package common

import (
	"database/sql"

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

var UserBlocks BlockStore

//var UserFriends FriendStore

type BlockStore interface {
    IsBlockedBy(blocker, blockee int) (bool, error)
    BulkIsBlockedBy(blockers []int, blockee int) (bool, error)
    Add(blocker, blockee int) error
    Remove(blocker, blockee int) error
    BlockedByOffset(blocker, offset, perPage int) ([]int, error)
    BlockedByCount(blocker int) int
}

type DefaultBlockStore struct {
    isBlocked      *sql.Stmt
    add            *sql.Stmt
    remove         *sql.Stmt
    blockedBy      *sql.Stmt
    blockedByCount *sql.Stmt
}

func NewDefaultBlockStore(acc *qgen.Accumulator) (*DefaultBlockStore, error) {
    ub := "users_blocks"
    return &DefaultBlockStore{
        isBlocked:      acc.Select(ub).Cols("blocker").Where("blocker=? AND blockedUser=?").Prepare(),
        add:            acc.Insert(ub).Columns("blocker,blockedUser").Fields("?,?").Prepare(),
        remove:         acc.Delete(ub).Where("blocker=? AND blockedUser=?").Prepare(),
        blockedBy:      acc.Select(ub).Columns("blockedUser").Where("blocker=?").Limit("?,?").Prepare(),
        blockedByCount: acc.Count(ub).Where("blocker=?").Prepare(),
    }, acc.FirstError()
}

func (s *DefaultBlockStore) IsBlockedBy(blocker, blockee int) (bool, error) {
    e := s.isBlocked.QueryRow(blocker, blockee).Scan(&blocker)
    if e == ErrNoRows {
        return false, nil
    }
    return e == nil, e
}

// TODO: Optimise the query to avoid preparing it on the spot? Maybe, use knowledge of the most common IN() parameter counts?
func (s *DefaultBlockStore) BulkIsBlockedBy(blockers []int, blockee int) (bool, error) {
    if len(blockers) == 0 {
        return false, nil
    }
    if len(blockers) == 1 {
        return s.IsBlockedBy(blockers[0], blockee)
    }
    idList, q := inqbuild(blockers)
    count, e := qgen.NewAcc().Count("users_blocks").Where("blocker IN(" + q + ") AND blockedUser=?").TotalP(idList...)
    if e == ErrNoRows {
        return false, nil
    }
    return count == 0, e
}

func (s *DefaultBlockStore) Add(blocker, blockee int) error {
    _, e := s.add.Exec(blocker, blockee)
    return e
}

func (s *DefaultBlockStore) Remove(blocker, blockee int) error {
    _, e := s.remove.Exec(blocker, blockee)
    return e
}

func (s *DefaultBlockStore) BlockedByOffset(blocker, offset, perPage int) (uids []int, err error) {
    rows, e := s.blockedBy.Query(blocker, offset, perPage)
    if e != nil {
        return nil, e
    }
    defer rows.Close()
    for rows.Next() {
        var uid int
        if e := rows.Scan(&uid); e != nil {
            return nil, e
        }
        uids = append(uids, uid)
    }
    return uids, rows.Err()
}

func (s *DefaultBlockStore) BlockedByCount(blocker int) (count int) {
    e := s.blockedByCount.QueryRow(blocker).Scan(&count)
    if e != nil {
        LogError(e)
    }
    return count
}

type FriendInvite struct {
    Requester int
    Target    int
}

type FriendStore interface {
    AddInvite(requester, target int) error
    Confirm(requester, target int) error
    GetOwSentInvites(uid int) ([]FriendInvite, error)
    GetOwnRecvInvites(uid int) ([]FriendInvite, error)
}

type DefaultFriendStore struct {
    addInvite         *sql.Stmt
    confirm           *sql.Stmt
    getOwnSentInvites *sql.Stmt
    getOwnRecvInvites *sql.Stmt
}

func NewDefaultFriendStore(acc *qgen.Accumulator) (*DefaultFriendStore, error) {
    ufi := "users_friends_invites"
    return &DefaultFriendStore{
        addInvite:         acc.Insert(ufi).Columns("requester,target").Fields("?,?").Prepare(),
        confirm:           acc.Insert("users_friends").Columns("uid,uid2").Fields("?,?").Prepare(),
        getOwnSentInvites: acc.Select(ufi).Cols("requester,target").Where("requester=?").Prepare(),
        getOwnRecvInvites: acc.Select(ufi).Cols("requester,target").Where("target=?").Prepare(),
    }, acc.FirstError()
}

func (s *DefaultFriendStore) AddInvite(requester, target int) error {
    _, e := s.addInvite.Exec(requester, target)
    return e
}

func (s *DefaultFriendStore) Confirm(requester, target int) error {
    _, e := s.confirm.Exec(requester, target)
    return e
}

func (s *DefaultFriendStore) GetOwnSentInvites(uid int) ([]FriendInvite, error) {
    return nil, nil
}
func (s *DefaultFriendStore) GetOwnRecvInvites(uid int) ([]FriendInvite, error) {
    return nil, nil
}