package common

import (
	"database/sql"
	"fmt"
	"strconv"
	"sync"
	"time"

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

var TopicList TopicListInt

const (
    TopicListDefault = iota
    TopicListMostViewed
    TopicListWeekViews
)

type TopicListHolder struct {
    List      []*TopicsRow
    ForumList []Forum
    Paginator Paginator
}

type ForumTopicListHolder struct {
    List      []*TopicsRow
    Paginator Paginator
}

// TODO: Should we return no rows errors on empty pages? Is this likely to break something?
type TopicListInt interface {
    GetListByCanSee(canSee []int, page, orderby int, filterIDs []int) (topicList []*TopicsRow, forumList []Forum, pagi Paginator, err error)
    GetListByGroup(g *Group, page, orderby int, filterIDs []int) (topicList []*TopicsRow, forumList []Forum, pagi Paginator, err error)
    GetListByForum(f *Forum, page, orderby int) (topicList []*TopicsRow, pagi Paginator, err error)
    GetList(page, orderby int, filterIDs []int) (topicList []*TopicsRow, forumList []Forum, pagi Paginator, err error)
}

type TopicListIntTest interface {
    RawGetListByForum(f *Forum, page, orderby int) (topicList []*TopicsRow, pagi Paginator, err error)
    Tick() error
}

type DefaultTopicList struct {
    // TODO: Rewrite this to put permTree as the primary and put canSeeStr on each group?
    oddGroups  map[int][2]*TopicListHolder
    evenGroups map[int][2]*TopicListHolder
    oddLock    sync.RWMutex
    evenLock   sync.RWMutex

    forums    map[int]*ForumTopicListHolder
    forumLock sync.RWMutex

    qcounts  map[int]*sql.Stmt
    qcounts2 map[int]*sql.Stmt
    qLock    sync.RWMutex
    qLock2   sync.RWMutex

    //permTree atomic.Value // [string(canSee)]canSee
    //permTree map[string][]int // [string(canSee)]canSee

    getTopicsByForum *sql.Stmt
    //getTidsByForum *sql.Stmt
}

// We've removed the topic list cache cap as admins really shouldn't be abusing groups like this with plugin_guilds around and it was extremely fiddly.
// If this becomes a problem later on, then we can revisit this with a fresh perspective, particularly with regards to what people expect a group to really be
// Also, keep in mind that as-long as the groups don't all have unique sets of forums they can see, then we can optimise a large portion of the work away.
func NewDefaultTopicList(acc *qgen.Accumulator) (*DefaultTopicList, error) {
    tList := &DefaultTopicList{
        oddGroups:        make(map[int][2]*TopicListHolder),
        evenGroups:       make(map[int][2]*TopicListHolder),
        forums:           make(map[int]*ForumTopicListHolder),
        qcounts:          make(map[int]*sql.Stmt),
        qcounts2:         make(map[int]*sql.Stmt),
        getTopicsByForum: acc.Select("topics").Columns("tid,title,content,createdBy,is_closed,sticky,createdAt,lastReplyAt,lastReplyBy,lastReplyID,views,postCount,likeCount").Where("parentID=?").Orderby("sticky DESC,lastReplyAt DESC,createdBy DESC").Limit("?,?").Prepare(),
        //getTidsByForum: acc.Select("topics").Columns("tid").Where("parentID=?").Orderby("sticky DESC,lastReplyAt DESC,createdBy DESC").Limit("?,?").Prepare(),
    }
    if e := acc.FirstError(); e != nil {
        return nil, e
    }
    if e := tList.Tick(); e != nil {
        return nil, e
    }

    Tasks.HalfSec.Add(tList.Tick)
    //Tasks.Sec.Add(tList.GroupCountTick) // TODO: Dynamically change the groups in the short list to be optimised every second
    return tList, nil
}

func (tList *DefaultTopicList) Tick() error {
    //fmt.Println("TopicList.Tick")
    if !TopicListThaw.Thawed() {
        return nil
    }
    //fmt.Println("building topic list")

    oddLists := make(map[int][2]*TopicListHolder)
    evenLists := make(map[int][2]*TopicListHolder)
    addList := func(gid int, h [2]*TopicListHolder) {
        if gid%2 == 0 {
            evenLists[gid] = h
        } else {
            oddLists[gid] = h
        }
    }

