// Copyright (C) 2019  Yuanle Song <root@emacsos.com>
//
// This file is part of mbackup-for-windows.
//
// mbackup-for-windows is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by the
// Free Software Foundation, either version 3 of the License, or (at your
// option) any later version.
//
// mbackup-for-windows is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
// more details.
//
// You should have received a copy of the GNU General Public License along with
// mbackup-for-windows.  If not, see <http://www.gnu.org/licenses/>.

module Mbackup.Lib

open System
open System.Text.RegularExpressions

type Logger() =
  let mutable level = Logger.DEBUG

  static member DEBUG = 10
  static member INFO = 20
  static member WARNING = 30
  static member ERROR = 40
  static member LevelToString level =
    match level with
      | 10 -> "DEBUG"
      | 20 -> "INFO"
      | 30 -> "WARNING"
      | 40 -> "ERROR"
      | _ -> failwith (sprintf "Unknown log level: %d" level)

  member this.Level = level

  member this.LogMaybe level fmt =
    let doAfter s =
      if this.Level <= level then
        let ts = DateTime.Now.ToString("s")
        printf "%s %s %s\n" ts (Logger.LevelToString level) s
      else
        printf ""
    Printf.ksprintf doAfter fmt

  member this.SetLevel level =
    this.Level = level
  member this.Debug fmt = this.LogMaybe Logger.DEBUG fmt
  member this.Info fmt = this.LogMaybe Logger.INFO fmt
  member this.Warning fmt = this.LogMaybe Logger.WARNING fmt
  member this.Error fmt = this.LogMaybe Logger.ERROR fmt

// append string s to list if pred is true
let appendWhen (pred: bool) (lst: string list) (s: string) = if pred then List.append lst [s] else lst

let getEnv (varName: string) = Environment.GetEnvironmentVariable varName
let setEnv (varName: string) (value: string) = Environment.SetEnvironmentVariable(varName, value)

let getEnvDefault (varName: string) (defaultValue: string) =
  let value = Environment.GetEnvironmentVariable varName
  match value with
    | null -> defaultValue
    | "" -> defaultValue
    | _ -> value

// Convert windows path to Mingw64 path.
// Supported windows path: C:\foo, C:/foo, /c/foo
// MingwPath format: /cygdrive/c/foo
let toMingwPath (windowsPath: string) =
  let pattern = Regex("^/([c-zC-Z])/", RegexOptions.None)
  let result =
    if pattern.IsMatch(windowsPath) then
      "/cygdrive" + windowsPath
    else
      let pattern = Regex("^([c-zC-Z]):", RegexOptions.None)
      if pattern.IsMatch(windowsPath) then
        let result = windowsPath.Replace('\\', '/')
        "/cygdrive/" + result.Substring(0, 1).ToLower() + result.Substring(2)
      else
        windowsPath
  result

// Convert Mingw64 path to windows path.
// supported mingwPath format: /cygdrive/x/xxx
// return null if given path is not in this format.
let toWinPath (mingwPath: string) =
  if mingwPath.StartsWith("/cygdrive/") then
    let driveLetter = mingwPath.Substring("/cygdrive/".Length, 1).ToUpper()
    let rest = mingwPath.Substring("/cygdrive/".Length + 1)
    driveLetter + ":" + rest.Replace('/', '\\')
  else
    null

let ensureDir (path: string) = if path.EndsWith "/" then path else path + "/"
let ensureWinDir (path: string) = if path.EndsWith "\\" then path else path + "\\"