u.Name, &u.Group, &u.Active, &u.IsSuperAdmin, &u.Session, &u.Email, &u.RawAvatar, &u.Message, &u.Level, &u.Score, &u.Posts, &u.Liked, &u.LastIP, &u.TempGroup, &u.CreatedAt, &embeds, &u.Privacy.ShowComments, &u.Privacy.AllowMessage)
    if err != nil {
        return nil, err
    }
    if embeds != -1 {
        u.ParseSettings = DefaultParseSettings.CopyPtr()
        u.ParseSettings.NoEmbed = embeds == 0
    }
    u.Init()
    s.cache.Set(u)
    return u, nil
}

// TODO: Optimise the query to avoid preparing it on the spot? Maybe, use knowledge of the most common IN() parameter counts?
// ! This bypasses the cache, use frugally
func (s *DefaultUserStore) BulkGetByName(names []string) (list []*User, err error) {
    if len(names) == 0 {
        return list, nil
    } else if len(names) == 1 {
        user, err := s.GetByName(names[0])
        if err != nil {
            return list, err
        }
        return []*User{user}, nil
    }

    idList, q := inqbuildstr(names)
    rows, err := qgen.NewAcc().Select("users").Columns("uid,name,group,active,is_super_admin,session,email,avatar,message,level,score,posts,liked,last_ip,temp_group,createdAt,enable_embeds,profile_comments,who_can_convo").Where("name IN(" + q + ")").Query(idList...)
    if err != nil {
        return list, err
    }
    defer rows.Close()

    var embeds int
    for rows.Next() {
        u := &User{Loggedin: true}
        err := rows.Scan(&u.ID, &u.Name, &u.Group, &u.Active, &u.IsSuperAdmin, &u.Session, &u.Email, &u.RawAvatar, &u.Message, &u.Level, &u.Score, &u.Posts, &u.Liked, &u.LastIP, &u.TempGroup, &u.CreatedAt, &embeds, &u.Privacy.ShowComments, &u.Privacy.AllowMessage)
        if err != nil {
            return list, err
        }
        if embeds != -1 {
            u.ParseSettings = DefaultParseSettings.CopyPtr()
            u.ParseSettings.NoEmbed = embeds == 0
        }
        u.Init()
        s.cache.Set(u)
        list = append(list, u)
    }
    if err = rows.Err(); err != nil {
        return list, err
    }

    // Did we miss any users?
    if len(names) > len(list) {
        return list, ErrSomeUsersNotFound
    }
    return list, err
}

// Special case function for efficiency
func (s *DefaultUserStore) RawBulkGetByNameForConvo(f func(int, string, int, bool, int, int) error, names []string) error {
    idList, q := inqbuildstr(names)
    rows, e := qgen.NewAcc().Select("users").Columns("uid,name,group,is_super_admin,temp_group,who_can_convo").Where("name IN(" + q + ")").Query(idList...)
    if e != nil {
        return e
    }
    defer rows.Close()
    for rows.Next() {
        var name string
        var id, group, temp_group, who_can_convo int
        var super_admin bool
        if e = rows.Scan(&id, &name, &group, &super_admin, &temp_group, &who_can_convo); e != nil {
            return e
        }
        if e = f(id, name, group, super_admin, temp_group, who_can_convo); e != nil {
            return e
        }
    }
    return rows.Err()
}

// TODO: Optimise this, so we don't wind up hitting the database every-time for small gaps
// TODO: Make this a little more consistent with DefaultGroupStore's GetRange method
func (s *DefaultUserStore) GetOffset(offset, perPage int) (users []*User, err error) {
    rows, err := s.getOffset.Query(offset, perPage)
    if err != nil {
        return users, err
    }
    defer rows.Close()

