e

-- Detect version and compatibility
local osVer = os.version()
local isLegacy = (osVer == "CraftOS 1.8")

local mode = 2
-- Safety check: Graphics mode is a CC:Tweaked feature.
-- Legacy CraftOS 1.8 will not have this function.
if term.setGraphicsMode then
    term.setGraphicsMode(mode)
else
    error("Graphics Mode not supported. Please use CC:Tweaked on a newer Minecraft version.")
end

local floor, abs, math_cos, math_sin = math.floor, math.abs, math.cos, math.sin
local m_min, m_max, m_random = math.min, math.max, math.random
local term_setPixel = term.setPixel
local term_setFrozen = term.setFrozen
local term_clear = term.clear
local pullEvent = os.pullEvent

local speaker = peripheral.find("speaker")
local musicStopFlag = {false}
local MUSIC_URL = "https://files.catbox.moe/fybww1.raw"
local MUSIC_FILE = "bgm.raw"

local rawChunkBuffer = {}
local processedChunkBuffer = {}

local function playPCM(filename, inputSampleRate, stopFlag)
    if not speaker then return end
    local localRaw = rawChunkBuffer
    local localProc = processedChunkBuffer

    while not stopFlag[1] do
        local file = fs.open(filename, "rb")
        if not file then break end
        local chunkSize = 1024
        local outputSampleRate = 48000
        local ratio = inputSampleRate / outputSampleRate

        while not stopFlag[1] do
            for i = 1, #localRaw do localRaw[i] = nil end
            for i = 1, #localProc do localProc[i] = nil end

            for i = 1, chunkSize do
                local byte = file.read()
                if not byte then break end
                localRaw[i] = byte - 128
            end
            if #localRaw == 0 then break end

            if inputSampleRate ~= outputSampleRate then
                for i = 1, floor(#localRaw / ratio) do
                    local src = (i - 1) * ratio + 1
                    local idx = floor(src)
                    local frac = src - idx
                    local s1 = localRaw[idx] or 0
                    local s2 = localRaw[idx + 1] or s1
                    localProc[i] = floor(s1 + (s2 - s1) * frac + 0.5)
                end
            else
                for i=1, #localRaw do localProc[i] = localRaw[i] end
            end

            while not speaker.playAudio(localProc) do
                pullEvent("speaker_audio_empty")
            end
        end
        file.close()
        if stopFlag[1] then break end
    end
end

local function setupColorCube(baseIndex)
    local i = baseIndex
    for r = 0, 5 do
        for g = 0, 5 do
            for b = 0, 5 do
                term.setPaletteColor(i, r/5, g/5, b/5)
                i = i + 1
            end
        end
    end
end
setupColorCube(16)

local w, h = term.getSize(mode)

local function downloadFile(url, filename)
    if not fs.exists(filename) then
        local response = http.get(url)
        if response then
            local f = fs.open(filename, "wb")
            f.write(response.readAll())
            f.close()
            response.close()
        end
    end
end

-- Download textures logic
-- Check for legacy to skip loading.bmp download
if not isLegacy then
    downloadFile("https://files.catbox.moe/tfdp1m.bmp", "loading.bmp")
end

downloadFile("https://files.catbox.moe/x7tf9n.bmp", "grass.bmp")
downloadFile("https://files.catbox.moe/zs25m6.bmp", "stone.bmp")

-- Only download music file if speaker is present
if speaker then
    downloadFile(MUSIC_URL, MUSIC_FILE)
end

local function loadTexture(filename)
    if not fs.exists(filename) then return nil end
    local file = fs.open(filename, "rb")
    file.seek("set", 10)
    local dataOffset = file.read() + file.read()*256
    file.seek("set", 18)
    local tw = file.read() + file.read()*256
    file.read(2)
    local th = file.read() + file.read()*256
    file.seek("set", dataOffset)
    local pixels = {}
    for y = th - 1, 0, -1 do
        for x = 0, tw - 1 do
            local b, g, r = file.read(), file.read(), file.read()
            local ri, gi, bi = floor(r/255*5+0.5), floor(g/255*5+0.5), floor(b/255*5+0.5)
            pixels[y * tw + x] = 16 + (ri * 36) + (gi * 6) + bi
        end
        local padding = (4 - (tw * 3 % 4)) % 4
        for i = 1, padding do file.read() end
    end
    file.close()
    return {w = tw, h = th, pixels = pixels}
end

local textures = {
    [1] = loadTexture("grass.bmp") or {w=1, h=1, pixels={60}},
    [2] = loadTexture("stone.bmp") or {w=1, h=1, pixels={140}}
}

