--[[-------------------------------------------------------------------------
    A script for controlling the behavior of falling NPC body parts (e.g., legs).
    Includes flinching effects and roll animation upon impact.
    Version 2: Fixed GetGameData and HitNormal errors.
---------------------------------------------------------------------------]]

MODULE = {}

MODULE.Model = "models/police.mdl" -- The model to which the script is applied (likely not used directly in this code)

-- A list of bones that MAY be affected by physics or animation.
-- Only the leg bones from this list will be used for pulling.
MODULE.BoneList =
{
    "ValveBiped.Bip01_Pelvis",
    -- "ValveBiped.Bip01_Spine2",
    -- "ValveBiped.Bip01_Head1",
    -- "ValveBiped.Bip01_R_Upperarm",
    -- "ValveBiped.Bip01_R_Forearm",
    -- "ValveBiped.Bip01_R_Hand",
    -- "ValveBiped.Bip01_L_Upperarm",
    -- "ValveBiped.Bip01_L_Forearm",
    -- "ValveBiped.Bip01_L_Hand",
    "ValveBiped.Bip01_R_Thigh",
    "ValveBiped.Bip01_R_Calf",
    "ValveBiped.Bip01_R_Foot",
    "ValveBiped.Bip01_L_Thigh",
    "ValveBiped.Bip01_L_Calf",
    "ValveBiped.Bip01_L_Foot"
}

-- A list of bones to which the jiggle effect WILL be applied.
-- Filtered from MODULE.BoneList to exclude the pelvis and other unwanted bones.
local twitchable_bone_names = {
    "ValveBiped.Bip01_R_Thigh",
    "ValveBiped.Bip01_R_Calf",
    "ValveBiped.Bip01_R_Foot",
    "ValveBiped.Bip01_L_Thigh",
    "ValveBiped.Bip01_L_Calf",
    "ValveBiped.Bip01_L_Foot"
}

-- Local Copies of Functions for Optimization
local math_Clamp = math.Clamp
local math_Rand = math.Rand
local math_random = math.random
local table_Random = table.Random -- We use `table.Random` to select a random element.
local IsValid = IsValid -- Local copy of IsValid
local CurTime = CurTime -- Local copy of CurTime
local timer_Create = timer.Create
local timer_Remove = timer.Remove
local VectorRand = VectorRand

--[[-------------------------------------------------------------------------
    Convars (Settings)
---------------------------------------------------------------------------]]
-- Twitching
local cv_twitch_enabled = CreateConVar("fedhoria_falling_twitch_enabled", "1", {FCVAR_ARCHIVE, FCVAR_REPLICATED}, "Включить дергание для падающих ног")
local cv_twitch_interval_min = CreateConVar("fedhoria_falling_twitch_interval_min", "3", {FCVAR_ARCHIVE, FCVAR_REPLICATED}, "Минимальный интервал между дерганиями (сек)")
local cv_twitch_interval_max = CreateConVar("fedhoria_falling_twitch_interval_max", "6", {FCVAR_ARCHIVE, FCVAR_REPLICATED}, "Максимальный интервал между дерганиями (сек)")
local cv_twitch_force_min = CreateConVar("fedhoria_falling_twitch_min", "100", {FCVAR_ARCHIVE, FCVAR_REPLICATED}, "Мин. угловая скорость для дергания")
local cv_twitch_force_max = CreateConVar("fedhoria_falling_twitch_max", "250", {FCVAR_ARCHIVE, FCVAR_REPLICATED}, "Макс. угловая скорость для дергания")

-- Roll
local cv_anim_roll_enabled = CreateConVar("fedhoria_falling_anim_roll_enabled", "1", {FCVAR_ARCHIVE, FCVAR_REPLICATED}, "Включить анимацию при ударе о землю")
local cv_anim_roll_min_delay = CreateConVar("fedhoria_falling_anim_roll_min_delay", "0.5", {FCVAR_ARCHIVE, FCVAR_REPLICATED}, "Мин. задержка перед возможной анимацией после удара (сек)")
local cv_anim_roll_duration = CreateConVar("fedhoria_falling_anim_roll_duration", "3.5", {FCVAR_ARCHIVE, FCVAR_REPLICATED}, "Продолжительность принудительной анимации (сек)")
local cv_anim_roll_impact_threshold = CreateConVar("fedhoria_falling_anim_roll_impact_threshold", "300", {FCVAR_ARCHIVE, FCVAR_REPLICATED}, "Мин. скорость удара для запуска анимации")
local cv_anim_roll_playback_rate = CreateConVar("fedhoria_falling_anim_roll_playback_rate", "3.0", {FCVAR_ARCHIVE, FCVAR_REPLICATED}, "Скорость воспроизведения анимации")

