MW3-like Controllable Turret

-------------------------
--- GENERAL FUNCTIONS ---
-------------------------

function contains(table, element)
    for _, value in ipairs(table) do
        if value == element then
            return true
        end
    end
    return false
end

function table.remove(table, element)
    if #table > 1 then
        for key, value in ipairs(table) do
            if value == element then
                table[key] = nil
            end
        end
    else
        table = {}
    end
end

function table.insert2(table, element)
    if #table > 0 then
        for key, value in ipairs(table) do
            if value == nil then
                table[key] = element
            end
        end
    else
        table[1]=element
    end
end

function angledir(rot,x,y,factor)
    if rot<-90 then rot=rot+360 end
    local angle=math.rad(math.abs(rot+90))-math.pi
    local cx=x+(math.cos(angle)*factor)
    local cy=y+(math.sin(angle)*factor)
    return cx,cy
end

function distance(x1,y1,x2,y2)
    local x=x1-x2
    local y=y1-y2
    return math.sqrt(x^2+y^2)
end

------------------------------
---- SCRIPT-RELATED STUFF ----
------------------------------

------ VARIABLES AND TABLES ------

turret={}
plydata={}

plydata.cimg = "gfx/sprites/block.bmp" -- image of the player controlling the turret; modify this variable to change

turret.hp = 250 -- health of any given turret; modify this variable to change
turret.bimg = "gfx/sprites/block.bmp" -- image of any given turret base; modify this variable to change
turret.gimg = "gfx/weapons/turret.bmp" -- image of any given turret gun; modify this variable to change
turret.aux = {} -- auxiliary functions table (e.g. say functions, switch functions etc.)
turret.controlling = {} -- table of players that are controlling turrets

------ TURRET-RELATED FUNCTIONS ------

function turret.new(ply,x,y) -- create new turret; x y are tiles!
    table.insert2(turret,{
        owner = ply,
        pos = {x,y},
        health = turret.hp,
        bimg = image(turret.bimg,x*32+16,y*32+16,3),
        gimg = image(turret.gimg,x*32+16,y*32+16,3),
    })
    local id = #turret
    if not plydata[ply] then plydata[ply]={} end
    plydata[ply].turret = id
    return id
end

function turret.kill(id) -- destroy a turret
    local ply = turret[id].owner
    if (turret[id].controlled) then
        turret.scontrol(ply)
    end
    parse("explosion "..(turret[id].pos[1]*32+16).." "..(turret[id].pos[2]*32+16).." 128 20 "..ply)
    freeimage(turret[id].bimg)
    freeimage(turret[id].gimg)
    turret[id] = nil
    return
end

function turret.hit(id,dmg) -- hit a turret
    if (turret[id].health > dmg) then
        turret[id].health = turret[id].health - dmg
        parse("effect \"flare\" "..(turret[id].pos[1]*32+16).." "..(turret[id].pos[2]*32+16).." 3 8 255 255 0")
    else
        turret.kill(id)
        return
    end
end

------ PLAYER-RELATED FUNCTIONS ------

function turret.control(ply) -- assume control of a turret
    plydata[ply].controlling = true
    local id = plydata[ply].turret
    turret[id].controlled = true
    table.insert2(turret.controlling,ply)
    plydata[ply].cimg = image(plydata.cimg,player(ply,"x"),player(ply,"y"),0)
    imagepos(plydata[ply].cimg,player(ply,"x"),player(ply,"y"),player(ply,"rot"))
    plydata[ply].armor = player(ply,"armor") -- old armor to revert to after destruction or control stop
    plydata[ply].pos = {player(ply,"x"),player(ply,"y")} -- old position to teleport to
    plydata[ply].speed = player(ply,"speedmod") -- old speedmod to revert to
    parse("setarmor "..ply.." 206")
    parse("setpos "..ply.." "..(turret[id].pos[1]*32+16).." "..(turret[id].pos[2]*32+16))
    if not contains(playerweapons(ply),40) then -- if a player doesn't already have a machine gun then it's equipped, leave it otherwise
        parse("equip "..id.." 40")
        plydata[ply].meq=true
    else
        plydata[ply].meq=false
    end
    parse("speedmod "..ply.." -100")
    parse("setweapon "..ply.." 40")
end

function turret.scontrol(ply) -- cease control of a turret
    plydata[ply].controlling = false
    local id = plydata[ply].turret
    turret[id].controlled = false
    parse("setarmor "..ply.." "..plydata[ply].armor)
    if (plydata[ply].meq) then
        parse("strip "..ply.." 40")
    end
    parse("setpos "..ply.." "..plydata[ply].pos[1].." "..plydata[ply].pos[2])
    parse("speedmod "..ply.." "..plydata[ply].speed)
    freeimage(plydata[ply].cimg)
    table.remove(turret.controlling,ply)
    plydata[ply].cimg = nil
    plydata[ply].armor = nil
    plydata[ply].pos = nil
    plydata[ply].speed = nil
end

function turret.acquire(ply)
    if not plydata[ply] then plydata[ply]={} end
    plydata[ply].tpacked = true -- player has turret packed
    msg2(ply,"You have acquired a remote controlled turret.")
end

