--by pavetr.top/ds
local BOARD_SIZE = 8

local initialBoard = {
    {" ", "b", " ", "b", " ", "b", " ", "b"},
    {"b", " ", "b", " ", "b", " ", "b", " "},
    {" ", "b", " ", "b", " ", "b", " ", "b"},
    {" ", " ", " ", " ", " ", " ", " ", " "},
    {" ", " ", " ", " ", " ", " ", " ", " "},
    {"w", " ", "w", " ", "w", " ", "w", " "},
    {" ", "w", " ", "w", " ", "w", " ", "w"},
    {"w", " ", "w", " ", "w", " ", "w", " "}
}

local whiteScore = 0
local blackScore = 0
local gameFrame = nil
local whiteScoreLabel = nil
local blackScoreLabel = nil

local function deepCopyBoard(board)
    local newBoard = {}
    for i = 1, BOARD_SIZE do
        newBoard[i] = {}
        for j = 1, BOARD_SIZE do
            newBoard[i][j] = board[i][j]
        end
    end
    return newBoard
end

local function mustCapture(board, player, lastPiece)
    local captures = {}
    for i = 1, BOARD_SIZE do
        for j = 1, BOARD_SIZE do
            if (not lastPiece or (lastPiece[1] == i and lastPiece[2] == j)) and 
               (board[i][j] == player or board[i][j] == player:upper()) then
                local isKing = board[i][j] == player:upper()
                if isKing then
                    for di = -1, 1, 2 do
                        for dj = -1, 1, 2 do
                            local k = 1
                            local enemyFound = false
                            local enemyPos = nil
                            while true do
                                local newI, newJ = i + di * k, j + dj * k
                                if newI < 1 or newI > BOARD_SIZE or newJ < 1 or newJ > BOARD_SIZE then break end
                                if board[newI][newJ] == " " and enemyFound then
                                    table.insert(captures, {{i, j}, {newI, newJ}, enemyPos})
                                    break
                                elseif board[newI][newJ] ~= " " then
                                    if board[newI][newJ] == player or board[newI][newJ] == player:upper() then break end
                                    if enemyFound then break end
                                    enemyFound = true
                                    enemyPos = {newI, newJ}
                                end
                                k = k + 1
                            end
                        end
                    end
                else
                    for di = -1, 1, 2 do
                        for dj = -1, 1, 2 do
                            local newI, newJ = i + di * 2, j + dj * 2
                            if newI >= 1 and newI <= BOARD_SIZE and newJ >= 1 and newJ <= BOARD_SIZE then
                                local midI, midJ = i + di, j + dj
                                if board[newI][newJ] == " " and board[midI][midJ] ~= " " and board[midI][midJ] ~= player and board[midI][midJ] ~= player:upper() then
                                    table.insert(captures, {{i, j}, {newI, newJ}, {midI, midJ}})
                                end
                            end
                        end
                    end
                end
            end
        end
    end
    return #captures > 0, captures
end

local function isValidMove(board, startX, startY, endX, endY, player, lastPiece)
    local piece = board[startX][startY]
    local target = board[endX][endY]
    local isKing = piece == player:upper()

    if piece == " " or target ~= " " or (player == "w" and piece ~= "w" and piece ~= "W") or (player == "b" and piece ~= "b" and piece ~= "B") then
        return false
    end

    if lastPiece and (startX ~= lastPiece[1] or startY ~= lastPiece[2]) then
        return false
    end

    local dx = endX - startX
    local dy = endY - startY

    if math.abs(dx) ~= math.abs(dy) then
        return false
    end

    if not isKing then
        if piece == "w" and dx > 0 and math.abs(dx) == 1 then return false end
        if piece == "b" and dx < 0 and math.abs(dx) == 1 then return false end

        if math.abs(dx) == 1 then
            local must, _ = mustCapture(board, player, lastPiece)
            return not must
        elseif math.abs(dx) == 2 then
            local midX, midY = (startX + endX) / 2, (startY + endY) / 2
            local midPiece = board[midX][midY]
            return midPiece ~= " " and midPiece ~= player and midPiece ~= player:upper()
        end
    else
        local stepX, stepY = dx > 0 and 1 or -1, dy > 0 and 1 or -1
        local steps = math.abs(dx)
        local enemyCount = 0
        local enemyPos = nil

        for k = 1, steps - 1 do
            local checkX, checkY = startX + stepX * k, startY + stepY * k
            local square = board[checkX][checkY]
            if square ~= " " then
                if square == player or square == player:upper() then return false end
                enemyCount = enemyCount + 1
                enemyPos = {checkX, checkY}
                if enemyCount > 1 then return false end
            end
        end

        if enemyCount == 1 then return true end
        if enemyCount == 0 then
            local must, _ = mustCapture(board, player, lastPiece)
            return not must
        end
    end
    return false
end

