depends.lua

-- depends.lua v0.1
--     by dlord


CONFIG = {
    DEPENDENCIES_LOCATION = "/lib",
    DEPENDENCIES = {},
    STARTUP = ""
}
local CONFIG_FILE = "dependencies_conf"

local CONFIG_TEMPLATE = [[-- dependencies_conf
-- Configuration file for the depends api helper.
-- You will need to provide a table of keys
-- containing the API names, and their respective
-- pastebin code.
DEPENDENCIES_LOCATION = "${DEPENDENCIES_LOCATION}"

DEPENDENCIES = ${DEPENDENCIES}

-- One of the dependencies can be set to run on startup.
STARTUP = "${STARTUP}"
]]

local function interpolate(s, params)
    return s:gsub('($%b{})', function(w) return params[w:sub(3, -2)] or w end)
end

local function saveConfig(config)
    if config == nil then
        config = depends.CONFIG or CONFIG
    end
    local h = fs.open("/"..CONFIG_FILE, "w")
    local configToSave = {
        DEPENDENCIES_LOCATION = config.DEPENDENCIES_LOCATION or "/lib",
        DEPENDENCIES = textutils.serialize(config.DEPENDENCIES or {}),
        STARTUP = config.STARTUP
    }

    h.write(interpolate(CONFIG_TEMPLATE, configToSave))
    h.close()
end

local function downloadFromPastebin(pastebinKey, path)
    if fs.exists(path) then
        print(path.." already exists.")
        print("If you are sure that you want to download a copy of this file, delete the existing one first, and try again.")
        error()
    end

    print("Retrieving from pastebin: "..pastebinKey)
    shell.run("pastebin", "get", pastebinKey, path)

    if fs.exists(path) == false then
        print("Unable to retrieve "..pastebinKey.." from pastebin.")
        print("Check your connection, and try again.")
        error()
    end
end

local function uploadDependencies()
    -- copy the existing dependencies, as we will mutate it.
    local dependencies = {}
    for k, v in pairs(depends.CONFIG.DEPENDENCIES) do
        dependencies[k] = v
    end

    for k, v in pairs(dependencies) do
        if v == "" then
            print("Uploading "..k)

            local h = fs.open(fs.combine(depends.CONFIG.DEPENDENCIES_LOCATION, k), "r")
            local text = h.readAll()
            h.close()

            local apiKey = "0ec2eb25b6166c0c27a394ae118ad829"
            local response = http.post(
                "http://pastebin.com/api/api_post.php",
                "api_option=paste&"..
                "api_dev_key="..apiKey.."&"..
                "api_paste_format=lua&"..
                "api_paste_name="..textutils.urlEncode(k).."&"..
                "api_paste_code="..textutils.urlEncode(text)
            )

            if response then
                local responseString = response.readAll()
                response.close()

                local pastebinKey = string.match(responseString, "[^/]+$")

                if pastebinKey == "Post limit, maximum pastes per 24h reached" then
                    print("You have reached pastebin's post limits. Try again later, or use the web interface.")
                    error()
                end

                depends.CONFIG.DEPENDENCIES[k] = pastebinKey
                saveConfig(depends.CONFIG)
            else
                print("Failed to upload "..k..". Check your internet connection, and try again.")
                error()
            end
        end
    end
end

-- main functions of depends.lua
reload = function(configFile)
    local configToLoad = configFile or CONFIG_FILE
    os.unloadAPI(configToLoad)

    if os.loadAPI("/"..configToLoad) == false then
        error("Could not load the config file!")
    end

    depends.CONFIG = getfenv(0)[configToLoad]

    if depends.CONFIG == nil then
        print("I could not find the necessary config.")
        print("You probably screwed something up.")
        error()
    end
end

on = function(name, pastebinKey)
    local dependencyPath = depends.CONFIG.DEPENDENCIES_LOCATION.."/"..name
    local isAvailable, key = depends.check(name, pastebinKey)

    os.unloadAPI(name)

    if isAvailable == false then
        print(name.." not found. Attempting to download from pastebin: "..key)

