shell

local sUserStartup = false
-- FORMAT FOR BIOS.LUA/OS MAKING:
-- #*path of OS startup INSIDE OF DISK (don't add disk/)*
-- *anything here will be ignored*
-- *insert ur code here*


local parentShell = shell

local bExit = false
local sDir = (parentShell and parentShell.dir()) or ""
local sPath = (parentShell and parentShell.path()) or ".:/rom/programs"
local tAliases = (parentShell and parentShell.aliases()) or {}
local tProgramStack = {}

local shell = {}
local tEnv = {
	["shell"] = shell,
}

-- Install shell API
function shell.run( _sCommand, ... )
	local sPath = shell.resolveProgram( _sCommand )
	if sPath ~= nil then
		tProgramStack[#tProgramStack + 1] = sPath
   		local result = os.run( tEnv, sPath, ... )
		tProgramStack[#tProgramStack] = nil
		return result
   	else
    	print( "No such program" )
    	return false
    end
end

function shell.exit()
    bExit = true
end

function shell.dir()
	return sDir
end

function shell.setDir( _sDir )
	sDir = _sDir
end

function shell.path()
	return sPath
end

function shell.setPath( _sPath )
	sPath = _sPath
end

function shell.resolve( _sPath )
	local sStartChar = string.sub( _sPath, 1, 1 )
	if sStartChar == "/" or sStartChar == "\\" then
		return fs.combine( "", _sPath )
	else
		return fs.combine( sDir, _sPath )
	end
end

function shell.resolveProgram( _sCommand )
	-- Substitute aliases firsts
	if tAliases[ _sCommand ] ~= nil then
		_sCommand = tAliases[ _sCommand ]
	end

    -- If the path is a global path, use it directly
    local sStartChar = string.sub( _sCommand, 1, 1 )
    if sStartChar == "/" or sStartChar == "\\" then
    	local sPath = fs.combine( "", _sCommand )
    	if fs.exists( sPath ) and not fs.isDir( sPath ) then
			return sPath
    	end
		return nil
    end

 	-- Otherwise, look on the path variable
    for sPath in string.gmatch(sPath, "[^:]+") do
    	sPath = fs.combine( shell.resolve( sPath ), _sCommand )
    	if fs.exists( sPath ) and not fs.isDir( sPath ) then
			return sPath
    	end
    end

	-- Not found
	return nil
end

function shell.programs( _bIncludeHidden )
	local tItems = {}

	-- Add programs from the path
    for sPath in string.gmatch(sPath, "[^:]+") do
    	sPath = shell.resolve( sPath )
		if fs.isDir( sPath ) then
			local tList = fs.list( sPath )
			for n,sFile in pairs( tList ) do
				if not fs.isDir( fs.combine( sPath, sFile ) ) and
				   (_bIncludeHidden or string.sub( sFile, 1, 1 ) ~= ".") then
					tItems[ sFile ] = true
				end
			end
		end
    end

	-- Sort and return
	local tItemList = {}
	for sItem, b in pairs( tItems ) do
		table.insert( tItemList, sItem )
	end
	table.sort( tItemList )
	return tItemList
end

function shell.getRunningProgram()
	if #tProgramStack > 0 then
		return tProgramStack[#tProgramStack]
	end
	return nil
end

function shell.setAlias( _sCommand, _sProgram )
	tAliases[ _sCommand ] = _sProgram
end

function shell.clearAlias( _sCommand )
	tAliases[ _sCommand ] = nil
end

function shell.aliases()
	-- Add aliases
	local tCopy = {}
	for sAlias, sCommand in pairs( tAliases ) do
		tCopy[sAlias] = sCommand
	end
	return tCopy
end

-- Attempt to boot the disks bios.
for n,sSide in pairs( redstone.getSides() ) do
	if disk.isPresent( sSide ) and disk.hasData( sSide ) then
		sDiskStartup = fs.exists( "disk/bios.lua" )
		if sDiskStartup then
			sUserStartup = true
			break
		end
	end
end

if sUserStartup then
	local tLines = {}
	local file = io.open("disk/bios.lua", "r")
	local line
	while true do
		line = file:read()
		if not line then break end
		tLines[#tLines+1] = line
	end
	file:close()
	if string.find( tLines[1], "#" ) then
		sUserStartup = string.sub( tLines[1], 2, string.len( tLines[1] ) )
		fs.delete("disk/.bios.lua.CNFG")
		local file2 = fs.open("disk/.bios.lua.CNFG", "w")
		for i = 3, #tLines do
			file2.writeLine(tLines[i])
		end
		file2:close()
		shell.run( "disk/.bios.lua.CNFG" )
		shell.run( "disk/" ..sUserStartup )
	else
		print( "unsuported/corrupted bios." )
		sleep(2)
		os.shutdown()
	end
else
	print( "bios undetected." )
	print( "Please insert a boot disk." )
	sleep(2)
	os.shutdown()
end