Zero Mission - Drops Predictor

--Makeshift droptype enum
local None, Bomb, Super, Missile, Small, Large = 0,1,2,3,4,5

neededDrop = None

rns = {13, 2, 6, 8, 7, 9, 14, 10, 2, 4, 14, 4, 12, 15, 13, 12, 11, 1, 3, 15, 0, 6, 7, 8, 11, 5, 0, 3, 5, 1, 9, 10}
enHealth = { }

chosenEnemyIndex = -1
clickBoxSize = 8
prevClick = false
pause = false

-- functions for displaying drop
function DrawHighlight(x, y)    -- displays a box
    gui.line(x-clickBoxSize, y-clickBoxSize, x+clickBoxSize, y-clickBoxSize, "green")
    gui.line(x-clickBoxSize, y-clickBoxSize, x-clickBoxSize, y+clickBoxSize, "green")
    gui.line(x-clickBoxSize, y+clickBoxSize, x+clickBoxSize, y+clickBoxSize, "green")
    gui.line(x+clickBoxSize, y-clickBoxSize, x+clickBoxSize, y+clickBoxSize, "green")
end

function DrawNone(x, y)     -- displays an X for no drop
    gui.line(1+x, 1+y, 6+x, 6+y, "white")
    gui.line(1+x, 6+y, 6+x, 1+y, "white")
end

function DrawSmall(x, y)    -- displays a small health drop
    gui.line(3+x, 1+y, 4+x, 1+y, "#D030D0")
    gui.pixel(2+x, 2+y, "#D030D0")
    gui.pixel(5+x, 2+y, "#D030D0")
    gui.line(1+x, 3+y, 1+x, 4+y, "#D030D0")
    gui.box(3+x, 3+y, 4+x, 4+y, "#D030D0")
    gui.line(6+x, 3+y, 6+x, 4+y, "#D030D0")
    gui.pixel(2+x, 5+y, "#D030D0")
    gui.pixel(5+x, 5+y, "#D030D0")
    gui.line(3+x, 6+y, 4+x, 6+y, "#D030D0")
end

function DrawLarge(x, y)    -- displays a large health drop
    gui.line(2+x, y, 5+x, y, "#D030D0")
    gui.pixel(1+x, 1+y, "#D030D0")
    gui.pixel(6+x, 1+y, "#D030D0")
    gui.line(x, 2+y, x, 5+y, "#D030D0")
    gui.line(3+x, 2+y, 4+x, 2+y, "#D030D0")
    gui.line(2+x, 3+y, 2+x, 4+y, "#D030D0")
    gui.line(5+x, 3+y, 5+x, 4+y, "#D030D0")
    gui.line(3+x, 5+y, 4+x, 5+y, "#D030D0")
    gui.line(7+x, 2+y, 7+x, 5+y, "#D030D0")
    gui.pixel(1+x, 6+y, "#D030D0")
    gui.pixel(6+x, 6+y, "#D030D0")
    gui.line(2+x, 7+y, 5+x, 7+y, "#D030D0")
end

function DrawMissile(x, y)  -- displays a missile drop
    gui.box(3+x, y, 4+x, 1+y, "#D030D0")
    gui.box(3+x, 2+y, 4+x, 4+y, "#A0A0A0")
    gui.line(2+x, 5+y, 5+x, 5+y, "#A0A0A0")
    gui.box(1+x, 6+y, 6+x, 7+y, "#A0A0A0")
end

function DrawSuper(x, y)    -- displays a super missile drop
    gui.line(2+x, y, 5+x, y, "#30D030")
    gui.line(1+x, 1+y, 6+x, 1+y, "#30D030")
    gui.box(1+x, 2+y, 6+x, 4+y, "#A0A0A0")
    gui.box(2+x, 5+y, 5+x, 6+y, "#A0A0A0")
    gui.line(3+x, 7+y, 4+x, 7+y, "#A0A0A0")
end

function DrawBomb(x, y)     -- displays a power bomb drop
    gui.line(2+x, 1+y, 5+x, 1+y, "#A0A0A0")
    gui.line(1+x, 2+y, 1+x, 5+y, "#A0A0A0")
    gui.line(2+x, 2+y, 2+x, 5+y, "#D030D0")
    gui.line(3+x, 2+y, 4+x, 2+y, "white")
    gui.box(3+x, 3+y, 4+x, 4+y, "#A0A0A0")
    gui.line(3+x, 5+y, 4+x, 5+y, "white")
    gui.line(5+x, 2+y, 5+x, 5+y, "#D030D0")
    gui.line(6+x, 2+y, 6+x, 5+y, "#A0A0A0")
    gui.line(2+x, 6+y, 5+x, 6+y, "#A0A0A0")
end

