----------------------------------------------------------------------------------
--- Mudlet Table Utils
----------------------------------------------------------------------------------


--- Tests if a table is empty: this is useful in situations where you find
--- yourself wanting to do 'if my_table == {}' and such.
---
--- @usage Testing if the table is empty.
---   <pre>
---   myTable = {}
---   if table.is_empty(myTable) then
---      echo("myTable is empty")
---   end
---   </pre>
function table.is_empty(tbl)
  assert(type(tbl) == "table", string.format("table.is_empty: bad argument #1 type (table expected, got %s!)", type(tbl)))
  return next(tbl) == nil
end

-- The filter() method creates a new table with all elements that pass the test
-- implemented by the provided function.
function table.n_filter(t, cb)
  local filtered = {}
  for i, v in ipairs(t) do
    if cb(v, i, t) then
      filtered[#filtered + 1] = v
    end
  end
  return filtered
end

-- The flatten() method creates a new table with all sub-table elements concatenated into it recursively.
function table.n_flatten(input)
  local flattened = {}
  for _, element in ipairs(input) do
    if type(element) == 'table' then
      for _, v in ipairs(table.n_flatten(element)) do
        flattened[#flattened + 1] = v
      end
    else
      flattened[#flattened + 1] = element
    end
  end
  return flattened
end

--- Lua debug function that prints the content of a Lua table on the screen, split up in keys and values.
--- Useful if you want to see what the capture groups contain i. e. the Lua table "matches".
---
--- @see display
function printTable( map )
  echo("-------------------------------------------------------\n");
  for k, v in pairs( map ) do
    echo( "key=" .. k .. " value=" .. v .. "\n" )
  end
  echo("-------------------------------------------------------\n");
end



-- NOT LUADOC
-- This is supporting function for printTable().
function __printTable( k, v )
  insertText("\nkey = " .. tostring(k) .. " value = " .. tostring( v )  )
end

-- originally found at https://stackoverflow.com/questions/15706270/sort-a-table-in-lua
--- Returns a sorted iterator for a tbl. Defaults to a basic table.sort against the keys
--@param tbl the table to iterator
--@param[opt] order Function to use to sort table. Should accept three arguments, the table being iterated, and the two keys in the table it is comparing. Otherwise similar to table.sort
--@usage local tbl = { Tom = 40, Mary = 50, Joe = 23 }
--for name, thingies in spairs(tbl) do
--  echo(string.format("%s has %d thingies\n", name, thingies))
--end
-- --"Joe has 23 thingies\nMary has 50 thingies\nTom has 40 thingies"
--for name, thingies in spairs(tbl, function(t,a,b) return t[a] < t[b] end) do --iterate from lowest value to highest
--  echo(string.format("%s has %d thingies\n", name, thingies))
--end
-- --"Joe has 23 thingies\nTom has 40 thingies\nMary has 50 thingies"
function spairs(tbl, order)
  local keys = table.keys(tbl)
  if order then
    table.sort(keys, function(a,b) return order(tbl, a, b) end)
  else
    table.sort(keys)
  end

  local i = 0
  return function()
    i = i + 1
    if keys[i] then
      return keys[i], tbl[keys[i]]
    end
  end
end

--- Lua debug function that prints the content of a Lua table on the screen. <br/>
--- There are currently 3 functions with similar behaviour.
---
--- @see display
--- @see printTable
function listPrint( map )
  echo("-------------------------------------------------------\n");
  for k, v in ipairs( map ) do
    echo( k .. ". ) " .. v .. "\n" );
  end
  echo("-------------------------------------------------------\n");
end



--- <b><u>TODO</u></b> listAdd( list, what )
function listAdd( list, what )
  table.insert( list, what );
end



--- <b><u>TODO</u></b> listRemove( list, what )
function listRemove( list, what )
  for k, v in ipairs( list ) do
    if v == what then
      table.remove( list, k )
    end
  end
end