    var embeds int
    for rows.Next() {
        u := &User{Loggedin: true}
        err := rows.Scan(&u.ID, &u.Name, &u.Group, &u.Active, &u.IsSuperAdmin, &u.Session, &u.Email, &u.RawAvatar, &u.Message, &u.Level, &u.Score, &u.Posts, &u.Liked, &u.LastIP, &u.TempGroup, &u.CreatedAt, &embeds, &u.Privacy.ShowComments, &u.Privacy.AllowMessage)
        if err != nil {
            return nil, err
        }
        if embeds != -1 {
            u.ParseSettings = DefaultParseSettings.CopyPtr()
            u.ParseSettings.NoEmbed = embeds == 0
        }
        u.Init()
        s.cache.Set(u)
        users = append(users, u)
    }
    return users, rows.Err()
}
func (s *DefaultUserStore) SearchOffset(name, email string, gid, offset, perPage int) (users []*User, err error) {
    rows, err := s.searchOffset.Query(name, name, email, email, gid, gid, offset, perPage)
    if err != nil {
        return users, err
    }
    defer rows.Close()

    var embeds int
    for rows.Next() {
        u := &User{Loggedin: true}
        err := rows.Scan(&u.ID, &u.Name, &u.Group, &u.Active, &u.IsSuperAdmin, &u.Session, &u.Email, &u.RawAvatar, &u.Message, &u.Level, &u.Score, &u.Posts, &u.Liked, &u.LastIP, &u.TempGroup, &u.CreatedAt, &embeds, &u.Privacy.ShowComments, &u.Privacy.AllowMessage)
        if err != nil {
            return nil, err
        }
        if embeds != -1 {
            u.ParseSettings = DefaultParseSettings.CopyPtr()
            u.ParseSettings.NoEmbed = embeds == 0
        }
        u.Init()
        s.cache.Set(u)
        users = append(users, u)
    }
    return users, rows.Err()
}
func (s *DefaultUserStore) Each(f func(*User) error) error {
    rows, e := s.getAll.Query()
    if e != nil {
        return e
    }
    defer rows.Close()
    var embeds int
    for rows.Next() {
        u := new(User)
        if e := rows.Scan(&u.ID, &u.Name, &u.Group, &u.Active, &u.IsSuperAdmin, &u.Session, &u.Email, &u.RawAvatar, &u.Message, &u.Level, &u.Score, &u.Posts, &u.Liked, &u.LastIP, &u.TempGroup, &u.CreatedAt, &embeds, &u.Privacy.ShowComments, &u.Privacy.AllowMessage); e != nil {
            return e
        }
        if embeds != -1 {
            u.ParseSettings = DefaultParseSettings.CopyPtr()
            u.ParseSettings.NoEmbed = embeds == 0
        }
        u.Init()
        if e := f(u); e != nil {
            return e
        }
    }
    return rows.Err()
}

// TODO: Optimise the query to avoid preparing it on the spot? Maybe, use knowledge of the most common IN() parameter counts?
// TODO: ID of 0 should always error?
func (s *DefaultUserStore) BulkGetMap(ids []int) (list map[int]*User, err error) {
    idCount := len(ids)
    list = make(map[int]*User)
    if idCount == 0 {
        return list, nil
    }

    var stillHere []int
    sliceList := s.cache.BulkGet(ids)
    if len(sliceList) > 0 {
        for i, sliceItem := range sliceList {
            if sliceItem != nil {
                list[sliceItem.ID] = sliceItem
            } else {
                stillHere = append(stillHere, ids[i])
            }
        }
        ids = stillHere
    }

    // If every user is in the cache, then return immediately
    if len(ids) == 0 {
        return list, nil
    } else if len(ids) == 1 {
        user, err := s.Get(ids[0])
        if err != nil {
            return list, err
        }
        list[user.ID] = user
        return list, nil
    }

    idList, q := inqbuild(ids)
    rows, err := qgen.NewAcc().Select("users").Columns("uid,name,group,active,is_super_admin,session,email,avatar,message,level,score,posts,liked,last_ip,temp_group,createdAt,enable_embeds,profile_comments,who_can_convo").Where("uid IN(" + q + ")").Query(idList...)
    if err != nil {
        return list, err
    }
    defer rows.Close()