    allGroups, err := Groups.GetAll()
    if err != nil {
        return err
    }

    gidToCanSee := make(map[int]string)
    permTree := make(map[string][]int) // [string(canSee)]canSee
    for _, g := range allGroups {
        // ? - Move the user count check to instance initialisation? Might require more book-keeping, particularly when a user moves into a zero user group
        if g.UserCount == 0 && g.ID != GuestUser.Group {
            continue
        }

        canSee := make([]byte, len(g.CanSee))
        for i, item := range g.CanSee {
            canSee[i] = byte(item)
        }

        canSeeInt := make([]int, len(canSee))
        copy(canSeeInt, g.CanSee)
        sCanSee := string(canSee)
        permTree[sCanSee] = canSeeInt
        gidToCanSee[g.ID] = sCanSee
    }

    canSeeHolders := make(map[string][2]*TopicListHolder)
    forumCounts := make(map[int]int)
    for name, canSee := range permTree {
        topicList, forumList, pagi, err := tList.GetListByCanSee(canSee, 1, 0, nil)
        if err != nil {
            return err
        }
        topicList2, forumList2, pagi2, err := tList.GetListByCanSee(canSee, 2, 0, nil)
        if err != nil {
            return err
        }
        canSeeHolders[name] = [2]*TopicListHolder{
            {topicList, forumList, pagi},
            {topicList2, forumList2, pagi2},
        }
        if len(canSee) > 1 {
            forumCounts[len(canSee)] += 1
        }
    }
    for gid, canSee := range gidToCanSee {
        addList(gid, canSeeHolders[canSee])
    }

    tList.oddLock.Lock()
    tList.oddGroups = oddLists
    tList.oddLock.Unlock()

    tList.evenLock.Lock()
    tList.evenGroups = evenLists
    tList.evenLock.Unlock()

    topc := []int{0, 0, 0, 0, 0, 0}
    addC := func(c int) {
        lowI, low := 0, topc[0]
        for i, top := range topc {
            if top < low {
                lowI = i
                low = top
            }
        }
        if c > low {
            topc[lowI] = c
        }
    }
    for forumCount := range forumCounts {
        addC(forumCount)
    }

    qcounts := make(map[int]*sql.Stmt)
    qcounts2 := make(map[int]*sql.Stmt)
    for _, top := range topc {
        if top == 0 {
            continue
        }

        qlist := inqbuild2(top - 1)
        cols := "tid,title,content,createdBy,is_closed,sticky,createdAt,lastReplyAt,lastReplyBy,lastReplyID,parentID,views,postCount,likeCount,attachCount,poll,data"

        stmt, err := qgen.Builder.SimpleSelect("topics", cols, "parentID IN("+qlist+")", "views DESC,lastReplyAt DESC,createdBy DESC", "?,?")
        if err != nil {
            return err
        }
        qcounts[top] = stmt

        stmt, err = qgen.Builder.SimpleSelect("topics", cols, "parentID IN("+qlist+")", "sticky DESC,lastReplyAt DESC,createdBy DESC", "?,?")
        if err != nil {
            return err
        }
        qcounts2[top] = stmt
    }

    tList.qLock.Lock()
    tList.qcounts = qcounts
    tList.qLock.Unlock()

    tList.qLock2.Lock()
    tList.qcounts2 = qcounts2
    tList.qLock2.Unlock()

    fmt.Printf("Forums: %+v\n", Forums)
    forums, err := Forums.GetAll()
    if err != nil {
        return err
    }

    top8 := []*Forum{nil, nil, nil, nil, nil, nil, nil, nil}
    z := true
    addScore2 := func(f *Forum) {
        for i, top := range top8 {
            if top.TopicCount < f.TopicCount {
                top8[i] = f
                return
            }
        }
    }
    addScore := func(f *Forum) {
        if z {
            for i, top := range top8 {
                if top == nil {
                    top8[i] = f
                    return
                }
            }
            z = false
            addScore2(f)
        }
        addScore2(f)
    }

    var fshort []*Forum
    for _, f := range forums {
        if f.Name == "" || !f.Active || (f.ParentType != "" && f.ParentType != "forum") {
            continue
        }
        if f.TopicCount == 0 {
            fshort = append(fshort, f)
            continue
        }
        addScore(f)
    }
    for _, f := range top8 {
        if f != nil {
            fshort = append(fshort, f)
        }
    }

