-- this outputs some information related to the map loading procedure when the screen scrolls,
-- hopefully helpful for researching and recreating the scroll bug
-- script by mugg ; with help from ais523, Sand

console.clear()
memory.usememorydomain("System Bus")

local cycles_at_frame_start = emu.totalexecutedcycles()
local cycles_at_frame_end = emu.totalexecutedcycles()
local print_after_this_frame = emu.framecount() + 1
local game_version = "-"
local t = ""

if gameinfo.getromhash() == "3A4DDB39B234A67FFB361EE7ABC3D23E0A8B1C89" then
    game_version = "1.0"
elseif gameinfo.getromhash() == "418203621B887CAA090215D97E3F509B79AFFD3E" then
    game_version = "1.1"
else
    print("This script will work only with GB Super Mario Land v1.0 or v1.1.")
    return
end

function text(x, y, text, color, backcolor)
    gui.pixelText(x, y, text, color, backcolor)
end

event.onframestart(function()
    cycles_at_frame_start = emu.totalexecutedcycles()
end)

event.onframeend(function()
    if emu.framecount() > print_after_this_frame then
        t = t .. "\nCycles this frame: " .. emu.totalexecutedcycles() - cycles_at_frame_end
    end
    if emu.islagged() then
        t = t .. "\n*** LAG ***"
    end

    cycles_at_frame_end = emu.totalexecutedcycles()
    t = t .. "\n\n----- Frame " .. emu.framecount() + 1 .. " -----"

    print(t)
    t = ""

    loadedstate = false
end)

tastudio.onbranchload(function()
    print_after_this_frame = emu.framecount() + 1
    console.clear()
end)

event.onloadstate(function()
    print_after_this_frame = emu.framecount() + 1
    console.clear()
end)

-- Write to $FFEA
-- passed val is always 0, it seems, hinting that this hook is not fully implemented
event.on_bus_write(function(addr, val, flags)
    if emu.framecount() > print_after_this_frame then
        local val = string.upper(string.format("%02x",memory.read_u8(0xFFEA)))
        t = t .. "\nWrite $FFEA (" .. val .. ") - current cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
    end
end, 0xFFEA)

-- Exec $0040
event.on_bus_exec(function(addr, val, flags)
    if emu.framecount() > print_after_this_frame then
        t = t .. "\nExecu $0040 (VBLANK) - current cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
    end
end, 0x0040)

-- game version dependent execs
if game_version == "1.0" then

    event.on_bus_exec(function(addr, val, flags)
        if emu.framecount() > print_after_this_frame then
            t = t .. "\nExecu $2258 (READ $FFEA) - current cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
        end
    end, 0x224F)

    event.on_bus_exec(function(addr, val, flags)
        if emu.framecount() > print_after_this_frame then
            t = t .. "\nExecu $2254 (READ $FFE9) - current cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
        end
    end, 0x2254)

elseif game_version == "1.1" then

    event.on_bus_exec(function(addr, val, flags)
        if emu.framecount() > print_after_this_frame then
            t = t .. "\nExecu $2258 (READ $FFEA) - current cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
        end
    end, 0x2258)

    event.on_bus_exec(function(addr, val, flags)
        if emu.framecount() > print_after_this_frame then
            t = t .. "\nExecu $225D (READ $FFE9) - current cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
        end
    end, 0x225D)

end

--[[
Read hook seems broken, maybe I should be using execution from ROM instead.

-- Read $FFEA
event.on_bus_read(function(addr, val, flags)
    if emu.framecount() > print_after_this_frame then
        local val = string.upper(string.format("%02x",memory.read_u8(0xFFEA)))
        print("Read $FFEA (" .. val .. ") - current cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start)
    end
end, 0xFFEA)

-- Read $FFE9
event.on_bus_read(function(addr, val, flags)
    if emu.framecount() > print_after_this_frame then
        local val = string.upper(string.format("%02x",memory.read_u8(0xFFE9)))
        print("Read $FFE9 (" .. val .. ") - current cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start)
    end
end, 0xFFE9)
]]

while true do
    emu.frameadvance()
end