--[[
###################################
##         Chess System          ##
##      Developed by Dalvo       ##
##       Date: 22/04/2012        ##
##   Tested on TFS 0.4_rev3884   ##
## Obs.: Need modifiqued sources ##
###################################

]]
-- const
INITIAL_POS = {x=90, y = 139, z = 7}
XADREZ_STORAGE = 759593
tile_white, tile_black = 9146, 407

Chess = {}

function Chess:new(cid)
    local attr = {cid = cid}
    return setmetatable(attr, {__index = self})
end

function Chess:hasTileSend(pos, namefind)
    if((getTileInfo(pos).itemid == tile_black or getTileInfo(pos).itemid == tile_white) and not (isCreature(getTopCreature(pos).uid) and getCreatureName(getTopCreature(pos).uid):find(namefind)))then
        return true
    end
    return false
end

function Chess:getDirsToPos(fromPos, toPos)
    local dirs, fakeFromPos, fakeToPos = {}, {}, {}
    fakeFromPos, fakeToPos = {x = fromPos.x, y=fromPos.y, z=fromPos.z}, {x = toPos.x, y = toPos.y, z= toPos.z}
    while (not self:tableCompare(fakeFromPos, fakeToPos)) do
        local dir = getDirectionTo(fakeFromPos, fakeToPos)
        table.insert(dirs, dir)
        local newPos = getPositionByDirection(fakeFromPos, dir, 1)
        fakeFromPos.x, fakeFromPos.y, fakeFromPos.z = newPos.x, newPos.y, newPos.z
    end
    return dirs
end

function Chess:moveDirs(uid, listDir, delayStep)
    for i, dir in pairs(listDir) do
        addEvent(function()
                if(isCreature(uid))then
                    doMoveCreature(uid, dir)
                end
            end, i*delayStep)
    end
end

function Chess:tableCompare(tab, tab2)
    bool = true
    for index,value in pairs(tab) do
        if not(value == tab2[index])then
            bool = false
        end
    end
    return bool
end

function Chess:isFirstPosPawn(pos, color)
    local fakePos = {}
    fakePos.x, fakePos.y, fakePos.z = pos.x,pos.y, pos.z
    fakePos.y = (color == "black") and (fakePos.y + 2) or (fakePos.y - 2)
    return ((getTileInfo(fakePos).itemid == tile_black or getTileInfo(fakePos).itemid == tile_white) == false)
end

function Chess:isPiece(name)
    local pieceType = name:sub(7)
    if(isPlayer(getCreatureByName(name)))then return false end
    return isInArray({"king", "pawn", "horse", "tower", "queen", "bishop"}, pieceType)
end
function Chess:getPathPos(uid_piece)
    local piece_moves =
    {
        ["king"] = {distMove=1, dirs = {0,1,2,3,4,5,6,7}},
        ["queen"] = {distMove=8, dirs = {0,1,2,3,4,5,6,7}},
        ["bishop"] = {distMove=8, dirs = {4,5,6,7}},
        ["horse"] = {posits = {{x = -1, y = -2}, {x = 1, y = -2}, {x = 2, y = 1}, {x = 2, y = -1},{x = -2, y = 1}, {x = -2, y = -1}, {x = -1, y = 2}, {x = 1, y = 2}}},
        ["tower"] = {distMove=8, dirs = {0,1,2,3}},
        ["pawn"] = 0 -- ignore this
    }
    if not(isCreature(uid_piece))then return error("[Chess System] Creature Not Found.") end
    local positions, piecename = {}, getCreatureName(uid_piece)
    local pieceType, pieceColor = piecename:sub(7):lower(), piecename:sub(1,5):lower()

    if(piece_moves[pieceType])then
        if(isInArray({"king", "queen", "tower", "bishop"}, pieceType))then
            for _, dir in pairs(piece_moves[pieceType].dirs)do
                for dist = 1, piece_moves[pieceType].distMove do
                    local pos = getPositionByDirection(getThingPos(uid_piece), dir, dist)
                    if(self:hasTileSend(pos, pieceColor))then
                        table.insert(positions, pos)
                    end
                    local uid_pos = getTopCreature(pos).uid
                    if(isCreature(uid_pos) or (not self:hasTileSend(pos, pieceColor)))then break end
                end
            end
        elseif(pieceType == "horse")then
            for _, mod_ in pairs(piece_moves[pieceType].posits) do
                local pos = getThingPos(uid_piece)
                pos.x, pos.y = pos.x + mod_.x, pos.y + mod_.y
                if(self:hasTileSend(pos, pieceColor))then
                    table.insert(positions, pos)
                end
            end
        elseif(pieceType == "pawn")then
            local dir = (pieceColor == "black") and 0 or 2
            local pos1 = getPositionByDirection(getThingPos(uid_piece), dir, 1)
            if not(isCreature(getTopCreature(pos1).uid))then
                table.insert(positions, pos1)
                local pos2 = getPositionByDirection(getThingPos(uid_piece), dir, 2)
                if(self:isFirstPosPawn(getThingPos(uid_piece), pieceColor) and #positions > 0)then
                    table.insert(positions, pos2)
                end
            end
        end
        return positions
    else
        error("[Chess System] Invalid piece name")
    end
end