    // TODO: Avoid rebuilding the entire list on every tick
    fList := make(map[int]*ForumTopicListHolder)
    for _, f := range fshort {
        topicList, pagi := []*TopicsRow{}, tList.defaultPagi()
        if f.TopicCount != 0 {
            topicList, pagi, err = tList.RawGetListByForum(f, 1, 0)
            if err != nil {
                return err
            }
        }
        fList[f.ID] = &ForumTopicListHolder{topicList, pagi}

        /*topicList, pagi, err := tList.GetListByForum(f, 1, 0)
        if err != nil {
            return err
        }
        fList[f.ID] = &ForumTopicListHolder{topicList, pagi}*/
    }

    //fmt.Printf("fList: %+v\n", fList)
    tList.setForumList(fList)

    hTbl := GetHookTable()
    _, _ = hTbl.VhookSkippable("tasks_tick_topic_list", tList)

    return nil
}

func (tList *DefaultTopicList) defaultPagi() Paginator {
    /*_, page, lastPage := PageOffset(f.TopicCount, page, Config.ItemsPerPage)
    pageList := Paginate(page, lastPage, 5)
    return topicList, Paginator{pageList, page, lastPage}, nil*/
    return Paginator{[]int{}, 1, 1}
}

func (tList *DefaultTopicList) setForumList(forums map[int]*ForumTopicListHolder) {
    tList.forumLock.Lock()
    tList.forums = forums
    tList.forumLock.Unlock()
}

/*var reloadForumMutex sync.Mutex

// TODO: Avoid firing this multiple times per sec tick
// TODO: Shard the forum topic list map
func (tList *DefaultTopicList) ReloadForum(id int) error {
    reloadForumMutex.Lock()
    defer reloadForumMutex.Unlock()

    forum, err := Forums.Get(id)
    if err != nil {
        return err
    }

    ofList := make(map[int]*ForumTopicListHolder)
    fList := make(map[int]*ForumTopicListHolder)
    tList.forumLock.Lock()
    ofList = tList.forums
    for id, f := range ofList {
        fList[id] = f
    }
    tList.forumLock.Unlock()

    topicList, pagi := []*TopicsRow{}, tList.defaultPagi()
    if forum.TopicCount != 0 {
        topicList, pagi, err = tList.getListByForum(forum, 1, 0)
        if err != nil {
            return err
        }
    }
    fList[forum.ID] = &ForumTopicListHolder{topicList, pagi}

    tList.setForumList(fList)
    return nil
}*/

// TODO: Add Topics() method to *Forum?
// TODO: Implement orderby
func (tList *DefaultTopicList) GetListByForum(f *Forum, page, orderby int) (topicList []*TopicsRow, pagi Paginator, err error) {
    if page == 0 {
        page = 1
    }
    if f.TopicCount == 0 {
        return topicList, tList.defaultPagi(), nil
    }
    if page == 1 && orderby == 0 {
        var h *ForumTopicListHolder
        var ok bool
        tList.forumLock.RLock()
        h, ok = tList.forums[f.ID]
        tList.forumLock.RUnlock()
        if ok {
            return h.List, h.Paginator, nil
        }
    }
    return tList.RawGetListByForum(f, page, orderby)
}

func (tList *DefaultTopicList) RawGetListByForum(f *Forum, page, orderby int) (topicList []*TopicsRow, pagi Paginator, err error) {
    // TODO: Does forum.TopicCount take the deleted items into consideration for guests? We don't have soft-delete yet, only hard-delete
    offset, page, lastPage := PageOffset(f.TopicCount, page, Config.ItemsPerPage)

    rows, err := tList.getTopicsByForum.Query(f.ID, offset, Config.ItemsPerPage)
    if err != nil {
        return nil, tList.defaultPagi(), err
    }
    defer rows.Close()

