local bsh = {}
local component = require("component")
local computer = require("computer")
local event = require("event")
local fs = require("filesystem")
local package = require("package")
_G.ExecPath = "/sbin/?.lua;/bin/?.lua"

if fs.exists("/etc/motd") then
    local motd_h = fs.open("/etc/motd", "r")
    print(fs.read(motd_h))
    fs.close(motd_h)
end

print("\n")

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

bsh.running = true
local cwd = "/home/"

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

function bsh.split(str)
    local words = {}
    for word in str:gmatch("%S+") do
      table.insert(words, word)
    end
    return words
  end

function bsh.is_in_arr(arr,elem)
    for i in ipairs(arr) do
        if tostring(arr[i]) == tostring(elem) then
            return true
        end
    end

    return false
end

function bsh.command(buffer)
    if #buffer == 0 then
        return
    end
    local command = bsh.split(buffer)
    if command[1] == "ls" then
        local cwdls
        if command[2] == nil then
            cwdls = fs.getlisting(cwd)
        else
            cwdls = fs.getlisting(command[2])
        end
        if cwdls ~= nil then
            for i = 1, #cwdls do
                print(cwdls[i] .. "  ")
            end
        else
            print("(Nothing here!)")
        end
        print("\r\n")
    elseif command[1] == "cd" then
        if command[2] == nil then
            error("no argument")
        else
            cwd = command[2]
        end
    elseif command[1] == "clear" then
        local w,h=component.gpu.getResolution()
        component.gpu.fill(1,1,w,h," ")
        component.gpu.setCursor(2,1)
    elseif command[1] == "exit" then
        bsh.running = false
    else -- execute file, this sucks tho
        local location = command[1]
        local s,_ = pcall(fs.loadfile,location)
        -- is in cwd?
        if not s then
            if bsh.is_in_arr(fs.getlisting(cwd),command[1]) then
                location = cwd .. command[1]
            else
                -- no, check path
                local a = package.search(command[1],ExecPath)
                if a ~= false then
                    location = a
                else
                    error("command not found")
                end
            end
        end
        
        local a = fs.loadfile(location)
        a(command)
    end
end

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

print("bsh v3\n")

local buffer = ""
local gpu = component.gpu

prompt()

local cursor = "█"
local cursorOnOff = 1
local history = {}
local history_index = 1

while bsh.running do
    local nextkeycode, code = keyin()
    local charAtCurLocation = " "
    local cur = gpu.getCursor()
    --print(nextkeycode,"=",code," ")

    if nextkeycode == nil and code == nil then
        -- timeout reached, invert cursor
        cursorOnOff = cursorOnOff * -1
        if cursorOnOff == 1 then
            charAtCurLocation = gpu.get(cur.x,cur.y)
            gpu.set(cur.x,cur.y,cursor)
        else
            gpu.set(cur.x,cur.y,charAtCurLocation)
        end
    end

    if nextkeycode == 0 or nextkeycode == nil then
        local preBuffer=buffer
        if code == 42 then -- shift
            -- ignore
        elseif code == 200 then -- up
            if history[history_index] then
                buffer = history[history_index]
                history_index = history_index - 1
                gpu.setCursor(1)
                prompt()
                for i=1,#preBuffer do print(" ") end 
                gpu.setCursor(1)
                prompt()
                print(buffer)
            end
        elseif code == 208 then -- down
            if history[history_index+1] then
                history_index = history_index + 2
                buffer = history[history_index]
                gpu.setCursor(1)
                prompt()
                for i=1,#preBuffer do print(" ") end 
                gpu.setCursor(1)
                prompt()
                print(buffer)
            end
        end
    else
        gpu.set(cur.x,cur.y,charAtCurLocation)
        local nextkey = string.char(nextkeycode)

        if nextkeycode == 13 then --enter
            table.insert(history, buffer)
            history_index = #history
            if cursorOnOff ~= 1 then
                gpu.set(cur.x,cur.y,charAtCurLocation)
            end
            print("\n")
            local success, reason = xpcall(bsh.command, function(a)
                return {a, debug.traceback()}
            end, buffer)
            
            if not success then
                if reason then
                    print(reason[1].."\n\n")
                    component.gpu.setForeground(0xff3333)
                    print(reason[2])
                    component.gpu.setForeground(0xffffff)
                end
            end

            buffer = ""
            nextkeycode = nil
            print("\n")
            prompt()
        elseif nextkeycode == 8 then --backsp
            if #buffer ~= 0 then
                buffer = buffer:sub(1, -2)
                gpu.moveCursor(-1)
                print(" ")
                gpu.moveCursor(-1)
            end
        else
            buffer = buffer .. nextkey
            print(nextkey)
        end
    end
end