-- source taken from http://github.com/kikito/
-- inspect.lua 3.1.0
-- Human-readable representations of tables

-- The MIT License (MIT)
--
-- Copyright (c) 2013 Enrique García Cota
--
-- Permission is hereby granted, free of charge, to any person obtaining a
-- copy of this software and associated documentation files (the
-- "Software"), to deal in the Software without restriction, including
-- without limitation the rights to use, copy, modify, merge, publish,
-- distribute, sublicense, and/or sell copies of the Software, and to
-- permit persons to whom the Software is furnished to do so, subject to
-- the following conditions:
--
-- The above copyright notice and this permission notice shall be included
-- in all copies or substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-- OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-- MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-- CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-- SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

local inspect = {}

local tostring = tostring

inspect.KEY       = setmetatable({}, {__tostring = function() return 'inspect.KEY' end})
inspect.METATABLE = setmetatable({}, {__tostring = function() return 'inspect.METATABLE' end})

local function rawpairs(t)
  return next, t, nil
end

-- Apostrophizes the string if it has quotes, but not aphostrophes
-- Otherwise, it returns a regular quoted string
local function smartQuote(str)
  if str:match('"') and not str:match("'") then
    return "'" .. str .. "'"
  end
  return '"' .. str:gsub('"', '\\"') .. '"'
end

-- \a => '\\a', \0 => '\\0', 31 => '\31'
local shortControlCharEscapes = {
  ["\a"] = "\\a",  ["\b"] = "\\b", ["\f"] = "\\f", ["\n"] = "\\n",
  ["\r"] = "\\r",  ["\t"] = "\\t", ["\v"] = "\\v"
}
local longControlCharEscapes = {} -- \a => nil, \0 => \000, 31 => \031
for i=0, 31 do
  local ch = string.char(i)
  if not shortControlCharEscapes[ch] then
    shortControlCharEscapes[ch] = "\\"..i
    longControlCharEscapes[ch]  = string.format("\\%03d", i)
  end
end

local function escape(str)
  return (str:gsub("\\", "\\\\")
             :gsub("(%c)%f[0-9]", longControlCharEscapes)
             :gsub("%c", shortControlCharEscapes))
end

local function isIdentifier(str)
  return type(str) == 'string' and str:match( "^[_%a][_%a%d]*$" )
end

local function isSequenceKey(k, sequenceLength)
  return type(k) == 'number'
     and 1 <= k
     and k <= sequenceLength
     and math.floor(k) == k
end

local defaultTypeOrders = {
  ['number']   = 1, ['boolean']  = 2, ['string'] = 3, ['table'] = 4,
  ['function'] = 5, ['userdata'] = 6, ['thread'] = 7
}

local function sortKeys(a, b)
  local ta, tb = type(a), type(b)

  -- strings and numbers are sorted numerically/alphabetically
  if ta == tb and (ta == 'string' or ta == 'number') then return a < b end

  local dta, dtb = defaultTypeOrders[ta], defaultTypeOrders[tb]
  -- Two default types are compared according to the defaultTypeOrders table
  if dta and dtb then return defaultTypeOrders[ta] < defaultTypeOrders[tb]
  elseif dta     then return true  -- default types before custom ones
  elseif dtb     then return false -- custom types after default ones
  end

  -- custom types are sorted out alphabetically
  return ta < tb
end

-- For implementation reasons, the behavior of rawlen & # is "undefined" when
-- tables aren't pure sequences. So we implement our own # operator.
local function getSequenceLength(t)
  local len = 1
  local v = rawget(t,len)
  while v ~= nil do
    len = len + 1
    v = rawget(t,len)
  end
  return len - 1
end

local function getNonSequentialKeys(t)
  local keys, keysLength = {}, 0
  local sequenceLength = getSequenceLength(t)
  for k,_ in rawpairs(t) do
    if not isSequenceKey(k, sequenceLength) then
      keysLength = keysLength + 1
      keys[keysLength] = k
    end
  end
  table.sort(keys, sortKeys)
  return keys, keysLength, sequenceLength
end

local function countTableAppearances(t, tableAppearances)
  tableAppearances = tableAppearances or {}

  if type(t) == 'table' then
    if not tableAppearances[t] then
      tableAppearances[t] = 1
      for k,v in rawpairs(t) do
        countTableAppearances(k, tableAppearances)
        countTableAppearances(v, tableAppearances)
      end
      countTableAppearances(getmetatable(t), tableAppearances)
    else
      tableAppearances[t] = tableAppearances[t] + 1
    end
  end

  return tableAppearances
end

local copySequence = function(s)
  local copy, len = {}, #s
  for i=1, len do copy[i] = s[i] end
  return copy, len
end