--- Gets the actual size of non-index based tables. <br/><br/>
---
--- For index based tables you can get the size with the # operator: <br/>
--- This is the standard Lua way of getting the size of index tables i.e. ipairs() type of tables with
--- numerical indices. To get the size of tables that use user defined keys instead of automatic indices
--- (pairs() type) you need to use the function table.size() referenced above.
---   <pre>
---   myTableSize = # myTable
---   </pre>
function table.size(t)
  if not t then
    return 0
  end
  local i = 0
  for k, v in pairs(t) do
    i = i + 1
  end
  return i
end



--- Determines if a table contains a value as a key or as a value (recursive).
function table._contains(t, value)
  if type(t) ~= "table" then
    return nil, "first parameter passed isn't a table"
  end

  for k, v in pairs(t) do
    if v == value then
      return true
    elseif k == value then
      return true
    elseif type(v) == "table" then
      if table.contains(v, value) then
        return true
      end
    end
  end
  return false
end

function table.contains(tbl, ...)
  for _,item in ipairs({...}) do
    if table._contains(tbl, item) then return true end
  end
  return false
end

--- Checks each item in a table against a provided function and returns a table of items
--- for which the function returns true
--- @param tbl table to collect items from
--- @param func function which is called as func(key,value) for each item in tbl
--- @return table of key-value pairs for which func returns true.
function table.collect(tbl, func)
  local tbl_type = type(tbl)
  assert(tbl_type == "table", string.format("table.collect: bad argument #1 type (table to collect items from as table expected, got %s)", tbl_type))
  local func_type = type(func)
  assert(func_type == "function", string.format("table.collect: bad argument #2 type (function to run against each item in tbl as function expected, got %s)", func_type))
  local matches = {}
  for key,value in pairs(tbl) do
    if func(key,value) == true then
      matches[key] = value
    end
  end
  return matches
end

--- Checks each item in a table against a provided function and returns a table of items
--- for which the function returns true. Unlike table.collect it ignores keys and returns 
--- a table which is guaranteed to be traversable using ipairs()
--- @param tbl table to collect items from
--- @param func function which is called as func(value) for each item in tbl
--- @return table of values for which func(value) returns true. Ignores keys, traversable using ipairs
function table.n_collect(tbl, func)
  local tbl_type = type(tbl)
  assert(tbl_type == "table", string.format("table.n_collect: bad argument #1 type (table to collect items from as table expected, got %s)", tbl_type))
  local func_type = type(func)
  assert(func_type == "function", string.format("table.n_collect: bad argument #2 type (function to run against each item in tbl as function expected, got %s)", func_type))
  local matches = {}
  for key,value in pairs(tbl) do
    if func(value) == true and not table.contains(matches, value) then
      table.insert(matches, value)
    end
  end
  return matches
end

-- not LDoc: table.matches and table.n_matches below do not use table.collect
-- or n_collect above in order to reduce the potential number of times tables 
-- need to be looped.

--- Checks each item in a table against each other argument using string.match
--- @param tbl table to check
--- @param pattern1 pattern to check using string.match
--- @param pattern2+ optional additional patterns to check
--- @param check_keys set as true if you want to also check the keys against the patterns
--- @return returns a table which contains every key value pair from tbl for which the value string.matches
---         if check_keys is passed as true, then the key value pair will be added if either the key or the value string.matches
function table.matches(tbl, ...)
  local tbl_type = type(tbl)
  assert(tbl_type == "table", string.format("table.matches: bad argument #1 type (table to check using string.match as table expected, got %s)", tbl_type))
  local patterns = {...}
  local matches = {}
  local check_keys
  if type(patterns[#patterns]) == "boolean" then check_keys = table.remove(patterns) end
  for index,pattern in ipairs(patterns) do
    local ptype = type(pattern)
    assert(ptype == "string", string.format("table.matches: bad argument #%d type (pattern to check as string expected, got %s)", index+1, ptype))
    for key,value in pairs(tbl) do
      local keyType = type(key)
      local valueType = type(value)
      if ((valueType == "string" or valueType == "number") and string.match(value, pattern)) or (check_keys and ((keyType == "string" or keyType == "number") and string.match(key, pattern))) then
        matches[key] = value
      end
    end
  end
  return matches
end