        if depends.download(name, key) then
            isAvailable = true
        end
    end

    if isAvailable then
        if depends.CONFIG.DEPENDENCIES[name] == nil then
            depends.CONFIG.DEPENDENCIES[name] = key or ""
            saveConfig(depends.CONFIG)
        end

        os.loadAPI(dependencyPath)
    end
end

check = function(name, pastebinKey)
    if name == "depends" then
        error("depends is a reserved name.")
    end
    depends.reload()

    local dependencyPath = depends.CONFIG.DEPENDENCIES_LOCATION.."/"..name
    local isAvailable = fs.exists(dependencyPath)
    local key = depends.CONFIG.DEPENDENCIES[name]

    if isAvailable == false and (key == nil or key == "") then
        key = pastebinKey

        if key == nil or key == "" then
            error(name.." is not available. You will need to provide a pastebin key.")
        end
    end

    return isAvailable, key
end

download = function(name, pastebinKey)
    local key = depends.CONFIG.DEPENDENCIES[name] or pastebinKey

    if key == nil and (pastebinKey == nil or pastebinKey == "") then
        error(name.." was not declared as a dependency.")
    end

    if key == "" then
        key = pastebinKey

        if key == "" then
            print("No pastebin key defined. Skipping.")
            return false
        end
    end

    local dependencyPath = depends.CONFIG.DEPENDENCIES_LOCATION.."/"..name

    downloadFromPastebin(key, dependencyPath)

    return true
end
-- main functions of depends.lua

local function setupAPI(force)
    local globalEnv = getfenv(0)
    if globalEnv.depends == nil or force then
        globalEnv.depends = {
            CONFIG = CONFIG,
            reload = reload,
            on = on,
            check = check,
            download = download
        }
    end
end

setupAPI()

local function downloadConfig(pastebinKey)
    local configPath = "/"..CONFIG_FILE

    downloadFromPastebin(pastebinKey, configPath)
end

local function runStartup(startupFile, shellArgs)
    local fileToRun = depends.CONFIG.DEPENDENCIES_LOCATION.."/"..startupFile

    if fs.exists(startupFile) then
        fileToRun = startupFile
    else
        local isAvailable, key = depends.check(startupFile)
        if isAvailable == false then
            depends.download(startupFile, key)
        end

        if depends.CONFIG.DEPENDENCIES[startupFile] == nil then
            depends.CONFIG.DEPENDENCIES[startupFile] = key or ""
        end
    end

    depends.CONFIG.STARTUP = startupFile

    saveConfig(depends.CONFIG)

    shell.run(fileToRun, unpack(shellArgs))
end

local function run(shellArgs)
    local configFile = CONFIG_FILE
    local startupFile = nil
    local args = shellArgs

    if #shellArgs > 0 then
        if shellArgs[1] == "--reload" then
            setupAPI(true)
        elseif shellArgs[1] == "--run" and shellArgs[2] then
            print("Running "..shellArgs[2])

            startupFile = shellArgs[2]
            args = {}
            for i=3, #shellArgs do
                table.insert(args, shellArgs[i])
            end
        elseif shellArgs[1] == "--get-config" and shellArgs[2] then
            downloadConfig(shellArgs[2])
            return
        elseif shellArgs[1] == "--config" and shellArgs[2] then
            configFile = shellArgs[2]
        elseif shellArgs[1] == "--publish" then
            uploadDependencies()
            return
        end
    end

    if fs.exists(CONFIG_FILE) == false then
        print("I can't find the config file: "..CONFIG_FILE)
        print("Generating one for you.")

        saveConfig()

        print("")
        print("Configuration file is located at /"..CONFIG_FILE)
        return
    end

    depends.reload(configFile)

    startupFile = startupFile or depends.CONFIG.STARTUP

    if startupFile and startupFile ~= "" then
        runStartup(startupFile, args)
    else
        print("No startup dependency defined.")
    end
end

if shell then
    run({...})
else
    print("Running depends.lua as an API")
end