------ AUXILIARY FUNCTIONS ------

function turret.aux.update()
    for id=1,#turret do
        if (turret[id].controlled) then
            imagepos(turret[id].gimg,player(turret[id].owner,"x"),player(turret[id].owner,"y"),player(turret[id].owner,"rot"))
        end
    end
end

function turret.aux.ms100()
    for id=1,#turret do
        if (turret[id].health<=turret.hp/2) then
            parse("effect \"smoke\" "..(turret[id].pos[1]*32+16).." "..(turret[id].pos[2]*32+16).." 3 4 255 255 0")
            if (turret[id].health<=turret.hp/4) then
                parse("effect \"fire\" "..(turret[id].pos[1]*32+16).." "..(turret[id].pos[2]*32+16).." 3 4 255 255 0")
            end
        end
    end
end

function turret.aux.say(ply,t)
    if (t:sub(1,8) == "!control") then
        if (plydata[ply].turret) then
            turret.control(ply)
        end
        return 1
    end
    if (t:sub(1,5) == "!stop") then
        if (plydata[ply].controlling) then
            turret.scontrol(ply)
        end
        return 1
    end
    if (t:sub(1,7) == "!deploy") then
        if (plydata[ply].tpacked) then
            turret.new(ply,player(ply,"tilex"),player(ply,"tiley"))
        end
        return 1
    end
end

function turret.aux.check(x1,y1,x2,y2) -- check path between two points (tiles)
    for x=math.max(x1,x2),math.min(x1,x2) do
        for y=math.max(y1,y2),math.min(y1,y2) do
            if not (tile(x,y,"walkable")) then
                return false
            end
        end
    end
    return true
end

function turret.aux.hit(ply,plys,_,hpdmg)
    if (plydata[ply] and plydata[ply].controlling) then
        turret.hit(plydata[ply].turret,hpdmg)
        return 1
    end
    if (plydata[plys] and plydata[plys].controlling and player(ply,"health")<=hpdmg) then
        parse("customkill "..plys.." \"RC Turret\" "..ply)
        return 1
    end
end

function turret.aux.shoot(ply)
    for i=1,#turret.controlling do
        local ply2=turret.controlling[i]
        if (turret.aux.check(player(ply,"tilex"),player(ply,"tiley"),player(ply2,"tilex"),player(ply2,"tiley"))) then
            for i=1,640 do
                local x,y=angledir(player(ply,"rot"),player(ply,"x"),player(ply,"y"),i)
                if (plydata[ply2].pos and distance(plydata[ply2].pos[1],plydata[ply2].pos[2],x,y)<=16) then
                    msg(x)
                    msg(y)
                    msg(plydata[ply2].pos[1])
                    msg(plydata[ply2].pos[2])
                    if (player(ply2,"health")>itemtype(player(ply,"weapon"),"dmg")) then
                        parse("sethealth "..ply2.." "..player(ply2,"health")-itemtype(player(ply,"weapon"),"dmg"))
                    else
                        parse("customkill "..ply.." "..itemtype(player(ply,"weapon"),"name").." "..ply2)
                    end
                    break
                end
            end
        end
    end
    for id=1,#turret do
        if (not turret[id].controlled and turret.aux.check(player(ply,"tilex"),player(ply,"tiley"),turret[id].pos[1],turret[id].pos[2])) then
            for i=32,640 do
                local x,y=angledir(player(ply,"rot"),player(ply,"x"),player(ply,"y"),i)
                if (distance(turret[id].pos[1]*32+16,turret[id].pos[2]*32+16,x,y)<=16) then
                    turret.hit(id,itemtype(player(ply,"weapon"),"dmg"))
                    break
                end
            end
        end
    end
end

function turret.aux.select(ply,type)
    if (plydata[ply].controlling) then
        if (type ~= 40) then
            parse("setweapon "..ply.." 40")
        end
    end
end

function turret.aux.die(ply)
    if (plydata[ply] and plydata[ply].controlling) then
        plydata[ply].spos = plydata[ply].pos
        turret.scontrol(ply)
    end
end

function turret.aux.spawn(ply)
    if (plydata[ply] and plydata[ply].spos) then
        parse("setpos "..ply.." "..plydata[ply].spos[1].." "..plydata[ply].spos[2])
        plydata[ply].spos = nil
    end
end

------ HOOKS ------

addhook("always","turret.aux.update")
addhook("ms100","turret.aux.ms100")
addhook("attack","turret.aux.shoot")
addhook("hit","turret.aux.hit")
addhook("say","turret.aux.say")
addhook("select","turret.aux.select")
addhook("die","turret.aux.die")
addhook("spawn","turret.aux.spawn")