# -------------- post unzip steps ---------------------------------------------

import strutils, os, osproc, streams, browsers

const
  arch = $(sizeof(int)*8)
  mingw = "mingw$1.7z" % arch
  url = r"https://nim-lang.org/download/" & mingw

var
  interactive = true

type
  DownloadResult = enum
    Failure,
    Manual,
    Success

proc expand(s: string): string =
  try:
    result = expandFilename(s)
  except OSError, IOError:
    result = s

proc unzip(): bool =
  if not fileExists("dist" / mingw):
    echo "Could not find ", "dist" / mingw
    return false
  try:
    let p = osproc.startProcess(r"bin\7zG.exe", getCurrentDir() / r"dist",
                                ["x", mingw])
    if p.waitForExit != 0:
      echo "Unpacking failed: " & mingw
    else:
      result = true
  except:
    result = false

proc downloadMingw(): DownloadResult =
  let curl = findExe"curl"
  var cmd: string
  if curl.len > 0:
    cmd = quoteShell(curl) & " --output " & "dist" / mingw & " " & url
  elif fileExists"bin/nimgrab.exe":
    cmd = r"bin\nimgrab.exe " & url & " dist" / mingw
  if cmd.len > 0:
    if execShellCmd(cmd) != 0:
      echo "download failed! ", cmd
      if interactive:
        openDefaultBrowser(url)
        result = Manual
      else:
        result = Failure
    else:
      if unzip(): result = Success
  else:
    if interactive:
      openDefaultBrowser(url)
      result = Manual
    else:
      result = Failure

when defined(windows):
  import registry

  proc askBool(m: string): bool =
    stdout.write m
    if not interactive:
      stdout.writeLine "y (non-interactive mode)"
      return true
    while true:
      try:
        let answer = stdin.readLine().normalize
        case answer
        of "y", "yes":
          return true
        of "n", "no":
          return false
        else:
          echo "Please type 'y' or 'n'"
      except EOFError:
        quit(1)

  proc askNumber(m: string; a, b: int): int =
    stdout.write m
    stdout.write " [" & $a & ".." & $b & "] "
    if not interactive:
      stdout.writeLine $a & " (non-interactive mode)"
      return a
    while true:
      let answer = stdin.readLine()
      try:
        result = parseInt answer
        if result < a or result > b:
          raise newException(ValueError, "number out of range")
        break
      except ValueError:
        echo "Please type in a number between ", a, " and ", b

  proc patchConfig(mingw: string) =
    const
      cfgFile = "config/nim.cfg"
      lookFor = """#gcc.path = r"$nim\dist\mingw\bin""""
      replacePattern = """gcc.path = r"$1""""
    try:
      let cfg = readFile(cfgFile)
      let newCfg = cfg.replace(lookFor, replacePattern % mingw)
      if newCfg == cfg:
        echo "Could not patch 'config/nim.cfg' [Error]"
        echo "Reason: patch substring not found:"
        echo lookFor
      else:
        writeFile(cfgFile, newCfg)
    except IOError:
      echo "Could not access 'config/nim.cfg' [Error]"

  proc tryGetUnicodeValue(path, key: string; handle: HKEY): string =
    try:
      result = getUnicodeValue(path, key, handle)
    except:
      result = ""

  proc addToPathEnv*(e: string) =
    var p = tryGetUnicodeValue(r"Environment", "Path", HKEY_CURRENT_USER)
    if p.len > 0:
      p.add ";"
      p.add e
    else:
      p = e
    setUnicodeValue(r"Environment", "Path", p, HKEY_CURRENT_USER)

  proc createShortcut(src, dest: string; icon = "") =
    var cmd = "bin\\makelink.exe \"" & src & "\" \"\" \"" & dest &
         ".lnk\" \"\" 1 \"" & splitFile(src).dir & "\""
    if icon.len != 0:
      cmd.add " \"" & icon & "\" 0"
    discard execShellCmd(cmd)

  proc createStartMenuEntry*(override = false) =
    let appdata = getEnv("APPDATA")
    if appdata.len == 0: return
    let dest = appdata & r"\Microsoft\Windows\Start Menu\Programs\Nim-" &
               NimVersion
    if dirExists(dest): return
    if override or askBool("Would like to add Nim-" & NimVersion &
               " to your start menu? (y/n) "):
      createDir(dest)
      createShortcut(getCurrentDir() / "tools" / "start.bat", dest / "Nim",
                     getCurrentDir() / r"icons\nim.ico")
      if fileExists("doc/overview.html"):
        createShortcut(getCurrentDir() / "doc" / "html" / "overview.html",
                       dest / "Overview")
      if dirExists(r"dist\aporia-0.4.0"):
        createShortcut(getCurrentDir() / r"dist\aporia-0.4.0\bin\aporia.exe",
                       dest / "Aporia")

  proc checkGccArch(mingw: string): bool =
    let gccExe = mingw / r"gcc.exe"
    if fileExists(gccExe):
      const nimCompat = "nim_compat.c"
      writeFile(nimCompat, """typedef int
        Nim_and_C_compiler_disagree_on_target_architecture[
          $# == sizeof(void*) ? 1 : -1];
      """ % $sizeof(int))
      try:
        let p = startProcess(gccExe, "", ["-c", nimCompat], nil,
                            {poStdErrToStdOut, poUsePath})
        #echo p.outputStream.readAll()
        result = p.waitForExit() == 0
      except OSError, IOError:
        result = false
      finally:
        removeFile(nimCompat)
        removeFile(nimCompat.changeFileExt("o"))