    var embeds int
    for rows.Next() {
        u := &User{Loggedin: true}
        err := rows.Scan(&u.ID, &u.Name, &u.Group, &u.Active, &u.IsSuperAdmin, &u.Session, &u.Email, &u.RawAvatar, &u.Message, &u.Level, &u.Score, &u.Posts, &u.Liked, &u.LastIP, &u.TempGroup, &u.CreatedAt, &embeds, &u.Privacy.ShowComments, &u.Privacy.AllowMessage)
        if err != nil {
            return list, err
        }
        if embeds != -1 {
            u.ParseSettings = DefaultParseSettings.CopyPtr()
            u.ParseSettings.NoEmbed = embeds == 0
        }
        u.Init()
        s.cache.Set(u)
        list[u.ID] = u
    }
    if err = rows.Err(); err != nil {
        return list, err
    }

    // Did we miss any users?
    if idCount > len(list) {
        var sidList string
        for _, id := range ids {
            _, ok := list[id]
            if !ok {
                sidList += strconv.Itoa(id) + ","
            }
        }
        if sidList != "" {
            sidList = sidList[0 : len(sidList)-1]
            err = errors.New("Unable to find users with the following IDs: " + sidList)
        }
    }

    return list, err
}

func (s *DefaultUserStore) BypassGet(id int) (*User, error) {
    u := &User{ID: id, Loggedin: true}
    embeds, err := s.scanUser(s.get.QueryRow(id), u)
    if err == nil {
        if embeds != -1 {
            u.ParseSettings = DefaultParseSettings.CopyPtr()
            u.ParseSettings.NoEmbed = embeds == 0
        }
        u.Init()
    }
    return u, err
}

func (s *DefaultUserStore) Reload(id int) error {
    u, err := s.BypassGet(id)
    if err != nil {
        s.cache.Remove(id)
        return err
    }
    _ = s.cache.Set(u)
    TopicListThaw.Thaw()
    return nil
}

func (s *DefaultUserStore) Exists(id int) bool {
    err := s.exists.QueryRow(id).Scan(&id)
    if err != nil && err != ErrNoRows {
        LogError(err)
    }
    return err != ErrNoRows
}

func (s *DefaultUserStore) ClearLastIPs() error {
    _, e := s.clearIPs.Exec()
    return e
}

// TODO: Change active to a bool?
// TODO: Use unique keys for the usernames
func (s *DefaultUserStore) Create(name, password, email string, group int, active bool) (int, error) {
    // TODO: Strip spaces?

    // ? This number might be a little screwy with Unicode, but it's the only consistent thing we have, as Unicode characters can be any number of bytes in theory?
    if len(name) > Config.MaxUsernameLength {
        return 0, ErrLongUsername
    }

    // Is this name already taken..?
    err := s.nameExists.QueryRow(name).Scan(&name)
    if err != ErrNoRows {
        return 0, ErrAccountExists
    }
    salt, err := GenerateSafeString(SaltLength)
    if err != nil {
        return 0, err
    }
    hashedPassword, err := bcrypt.GenerateFromPassword([]byte(password+salt), bcrypt.DefaultCost)
    if err != nil {
        return 0, err
    }

    res, err := s.register.Exec(name, email, string(hashedPassword), salt, group, active)
    if err != nil {
        return 0, err
    }
    lastID, err := res.LastInsertId()
    return int(lastID), err
}

// Count returns the total number of users registered on the forums
func (s *DefaultUserStore) Count() (count int) {
    return Countf(s.count)
}

func (s *DefaultUserStore) CountSearch(name, email string, gid int) (count int) {
    return Countf(s.countSearch, name, name, email, email, gid, gid)
}

func (s *DefaultUserStore) SetCache(cache UserCache) {
    s.cache = cache
}

// TODO: We're temporarily doing this so that you can do ucache != nil in getTopicUser. Refactor it.
func (s *DefaultUserStore) GetCache() UserCache {
    _, ok := s.cache.(*NullUserCache)
    if ok {
        return nil
    }
    return s.cache
}