local function makeMove(board, startX, startY, endX, endY)
    local piece = board[startX][startY]
    local isKing = piece == piece:upper()
    board[endX][endY] = piece
    board[startX][startY] = " "

    local dx = endX - startX
    local dy = endY - startY
    local stepX, stepY = dx > 0 and 1 or -1, dy > 0 and 1 or -1

    if isKing then
        local steps = math.abs(dx)
        for k = 1, steps - 1 do
            local checkX, checkY = startX + stepX * k, startY + stepY * k
            if board[checkX][checkY] ~= " " then
                board[checkX][checkY] = " "
                break
            end
        end
    elseif math.abs(dx) == 2 then
        local midX, midY = (startX + endX) / 2, (startY + endY) / 2
        board[midX][midY] = " "
    end

    if piece == "w" and endX == 1 then board[endX][endY] = "W" end
    if piece == "b" and endX == 8 then board[endX][endY] = "B" end
end

local function countPieces(board, player)
    local count = 0
    for i = 1, BOARD_SIZE do
        for j = 1, BOARD_SIZE do
            if board[i][j] == player or board[i][j] == player:upper() then
                count = count + 1
            end
        end
    end
    return count
end

local function evaluateBoard(board)
    local whiteCount, blackCount = 0, 0
    for i = 1, BOARD_SIZE do
        for j = 1, BOARD_SIZE do
            if board[i][j] == "w" then whiteCount = whiteCount + 1
            elseif board[i][j] == "W" then whiteCount = whiteCount + 3
            elseif board[i][j] == "b" then blackCount = blackCount + 1
            elseif board[i][j] == "B" then blackCount = blackCount + 3
            end
        end
    end
    return blackCount - whiteCount
end

local function minimax(board, depth, isMaximizingPlayer, alpha, beta)
    if depth == 0 then return evaluateBoard(board), nil end

    local bestValue = isMaximizingPlayer and -math.huge or math.huge
    local bestMove = nil
    local player = isMaximizingPlayer and "b" or "w"

    local must, captures = mustCapture(board, player, nil)
    local possibleMoves = {}

    if must then
        possibleMoves = captures
    else
        for i = 1, BOARD_SIZE do
            for j = 1, BOARD_SIZE do
                if board[i][j] == player or board[i][j] == player:upper() then
                    local isKing = board[i][j] == player:upper()
                    if isKing then
                        for di = -1, 1, 2 do
                            for dj = -1, 1, 2 do
                                local k = 1
                                while true do
                                    local newI, newJ = i + di * k, j + dj * k
                                    if newI < 1 or newI > BOARD_SIZE or newJ < 1 or newJ > BOARD_SIZE then break end
                                    if isValidMove(board, i, j, newI, newJ, player, nil) then
                                        table.insert(possibleMoves, {{i, j}, {newI, newJ}})
                                    end
                                    k = k + 1
                                end
                            end
                        end
                    else
                        for di = -1, 1, 2 do
                            for dj = -1, 1, 2 do
                                local newI, newJ = i + di, j + dj
                                if newI >= 1 and newI <= BOARD_SIZE and newJ >= 1 and newJ <= BOARD_SIZE and isValidMove(board, i, j, newI, newJ, player, nil) then
                                    table.insert(possibleMoves, {{i, j}, {newI, newJ}})
                                end
                                newI, newJ = i + di * 2, j + dj * 2
                                if newI >= 1 and newI <= BOARD_SIZE and newJ >= 1 and newJ <= BOARD_SIZE and isValidMove(board, i, j, newI, newJ, player, nil) then
                                    table.insert(possibleMoves, {{i, j}, {newI, newJ}})
                                end
                            end
                        end
                    end
                end
            end
        end
    end

    if #possibleMoves == 0 then return evaluateBoard(board), nil end

    for _, move in ipairs(possibleMoves) do
        local i, j = move[1][1], move[1][2]
        local newI, newJ = move[2][1], move[2][2]
        local newBoard = deepCopyBoard(board)
        makeMove(newBoard, i, j, newI, newJ)
        local value, _ = minimax(newBoard, depth - 1, not isMaximizingPlayer, alpha, beta)

        if isMaximizingPlayer then
            if value > bestValue then
                bestValue = value
                bestMove = {i, j, newI, newJ}
            end
            alpha = math.max(alpha, bestValue)
            if beta <= alpha then break end
        else
            if value < bestValue then
                bestValue = value
                bestMove = {i, j, newI, newJ}
            end
            beta = math.min(beta, bestValue)
            if beta <= alpha then break end
        end
    end

    return bestValue, bestMove
end

local function resetBoard(boardPanel)
    local board = deepCopyBoard(initialBoard)
    local currentPlayer = "w"
    local selectedPos = nil
    whiteScoreLabel:SetText("White: " .. whiteScore)
    blackScoreLabel:SetText("Black: " .. blackScore)
    whiteScoreLabel:SizeToContents()
    blackScoreLabel:SizeToContents()
    return board, currentPlayer, selectedPos
end