-- Ensure loadingBmp is nil if on CraftOS 1.8
local loadingBmp = (not isLegacy) and loadTexture("loading.bmp") or nil
local selectedBlock = 1

term.setPaletteColor(1, 0, 0.8, 1)
term.setPaletteColor(255, 1, 1, 0.5)

local MAP_W, MAP_H, MAP_D = 256, 64, 256
local map = {}
for y = 0, MAP_H - 1 do
    local plane = y * 65536
    for z = 0, MAP_D - 1 do
        local row = plane + (z * 256)
        for x = 0, MAP_W - 1 do
            local b = (y == 4) and 1 or (y < 4 and 2 or 0)
            map[row + x] = b
        end
    end
end

local camX, camY, camZ = 128, 6.5, 128
local lookDir, pitch = 0, 0
local velocityY, gravity, isOnGround, jumpPower = 0, -20.0, false, 7.5

local function raycastInteract(maxSteps)
    local localMap = map
    local cL, sL, cP, sP = math_cos(lookDir), math_sin(lookDir), math_cos(pitch), math_sin(pitch)
    local dX, dZ = cL * cP, sL * cP
    local dY = sP
    local x, y, z = camX, camY, camZ
    local stepSize = 0.05

    for i = 1, (maxSteps or 8) / stepSize do
        local ix, iy, iz = floor(x), floor(y), floor(z)
        if ix >= 0 and ix < MAP_W and iy >= 0 and iy < MAP_H and iz >= 0 and iz < MAP_D then
            if localMap[(iy * 65536) + (iz * 256) + ix] > 0 then
                local lix, liy, liz = floor(x - dX*stepSize), floor(y - dY*stepSize), floor(z - dZ*stepSize)
                local face = "north"
                if lix ~= ix then
                    face = (lix < ix) and "west" or "east"
                elseif liy ~= iy then
                    face = (liy < iy) and "bottom" or "top"
                elseif liz ~= iz then
                    face = (liz < iz) and "north" or "south"
                end
                return ix, iy, iz, face
            end
        end
        x, y, z = x + dX * stepSize, y + dY * stepSize, z + dZ * stepSize
    end
end

local function checkCollision(x, y, z)
    local localMap = map
    local minX, maxX = floor(x - 0.3), floor(x + 0.3)
    local minZ, maxZ = floor(z - 0.3), floor(z + 0.3)
    local fY, hY = floor(y - 1.4), floor(y)
    for ix = minX, maxX do
        for iz = minZ, maxZ do
            for iy = fY, hY do
                if ix >= 0 and ix < MAP_W and iy >= 0 and iy < MAP_H and iz >= 0 and iz < MAP_D then
                    if localMap[(iy * 65536) + (iz * 256) + ix] > 0 then return true end
                end
            end
        end
    end
    return false
end

local function render()
    local localMap = map
    term_setFrozen(true)
    term_clear(1)

    local hX, hY, hZ = raycastInteract(8)
    local cL, sL, cP, sP = math_cos(lookDir), math_sin(lookDir), math_cos(pitch), math_sin(pitch)
    local step, fov = 2, 1.1
    local aspect = h / w

    for x = 0, w - 1, step do
        local vX = (x / w - 0.5) * fov
        for y = 0, h - 1, step do
            local vY = (0.5 - (y / h)) * fov * aspect

            local rDX = cL * cP - vX * sL - vY * cL * sP
            local rDZ = sL * cP + vX * cL - vY * sL * sP
            local rDY = sP + vY * cP

            local mX, mY, mZ = floor(camX), floor(camY), floor(camZ)
            local dX, dY, dZ = abs(1/(rDX+1e-7)), abs(1/(rDY+1e-7)), abs(1/(rDZ+1e-7))
            local sX, sY, sZ = (rDX<0 and -1 or 1), (rDY<0 and -1 or 1), (rDZ<0 and -1 or 1)
            local sdX = (rDX<0 and (camX-mX)*dX or (mX+1-camX)*dX)
            local sdY = (rDY<0 and (camY-mY)*dY or (mY+1-camY)*dY)
            local sdZ = (rDZ<0 and (camZ-mZ)*dZ or (mZ+1-camZ)*dZ)

            local hit = false
            for i = 1, 64 do
                local side = 0
                if sdX < sdY and sdX < sdZ then sdX, mX, side = sdX + dX, mX + sX, 0
                elseif sdY < sdZ then sdY, mY, side = sdY + dY, mY + sY, 1
                else sdZ, mZ, side = sdZ + dZ, mZ + sZ, 2 end

                if mX<0 or mX>=MAP_W or mY<0 or mY>=MAP_H or mZ<0 or mZ>=MAP_D then break end
                local bType = localMap[(mY*65536)+(mZ*256)+mX]

                if bType > 0 then
                    local tex = textures[bType]
                    local wX, wY
                    if side == 1 then
                        wX, wY = camX + ((mY-camY+(1-sY)/2)/rDY)*rDX, camZ + ((mY-camY+(1-sY)/2)/rDY)*rDZ
                    else
                        wX = (side == 0) and camZ + ((mX-camX+(1-sX)/2)/rDX)*rDZ or camX + ((mZ-camZ+(1-sZ)/2)/rDZ)*rDX
                        wY = camY + (((side==0 and mX or mZ)-(side==0 and camX or camZ)+(1-(side==0 and sX or sZ))/2)/(side==0 and rDX or rDZ))*rDY
                    end
                    local tx, ty = floor((wX - floor(wX)) * (tex.w - 1)), floor((1 - (wY - floor(wY))) * (tex.h - 1))
                    local color = tex.pixels[ty * tex.w + tx + 1] or 0

