install-mod.lua

--installs a modpack
-- args: modpack_name [-i|install|-if] [-u|uninstall] [entity_to_patch]

args={...}
if args[1]==nil or #args<2 then
    print("Usage: modpack_name [-i|install|-if] [-u|uninstall] [entity_to_patch]")
end
local modPath=dfhack.getDFPath()..'/mods/'..args[1]..'/'
local dfMod=dofile(modPath..'init.lua')
local name=dfMod.name
local guard={">>"..name.." patch","<<End "..name.." patch"}
local guard_init={"--"..guard[1],"--"..guard[2]}
local entity_file=dfhack.getDFPath().."/raw/objects/entity_default.txt"
local init_file=dfhack.getDFPath().."/raw/init.lua"
function fileExists(filename)
	local file=io.open(filename,"rb")
	if file==nil then
		return
	else
		file:close()
	end
end
function copyFile(from,to) --oh so primitive
    local filefrom=io.open(from,"rb")
    local fileto=io.open(to,"w+b")
    local buf=filefrom:read("*a")
    printall(buf)
    fileto:write(buf)
    filefrom:close()
    fileto:close()
end
function patchInit(initFileName,patch_guard,code)
	local initFile=io.open(initFileName,"a")
	initFile:write(string.format("%s\n%s\n%s",patch_guard[1],
		code,patch_guard[2]))
	initFile:close()
end
function patchEntity(file_name,patch_guard,entity_name,code)
    local input_lines=patch_guard[1].."\n"..code.."\n"..patch_guard[2]
    
    local badchars="[%:%[%]]"
    local find_string=entity_name:gsub(badchars,"%%%1") --escape some bad chars
	
    local entityFile=io.open(file_name,"r")
    local buf=entityFile:read("*all")
    entityFile:close()
    local entityFile=io.open(file_name,"w+")
    print("Patching:"..entity_name)
    buf=string.gsub(buf,find_string,entity_name.."\n"..input_lines)
    entityFile:write(buf)
    entityFile:close()
end
function findGuards(str,start,patch_guard)
	local pStart=string.find(str,patch_guard[1],start)
	if pStart==nil then return nil end
	local pEnd=string.find(str,patch_guard[2],pStart)
	if pEnd==nil then error("Start guard token found, but end was not found") end
	return pStart-1,pEnd+#patch_guard[2]+1
end
function findGuardsFile(filename,patch_guard)
	local file=io.open(filename,"r")
	local buf=file:read("*all")
	return findGuards(buf,1,patch_guard)
end
function unPatchFile(filename,patch_guard)
	local file=io.open(filename,"r")
	local buf=file:read("*all")
	file:close()
	
	local newBuf=""
	local pos=1
	local lastPos=1
	repeat 
		local endPos
		pos,endPos=findGuards(buf,lastPos,patch_guard)
		newBuf=newBuf..string.sub(buf,lastPos,pos)
		if endPos~=nil then
			lastPos=endPos
		end
	until pos==nil
	
	local file=io.open(filename,"w+")
	file:write(newBuf)
    file:close()
end
function checkInstalled() --try to figure out if installed
	if dfMod.checkInstalled then
		return dfMod.checkInstalled()
	else
		if dfMod.raws_list then
			for k,v in pairs(dfMod.raws_list) do
				if fileExists(dfhack.getDFPath().."/raw/objects/"..v) then
					return true
				end
			end
		end
		if dfMod.patch_entity then
			if findGuardsFile(entity_file,guard)~=nil then
				return true
			end
		end
		if dfMod.patch_init then
			if findGuardsFile(init_file,guard_init)~=nil then
				return true
			end
		end
	end
end
if args[2]=="install" or args[2]=="-i" or args[2]=="-if" then
	if args[2]~='-if' and checkInstalled() then
		qerror("Mod already installed.")
		return
	end
    if dfMod.pre_install then
        dfMod.pre_install(args)
    end
	if dfMod.raws_list then
		for k,v in pairs(dfMod.raws_list) do
			copyFile(modPath..v,dfhack.getDFPath().."/raw/objects/"..v)
		end
	end
	if dfMod.patch_entity then
		local entity_target
		if args[3]==nil then
			entity_target="[ENTITY:MOUNTAIN]"
		else
			entity_target="[ENTITY:"..args[3].."]" -- todo multiple entities
		end
		patchEntity(entity_file,guard,entity_target,dfMod.patch_entity)
	end
	if dfMod.patch_init then
		patchInit(init_file,guard_init,dfMod.patch_init)
	end
    
    if dfMod.post_install then
        dfMod.post_install(args)
    end
    
	return
elseif args[2]=="uninstall" or args[2]=="-u" then

	if dfMod.pre_uninstall then
        dfMod.pre_uninstall(args)
    end
    
	if dfMod.raws_list then
		for k,v in pairs(dfMod.raws_list) do
			os.remove(dfhack.getDFPath().."/raw/objects/"..v)
		end
	end
	if dfMod.patch_entity then
		unPatchFile(entity_file,guard)
	end
	if dfMod.patch_init then
		unPatchFile(init_file,guard_init)
	end
	if dfMod.post_uninstall then
        dfMod.post_uninstall(args)
    end
	return
end