local function updateBoardDisplay(board, boardPanel, selectedPos, currentPlayer, lastPiece)
    boardPanel:Clear()
    for i = 1, BOARD_SIZE do
        for j = 1, BOARD_SIZE do
            local button = vgui.Create("DButton", boardPanel)
            button:SetSize(60, 60)
            button:SetPos((j - 1) * 60, (i - 1) * 60)
            button:SetText("")
            button.animScale = 1
            button.glowAlpha = 0
            button.DoClick = function()
                if selectedPos then
                    if isValidMove(board, selectedPos[1], selectedPos[2], i, j, currentPlayer, lastPiece) then
                        button.animScale = 1.2
                        button.glowAlpha = 255
                        timer.Simple(0.2, function() button.animScale = 1 button.glowAlpha = 0 end)
                        local isCapture = math.abs(selectedPos[1] - i) >= 2
                        makeMove(board, selectedPos[1], selectedPos[2], i, j)
                        if countPieces(board, "b") + countPieces(board, "B") == 0 then
                            whiteScore = whiteScore + 1
                            board, currentPlayer, selectedPos = resetBoard(boardPanel)
                            updateBoardDisplay(board, boardPanel, selectedPos, currentPlayer, nil)
                            return
                        end
                        local must, captures = mustCapture(board, currentPlayer, isCapture and {i, j} or nil)
                        if must and isCapture then
                            updateBoardDisplay(board, boardPanel, {i, j}, currentPlayer, {i, j})
                        else
                            currentPlayer = currentPlayer == "w" and "b" or "w"
                            selectedPos = nil
                            if currentPlayer == "b" then
                                timer.Simple(0.5, function()
                                    local _, aiMove = minimax(board, 3, true, -math.huge, math.huge)
                                    if aiMove then
                                        makeMove(board, aiMove[1], aiMove[2], aiMove[3], aiMove[4])
                                        if countPieces(board, "w") + countPieces(board, "W") == 0 then
                                            blackScore = blackScore + 1
                                            board, currentPlayer, selectedPos = resetBoard(boardPanel)
                                            updateBoardDisplay(board, boardPanel, selectedPos, currentPlayer, nil)
                                            return
                                        end
                                        currentPlayer = "w"
                                        updateBoardDisplay(board, boardPanel, nil, currentPlayer, nil)
                                    else
                                        whiteScore = whiteScore + 1
                                        board, currentPlayer, selectedPos = resetBoard(boardPanel)
                                        updateBoardDisplay(board, boardPanel, selectedPos, currentPlayer, nil)
                                    end
                                end)
                            else
                                updateBoardDisplay(board, boardPanel, nil, currentPlayer, nil)
                            end
                        end
                    else
                        updateBoardDisplay(board, boardPanel, {i, j}, currentPlayer, lastPiece)
                    end
                else
                    updateBoardDisplay(board, boardPanel, {i, j}, currentPlayer, lastPiece)
                end
            end

            button.Paint = function(self, w, h)
                -- Фон клетки с текстурным эффектом
                if (i + j) % 2 == 0 then
                    surface.SetDrawColor(245, 222, 179, 255) -- Светлый (пшеничный)
                    surface.DrawRect(0, 0, w, h)
                    surface.SetDrawColor(255, 245, 220, 50) -- Лёгкий градиент
                    surface.DrawRect(0, 0, w, h / 2)
                else
                    surface.SetDrawColor(139, 69, 19, 255) -- Тёмный (коричневый)
                    surface.DrawRect(0, 0, w, h)
                    surface.SetDrawColor(160, 82, 45, 50) -- Лёгкий градиент
                    surface.DrawRect(0, 0, w, h / 2)
                end

                -- Тонкая рамка для глубины
                surface.SetDrawColor(50, 50, 50, 100)
                surface.DrawOutlinedRect(0, 0, w, h)

                -- Отрисовка шашек с эффектами
                local scale = self.animScale or 1
                local pieceSize = 25 * scale
                local glowAlpha = self.glowAlpha or 0

                if board[i][j] ~= " " then
                    -- Тень под шашкой
                    surface.SetDrawColor(0, 0, 0, 100)
                    surface.DrawCircle(w / 2 + 3, h / 2 + 3, pieceSize)

                    -- Основной цвет шашки
                    if board[i][j] == "w" or board[i][j] == "W" then
                        surface.SetDrawColor(255, 255, 255, 255)
                    else
                        surface.SetDrawColor(40, 40, 40, 255)
                    end
                    surface.DrawCircle(w / 2, h / 2, pieceSize)