                    local isShaded = false
                    for sy = mY + 2, m_min(mY + 15, MAP_H - 1) do
                        if localMap[(sy*65536)+(mZ*256)+mX] > 0 then
                            isShaded = true
                            break
                        end
                    end

                    local base = color - 16
                    local r = floor(base / 36)
                    local g = floor((base % 36) / 6)
                    local b = base % 6

                    if isShaded then
                        r, g, b = m_max(0, r-2), m_max(0, g-2), m_max(0, b-2)
                    elseif side ~= 1 then
                        r, g, b = m_max(0, r-1), m_max(0, g-1), m_max(0, b-1)
                    end
                    color = 16 + (r * 36) + (g * 6) + b

                    local isHigh = (hX==mX and hY==mY and hZ==mZ)
                    local finalCol = isHigh and 255 or color
                    for i=0,step-1 do
                        for j=0,step-1 do
                            if x+i<w and y+j<h then term_setPixel(x+i, y+j, finalCol) end
                        end
                    end
                    hit = true break
                end
            end
            if not hit then
                for i=0,step-1 do
                    for j=0,step-1 do
                        if x+i<w and y+j<h then term_setPixel(x+i, y+j, 1) end
                    end
                end
            end
        end
    end
    term_setFrozen(false)
end

if loadingBmp then
    term_setFrozen(true)
    term_clear(0)
    local sX, sY = loadingBmp.w / w, loadingBmp.h / h
    for sy = 0, h - 1 do
        local row = floor(sy * sY) * loadingBmp.w
        for sx = 0, w - 1 do
            term_setPixel(sx, sy, loadingBmp.pixels[row + floor(sx * sX)])
        end
    end
    term_setFrozen(false)
    pullEvent("key")
end

local function gameLoop()
    local lastTime = os.clock()
    local localMap = map
    while true do
        local dT = m_min(os.clock() - lastTime, 0.033)
        lastTime = os.clock()
        velocityY = velocityY + gravity * dT
        local nY = camY + velocityY * dT
        if not checkCollision(camX, nY, camZ) then camY = nY else velocityY = 0 end
        isOnGround = (camY <= 1.41 or checkCollision(camX, camY-0.1, camZ))
        if camY < 1.4 then camY, velocityY, isOnGround = 1.4, 0, true end

        render()

        local ev, p1 = pullEvent()
        local cL, sL = math_cos(lookDir), math_sin(lookDir)
        if ev == "key" then
            if p1 == keys.w then if not checkCollision(camX+cL*0.5, camY, camZ+sL*0.5) then camX, camZ = camX+cL*0.5, camZ+sL*0.5 end
            elseif p1 == keys.s then if not checkCollision(camX-cL*0.5, camY, camZ-sL*0.5) then camX, camZ = camX-cL*0.5, camZ-sL*0.5 end
            elseif p1 == keys.a then if not checkCollision(camX+sL*0.5, camY, camZ-cL*0.5) then camX, camZ = camX+sL*0.5, camZ-cL*0.5 end
            elseif p1 == keys.d then if not checkCollision(camX-sL*0.5, camY, camZ+cL*0.5) then camX, camZ = camX-sL*0.5, camZ+cL*0.5 end
            elseif p1 == keys.one then selectedBlock = 1
            elseif p1 == keys.two then selectedBlock = 2
            elseif p1 == keys.r then camX, camZ, camY, velocityY = m_random(20, 230), m_random(20, 230), 15, 0
            elseif p1 == keys.space and isOnGround then velocityY = jumpPower
            elseif p1 == keys.left then lookDir = lookDir - 0.1
            elseif p1 == keys.right then lookDir = lookDir + 0.1
            elseif p1 == keys.up then pitch = m_min(pitch + 0.1, 1.4)
            elseif p1 == keys.down then pitch = m_max(pitch - 0.1, -1.4)
            elseif p1 == keys.e or p1 == keys.b then
                local bx, by, bz, face = raycastInteract(8)
                if bx then
                    if p1 == keys.e then localMap[(by*65536)+(bz*256)+bx] = 0
                    else
                        if face == "north" then bz=bz-1 elseif face == "south" then bz=bz+1
                        elseif face == "west" then bx=bx-1 elseif face == "east" then bx=bx+1
                        elseif face == "bottom" then by=by-1 elseif face == "top" then by=by+1 end
                        if bx>=0 and bx<MAP_W and by>=0 and by<MAP_H and bz>=0 and bz<MAP_D then
                            localMap[(by*65536)+(bz*256)+bx] = selectedBlock
                        end
                    end
                end
            elseif p1 == keys.q then
                musicStopFlag[1] = true
                break
            end
        end
    end
end

-- Only run music if speaker exists, otherwise just run game
if speaker then
    parallel.waitForAny(
        function() playPCM(MUSIC_FILE, 16000, musicStopFlag) end,
        gameLoop
    )
else
    gameLoop()
end

term.setGraphicsMode(0)