local bsh = {}
local component = require("component")
local computer = require("computer")
local event = {}

function event.pull(name, timeout)
    local rawSignal = {}
    local signals_recieved_in_mean_time = {}
    local timeouts = 0
    if not timeout then
        timeout = 99999999999
    end

    while rawSignal[1] ~= name do
        -- pull any signal
        rawSignal = table.pack(computer.pullSignal(0.1))

        -- if no signal then add to time timeout
        if rawSignal[1] == nil then
            timeouts = timeouts + 0.1
        else
            if rawSignal[1] ~= name then
                -- not the signal, push to the signals we got in the mean time
                table.insert(signals_recieved_in_mean_time,rawSignal)
            else
                -- got the signal
                break
            end
        end
        if timeouts >= timeout then
            -- we never got the signal :(
            return nil
        end
    end

    -- rethrow all signals... they weren't what we wanted
    if #signals_recieved_in_mean_time > 0 then
        for i in ipairs(signals_recieved_in_mean_time) do
            computer.pushSignal(table.unpack(signals_recieved_in_mean_time[i]))
        end
    end

    return table.unpack(rawSignal)
end

-- BUG: when in /bin directory, running something tries to run /binhello.lua
-- FEAT: autofill slashes, and .lua
-- FEAT: handle ..

bsh.running = true

local function keyin()
    while true do
        local _,_,letterAsciiCode,_,_ = event.pull("key_down")
        return letterAsciiCode
    end
end

function Align(String,Number,append)
    if not append then
        append = " "
    end
    if #String > Number then
        while #String > Number do
            String = String:sub(1, -2)
        end
        String = String:sub(1, -5) .. "..."
    end
    if #String < Number then
        while #String < Number do
            String = String .. append
        end
    end

    return String
end

function bsh.command(buffer)
    local command = Split(buffer)
    if command[1] == "ls" then
        for i = 1, #Filetable do
            print(
                string.format("%s   off %sb    size%s(*512)\r\n",
                Align(Filetable[i]["name"],16),
                Align(tostring(Filetable[i]["offset"]),8),
                Align(tostring(Filetable[i]["size"]),2)))
        end
    elseif command[1] == "clear" then
        clearscr()
        screen_x = 2
        screen_y = 1
    elseif command[1] == "exit" then
        bsh.running = false
    else
        local file, err = loadfile(command[1])

        if file == nil then
            print("error while loading"  .. tostring(err))
            return
        end

        local success, result = pcall(file, command)
        if not success then
            print(result.."\r\n")
        end
    end
end

local function prompt()
    print(cwd .." #> ")
end

if _G.cwd == nil then
    _G.cwd = "/"
end

print("bsh v2.1\r\n")

local buffer = ""

prompt()

while bsh.running do
    local nextkeycode = keyin()
    if nextkeycode == nil then
        nextkeycode = 0
    end
    local nextkey = string.char(nextkeycode)
    if nextkeycode == 13 then
        print("\r\n")
        local success, reason = pcall(bsh.command, buffer)
        if not success then
            print(reason)
        end
        buffer = ""
        nextkeycode = nil
        print("\r\n")
        if _G.PROCESS_RUNNER then
            coroutine.yield()
        end
        prompt()
    elseif nextkeycode == 8 then
        if #buffer ~= 0 then
            buffer = buffer:sub(1, -2)
            screen_x = screen_x - 1
            print(" ")
            screen_x = screen_x - 1
        end
    elseif nextkeycode == 16 then
        -- ignore.
    else
        buffer = buffer .. nextkey
        print(nextkey)
    end
end