local display_solution = false
local auto_solve = true


--beware
--lots of spaghetti code follows below this line

local pic_data = {{}}
local pic_size_x
local pic_size_y
local base_x = {[5] = 139, [10] = 121, [15] = 104, [20] = 87, [25] = 69}
local base_y = {[5] = 123, [10] = 105, [15] = 88, [20] = 71, [25] = 71}
local drop_nth_frame_per_level_id = {[105]=50, [108] = 150, [118] = 20, [119] = 220, [126] = 10, [130] = 200, [225] = 60, [255] = 33, [264]= 140, [279] = 255, [284] = 200}
local box_size = 7
local frame_delay = 1
local x_pos = 0
local y_pos = 0
local status
local pic_done
local need_read = true
local read_now = false
local marked = false
local prev_right = false
local prev_left = false
local prev_up = false
local prev_down = false
local prev_A = false
local prev_Y = false
local prev_A2 = false
local prev_Y2 = false
local course_corrected = false
local sol_frame = 0
local solve_done = false
local moved = false
local to_move_down = 2
local level_id = -1


gui.transparency(2)

function draw_gui()
    if need_read == false and display_solution then
        for i=0,pic_size_x do
            for j=0,pic_size_y do
                if pic_data[i][j] % 2 == 1 then
                    local x = base_x[pic_size_x]+box_size*i
                    local y = base_y[pic_size_x]+box_size*j
                    gui.drawbox(x,y,x+box_size,y+box_size,"#cccc00","#ffff00")
                end
            end
        end
    end
end
gui.register(draw_gui)


while true do
    pic_done = memory.readbyte(0x7e0037) --done if 3, fade if 0
    status = memory.readbyte(0x7e119e)
    if status == 4 and need_read and pic_done ~= 0 then
        read_now = true
    else
        read_now = false
    end
    if status ~= 4 or pic_done == 0 then
        need_read = true
    end
    if need_read == true and read_now == true then
        pic_size_x = memory.readbyte(0x7e1110)
        pic_size_y = memory.readbyte(0x7e1112)
        level_id = memory.readword(0x7e0e46)

        for i=0,pic_size_x do
            for j=0,pic_size_y do
                if pic_data[i] == nil then
                    pic_data[i] = {}
                end
                pic_data[i][j] = memory.readbyte(0x7e1234+i+j*0x20)