    // TODO: Use something other than TopicsRow as we don't need to store the forum name and link on each and every topic item?
    reqUserList := make(map[int]bool)
    for rows.Next() {
        t := TopicsRow{Topic: Topic{ParentID: f.ID}}
        err := rows.Scan(&t.ID, &t.Title, &t.Content, &t.CreatedBy, &t.IsClosed, &t.Sticky, &t.CreatedAt, &t.LastReplyAt, &t.LastReplyBy, &t.LastReplyID, &t.ViewCount, &t.PostCount, &t.LikeCount)
        if err != nil {
            return nil, tList.defaultPagi(), err
        }

        t.Link = BuildTopicURL(NameToSlug(t.Title), t.ID)
        // TODO: Create a specialised function with a bit less overhead for getting the last page for a post count
        _, _, lastPage := PageOffset(t.PostCount, 1, Config.ItemsPerPage)
        t.LastPage = lastPage

        //header.Hooks.VhookNoRet("forum_trow_assign", &t, &forum)
        topicList = append(topicList, &t)
        reqUserList[t.CreatedBy] = true
        reqUserList[t.LastReplyBy] = true
    }
    if err = rows.Err(); err != nil {
        return nil, tList.defaultPagi(), err
    }

    // Convert the user ID map to a slice, then bulk load the users
    idSlice := make([]int, len(reqUserList))
    var i int
    for userID := range reqUserList {
        idSlice[i] = userID
        i++
    }

    // TODO: What if a user is deleted via the Control Panel?
    userList, err := Users.BulkGetMap(idSlice)
    if err != nil {
        return nil, tList.defaultPagi(), err
    }

    // Second pass to the add the user data
    // TODO: Use a pointer to TopicsRow instead of TopicsRow itself?
    for _, t := range topicList {
        t.Creator = userList[t.CreatedBy]
        t.LastUser = userList[t.LastReplyBy]
    }

    if len(topicList) == 0 {
        return topicList, tList.defaultPagi(), nil
    }
    pageList := Paginate(page, lastPage, 5)
    return topicList, Paginator{pageList, page, lastPage}, nil
}

func (tList *DefaultTopicList) GetListByGroup(g *Group, page, orderby int, filterIDs []int) (topicList []*TopicsRow, forumList []Forum, pagi Paginator, err error) {
    if page == 0 {
        page = 1
    }
    // TODO: Cache the first three pages not just the first along with all the topics on this beaten track
    // TODO: Move this into CanSee to reduce redundancy
    if (page == 1 || page == 2) && orderby == 0 && len(filterIDs) == 0 {
        var h [2]*TopicListHolder
        var ok bool
        if g.ID%2 == 0 {
            tList.evenLock.RLock()
            h, ok = tList.evenGroups[g.ID]
            tList.evenLock.RUnlock()
        } else {
            tList.oddLock.RLock()
            h, ok = tList.oddGroups[g.ID]
            tList.oddLock.RUnlock()
        }
        if ok {
            return h[page-1].List, h[page-1].ForumList, h[page-1].Paginator, nil
        }
    }

    // TODO: Make CanSee a method on *Group with a canSee field? Have a CanSee method on *User to cover the case of superadmins?
    //log.Printf("deoptimising for %d on page %d\n", g.ID, page)
    return tList.GetListByCanSee(g.CanSee, page, orderby, filterIDs)
}

func (tList *DefaultTopicList) GetListByCanSee(canSee []int, page, orderby int, filterIDs []int) (topicList []*TopicsRow, forumList []Forum, pagi Paginator, err error) {
    // TODO: Optimise this by filtering canSee and then fetching the forums?
    // We need a list of the visible forums for Quick Topic
    // ? - Would it be useful, if we could post in social groups from /topics/?
    for _, fid := range canSee {
        f := Forums.DirtyGet(fid)
        if f.Name != "" && f.Active && (f.ParentType == "" || f.ParentType == "forum") /*&& f.TopicCount != 0*/ {
            fcopy := f.Copy()
            // TODO: Add a hook here for plugin_guilds !!
            forumList = append(forumList, fcopy)
        }
    }

    inSlice := func(haystack []int, needle int) bool {
        for _, it := range haystack {
            if needle == it {
                return true
            }
        }
        return false
    }

    var filteredForums []Forum
    if len(filterIDs) > 0 {
        for _, f := range forumList {
            if inSlice(filterIDs, f.ID) {
                filteredForums = append(filteredForums, f)
            }
        }
    } else {
        filteredForums = forumList
    }
    if len(filteredForums) == 1 && orderby == 0 {
        topicList, pagi, err = tList.GetListByForum(&filteredForums[0], page, orderby)
        return topicList, forumList, pagi, err
    }

    var topicCount int
    for _, f := range filteredForums {
        topicCount += f.TopicCount
    }

