package common

import (
	"database/sql"
	//"log"
	"time"

	qgen "git.tuxpa.in/a/gosora/query_gen"
)

var GroupPromotions GroupPromotionStore

type GroupPromotion struct {
    ID     int
    From   int
    To     int
    TwoWay bool

    Level         int
    Posts         int
    MinTime       int
    RegisteredFor int
}

type GroupPromotionStore interface {
    GetByGroup(gid int) (gps []*GroupPromotion, err error)
    Get(id int) (*GroupPromotion, error)
    PromoteIfEligible(u *User, level, posts int, registeredAt time.Time) error
    Delete(id int) error
    Create(from, to int, twoWay bool, level, posts, registeredFor int) (int, error)
}

type DefaultGroupPromotionStore struct {
    getByGroup *sql.Stmt
    get        *sql.Stmt
    delete     *sql.Stmt
    create     *sql.Stmt

    getByUser     *sql.Stmt
    getByUserMins *sql.Stmt
    updateUser    *sql.Stmt
    updateGeneric *sql.Stmt
}

func NewDefaultGroupPromotionStore(acc *qgen.Accumulator) (*DefaultGroupPromotionStore, error) {
    ugp := "users_groups_promotions"
    prs := &DefaultGroupPromotionStore{
        getByGroup: acc.Select(ugp).Columns("pid, from_gid, to_gid, two_way, level, posts, minTime, registeredFor").Where("from_gid=? OR to_gid=?").Prepare(),
        get:        acc.Select(ugp).Columns("from_gid, to_gid, two_way, level, posts, minTime, registeredFor").Where("pid=?").Prepare(),
        delete:     acc.Delete(ugp).Where("pid=?").Prepare(),
        create:     acc.Insert(ugp).Columns("from_gid, to_gid, two_way, level, posts, minTime, registeredFor").Fields("?,?,?,?,?,?,?").Prepare(),

        getByUserMins: acc.Select(ugp).Columns("pid, to_gid, two_way, level, posts, minTime, registeredFor").Where("from_gid=? AND level<=? AND posts<=? AND registeredFor<=?").Orderby("level DESC").Limit("1").Prepare(),
        getByUser:     acc.Select(ugp).Columns("pid, to_gid, two_way, level, posts, minTime, registeredFor").Where("from_gid=? AND level<=? AND posts<=?").Orderby("level DESC").Limit("1").Prepare(),
        updateUser:    acc.Update("users").Set("group=?").Where("group=? AND uid=?").Prepare(),
        updateGeneric: acc.Update("users").Set("group=?").Where("group=? AND level>=? AND posts>=?").Prepare(),
    }
    Tasks.FifteenMin.Add(prs.Tick)
    return prs, acc.FirstError()
}

func (s *DefaultGroupPromotionStore) Tick() error {
    return nil
}

func (s *DefaultGroupPromotionStore) GetByGroup(gid int) (gps []*GroupPromotion, err error) {
    rows, err := s.getByGroup.Query(gid, gid)
    if err != nil {
        return nil, err
    }
    defer rows.Close()

    for rows.Next() {
        g := &GroupPromotion{}
        err := rows.Scan(&g.ID, &g.From, &g.To, &g.TwoWay, &g.Level, &g.Posts, &g.MinTime, &g.RegisteredFor)
        if err != nil {
            return nil, err
        }
        gps = append(gps, g)
    }
    return gps, rows.Err()
}

// TODO: Cache the group promotions to avoid hitting the database as much
func (s *DefaultGroupPromotionStore) Get(id int) (*GroupPromotion, error) {
    /*g, err := s.cache.Get(id)
    if err == nil {
        return u, nil
    }*/

    g := &GroupPromotion{ID: id}
    err := s.get.QueryRow(id).Scan(&g.From, &g.To, &g.TwoWay, &g.Level, &g.Posts, &g.MinTime, &g.RegisteredFor)
    if err == nil {
        //s.cache.Set(u)
    }
    return g, err
}

// TODO: Optimise this to avoid the query
func (s *DefaultGroupPromotionStore) PromoteIfEligible(u *User, level, posts int, registeredAt time.Time) error {
    mins := time.Since(registeredAt).Minutes()
    g := &GroupPromotion{From: u.Group}
    //log.Printf("pre getByUserMins: %+v\n", u)
    err := s.getByUserMins.QueryRow(u.Group, level, posts, mins).Scan(&g.ID, &g.To, &g.TwoWay, &g.Level, &g.Posts, &g.MinTime, &g.RegisteredFor)
    if err == sql.ErrNoRows {
        //log.Print("no matches found")
        return nil
    } else if err != nil {
        return err
    }
    //log.Printf("g: %+v\n", g)
    if g.RegisteredFor == 0 {
        _, err = s.updateGeneric.Exec(g.To, g.From, g.Level, g.Posts)
    } else {
        _, err = s.updateUser.Exec(g.To, g.From, u.ID)
    }
    return err
}

func (s *DefaultGroupPromotionStore) Delete(id int) error {
    _, err := s.delete.Exec(id)
    return err
}

func (s *DefaultGroupPromotionStore) Create(from, to int, twoWay bool, level, posts, registeredFor int) (int, error) {
    res, err := s.create.Exec(from, to, twoWay, level, posts, 0, registeredFor)
    if err != nil {
        return 0, err
    }
    lastID, err := res.LastInsertId()
    return int(lastID), err
}