local tArgs = { ... }

function printUsage()
    print(" Usage: Update run")
    print(" Usage: Update remove <path>")
    print(" Usage: Update add <paste> <path>")
    print(" Usage: Update <paste> <path>")
    error()
end

if #tArgs < 1 or #tArgs > 3 then
    printUsage()
end

--- Attempts to guess the pastebin ID from the given code or URL
local function extractId(paste)
    local patterns = {
        "^([%a%d]+)$",
        "^https?://pastebin.com/([%a%d]+)$",
        "^https?://pastebin.com/edit/([%a%d]+)$",
        "^pastebin.com/([%a%d]+)$",
        "^pastebin.com/edit/([%a%d]+)$",
        "^https?://pastebin.com/raw/([%a%d]+)$",
        "^pastebin.com/raw/([%a%d]+)$",
    }

    for i = 1, #patterns do
        local code = paste:match( patterns[i] )
        if code then return code end
    end

    return nil
end

function isPaste(url)
    if not url then return false end
    local paste = extractId( url )
    if not paste then
        io.stderr:write( "Invalid pastebin code.\n" )
        io.write( "The code is the ID at the end of the pastebin.com URL.\n" )
        return false
    end
    local cacheBuster = ("%x"):format(math.random(0, 2^30))
    local response, err = http.get(
        "https://pastebin.com/raw/"..textutils.urlEncode( paste ).."?cb="..cacheBuster
    )
    if response then
        -- If spam protection is activated, we get redirected to /paste with Content-Type: text/html
        local headers = response.getResponseHeaders()
        if not headers["Content-Type"] or not headers["Content-Type"]:find( "^text/plain" ) then
            io.stderr:write( "Failed.\n" )
            print( "Pastebin blocked the download due to spam protection. Please complete the captcha in a web browser: https://pastebin.com/" .. textutils.urlEncode( paste ) )
            return false
        end
        return true
    else
        return false
    end
end

function checkPath(path, shouldAskToReplace, shouldCreate)
    local hasPath = fs.exists(path)
    if not hasPath then
        -- Create directories if they does not exist.
        local hasDirs = string.find(path, "/")
        if hasDirs ~= nil then
            if not shouldCreate then
                print("Error: File was not found!")
                error()
            end
            local dirs = string.match(path, "^(.+/)")
            fs.makeDir(dirs)
            print("Created directory:", dirs)
        end

        -- Check if the file exists
        hasPath = fs.exists(path)
        if not hasPath then
            if not shouldCreate then
                print("Error: File was not found!")
                error()
            end
            -- Create the file
            f = fs.open(path, "w")
            f.close()
            print("Created file:", path)
        end
    else
        if not shouldAskToReplace then
            return
        end

        print("File already exists, do you want to replace it? [Y/N]")
        local input = read()
        if input == "Y" or input == "y" then
            return
        else
            print("Abort command!")
            error()
        end
    end
end

function checkPastePath(paste, path, shouldAskToReplace, shouldCreate)
    local hasPaste = isPaste(paste)
    if not hasPaste then
        print("That was not a valid paste!")
        printUsage()
    end
    checkPath(path, shouldAskToReplace, shouldCreate)
end

function runPaste(paste, path)
    checkPastePath(paste, path, false, true)
    print("----", paste, path, "----")
    fs.delete(path)
    shell.run("pastebin", "get", paste, path)
end

local tmpFile = "tmpUPDATE.lua"
-- Run command
if tArgs[1] == "run" then
    local file = fs.open(tmpFile, fs.exists(tmpFile) and "r")
    if not file then
        print("Error: No entries as been added!")
        printUsage()
    end
    local list = {}
    local line = nil
    repeat
        line = file.readLine()
        local ps = line
        line = file.readLine()
        local pt = line
        -- Add entry
        table.insert(list, #list+1, {paste=ps, path=pt})
    until not line
    file.close()

    for i=1, #list-1 do
        local entry = list[i]
        runPaste(entry.paste, entry.path)
    end
    return
end

-- Add command
if tArgs[1] == "add" then
    local paste = tArgs[2]
    local path = tArgs[3]
    checkPastePath(paste, path, true, true)
    paste = extractId(paste)
    local file = fs.open(tmpFile, fs.exists(tmpFile) and "a" or "w")
    file.writeLine(paste)
    file.writeLine(path)
    file.close()
    return
end

-- Remove command
if tArgs[1] == "remove" then
    local path = tArgs[2]
    checkPath(path, false, false)
    local file = fs.open(tmpFile, fs.exists(tmpFile) and "r")
    if not file then error() end

    -- Open the file and fetch all but the given entry.
    local list = {}
    local line = nil
    repeat
        line = file.readLine()
        -- If eof, break
        if line == nil then break end

        line2 = line
        line = file.readLine()
        -- If eof, break
        if line == nil then break end
        -- If this is not the entry we are searching for, add it to the list, else ignore it.
        if line ~= path then
            -- Add current paste
            table.insert(list, #list+1, line2)
            -- Add corresponding path
            table.insert(list, #list+1, line)
        end
    until not line
    file.close()

    -- Create the file again from scratch and add the entries.
    local file = fs.open(tmpFile, fs.exists(tmpFile) and "w")
    for i=1, #list do
        file.write(list[i])
        file.write("\n")
    end
    file.close()
    return
end

if #tArgs ~= 2 then
    printUsage()
end

-- Normal command
local paste = tArgs[1]
local path = tArgs[2]
runPaste(paste, path)