  proc defaultMingwLocations(): seq[string] =
    proc probeDir(dir: string; result: var seq[string]) =
      for k, x in walkDir(dir, relative=true):
        if k in {pcDir, pcLinkToDir}:
          if x.contains("mingw") or x.contains("posix"):
            let dest = dir / x
            probeDir(dest, result)
            result.add(dest)

    result = @["dist/mingw", "../mingw", r"C:\mingw"]
    let pfx86 = getEnv("programfiles(x86)")
    let pf = getEnv("programfiles")
    when hostCPU == "i386":
      probeDir(pfx86, result)
      probeDir(pf, result)
    else:
      probeDir(pf, result)
      probeDir(pfx86, result)

  proc tryDirs(incompat: var seq[string]; dirs: varargs[string]): string =
    let bits = $(sizeof(pointer)*8)
    for d in dirs:
      if dirExists d:
        let x = expand(d / "bin")
        if x.len != 0:
          if checkGccArch(x): return x
          else: incompat.add x
      elif dirExists(d & bits):
        let x = expand((d & bits) / "bin")
        if x.len != 0:
          if checkGccArch(x): return x
          else: incompat.add x

proc main() =
  when defined(windows):
    let nimDesiredPath = expand(getCurrentDir() / "bin")
    let nimbleBin = getEnv("USERPROFILE") / ".nimble" / "bin"
    let nimbleDesiredPath = expand(nimbleBin)
    let p = tryGetUnicodeValue(r"Environment", "Path",
      HKEY_CURRENT_USER) & ";" & tryGetUnicodeValue(
        r"System\CurrentControlSet\Control\Session Manager\Environment", "Path",
        HKEY_LOCAL_MACHINE)
    var nimAlreadyInPath = false
    var nimbleAlreadyInPath = false
    var mingWchoices: seq[string] = @[]
    var incompat: seq[string] = @[]
    for x in p.split(';'):
      if x.len == 0: continue
      let y = try: expandFilename(if x[0] == '"' and x[^1] == '"':
                                    substr(x, 1, x.len-2) else: x)
              except OSError as e:
                if e.errorCode == 0: x else: ""
              except: ""
      if y.cmpIgnoreCase(nimDesiredPath) == 0:
        nimAlreadyInPath = true
      elif y.cmpIgnoreCase(nimbleDesiredPath) == 0:
        nimbleAlreadyInPath = true
      elif y.toLowerAscii.contains("mingw"):
        if dirExists(y):
          if checkGccArch(y): mingWchoices.add y
          else: incompat.add y

    if nimAlreadyInPath:
      echo "bin\\nim.exe is already in your PATH [Skipping]"
    else:
      if askBool("nim.exe is not in your PATH environment variable.\n" &
          "Should it be added permanently? (y/n) "):
        addToPathEnv(nimDesiredPath)

    if nimbleAlreadyInPath:
      echo nimbleDesiredPath & " is already in your PATH [Skipping]"
    else:
      if askBool(nimbleDesiredPath & " is not in your PATH environment variable.\n" &
          "Should it be added permanently? (y/n) "):
        addToPathEnv(nimbleDesiredPath)

    if mingWchoices.len == 0:
      # No mingw in path, so try a few locations:
      let alternative = tryDirs(incompat, defaultMingwLocations())
      if alternative.len == 0:
        if incompat.len > 0:
          echo "The following *incompatible* MingW installations exist"
          for x in incompat: echo x
          echo "*incompatible* means Nim and GCC disagree on the size of a pointer."
        echo "No compatible MingW candidates found " &
             "in the standard locations [Error]"
        if askBool("Do you want to download MingW from Nim's website? (y/n) "):
          let dest = getCurrentDir() / "dist"
          var retry = false
          case downloadMingw()
          of Manual:
            echo "After download, move it to: ", dest
            if askBool("Download successful? (y/n) "):
              while not fileExists("dist" / mingw):
                echo "could not find: ", "dist" / mingw
                if not askBool("Try again? (y/n) "): break
              if unzip(): retry = true
          of Failure: discard
          of Success:
            retry = true
          if retry:
            incompat.setLen 0
            let alternative = tryDirs(incompat, defaultMingwLocations())
            if alternative.len == 0:
              if incompat.len > 0:
                echo "The following *incompatible* MingW installations exist"
                for x in incompat: echo x
                echo "*incompatible* means Nim and GCC disagree on the size of a pointer."
              echo "Still no compatible MingW candidates found " &
                   "in the standard locations [Error]"
            else:
              echo "Patching Nim's config to use:"
              echo alternative
              patchConfig(alternative)
      else:
        if askBool("Found a MingW directory that is not in your PATH.\n" &
                   alternative &
                   "\nShould it be added to your PATH permanently? (y/n) "):
          addToPathEnv(alternative)
        elif askBool("Do you want to patch Nim's config to use this? (y/n) "):
          patchConfig(alternative)
    elif mingWchoices.len == 1:
      if askBool("MingW installation found at " & mingWchoices[0] & "\n" &
         "Do you want to patch Nim's config to use this?\n" &
         "(Not required since it's in your PATH!) (y/n) "):
        patchConfig(mingWchoices[0])
    else:
      echo "Multiple MingW installations found: "
      for i in 0..high(mingWchoices):
        echo "[", i, "] ", mingWchoices[i]
      if askBool("Do you want to patch Nim's config to use one of these? (y/n) "):
        let idx = askNumber("Which one do you want to use for Nim? ",
            1, len(mingWchoices))
        patchConfig(mingWchoices[idx-1])
    createStartMenuEntry()
  else:
    echo("Add ", getCurrentDir(), "/bin to your PATH...")

when isMainModule:
  when defined(testdownload):
    discard downloadMingw()
  else:
    if "-y" in commandLineParams():
      interactive = false
    main()