--- Checks each item in a table against each other argument using string.match. Returns a list
--- @param tbl table to check
--- @param pattern1 pattern to check using string.match
--- @param pattern2+ optional additional patterns to check
--- @param check_keys set as true if you want to also check the keys against the patterns
--- @return returns a which contains every unique value from tbl for which the value string.matches
---         does not preserve the order or keys of the original table, but does return a table traverable using ipairs
function table.n_matches(tbl, ...)
  local tbl_type = type(tbl)
  assert(tbl_type == "table", string.format("table.n_matches: bad argument #1 type (table to check using string.match as table expected, got %s)", tbl_type))
  local patterns = {...}
  local matches = {}
  for index,pattern in ipairs(patterns) do
    local ptype = type(pattern)
    assert(ptype == "string", string.format("table.n_matches: bad argument #%d type (pattern to check as string expected, got %s)", index+1, ptype))
    for key,value in pairs(tbl) do
      local valueType = type(value)
      if (valueType == "string" or valueType == "number") and string.match(value, pattern) and not table.index_of(matches, value) then
        table.insert(matches, value)
      end
    end
  end
  return matches
end


--- Table Union.
---
--- @return Returns a table that is the union of the provided tables. This is a union of key/value
---   pairs. If two or more tables contain different values associated with the same key,
---   that key in the returned table will contain a subtable containing all relevant values.
---   See table.n_union() for a union of values. Note that the resulting table may not be
---   reliably traversable with ipairs() due to the fact that it preserves keys. If there
---   is a gap in numerical indices, ipairs() will cease traversal.
---
--- @usage Example:
---   <pre>
---   tableA = {
---      [1] = 123,
---      [2] = 456,
---      ["test"] = "test",
---   }
---
---   tableB = {
---      [1] = 23,
---      [3] = 7,
---      ["test2"] = function() return true end,
---   }
---
---   tableC = {
---      [5] = "c",
---   }
---
---   table.union(tableA, tableB, tableC) will return:
---   {
---      [1] = {
---         123,
---         23,
---      },
---      [2] = 456,
---      [3] = 7,
---      [5] = "c",
---      ["test"] = "test",
---      ["test2"] = function() return true end,
---   }
---   </pre>
function table.union(...)
  local sets = { ... }
  local union = {}

  for _, set in ipairs(sets) do
    for key, val in pairs(set) do
      if union[key] and union[key] ~= val then
        if type(union[key]) == 'table' then
          table.insert(union[key], val)
        else
          union[key] = { union[key], val }
        end
      else
        union[key] = val
      end
    end
  end

  return union
end



--- Table Union.
---
--- @return Returns a numerically indexed table that is the union of the provided tables. This is
---   a union of unique values. The order and keys of the input tables are not preserved.
function table.n_union(...)
  local sets = { ... }
  local union = {}
  local union_keys = {}

  for _, set in ipairs(sets) do
    for key, val in pairs(set) do
      if not union_keys[val] then
        union_keys[val] = true
        table.insert(union, val)
      end
    end
  end

  return union
end



--- Table Intersection.
---
--- @return Returns a table that is the intersection of the provided tables. This is an
---   intersection of key/value pairs. See table.n_intersection() for an intersection of values.
---   Note that the resulting table may not be reliably traversable with ipairs() due to
---   the fact that it preserves keys. If there is a gap in numerical indices, ipairs() will
---   cease traversal.
---
--- @usage Example:
---   <pre>
---   tableA = {
---      [1] = 123,
---      [2] = 456,
---      [4] = { 1, 2 },
---      [5] = "c",
---      ["test"] = "test",
---   }
---
---   tableB = {
---      [1] = 123,
---      [2] = 4,
---      [3] = 7,
---      [4] = { 1, 2 },
---      ["test"] = function() return true end,
---   }
---
---   tableC = {
---      [1] = 123,
---      [4] = { 1, 2 },
---      [5] = "c",
---   }
---
---   table.intersection(tableA, tableB, tableC) will return:
---   {
---      [1] = 123,
---      [4] = { 1, 2 },
---   }
---   </pre>
function table.intersection(...)
  local sets = { ... }
  if #sets < 2 then
    return false
  end

