inifiles.nim

## Provide simple wrapper for ini files.
## Files are read in their totality and arranged as a dictionary of:
## section title, value title, value
import os, tables, strutils

type
  IniFile* = ref object
    filename*: string
    sections*: TableRef[string, TableRef[string, string]]

proc clear*(inifile: var IniFile) =
  inifile.sections = newTable[string, TableRef[string, string]](initialsize = 2)

proc newIniFile*: IniFile =
  new(result)
  result.sections = newTable[string, TableRef[string, string]](initialsize = 2)

proc find*(inifile: IniFile, section: string, key: string): string =
  ## Look up key in section.
  var
    lkey = key.toLower
    lsec = section.toLower

  result = ""
  if inifile.sections.hasKey(lsec) and inifile.sections[lsec].hasKey(lkey):
    result = inifile.sections[lsec][lkey]

proc find*(inifile: IniFile, key: string): string =
  ## Look through all sections for a key.
  # here we don't specify a section, so we need to search all items.
  var lkey = key.toLower
  result = ""
  for section in inifile.sections.pairs:
    var secItems = section[1]

    if secItems.hasKey(lkey):
      result = secItems[lkey]
      break

proc loadIni*(inifile: var IniFile, filename: string = ""): bool =
  ## Load ini file and split into dictionaries.
  ## Double quotes are stripped.
  # assumes inifile has been initialised with filename, otherwise initialises for you
  # returns true when at least one key/value pair has been registered
  result = false
  if inifile == nil: inifile = newIniFile()
  inifile.clear
  if filename != "": inifile.filename = filename

  var
    curSection: string = ""

  if not fileExists(iniFile.filename):
    return

  for line in lines inifile.filename:
    let sLine = line.strip

    if sLine.len > 2 and sLine.startsWith("[") and sLine.endsWith("]"):
      # this is a section
      var newTable = newTable[string, string]()
      curSection = substr(sLine.toLower, 1, sLine.len - 2)
      inifile.sections.add(curSection, newTable)
    elif sLine.startsWith(";") or sLine.startsWith("#"):
      # comment
      discard
    elif sLine != "" and sLine.len > 3:
      # Anything else is checked to be a key/value pair
      let
        sepPoint = sLine.find("=")

      if sepPoint > 0:
        # qualifies as a key/value pair
        var sectionItems: TableRef[string, string]

        if not inifile.sections.hasKey(curSection):
          # handle items under no/blank section
          sectionItems = newTable[string, string]()
          inifile.sections.add(curSection, sectionItems)
        else:
          # retrieve from existing section table
          sectionItems = inifile.sections.mget(curSection)

        let
          lsLine = sLine.toLower
          # note: quotes are stripped
          k = lsLine.subStr(0, sepPoint - 1).replace("\"")
          v = lsLine.subStr(sepPoint + 1).replace("\"")
        sectionItems.add(k, v)
        result = true

proc `$`*(ini: IniFile): string =
  ## Return ini file as structured string.
  result = ""
  for sec in ini.sections.pairs:
    echo "[section: " & sec[0] & ']'
    for v in sec[1].pairs:
      echo " " & v[0] & " : " & v[1]
    echo repeat("-", 10)

when isMainModule:
  var ini = newIniFile()
  ini.filename = getCurrentDir().joinPath("MyIni.ini")
  if ini.loadIni:
    echo "Full ini file:"
    echo ini

    var
      item = ini.find("name")
      sectionItem = ini.find("section", "name")
      
    echo "item: ", item
    echo "section item: ", sectionItem
  else:
    echo "File not found or doesn't contain any key/value pairs."