function DrawPause(x, y)        -- displays a pause sign
    local color = "#000000A0"
    if(pause) then
        color = "#00FFFFFF"
    end

    gui.box(  x, y-1, x+7, y+8, color)
    gui.box(2+x, 1+y, 2+x, 6+y, "white")
    gui.box(5+x, 1+y, 5+x, 6+y, "white")
end

function DrawArrow(x, y)    -- displays an arrow
    gui.line(10+x, 4+y, 16+x, 4+y, "red")
    gui.line(9+x, 4+y, 12+x, 1+y, "red")
    gui.line(9+x, 4+y, 12+x, 7+y, "red")
end

function DrawMenu()
    local x = 10
    local y = 10

    DrawDrop(Small, x, y, (neededDrop == Small))
    DrawDrop(Large, x+10, y, (neededDrop == Large))
    DrawDrop(Missile, x+20, y, (neededDrop == Missile))
    DrawDrop(Super, x+30, y, (neededDrop == Super))
    DrawDrop(Bomb, x+40, y, (neededDrop == Bomb))
    DrawPause(x+50, y)
end

function PerformMenu(mouseX, mouseY)
    local hit = false

    local x = 14
    local y = 14

    local selectedDrop = None

    if math.abs(mouseX - x) < 4 and math.abs(mouseY - y) < 4 then
        selectedDrop = Small
        hit = true
    end

    if math.abs(mouseX - (x + 10)) < 4 and math.abs(mouseY - y) < 4 then
        selectedDrop = Large
        hit = true
    end

    if math.abs(mouseX - (x + 20)) < 4 and math.abs(mouseY - y) < 4 then
        selectedDrop = Missile
        hit = true
    end

    if math.abs(mouseX - (x + 30)) < 4 and math.abs(mouseY - y) < 4 then
        selectedDrop = Super
        hit = true
    end

    if math.abs(mouseX - (x + 40)) < 4 and math.abs(mouseY - y) < 4 then
        selectedDrop = Bomb
        hit = true
    end

    --Pause
    if math.abs(mouseX - (x + 50)) < 4 and math.abs(mouseY - y) < 4 then
        pause = (pause == false)
        hit = true
    end

    if selectedDrop ~= None then
        if neededDrop == selectedDrop then
            neededDrop = None
        else
            neededDrop = selectedDrop
        end
    end

    return hit
end

function DrawDrop(dropType, posX, posY, highlight)
    local color = "#000000A0"
    if(highlight) then
        color = "#FFFF00FF"
    end

    gui.box(posX, posY-1, posX+7, posY+8, color, color)
    if dropType == Bomb then
        DrawBomb(posX, posY)
    elseif dropType == Super then
        DrawSuper(posX, posY)
    elseif dropType == Missile then
        DrawMissile(posX, posY)
    elseif dropType == Large then
        DrawLarge(posX, posY)
    elseif dropType == Small then
        DrawSmall(posX, posY)
    else
        DrawNone(posX, posY)
    end
end

function GetDrop(enID, enProp, dropRN)

    -- get necessary values
    local maxHealth = memory.readword(0x3001530)
    local maxMissiles = memory.readbyte(0x3001532)
    local maxSupers = memory.readbyte(0x3001534)
    local maxBombs = memory.readbyte(0x3001535)

    local currHealth = memory.readword(0x3001536)
    local currMissiles = memory.readbyte(0x3001538)
    local currSupers = memory.readbyte(0x300153A)
    local currBombs = memory.readbyte(0x300153B)
    local fullHealth = (currHealth == maxHealth)

    -- get drop rates
    local offset
    if enProp < 0x80 then
        offset = 0x82B0D70 + (enID * 18)
    else
        offset = 0x82B1BEC + (enID * 18)
    end

    local cmpBomb = 1024 - memory.readword(offset + 8)
    local cmpSuper = cmpBomb - memory.readword(offset + 6)
    local cmpMissile = cmpSuper - memory.readword(offset + 4)
    local cmpLarge = cmpMissile - memory.readword(offset + 2)
    local cmpSmall = cmpLarge - memory.readword(offset)

    if dropRN > cmpBomb then
        if maxBombs > currBombs then
            return Bomb
        elseif fullHealth == false then
            return Large
        elseif maxBombs == 0 then
            return Small
        else
            return Bomb
        end
    elseif dropRN > cmpSuper then
        if maxSupers > currSupers then
            return Super
        elseif fullHealth == false then
            return Large
        elseif maxSupers == 0 then
            return Small
        else
            return Super
        end
    elseif dropRN > cmpMissile then
        if maxMissiles > currMissiles then
            return Missile
        elseif fullHealth == false then
            return Large
        elseif maxMissiles == 0 then
            return Small
        else
            return Missile
        end
    elseif dropRN > cmpLarge then
        if fullHealth == false then
            return Large
        elseif maxMissiles > currMissiles then
            return Missile
        else
            return Large
        end
    elseif dropRN > cmpSmall then
        if fullHealth == false then
            return Small
        elseif maxMissiles > currMissiles then
            return Missile
        else
            return Small
        end
    else
        return None
    end
end