            end
        end
        need_read = false
        wait_frames = frame_delay
        sol_frame = 0
        x_pos = memory.readbyte(0x7e11d2)
        y_pos = memory.readbyte(0x7e11d6)
        --x_pos = 0
        --y_pos = 0
        prev_left = false
        prev_right = false
        prev_A = false
        prev_Y = false
        solve_done = false
        course_corrected = false
        to_move_down = 1
    end
    if need_read == false and solve_done == false and auto_solve == true then
        if wait_frames == frame_delay and (x_pos ~= 0 or y_pos ~=0) then
            local but = {}
            if x_pos ~= 0 then
                but["left"] = true
                x_pos = x_pos - 1
            end
            if y_pos ~= 0 then
                but["up"] = true
                y_pos = y_pos - 1
            end
            joypad.set(1,but)
            wait_frames = frame_delay + 2
        end
        if wait_frames == 1 then
            local buttons3 = {}
            buttons3["L"] = true
            joypad.set(2,buttons3)
        end
        if wait_frames <= 0 then
            local buttons = {}
            local buttons2 = {}
            if sol_frame == 0 then
                if pic_data[x_pos][y_pos] % 4 == 1 then
                    buttons["A"] = true
                    prev_A = true
                end
                if pic_data[pic_size_x-1-x_pos][pic_size_y-1-y_pos] % 4 == 1 then
                    buttons2["A"] = true
                    prev_A2 = true
                end
            elseif drop_nth_frame_per_level_id[level_id] ~= sol_frame then
                moved = true
                local dir = (math.floor(y_pos/2)%2-0.5)*(-2)
                if prev_left == false and prev_right == false then
                    if x_pos == pic_size_x - 1 or x_pos == 0 then
                        if y_pos < pic_size_y/2 then
                            if prev_down == true then
                                if to_move_down == -1 then
                                    if (y_pos == math.floor(pic_size_y/2) - 2 and pic_size_y == 10) or y_pos == math.floor(pic_size_y/2) - 1 then
                                        to_move_down = 1
                                    else
                                        to_move_down = 2
                                    end
                                end
                                if to_move_down == 0 then
                                    prev_down = false
                                    if dir > 0 then
                                        buttons["right"] = true
                                        prev_right = true
                                        prev_left = false
                                    else
                                        buttons["left"] = true
                                        prev_left = true
                                        prev_right = false
                                    end
                                    x_pos = x_pos + dir
                                    to_move_down = -1
                                else
                                    moved = false
                                    prev_down = false
                                end
                            else
                                buttons["down"] = true
                                prev_down = true
                                course_corrected = false
                                y_pos = y_pos + 1
                                to_move_down = to_move_down - 1
                            end
                        else
                            solve_done = true
                        end
                    else
                        if dir > 0 then
                            buttons["right"] = true
                            prev_right = true
                            prev_left = false
                        else
                            buttons["left"] = true
                            prev_left = true
                            prev_right = false
                        end
                        if course_corrected == false and pic_size_x %2 == 0 and not (pic_size_y / 2 == y_pos + 1) then
                            if prev_up == true then
                                buttons["down"] = true
                                prev_down = true
                                prev_up = false
                                y_pos = y_pos + 1
                            else
                                buttons["up"] = true
                                prev_up = true
                                prev_down = false
                                y_pos = y_pos - 1
                            end
                            course_corrected = true
                        else
                            prev_up = false
                            prev_down = false
                        end
                        x_pos = x_pos + dir
                    end
                else
                    prev_up = false
                    prev_left = false
                    prev_right = false
                    prev_down = false
                    if not (pic_size_y == 10 and y_pos + 1 == pic_size_y / 2) and not (pic_size_y == 5 and y_pos == math.floor(pic_size_y/2)) then
                        if y_pos % 2 == 0  then
                            buttons["down"] = true
                            prev_down = true
                            y_pos = y_pos + 1
                        else
                            buttons["up"] = true
                            prev_up = true
                            y_pos = y_pos - 1
                        end
                    else
                        prev_up = true
                        moved = false
                    end
                end

                if buttons["left"] == true then
                    buttons2["right"] = true
                end
                if buttons["right"] == true then
                    buttons2["left"] = true
                end
                if buttons["up"] == true then
                    buttons2["down"] = true
                end
                if buttons["down"] == true then
                    buttons2["up"] = true
                end
                --print(x_pos,y_pos, " ",pic_size_x-1-x_pos,pic_size_y-1-y_pos)

                if moved == true and pic_data[x_pos][y_pos] % 4 == 1 then
                    if prev_A then
                        buttons["Y"] = true
                        prev_Y = true
                        prev_A = false
                    else
                        buttons["A"] = true
                        prev_A = true
                        prev_Y = false
                    end
                else
                    prev_A = false
                    prev_Y = false
                end
                local spaghetti_code_y_pos = y_pos
                local spaghetti_code_moved = moved
                if (pic_size_y == 15 and y_pos + 2 > math.floor(pic_size_y/2)) then
                    if (buttons["up"] == true or buttons["down"] == true) and to_move_down ~= 0 then
                        buttons2["down"] = nil
                        buttons2["up"] = nil
                        spaghetti_code_moved = false
                    end
                    spaghetti_code_y_pos = 6
                end
                if spaghetti_code_moved == true and pic_data[pic_size_x-1-x_pos][pic_size_y-1-spaghetti_code_y_pos] % 4 == 1 then
                    if prev_A2 then
                        buttons2["Y"] = true
                        prev_Y2 = true
                        prev_A2 = false
                    else
                        buttons2["A"] = true
                        prev_Y2 = false
                        prev_A2 = true
                    end
                else
                    prev_A2 = false
                    prev_Y2 = false
                end
            end
            sol_frame = sol_frame + 1
            joypad.set(1,buttons)
            joypad.set(2,buttons2)
        else
            wait_frames = wait_frames - 1
        end
    end
    snes9x.frameadvance()
end