function Chess:isValidPos(uid, pos)
    local listPos = self:getPathPos(uid)
    for _, posi in pairs(listPos) do
        if(posi.x == pos.x and posi.y == pos.y and posi.z == pos.z)then
            return true
        end
    end
    return false
end

function Chess:verifyXeque(uid, toPos)
    -- Chess:verifyXeque(uid[, toPos])
    --[[
    * listar peças adversarias
    * iterar sobre elas gerando o pathpos de cada uma e verificando se coincide com a pos do rei
    * caso uma seja verdadeiro retornar true finalizando o loop
    * caso nenhum seja verdadeira retornar false
    ]]
    if(isCreature(uid))then
        local piecename = getCreatureName(uid)
        local pieceType, pieceColor = piecename:sub(7):lower(), piecename:sub(1,5):lower()
        if(self:isPiece(piecename) and pieceType == "king")then
            local black, white = self:getPiecesOnTab()
            for _, piece in pairs(pieceColor == "black" and white or black) do
                if(self:isValidPos(piece, type(toPos) == "table" and toPos or getThingPos(uid)))then
                    return true
                end
            end
        end
    end
    return false
end

function Chess:sendEffects(uid)
    local positions = self:getPathPos(uid)
    doSendMagicEffect(getThingPos(uid), 55)
    for _, pos in pairs(positions) do
        doSendMagicEffect(pos, 56)
    end
end

function Chess:getPiecesOnTab()
    local black, white = {}, {}
    for x = 0, 7 do
        for y = 0, 7 do
            local pos = {x = INITIAL_POS.x, y = INITIAL_POS.y, z = INITIAL_POS.z}
            pos.x, pos.y = pos.x + x, pos.y + y
            local creature = getTopCreature(pos)
            if(isCreature(creature.uid) and (not isPlayer(creature.uid)))then
                local name = getCreatureName(creature.uid)
                if(self:isPiece(name))then
                    table.insert(name:find("black") and black or white, creature.uid)
                end
            end
        end
    end
    return black, white
end

function Chess:createPieces()
    local piecepos = {}
    pieces = {"tower", "horse", "bishop", "queen", "king","bishop","horse","tower"}
    for _, index in pairs({0,1,6,7}) do piecepos[index] = {} end
    for index, piece in pairs(pieces) do
        piecepos[0][index-1] = "white "..piece
        piecepos[7][index-1] = "black "..piece
    end
    for i = 0, 7 do
        piecepos[1][i] = "white pawn"
        piecepos[6][i] = "black pawn"
    end

    for x = 0, 7 do
        for y = 0, 7 do
            local pos = {x = INITIAL_POS.x, y = INITIAL_POS.y, z = INITIAL_POS.z}
            pos.x, pos.y = (pos.x + x), (pos.y + y)
            local creature = getTopCreature(pos)
            if(isCreature(creature.uid) and not isPlayer(creature.uid))then
                doRemoveCreature(creature.uid)
            end
            if(piecepos[y] and piecepos[y][x]) then
                doCreateMonster(piecepos[y][x], pos)
            end
        end
    end
end

function onPush(cid, target, toTile)
    local chess = Chess:new(cid)
    local piecetarget = getTopCreature(getThingPos(toTile.uid)).uid
    local namefind = getCreatureName(target):sub(1,5) == "black" and "white" or "black"

    if(chess:isValidPos(target,getThingPos(toTile.uid)))then
        if(chess:verifyXeque(target, getThingPos(toTile.uid)))then
            doPlayerSendCancel(cid, "You can not leave his king in check.")
            return false
        end

        local dirs = chess:getDirsToPos(getThingPos(target), getThingPos(toTile.uid))
        chess:moveDirs(target, dirs,1000)

        if(isCreature(piecetarget) and getCreatureName(piecetarget):find(namefind))then
            doRemoveCreature(piecetarget)
        end
    else
        doPlayerSendCancel(cid, "You can not move this piece for this position.")
    end
    return false
end

function onLook(cid, thing, position, lookDistance)

    if(isPlayer(thing.uid) or (not isCreature(thing.uid)))then return true end
    if not(exhaustion.check(cid, XADREZ_STORAGE))then
        exhaustion.set(cid, XADREZ_STORAGE, 8)
        local chess = Chess:new(cid)
        chess:sendEffects(thing.uid)
        return false
    end
end