while true do

    -- get necessary values
    local frame1 = (memory.readbyte(0x3000C77) + 1) % 256
    local frame2 = (memory.readword(0x3000002) + 1) % 65536

    local cameraX, cameraY = memory.readword(0x30013B8), memory.readword(0x30013BA)

    --Check mouse status
    local nowClick = input.get()["leftclick"]

    local mouseX
    local mouseY
    local clicked = (nowClick and prevClick ~= true)

    prevClick = nowClick

    if clicked then
        mouseX = input.get()["xmouse"]
        mouseY = input.get()["ymouse"]
        if(PerformMenu(mouseX, mouseY)) then
            clicked = false
        end
    end


    --Display Enemy Info
    for i=0,23 do
        local status = memory.readbyte(0x30001AC + i*56)
        local enID = memory.readbyte(0x30001C9 + i*56)
        local enProp = memory.readbyte(0x30001DE + i*56)

        -- handle second part of metroids
        local isMetroid = (enID == 26 and enProp >= 0x80)
        if isMetroid then
            enID = 101
            enProp = 0
        end

        local dropNone
        if enProp < 0x80 then
            dropNone = memory.readword(0x82B0D6E + (enID * 18))
        else
            dropNone = memory.readword(0x82B1BEA + (enID * 18))
        end

        if status > 0 and dropNone < 0x400 then
            -- update enemy's past/current health
            local pastHealth = enHealth[i+1]
            local enemyHealth = memory.readword(0x30001C0 + i*56)
            enHealth[i+1] = enemyHealth

            local enemyX, enemyY = memory.readword(0x30001B0 + i*56), memory.readword(0x30001AE + i*56)
            local posX, posY = bit.arshift(enemyX - cameraX, 2), bit.arshift(enemyY - cameraY, 2)

            if isMetroid then
                posX = posX - 10
            end

            --Select Enemy
            if clicked and math.abs(mouseX - posX) < clickBoxSize and math.abs(mouseY - posY) < clickBoxSize then
                if chosenEnemyIndex == i then
                    chosenEnemyIndex = -1
                else
                    chosenEnemyIndex = i
                end
            end

            --draw enemy highlight
            if chosenEnemyIndex == i then
                DrawHighlight(posX, posY)
            end

            --draw enemy modPos
            if not isMetroid then
                gui.text(posX, posY+8, (enemyX + enemyY) % 32, "#E04040")
            end

            --Calculate drop RNG and draw drop
            local enRN = rns[((frame1 + bit.rshift(frame2, 4) + i + enemyX + enemyY) % 32) + 1]
            local dropRN = (frame1 + frame2 + enRN*256) % 1024
            if dropRN == 0 then
                dropRN = 1
            end

            DrawDrop(GetDrop(enID, enProp, dropRN), posX, posY)

            -- draw arrow to indicate drop
            if pastHealth ~= enemyHealth and enemyHealth == 0 then
                DrawArrow(posX, posY)
            end

            --Find viable position for chosen enemy and droptype
            if(i == chosenEnemyIndex) then

                acceptedRNs = {}

                local modVal = ((frame1 + bit.rshift(frame2, 4) + chosenEnemyIndex) % 32) + 1

                --Find indexes in rn list that would yield desired result
                for i=1,#rns do
                    local dropRN = (frame1 + frame2 + rns[i]*256) % 1024
                    if dropRN == 0 then
                        dropRN = 1
                    end

                    if GetDrop(enID, enProp, dropRN) == neededDrop then
                        table.insert(acceptedRNs, (i - modVal) % 32)
                    end
                end

                --Figure out and print required modPos for viable index to occur
                if(#acceptedRNs > 0) then
                    local concatString = ""

                    local count = 0
                    table.sort(acceptedRNs)
                    for key, val in ipairs(acceptedRNs) do
                        concatString = concatString .. val .. " "
                        count = count + 1
                        if(count > 7) then
                            concatString = concatString .. "\n"
                            count = 0
                        end
                    end

                    gui.text(posX, posY+16, concatString, "#40E040")

                    if(pause == true) then
                        vba.pause()
                    end
                end
            end
        end
    end

    DrawMenu();

    vba.frameadvance()
end