  local intersection = {}

  local function intersect(set1, set2)
    local result = {}
    for key, val in pairs(set1) do
      if set2[key] then
        if _comp(val, set2[key]) then
          result[key] = val
        end
      end
    end
    return result
  end

  intersection = intersect(sets[1], sets[2])

  for i, _ in ipairs(sets) do
    if i > 2 then
      intersection = intersect(intersection, sets[i])
    end
  end

  return intersection
end



--- Table Intersection.
---
--- @return Returns a numerically indexed table that is the intersection of the provided tables.
---   This is an intersection of unique values. The order and keys of the input tables are
---   not preserved.
function table.n_intersection(...)
  local sets = { ... }
  if #sets < 2 then
    return false
  end

  local intersection = {}

  local function intersect(set1, set2)
    local intersection_keys = {}
    local result = {}
    for _, val1 in pairs(set1) do
      for _, val2 in pairs(set2) do
        if _comp(val1, val2) and not intersection_keys[val1] then
          table.insert(result, val1)
          intersection_keys[val1] = true
        end
      end
    end
    return result
  end

  intersection = intersect(sets[1], sets[2])

  for i, _ in ipairs(sets) do
    if i > 2 then
      intersection = intersect(intersection, sets[i])
    end
  end

  return intersection
end



--- Table Complement.
---
--- @return Returns a table that is the relative complement of the first table with respect to
---   the second table. Returns a complement of key/value pairs.
function table.complement(set1, set2)
  if not set1 and set2 then
    return false
  end
  if type(set1) ~= 'table' or type(set2) ~= 'table' then
    return false
  end

  local complement = {}

  for key, val in pairs(set1) do
    if not _comp(set2[key], val) then
      complement[key] = val
    end
  end
  return complement
end



--- Table Complement.
---
--- @return Returns a table that is the relative complement of the first table with respect to
---   the second table. Returns a complement of values.
function table.n_complement(set1, set2)
  if not set1 and set2 then
    return false
  end

  local complement = {}

  for _, val1 in pairs(set1) do
    local insert = true
    for _, val2 in pairs(set2) do
      if _comp(val1, val2) then
        insert = false
      end
    end
    if insert then
      table.insert(complement, val1)
    end
  end

  return complement
end


function table.update(t1, t2)
  local tbl = {}
  for k, v in pairs(t1) do
    tbl[k] = v
  end
  for k, v in pairs(t2) do
    if type(v) == "table" then
      tbl[k] = table.update(tbl[k] or {}, v)
    else
      tbl[k] = v
    end
  end
  return tbl
end

---Returns the index of the value in a table
function table.index_of(table, element)
  for index, value in ipairs(table) do
    if value == element then
      return index
    end
  end
  return nil
end

-- returns a deep copy of the table with the metatable intact. Credit to Steve Donovan of Penlight.
function table.deepcopy(t)
  if type(t) ~= 'table' then
    return t
  end
  local mt = getmetatable(t)
  local res = {}
  for k, v in pairs(t) do
    if type(v) == 'table' then
      v = table.deepcopy(v)
    end
    res[k] = v
  end
  setmetatable(res, mt)
  return res
end

-- Table keys
--
-- @return a table that is the collection of the keys in use by the table passed in.
---
--- @usage Example:
---   <pre>
---   local testTable = {
---     name = "thing",
---     type = "test",
---     malfunction = "major"
---   }
---   local keys = table.keys(testTable)
---   -- key is now a table { "name", "type", "malfunction" } but the order cannot be guaranteed
---   -- as pairs() does not iterate in a guaranteed order. If you want the keys in alphabetical
---   -- run table.sort(keys) and keys == { "malfunction", "name", "type" }
---   </pre>
function table.keys(t)
  local keys={}
  local index=0

  for key,_ in pairs(t) do
    index=index+1
    keys[index]=key
  end
	return keys
end