    // ? - Should we be showing plugin_guilds posts on /topics/?
    argList, qlist := ForumListToArgQ(filteredForums)
    if qlist == "" {
        // We don't want to kill the page, so pass an empty slice and nil error
        return topicList, filteredForums, tList.defaultPagi(), nil
    }

    topicList, pagi, err = tList.getList(page, orderby, topicCount, argList, qlist)
    return topicList, filteredForums, pagi, err
}

// TODO: Reduce the number of returns
func (tList *DefaultTopicList) GetList(page, orderby int, filterIDs []int) (topicList []*TopicsRow, forumList []Forum, pagi Paginator, err error) {
    // TODO: Make CanSee a method on *Group with a canSee field? Have a CanSee method on *User to cover the case of superadmins?
    cCanSee, err := Forums.GetAllVisibleIDs()
    if err != nil {
        return nil, nil, tList.defaultPagi(), err
    }
    //log.Printf("cCanSee: %+v\n", cCanSee)
    inSlice := func(haystack []int, needle int) bool {
        for _, it := range haystack {
            if needle == it {
                return true
            }
        }
        return false
    }

    var canSee []int
    if len(filterIDs) > 0 {
        for _, fid := range cCanSee {
            if inSlice(filterIDs, fid) {
                canSee = append(canSee, fid)
            }
        }
    } else {
        canSee = cCanSee
    }
    //log.Printf("canSee: %+v\n", canSee)

    // We need a list of the visible forums for Quick Topic
    // ? - Would it be useful, if we could post in social groups from /topics/?
    var topicCount int
    for _, fid := range canSee {
        f := Forums.DirtyGet(fid)
        if f.Name != "" && f.Active && (f.ParentType == "" || f.ParentType == "forum") /*&& f.TopicCount != 0*/ {
            fcopy := f.Copy()
            // TODO: Add a hook here for plugin_guilds
            forumList = append(forumList, fcopy)
            topicCount += fcopy.TopicCount
        }
    }
    if len(forumList) == 1 && orderby == 0 {
        topicList, pagi, err = tList.GetListByForum(&forumList[0], page, orderby)
        return topicList, forumList, pagi, err
    }

    // ? - Should we be showing plugin_guilds posts on /topics/?
    argList, qlist := ForumListToArgQ(forumList)
    if qlist == "" {
        // If the super admin can't see anything, then things have gone terribly wrong
        return topicList, forumList, tList.defaultPagi(), err
    }

    topicList, pagi, err = tList.getList(page, orderby, topicCount, argList, qlist)
    return topicList, forumList, pagi, err
}