                    -- Градиент на шашке
                    local gradColor = board[i][j] == "w" or board[i][j] == "W" and Color(220, 220, 220, 150) or Color(60, 60, 60, 150)
                    surface.SetDrawColor(gradColor)
                    surface.DrawCircle(w / 2, h / 2, pieceSize * 0.8)

                    -- Свечение при ходе
                    if glowAlpha > 0 then
                        surface.SetDrawColor(255, 215, 0, glowAlpha)
                        surface.DrawCircle(w / 2, h / 2, pieceSize * 1.2)
                    end

                    -- Дамка: золотое кольцо
                    if board[i][j] == "W" or board[i][j] == "B" then
                        surface.SetDrawColor(255, 215, 0, 255)
                        surface.DrawCircle(w / 2, h / 2, pieceSize * 0.6)
                        surface.SetDrawColor(255, 255, 255, 100)
                        surface.DrawCircle(w / 2, h / 2, pieceSize * 0.5)
                    end
                end

                -- Подсветка выбранной шашки
                if selectedPos and selectedPos[1] == i and selectedPos[2] == j then
                    surface.SetDrawColor(255, 100, 100, 200)
                    surface.DrawOutlinedRect(2, 2, w - 4, h - 4, 3)
                    surface.SetDrawColor(255, 100, 100, 50)
                    surface.DrawCircle(w / 2, h / 2, pieceSize * 1.5)
                end

                -- Подсветка возможных ходов
                if selectedPos and isValidMove(board, selectedPos[1], selectedPos[2], i, j, currentPlayer, lastPiece) then
                    surface.SetDrawColor(100, 255, 100, 150)
                    surface.DrawCircle(w / 2, h / 2, 12)
                    surface.SetDrawColor(100, 255, 100, 50)
                    surface.DrawCircle(w / 2, h / 2, 18)
                end
            end
        end
    end
end

local function playGame()
    if IsValid(gameFrame) then return end

    local board = deepCopyBoard(initialBoard)
    local currentPlayer = "w"
    local selectedPos = nil

    gameFrame = vgui.Create("DFrame")
    gameFrame:SetSize(550, 650)
    gameFrame:Center()
    gameFrame:SetTitle("Steve Checkers Alpha 0.6")
    gameFrame:MakePopup()
    gameFrame.OnClose = function() gameFrame = nil end
    gameFrame.Paint = function(self, w, h)
        -- Фон с градиентом
        surface.SetDrawColor(60, 60, 60, 255)
        surface.DrawRect(0, 0, w, h)
        for i = 0, h, 10 do
            surface.SetDrawColor(80, 80, 80, 50)
            surface.DrawRect(0, i, w, 5)
        end
        -- Рамка окна
        surface.SetDrawColor(255, 215, 0, 200)
        surface.DrawOutlinedRect(0, 0, w, h, 2)
    end

    local boardPanel = vgui.Create("DPanel", gameFrame)
    boardPanel:SetSize(480, 480)
    boardPanel:SetPos(35, 100)
    boardPanel.Paint = function(self, w, h)
        -- Текстурный фон доски
        surface.SetDrawColor(30, 30, 30, 255)
        surface.DrawRect(0, 0, w, h)
        surface.SetDrawColor(255, 215, 0, 50)
        surface.DrawOutlinedRect(0, 0, w, h, 3)
        -- Тень под доской
        surface.SetDrawColor(0, 0, 0, 100)
        surface.DrawRect(5, 5, w + 5, h + 5)
    end

    whiteScoreLabel = vgui.Create("DLabel", gameFrame)
    whiteScoreLabel:SetPos(35, 30)
    whiteScoreLabel:SetText("White: " .. whiteScore)
    whiteScoreLabel:SetFont("DermaLarge")
    whiteScoreLabel:SetTextColor(Color(255, 255, 255, 255))
    whiteScoreLabel:SizeToContents()

    blackScoreLabel = vgui.Create("DLabel", gameFrame)
    blackScoreLabel:SetPos(35, 60)
    blackScoreLabel:SetText("Black: " .. blackScore)
    blackScoreLabel:SetFont("DermaLarge")
    blackScoreLabel:SetTextColor(Color(255, 255, 255, 255))
    blackScoreLabel:SizeToContents()

    updateBoardDisplay(board, boardPanel, selectedPos, currentPlayer, nil)
end

concommand.Add("start_checkers_game", function(ply)
    if IsValid(ply) and ply:IsPlayer() then playGame() end
end)

function surface.DrawCircle(x, y, radius)
    local cir = {}
    for i = 0, 360 do
        local rad = math.rad(i)
        table.insert(cir, {x = x + math.cos(rad) * radius, y = y + math.sin(rad) * radius})
    end
    draw.NoTexture()
    surface.DrawPoly(cir)
end

hook.Add("Think", "CheckersGame", function()
    if input.IsKeyDown(KEY_F6) then playGame() end
end)