require "Vehicles/Papa_Chad_Tank_Cannon"
require "Vehicles/Papa_Chad_Tank_Aim"

MTKViewpointTurrets = MTKViewpointTurrets or {}
local M = MTKViewpointTurrets
local seats = { [0] = "SeatFrontLeft", [1] = "SeatGunner", [2] = "SeatFrontRight", [3] = "SeatRearRight" }
local scope = nil

local function enabled()
    return MTKViewpointCamera and MTKViewpointCamera.enabled()
end

local function allowed(player, vehicle, weapon)
    return player == getPlayer() and not player:isDead()
        and MTKViewpointCamera.captured() and getGameSpeed() > 0
        and not (UIManager and UIManager.isMouseOverInventory and UIManager.isMouseOverInventory())
        and seats[vehicle:getSeat(player)] == weapon.requiredSeat
        and player:getCharacterActions():isEmpty()
end

function M.install()
    -- These local adapters register their own wrappers at boot/start. Install
    -- them first, then wrap the completed chain, regardless of event order.
    if KFTFerret and KFTFerret.installClient then KFTFerret.installClient() end
    if KLTLAV and KLTLAV.installClient then KLTLAV.installClient() end
    if not tankAimSystemPC or not chooseWeaponPC or not ISCoordConversion then return end

    if ISCoordConversion.ToWorld ~= M.toWorld then
        local previousToWorld = ISCoordConversion.ToWorld
        M.toWorld = function(x, y, z)
            -- Only override conversions inside this turret update. The Ferret
            -- and LAV wrappers otherwise overwrite our camera heading with a
            -- floor pick (or the screen-centre isometric fallback).
            if scope and scope.x then return scope.x, scope.y end
            return previousToWorld(x, y, z)
        end
        ISCoordConversion.ToWorld = M.toWorld
    end

    if chooseWeaponPC ~= M.choose then
        local previousChoose = chooseWeaponPC
        M.choose = function(vehicle)
            -- MTK still advances existing projectiles when weapon input is
            -- blocked; no simulation callback is removed or duplicated.
            if scope and scope.blocked then return nil end
            return previousChoose(vehicle)
        end
        chooseWeaponPC = M.choose
    end

    if tankAimSystemPC ~= M.aim then
        local previousAim = tankAimSystemPC
        Events.OnPlayerUpdate.Remove(previousAim)
        M.aim = function(player)
            local vehicle = player and player:getVehicle()
            if not enabled() or not vehicle then return previousAim(player) end
            local weapon = chooseWeaponPC(vehicle)
            if not weapon then return previousAim(player) end

            local oldScope = scope
            scope = { blocked = not allowed(player, vehicle, weapon) }
            local oldDirection = nil
            if not scope.blocked and isMouseButtonDown(1) then
                local heading = MTKViewpointCamera.heading()
                if type(heading) == "number" and heading == heading and math.abs(heading) < math.huge then
                    oldDirection = player:getDirectionAngle()
                    local rad = math.rad(heading)
                    scope.x = player:getX() + math.cos(rad) * 100
                    scope.y = player:getY() + math.sin(rad) * 100
                    player:setDirectionAngle(heading)
                else
                    scope.blocked = true
                end
            end

            -- Restore temporary input even if a dependency raises an error.
            local ok, err = pcall(previousAim, player)
            scope = oldScope
            if oldDirection ~= nil then player:setDirectionAngle(oldDirection) end
            if not ok then error(err) end
        end
        tankAimSystemPC = M.aim
        Events.OnPlayerUpdate.Add(M.aim)
        print("[MTKViewpointTurrets] MTK camera aiming registered; Ferret/LAV wrappers retained.")
    end

    if TankCursor and TankCursor.prerender ~= M.cursor then
        local previousCursor = TankCursor.prerender
        M.cursor = function(self)
            if not enabled() then return previousCursor(self) end
            -- MTK's two iso-projected textures cannot represent the 3D view.
            -- A centred cross marks camera bearing; green means the turret
            -- has caught up in yaw, not that ammunition or a hit is guaranteed.
            local player = getPlayer()
            local vehicle = player and player:getVehicle()
            local weapon = vehicle and chooseWeaponPC(vehicle)
            if not weapon or not allowed(player, vehicle, weapon) or not isMouseButtonDown(1) then return end
            local heading = MTKViewpointCamera.heading()
            if not heading then return end
            local turret = turretAngles and turretAngles[vehicle:getId()]
            local aligned = turret and math.abs(((turret - heading + 540) % 360) - 180) <= 2
            local r, g, b = 1, 0.75, 0.25
            if aligned then r, g, b = 0.3, 1, 0.4 end
            local x = getCore():getScreenWidth() / 2 - self.x
            local y = getCore():getScreenHeight() / 2 - self.y
            self:drawRect(x - 9, y, 5, 1, 0.9, r, g, b)
            self:drawRect(x + 4, y, 5, 1, 0.9, r, g, b)
            self:drawRect(x, y - 9, 1, 5, 0.9, r, g, b)
            self:drawRect(x, y + 4, 1, 5, 0.9, r, g, b)
        end
        TankCursor.prerender = M.cursor
    end
end

Events.OnGameBoot.Add(M.install)
Events.OnGameStart.Add(M.install)
Events.OnGameStart.Add(function()
    if not MTKViewpointCamera then
        print("[MTKViewpointTurrets] Camera bridge unavailable. Enable this mod and approve its local JAR in ZombieBuddy, then fully restart the game.")
    end
end)