// TODO: Rename this to TopicListStore and pass back a TopicList instance holding the pagination data and topic list rather than passing them back one argument at a time
// TODO: Make orderby an enum of sorts
func (tList *DefaultTopicList) getList(page, orderby, topicCount int, argList []interface{}, qlist string) (topicList []*TopicsRow, paginator Paginator, err error) {
    if topicCount == 0 {
        return nil, tList.defaultPagi(), err
    }
    //log.Printf("argList: %+v\n",argList)
    //log.Printf("qlist: %+v\n",qlist)
    var cols, orderq string
    var stmt *sql.Stmt
    switch orderby {
    case TopicListWeekViews:
        tList.qLock.RLock()
        stmt = tList.qcounts[len(argList)-2]
        tList.qLock.RUnlock()
        if stmt == nil {
            orderq = "weekViews DESC,lastReplyAt DESC,createdBy DESC"
            now := time.Now()
            _, week := now.ISOWeek()
            day := int(now.Weekday()) + 1
            if week%2 == 0 { // is even?
                cols = "tid,title,content,createdBy,is_closed,sticky,createdAt,lastReplyAt,lastReplyBy,lastReplyID,parentID,views,postCount,likeCount,attachCount,poll,data,FLOOR(weekEvenViews+((weekOddViews/7)*" + strconv.Itoa(day) + ")) AS weekViews"
            } else {
                cols = "tid,title,content,createdBy,is_closed,sticky,createdAt,lastReplyAt,lastReplyBy,lastReplyID,parentID,views,postCount,likeCount,attachCount,poll,data,FLOOR(weekOddViews+((weekEvenViews/7)*" + strconv.Itoa(day) + ")) AS weekViews"
            }
            topicCount, err = ArgQToWeekViewTopicCount(argList, qlist)
            if err != nil {
                return nil, tList.defaultPagi(), err
            }
            acc := qgen.NewAcc()
            stmt = acc.Select("topics").Columns(cols).Where("parentID IN(" + qlist + ") AND (weekEvenViews!=0 OR weekOddViews!=0)").Orderby(orderq).Limit("?,?").ComplexPrepare()
            if e := acc.FirstError(); e != nil {
                return nil, tList.defaultPagi(), e
            }
            defer stmt.Close()
        }
    case TopicListMostViewed:
        tList.qLock.RLock()
        stmt = tList.qcounts[len(argList)-2]
        tList.qLock.RUnlock()
        if stmt == nil {
            orderq = "views DESC,lastReplyAt DESC,createdBy DESC"
            cols = "tid,title,content,createdBy,is_closed,sticky,createdAt,lastReplyAt,lastReplyBy,lastReplyID,parentID,views,postCount,likeCount,attachCount,poll,data,weekEvenViews"
        }
    default:
        tList.qLock2.RLock()
        stmt = tList.qcounts2[len(argList)-2]
        tList.qLock2.RUnlock()
        if stmt == nil {
            orderq = "sticky DESC,lastReplyAt DESC,createdBy DESC"
            cols = "tid,title,content,createdBy,is_closed,sticky,createdAt,lastReplyAt,lastReplyBy,lastReplyID,parentID,views,postCount,likeCount,attachCount,poll,data,weekEvenViews"
        }
    }
    offset, page, lastPage := PageOffset(topicCount, page, Config.ItemsPerPage)

    // TODO: Prepare common qlist lengths to speed this up in common cases, prepared statements are prepared lazily anyway, so it probably doesn't matter if we do ten or so
    if stmt == nil {
        stmt, err = qgen.Builder.SimpleSelect("topics", cols, "parentID IN("+qlist+")", orderq, "?,?")
        if err != nil {
            return nil, tList.defaultPagi(), err
        }
        defer stmt.Close()
    }

    argList = append(argList, offset)
    argList = append(argList, Config.ItemsPerPage)

    rows, err := stmt.Query(argList...)
    if err != nil {
        return nil, tList.defaultPagi(), err
    }
    defer rows.Close()

    rc, tc := Rstore.GetCache(), Topics.GetCache()
    rcap := rc.GetCapacity()
    rlen := rc.Length()
    reqUserList := make(map[int]bool)
    for rows.Next() {
        // TODO: Embed Topic structs in TopicsRow to make it easier for us to reuse this work in the topic cache
        t := TopicsRow{}
        //var weekViews []uint8
        err := rows.Scan(&t.ID, &t.Title, &t.Content, &t.CreatedBy, &t.IsClosed, &t.Sticky, &t.CreatedAt, &t.LastReplyAt, &t.LastReplyBy, &t.LastReplyID, &t.ParentID, &t.ViewCount, &t.PostCount, &t.LikeCount, &t.AttachCount, &t.Poll, &t.Data, &t.WeekViews)
        if err != nil {
            return nil, tList.defaultPagi(), err
        }
        //t.WeekViews = int(weekViews[0])
        //log.Printf("t: %+v\n", t)
        //log.Printf("weekViews: %+v\n", weekViews)

        t.Link = BuildTopicURL(NameToSlug(t.Title), t.ID)
        // TODO: Pass forum to something like topicItem.Forum and use that instead of these two properties? Could be more flexible.
        forum := Forums.DirtyGet(t.ParentID)
        t.ForumName = forum.Name
        t.ForumLink = forum.Link

        // TODO: Create a specialised function with a bit less overhead for getting the last page for a post count
        _, _, lastPage := PageOffset(t.PostCount, 1, Config.ItemsPerPage)
        t.LastPage = lastPage

        // TODO: Rename this Vhook to better reflect moving the topic list from /routes/ to /common/
        GetHookTable().Vhook("topics_topic_row_assign", &t, &forum)
        topicList = append(topicList, &t)
        reqUserList[t.CreatedBy] = true
        reqUserList[t.LastReplyBy] = true

