figura-skin/scripts/libs/SquAPI_modules/tail.lua

---@meta _
local squassets
local assetPath = "./SquAssets"
if pcall(require, assetPath) then squassets = require(assetPath) end
assert(squassets, "§4The tail module requires SquAssets, which was not found!§c")


---@class tail
local tail = {}
tail.all = {}

---*CONSTRUCTOR
---@param tailSegmentList table<ModelPart> The list of each individual tail segment of your tail.
---@param idleXMovement? number Defaults to `15`, how much the tail should sway side to side.
---@param idleYMovement? number Defaults to `5`, how much the tail should sway up and down.
---@param idleXSpeed? number Defaults to `1.2`, how fast the tail should sway side to side.
---@param idleYSpeed? number Defaults to `2`, how fast the tail should sway up and down.
---@param bendStrength? number Defaults to `2`, how strongly the tail moves when you move.
---@param velocityPush? number Defaults to `0`, this will cause the tail to bend when you move forward/backward, good if your tail is bent downward or upward.
---@param initialMovementOffset? number Defaults to `0`, this will offset the tails initial sway, this is good for when you have multiple tails and you want to desync them.
---@param offsetBetweenSegments? number Defaults to `1`, how much each tail segment should be offset from the previous one.
---@param stiffness? number Defaults to `0.005`, how stiff the tail should be.
---@param bounce? number Defaults to `0.9`, how bouncy the tail should be.
---@param flyingOffset? number Defaults to `90`, when flying, riptiding, or swimming, it may look strange to have the tail stick out, so instead it will rotate to this value(so use this to flatten your tail during these movements).
---@param downLimit? number Defaults to `-90`, the lowest each tail segment can rotate.
---@param upLimit? number Defaults to `45`, the highest each tail segment can rotate.
---@return SquAPI.Tail
function tail:new(tailSegmentList, idleXMovement, idleYMovement, idleXSpeed, idleYSpeed,
    bendStrength, velocityPush, initialMovementOffset, offsetBetweenSegments,
    stiffness, bounce, flyingOffset, downLimit, upLimit)
    ---@class SquAPI.tail
    local self = setmetatable({}, {__index = tail})

    --error checker
    self.tailSegmentList = tailSegmentList
        if type(self.tailSegmentList) == "ModelPart" then
            self.tailSegmentList = {self.tailSegmentList}
        end
        assert(type(self.tailSegmentList) == "table", 
        "your tailSegmentList table seems to to be incorrect")
        
    self.berps = {}
    self.targets = {}
    self.stiffness = stiffness or .005
    self.bounce = bounce or .9

    if type(self.tailSegmentList[2]) == "number" then --ah I see you stumbled across my custom tail list creator, if you curious ask me. tail must be >= 3 segments. Naming: tail, tailseg, tailseg2, tailseg3..., tailtip
        local range = self.tailSegmentList[2]
        local str = ""
        if self.tailSegmentList[3] then
            str = self.tailSegmentList[3]
        end

        self.tailSegmentList[2] = self.tailSegmentList[1][str .. "tailseg"]
        for i = 2, range - 2 do
            self.tailSegmentList[i + 1] = self.tailSegmentList[i][str .. "tailseg" .. i]
        end
        self.tailSegmentList[range] = self.tailSegmentList[range - 1][str .. "tailtip"]
    end

    for i = 1, #self.tailSegmentList do
        assert(self.tailSegmentList[i]:getType() == "GROUP",
        "§4The tail segment at position "..i.." of the table is not a group. The tail segments need to be groups that are nested inside the previous segment.§c")
        self.berps[i] = {squassets.BERP:new(self.stiffness, self.bounce), squassets.BERP:new(self.stiffness, self.bounce, self.downLimit, self.upLimit)}
        self.targets[i] = {0, 0}
    end

    self.downLimit = downLimit or -90
    self.upLimit = upLimit or 45
    self.tailSegmentList = tailSegmentList
    self.idleXMovement = idleXMovement or 15
    self.idleYMovement = idleYMovement or 5
    self.idleXSpeed = idleXSpeed or 1.2
    self.idleYSpeed = idleYSpeed or 2
    self.bendStrength = bendStrength or 2
    self.velocityPush = velocityPush or 0
    self.initialMovementOffset = initialMovementOffset or 0
    self.flyingOffset = flyingOffset or 90
    self.offsetBetweenSegments = offsetBetweenSegments or 1

    self.currentBodyRot = 0
    self.oldBodyRot = 0
    self.bodyRotSpeed = 0

    self.enabled = true

    table.insert(tail.all, self)
    return self
end


--*CONTROL FUNCTIONS

---tail enable handling
function tail:disable() self.enabled = false return self end
function tail:enable() self.enabled = true return self end
function tail:toggle() self.enabled = not self.enabled return self end

---@param bool boolean
function tail:setEnabled(bool)
    self.enabled = bool or false
    return self
end

function tail:zero()
    for _, v in pairs(self.tailSegmentList) do
      v:setOffsetRot(0, 0, 0)
    end
    return self
end

--*UPDATE FUNCTIONS

function tail:tick()
    if self.enabled then
        self.oldBodyRot = self.currentBodyRot
        self.currentBodyRot = player:getBodyYaw()
        self.bodyRotSpeed = math.max(math.min(self.currentBodyRot-self.oldBodyRot, 20), -20)

        local time = world.getTime()
        local vel = squassets.forwardVel()
        local yvel = squassets.verticalVel()
        local svel = squassets.sideVel()
        local bendStrength = self.bendStrength/(math.abs((yvel*30))+vel*30 + 1)
        local pose = player:getPose()
    
        for i = 1, #self.tailSegmentList do
            self.targets[i][1] = math.sin((time * self.idleXSpeed)/10 - (i * self.offsetBetweenSegments)) * self.idleXMovement
            self.targets[i][2] = math.sin((time * self.idleYSpeed)/10 - (i * self.offsetBetweenSegments) + self.initialMovementOffset) * self.idleYMovement

            self.targets[i][1] = self.targets[i][1] + self.bodyRotSpeed*self.bendStrength + svel*self.bendStrength*40
            self.targets[i][2] = self.targets[i][2] + yvel * 15 * self.bendStrength - vel*self.bendStrength*15*self.velocityPush

            if i == 1 then
                if pose == "FALL_FLYING" or pose == "SWIMMING" or player:riptideSpinning() then
                    self.targets[i][2] = self.flyingOffset
                end	
            end  
        end
    end
end


---@param dt number Tick delta
function tail:render(dt, _)
    if self.enabled then
      local pose = player:getPose()
      if pose ~= "SLEEPING" then
        for i, tail in ipairs(self.tailSegmentList) do
          tail:setOffsetRot(
            self.berps[i][2]:berp(self.targets[i][2], dt),
            self.berps[i][1]:berp(self.targets[i][1], dt),
            0
          )
        end  
      end
    end
end

return tail