-- Death timer
local die_time = CreateConVar("fedhoria_dietime", 5, {FCVAR_ARCHIVE, FCVAR_REPLICATED})
local die_time_variation = CreateConVar("fedhoria_dietime_variation", 3, {FCVAR_ARCHIVE, FCVAR_REPLICATED})

--[[-------------------------------------------------------------------------
    Tug function
    Applies a random impulse to one of the leg bones.
---------------------------------------------------------------------------]]
function MODULE:DoTwitch()
    if not IsValid(self) or not IsValid(self:GetTarget()) then return end
    if not cv_twitch_enabled:GetBool() then return end

    local phys = self:GetPhysicsObject()
    if not IsValid(phys) then return end

    if #twitchable_bone_names == 0 then return end

    local random_bone_name = table_Random(twitchable_bone_names)
    if not random_bone_name then return end

    -- Get bone index by name
    local bone_index = self:LookupBone(random_bone_name)
    if not bone_index then
        -- print("[Fedhoria Twitch] Bone index not found for name:", random_bone_name)
        return
    end

    -- We retrieve the physical bone object by its index.
    local phys_bone = self:GetPhysicsObjectNum(bone_index) -- We use GetPhysicsObjectNum to retrieve the physics object for a specific bone.

    if IsValid(phys_bone) then
        local force = math_Rand(cv_twitch_force_min:GetFloat(), cv_twitch_force_max:GetFloat())
        local torque = VectorRand():GetNormal() * force
        phys_bone:AddAngleVelocity(torque)
        -- print("[Fedhoria Twitch] Applied torque", torque, "to bone", random_bone_name, "(index:", bone_index, ")")
    -- else
        -- print("[Fedhoria Twitch] Could not find a valid physics bone for index:", bone_index, "name:", random_bone_name)
    end

    self:ScheduleNextTwitch()
end


--[[-------------------------------------------------------------------------
    Planning the next DoTwitch call
---------------------------------------------------------------------------]]
function MODULE:ScheduleNextTwitch()
    if not IsValid(self) then return end
    if not cv_twitch_enabled:GetBool() then return end

    local timer_name = "Fedhoria_FallingLegs_Twitch_" .. self:EntIndex()
    timer_Remove(timer_name)

    local delay = math_Rand(cv_twitch_interval_min:GetFloat(), cv_twitch_interval_max:GetFloat())

    timer_Create(timer_name, delay, 1, function()
        if not IsValid(self) then return end
        self:DoTwitch()
    end)
end

--[[-------------------------------------------------------------------------
    Starting the roll animation
---------------------------------------------------------------------------]]
function MODULE:StartAnimationRoll()
    if not cv_anim_roll_enabled:GetBool() then return end

    local target = self:GetTarget()
    if not IsValid(target) then return end

    local cur_time = CurTime()
    self.AnimationRollEndTime = cur_time + cv_anim_roll_duration:GetFloat()

    local seq = self:LookupSequence("Choked_Barnacle")
    if seq and seq > 0 then
        self:ResetSequence(seq)
        self:SetPlaybackRate(cv_anim_roll_playback_rate:GetFloat())
    else
        self.AnimationRollEndTime = 0
        return
    end

    --self.StartDie = nil
end

function MODULE:Init()
    local seq = self:LookupSequence("Choked_Barnacle")
    if seq then self:ResetSequence(seq) end
    self:SetPlaybackRate(1)
    self.LastCollideTime = 0
    self.LastGroundCollideTime = 0
    self.StartDie = nil
    self.AnimationRollEndTime = 0
    
    -- Add damping to all bones.
    local phys = self:GetPhysicsObject()
    if IsValid(phys) then
        local bone_count = phys:GetBoneCount()
        for bone_index = 0, bone_count - 1 do
            local phys_bone = phys:GetBone(bone_index)
            if IsValid(phys_bone) then
                phys_bone:SetDamping(0.8, 0.9) -- Linear and Angular Damping
            end
        end
    end
    
    -- запускаем систему дергания
    self:ScheduleNextTwitch()
end


--[[-------------------------------------------------------------------------
    Think-hook
---------------------------------------------------------------------------]]
function MODULE:Think()
    -- Space for additional logic
end