        //log.Print("rlen: ", rlen)
        //log.Print("rcap: ", rcap)
        //log.Print("t.PostCount: ", t.PostCount)
        //log.Print("t.PostCount == 2 && rlen < rcap: ", t.PostCount == 2 && rlen < rcap)

        // Avoid the extra queries on topic list pages, if we already have what we want...
        hRids := false
        if tc != nil {
            if t, e := tc.Get(t.ID); e == nil {
                hRids = len(t.Rids) != 0
            }
        }

        if t.PostCount == 2 && rlen < rcap && !hRids && page < 5 {
            rids, err := GetRidsForTopic(t.ID, 0)
            if err != nil {
                return nil, tList.defaultPagi(), err
            }

            //log.Print("rids: ", rids)
            if len(rids) == 0 {
                continue
            }
            _, _ = Rstore.Get(rids[0])
            rlen++
            t.Rids = []int{rids[0]}
        }

        if tc != nil {
            if _, e := tc.Get(t.ID); e == sql.ErrNoRows {
                //_ = tc.Set(t.Topic())
                _ = tc.Set(&t.Topic)
            }
        }
    }
    if err = rows.Err(); err != nil {
        return nil, tList.defaultPagi(), err
    }

    // TODO: specialcase for when reqUserList only has one or two items to avoid map alloc
    if len(reqUserList) == 1 {
        var u *User
        for uid, _ := range reqUserList {
            u, err = Users.Get(uid)
            if err != nil {
                return nil, tList.defaultPagi(), err
            }
        }
        for _, t := range topicList {
            t.Creator = u
            t.LastUser = u
        }
    } else if len(reqUserList) > 0 {
        // Convert the user ID map to a slice, then bulk load the users
        idSlice := make([]int, len(reqUserList))
        var i int
        for userID := range reqUserList {
            idSlice[i] = userID
            i++
        }

        // TODO: What if a user is deleted via the Control Panel?
        userList, err := Users.BulkGetMap(idSlice)
        if err != nil {
            return nil, tList.defaultPagi(), err
        }

        // Second pass to the add the user data
        // TODO: Use a pointer to TopicsRow instead of TopicsRow itself?
        for _, t := range topicList {
            t.Creator = userList[t.CreatedBy]
            t.LastUser = userList[t.LastReplyBy]
        }
    }

    pageList := Paginate(page, lastPage, 5)
    return topicList, Paginator{pageList, page, lastPage}, nil
}

// Internal. Don't rely on it.
func ForumListToArgQ(forums []Forum) (argList []interface{}, qlist string) {
    for _, forum := range forums {
        argList = append(argList, strconv.Itoa(forum.ID))
        qlist += "?,"
    }
    if qlist != "" {
        qlist = qlist[0 : len(qlist)-1]
    }
    return argList, qlist
}

// Internal. Don't rely on it.
// TODO: Check the TopicCount field on the forums instead? Make sure it's in sync first.
func ArgQToTopicCount(argList []interface{}, qlist string) (topicCount int, err error) {
    topicCountStmt, err := qgen.Builder.SimpleCount("topics", "parentID IN("+qlist+")", "")
    if err != nil {
        return 0, err
    }
    defer topicCountStmt.Close()

    err = topicCountStmt.QueryRow(argList...).Scan(&topicCount)
    if err != nil && err != ErrNoRows {
        return 0, err
    }
    return topicCount, err
}

// Internal. Don't rely on it.
func ArgQToWeekViewTopicCount(argList []interface{}, qlist string) (topicCount int, err error) {
    topicCountStmt, err := qgen.Builder.SimpleCount("topics", "parentID IN("+qlist+") AND (weekEvenViews!=0 OR weekOddViews!=0)", "")
    if err != nil {
        return 0, err
    }
    defer topicCountStmt.Close()

    err = topicCountStmt.QueryRow(argList...).Scan(&topicCount)
    if err != nil && err != ErrNoRows {
        return 0, err
    }
    return topicCount, err
}

func TopicCountInForums(forums []Forum) (topicCount int, err error) {
    for _, f := range forums {
        topicCount += f.TopicCount
    }
    return topicCount, nil
}