local function makePath(path, ...)
  local keys = {...}
  local newPath, len = copySequence(path)
  for i=1, #keys do
    newPath[len + i] = keys[i]
  end
  return newPath
end

local function processRecursive(process, item, path, visited)
  if item == nil then return nil end
  if visited[item] then return visited[item] end

  local processed = process(item, path)
  if type(processed) == 'table' then
    local processedCopy = {}
    visited[item] = processedCopy
    local processedKey

    for k,v in rawpairs(processed) do
      processedKey = processRecursive(process, k, makePath(path, k, inspect.KEY), visited)
      if processedKey ~= nil then
        processedCopy[processedKey] = processRecursive(process, v, makePath(path, processedKey), visited)
      end
    end

    local mt  = processRecursive(process, getmetatable(processed), makePath(path, inspect.METATABLE), visited)
    if type(mt) ~= 'table' then mt = nil end -- ignore not nil/table __metatable field
    setmetatable(processedCopy, mt)
    processed = processedCopy
  end
  return processed
end



-------------------------------------------------------------------

local Inspector = {}
local Inspector_mt = {__index = Inspector}

function Inspector:puts(...)
  local args   = {...}
  local buffer = self.buffer
  local len    = #buffer
  for i=1, #args do
    len = len + 1
    buffer[len] = args[i]
  end
end

function Inspector:down(f)
  self.level = self.level + 1
  f()
  self.level = self.level - 1
end

function Inspector:tabify()
  self:puts(self.newline, string.rep(self.indent, self.level))
end

function Inspector:alreadyVisited(v)
  return self.ids[v] ~= nil
end

function Inspector:getId(v)
  local id = self.ids[v]
  if not id then
    local tv = type(v)
    id              = (self.maxIds[tv] or 0) + 1
    self.maxIds[tv] = id
    self.ids[v]     = id
  end
  return tostring(id)
end

function Inspector:putKey(k)
  if isIdentifier(k) then return self:puts(k) end
  self:puts("[")
  self:putValue(k)
  self:puts("]")
end

function Inspector:putTable(t)
  if t == inspect.KEY or t == inspect.METATABLE then
    self:puts(tostring(t))
  elseif self:alreadyVisited(t) then
    self:puts('<table ', self:getId(t), '>')
  elseif self.level >= self.depth then
    self:puts('{...}')
  else
    if self.tableAppearances[t] > 1 then self:puts('<', self:getId(t), '>') end

    local nonSequentialKeys, nonSequentialKeysLength, sequenceLength = getNonSequentialKeys(t)
    local mt                = getmetatable(t)

    self:puts('{')
    self:down(function()
      local count = 0
      for i=1, sequenceLength do
        if count > 0 then self:puts(',') end
        self:puts(' ')
        self:putValue(t[i])
        count = count + 1
      end

      for i=1, nonSequentialKeysLength do
        local k = nonSequentialKeys[i]
        if count > 0 then self:puts(',') end
        self:tabify()
        self:putKey(k)
        self:puts(' = ')
        self:putValue(t[k])
        count = count + 1
      end

      if type(mt) == 'table' then
        if count > 0 then self:puts(',') end
        self:tabify()
        self:puts('<metatable> = ')
        self:putValue(mt)
      end
    end)

    if nonSequentialKeysLength > 0 or type(mt) == 'table' then -- result is multi-lined. Justify closing }
      self:tabify()
    elseif sequenceLength > 0 then -- array tables have one extra space before closing }
      self:puts(' ')
    end

    self:puts('}')
  end
end

function Inspector:putValue(v)
  local tv = type(v)

  if tv == 'string' then
    self:puts(smartQuote(escape(v)))
  elseif tv == 'number' or tv == 'boolean' or tv == 'nil' or
         tv == 'cdata' or tv == 'ctype' then
    self:puts(tostring(v))
  elseif tv == 'table' then
    self:putTable(v)
  else
    self:puts('<', tv, ' ', self:getId(v), '>')
  end
end

-------------------------------------------------------------------

function inspect.inspect(root, options)
  options       = options or {}

  local depth   = options.depth   or math.huge
  local newline = options.newline or '\n'
  local indent  = options.indent  or '  '
  local process = options.process

  if process then
    root = processRecursive(process, root, {}, {})
  end

  local inspector = setmetatable({
    depth            = depth,
    level            = 0,
    buffer           = {},
    ids              = {},
    maxIds           = {},
    newline          = newline,
    indent           = indent,
    tableAppearances = countTableAppearances(root)
  }, Inspector_mt)

  inspector:putValue(root)

  return table.concat(inspector.buffer)
end

setmetatable(inspect, { __call = function(_, ...) return inspect.inspect(...) end })

return inspect