--[[-------------------------------------------------------------------------
    Physics Collision Hook (FIXED)
---------------------------------------------------------------------------]]
function MODULE:PhysicsCollide(data, phys)
    -- Checking the validity of collision data and the presence of HitNormal.
    if not data or not data.HitNormal then
        -- print("[Fedhoria Collide] Invalid collision data received.")
        return
    end

    if data.HitEntity == self then return end

    local cur_time = CurTime()
    self.LastCollideTime = cur_time

    -- Ground collision check (normal points upward)
    if data.HitNormal.z > 0.7 then
        local impact_speed = data.Speed

        -- print("[Fedhoria Collide] Ground collision detected. Speed:", impact_speed)

        if cv_anim_roll_enabled:GetBool() and
           impact_speed > cv_anim_roll_impact_threshold:GetFloat() and
           cur_time > self.AnimationRollEndTime and
           cur_time > self.LastGroundCollideTime + cv_anim_roll_min_delay:GetFloat() then
            self:StartAnimationRoll()
        end

        self.LastGroundCollideTime = cur_time
    end
end


--[[-------------------------------------------------------------------------
    Physics Simulation Hook (FIXED)
---------------------------------------------------------------------------]]
function MODULE:PhysicsSimulate(phys, dt)
    local cur_time = CurTime()
    local target = self:GetTarget()
    if not IsValid(target) then self:Remove(); return false end

    -- Check for active animation
    if cur_time < self.AnimationRollEndTime then
        --self.StartDie = nil -- Resetting the "death" timer
        return true -- We use standard physics.
    end

    -- Logic for the disappearance timer
    local f = 1 -- Force multiplier (default: 1)
    if self.StartDie then
        f = math_Clamp(1 - (cur_time - self.StartDie) / die_time:GetFloat(), 0, 1)
    end

    -- Support for RagMod
    if ragmod and ragmod:IsRagmodRagdoll(target) then
        local owner = target:GetOwningPlayer()
        f = (IsValid(owner) and owner:Alive()) and 1 or 0
        --self.StartDie = nil

        if f <= 0 then self.AnimationRollEndTime = 0 end
    end

    -- Deletion if the time-to-live has expired
    if (f <= 0) then
        self:Remove()
        return false
    end

    local phys_bone_id = phys:GetID()

    -- Main logic for the root bone
    if (phys_bone_id == 0) then
        -- Water Logic
        if target:WaterLevel() > 0 then
            self.AnimationRollEndTime = 0
            local seq_choked = self:LookupSequence("Choked_Barnacle")
            if seq_choked then self:ResetSequence(seq_choked) end
            return false
        end

        -- Logic for fall animation
        local vel = phys:GetVelocity()
        local pbr = math_Clamp(vel.z / -600, 0.5, 1.5)

        if self:GetSequence() ~= self:LookupSequence("Choked_Barnacle") or self:GetPlaybackRate() ~= pbr then
            local seq_idle = self:LookupSequence("Choked_Barnacle")
            if seq_idle then
                self:ResetSequence(seq_idle)
                self:SetPlaybackRate(pbr)
            end
        end

        -- Fix: Safe vector handling
        local pos = phys:GetPos()
        if not pos then return true, f end -- If `pos` is invalid, do nothing.

        self.last_pos = self.last_pos or pos
        if not self.last_pos then self.last_pos = pos end

        local offset_sqr = (pos - self.last_pos):LengthSqr()
        self.last_pos = pos

        if (offset_sqr < (10*10 * dt*dt) and not (ragmod and ragmod:IsRagmodRagdoll(target))) then
            self.StartDie = self.StartDie or cur_time
        else
            --self.StartDie = nil
        end

        -- Physics correction after collision
        local delta_collide = cur_time - self.LastCollideTime
        if (delta_collide < 0.2) then
            return true, 1 * f
        elseif (delta_collide < 1.2) then
            return true, (1 - (delta_collide - 0.2)) * f
        end

        return true, f
    end

    -- Logic for other bones
    local delta_collide = cur_time - self.LastCollideTime
    if (delta_collide < 0.2) then
        return true, 1 * f
    elseif (delta_collide < 1.2) then
        return true, (1 - (delta_collide - 0.2)) * f
    end
    return true, f
end

--[[-------------------------------------------------------------------------
    Entity Deletion Hook
---------------------------------------------------------------------------]]
function MODULE:OnRemove()
    local timer_name = "Fedhoria_FallingLegs_Twitch_" .. self:EntIndex()
    timer_Remove(timer_name)
end

--[[-------------------------------------------------------------------------
    Module registration (if it is part of a module system)
---------------------------------------------------------------------------]]
-- Registration Example:
-- falling_legs_manager:RegisterModule("FedhoriaFallingLegs", MODULE)