library

local component = require("component")
local event = require("event")
local term = require("term")
local internet = require("internet")
local fs = require("filesystem")
local serial = require("serialization")

-- The directory where all entries are stored.
local ENTRIES_DIRECTORY = "/home/entries"

-- Global state variable.
local RUNNING = true

-- Fetches the real-world date and time from the interwebs.
local function getRealWorldTime()
  local response = internet.request("http://worldtimeapi.org/api/ip")
  if response == nil then
    return nil
  end

  local content = response()
  local start_idx, end_idx = string.find(content, "\"datetime\":\"")
  local time_string = string.sub(content, end_idx + 1, end_idx + 19)
  local time = {}
  time.year = tonumber(string.sub(time_string, 1, 4))
  time.month = tonumber(string.sub(time_string, 6, 7))
  time.day = tonumber(string.sub(time_string, 9, 10))
  time.hour = tonumber(string.sub(time_string, 12, 13))
  time.minute = tonumber(string.sub(time_string, 15, 16))
  time.second = tonumber(string.sub(time_string, 18, 19))
  time.string = time_string
  return time
end

-- Checks if a directory with the given name exists, and makes it if it doesn't.
local function makeDirIfNotExists(name)
  if not fs.exists(name) then
    if not fs.makeDirectory(name) then
      io.stderr:write("Could not make directory: "..name.."\n")
      return false
    end
  end
  return true
end

-- Saves the given text into a file in the entries directory.
local function saveEntry(entry_text, time)
  if not makeDirIfNotExists(ENTRIES_DIRECTORY) then
    return false
  end
  local year_str = tostring(time.year)
  local month_str = tostring(time.month)
  --local filename = time.hour .. "_" .. time.minute .. "_" .. time.second .. ".txt"
  local filename = time.string .. ".txt"
  local full_path = fs.concat(ENTRIES_DIRECTORY, year_str, month_str, filename)
  if not makeDirIfNotExists(fs.concat(ENTRIES_DIRECTORY, year_str)) then
    return false
  end
  if not makeDirIfNotExists(fs.concat(ENTRIES_DIRECTORY, year_str, month_str)) then
    return false
  end
  local f = io.open(full_path, "w")
  if f == nil then
    io.stderr:write("Could not open file for writing: "..full_path.."\n")
    return false
  end
  f:write(entry_text)
  f:close()
  return true
end

-- Creates a new entry with the given user input.
local function createEntry()
  print("Enter some text below.")
  local input = io.read()
  if input == nil or #input == 0 then
    print("No valid input given, cancelling this entry.")
    return
  end
  print("Getting real-world time...")
  local time = getRealWorldTime()
  print("Saving entry for timestamp " .. time.string .. "...")
  if saveEntry(input, time) then
    print("Entry saved successfully!")
  else
    print("An error occurred, and the entry could not be saved.")
  end
end

-- Shows the main menu to the user.
local function mainMenu()
  print("[Main Menu]")
  print("What would you like to do?")
  print("1. Create a new log entry.")
  print("2. View a list of log entries.")
  print("3. Quit the program.")

  local choice = tonumber(io.read())
  while choice == nil or choice < 1 or choice > 3 do
    print("Invalid choice. Please enter an integer corresponding to one of the options.")
    choice = tonumber(io.read())
  end

  if choice == 1 then
    createEntry()
  elseif choice == 2 then
    -- view entries list
  else
    -- quit
    print("Quitting the program...")
    RUNNING = false
  end
end

while RUNNING do
  mainMenu()
end