--[[
table.lua - Extended table library functions
]]--

local table_ext = {}

-- ======================================================================
-- SET OPERATIONS
-- ======================================================================

-- Remove duplicate values (like array_unique)
function table_ext.unique(t)
	if type(t) ~= "table" then return {} end
	
	local seen = {}
	local result = {}
	
	for _, v in ipairs(t) do
		if not seen[v] then
			seen[v] = true
			table.insert(result, v)
		end
	end
	
	return result
end

-- Return items in first table that are present in all other tables (like array_intersect)
function table_ext.intersect(t1, ...)
	if type(t1) ~= "table" then return {} end
	
	local args = {...}
	local result = {}
	
	-- Convert all tables to sets for O(1) lookups
	local sets = {}
	for i, t in ipairs(args) do
		if type(t) ~= "table" then
			return {}
		end
		
		sets[i] = {}
		for _, v in ipairs(t) do
			sets[i][v] = true
		end
	end
	
	-- Check each element in t1 against all other tables
	for _, v in ipairs(t1) do
		local present_in_all = true
		
		for i = 1, #args do
			if not sets[i][v] then
				present_in_all = false
				break
			end
		end
		
		if present_in_all then
			table.insert(result, v)
		end
	end
	
	return result
end

-- Return items in first table that are not present in other tables (like array_diff)
function table_ext.diff(t1, ...)
	if type(t1) ~= "table" then return {} end
	
	local args = {...}
	local result = {}
	
	-- Build unified set of elements from other tables
	local others = {}
	for _, t in ipairs(args) do
		if type(t) == "table" then
			for _, v in ipairs(t) do
				others[v] = true
			end
		end
	end
	
	-- Add elements from t1 that aren't in other tables
	for _, v in ipairs(t1) do
		if not others[v] then
			table.insert(result, v)
		end
	end
	
	return result
end

-- ======================================================================
-- SEARCH AND FILTERING
-- ======================================================================

-- Check if value exists in table (like in_array)
function table_ext.contains(t, value)
	if type(t) ~= "table" then return false end
	
	for _, v in ipairs(t) do
		if v == value then
			return true
		end
	end
	
	return false
end

-- Find key for a value (like array_search)
function table_ext.find(t, value)
	if type(t) ~= "table" then return nil end
	
	for k, v in pairs(t) do
		if v == value then
			return k
		end
	end
	
	return nil
end

-- Filter table elements (like array_filter)
function table_ext.filter(t, func)
	if type(t) ~= "table" or type(func) ~= "function" then return {} end
	
	local result = {}
	
	for k, v in pairs(t) do
		if func(v, k) then
			if type(k) == "number" and k % 1 == 0 and k > 0 then
				-- For array-like tables, maintain numerical indices
				table.insert(result, v)
			else
				-- For associative tables, preserve the key
				result[k] = v
			end
		end
	end
	
	return result
end

-- ======================================================================
-- TRANSFORMATION FUNCTIONS
-- ======================================================================

-- Apply a function to all values (like array_map)
function table_ext.map(t, func)
	if type(t) ~= "table" or type(func) ~= "function" then return {} end
	
	local result = {}
	
	for k, v in pairs(t) do
		if type(k) == "number" and k % 1 == 0 and k > 0 then
			-- For array-like tables, maintain numerical indices
			table.insert(result, func(v, k))
		else
			-- For associative tables, preserve the key
			result[k] = func(v, k)
		end
	end
	
	return result
end

-- Reduce a table to a single value (like array_reduce)
function table_ext.reduce(t, func, initial)
	if type(t) ~= "table" or type(func) ~= "function" then 
		return initial
	end
	
	local result = initial
	
	for k, v in pairs(t) do
		if result == nil then
			result = v
		else
			result = func(result, v, k)
		end
	end
	
	return result
end

-- ======================================================================
-- ADVANCED OPERATIONS
-- ======================================================================

-- Split table into chunks (like array_chunk)
function table_ext.chunk(t, size)
	if type(t) ~= "table" or type(size) ~= "number" or size <= 0 then 
		return {}
	end
	
	local result = {}
	local chunk = {}
	local count = 0
	
	for _, v in ipairs(t) do
		count = count + 1
		chunk[count] = v
		
		if count == size then
			table.insert(result, chunk)
			chunk = {}
			count = 0
		end
	end
	
	-- Add the last chunk if it has any elements
	if count > 0 then
		table.insert(result, chunk)
	end
	
	return result
end

-- Extract a column from a table of tables (like array_column)
function table_ext.column(t, column_key, index_key)
	if type(t) ~= "table" or column_key == nil then return {} end
	
	local result = {}
	
	for _, row in ipairs(t) do
		if type(row) == "table" and row[column_key] ~= nil then
			if index_key ~= nil and row[index_key] ~= nil then
				result[row[index_key]] = row[column_key]
			else
				table.insert(result, row[column_key])
			end
		end
	end
	
	return result
end

-- Merge tables (like array_merge, but preserves keys)
function table_ext.merge(...)
	local result = {}
	
	for _, t in ipairs({...}) do
		if type(t) == "table" then
			for k, v in pairs(t) do
				if type(k) == "number" and k % 1 == 0 and k > 0 then
					-- For array-like tables, append values
					table.insert(result, v)
				else
					-- For associative tables, overwrite with latest value
					result[k] = v
				end
			end
		end
	end
	
	return result
end

-- ======================================================================
-- KEY MANIPULATION
-- ======================================================================

-- Exchange keys with values (like array_flip)
function table_ext.flip(t)
	if type(t) ~= "table" then return {} end
	
	local result = {}
	
	for k, v in pairs(t) do
		if type(v) == "string" or type(v) == "number" then
			result[v] = k
		end
	end
	
	return result
end

-- Get all keys from a table (like array_keys)
function table_ext.keys(t)
	if type(t) ~= "table" then return {} end
	
	local result = {}
	
	for k, _ in pairs(t) do
		table.insert(result, k)
	end
	
	return result
end

-- Get all values from a table (like array_values)
function table_ext.values(t)
	if type(t) ~= "table" then return {} end
	
	local result = {}
	
	for _, v in pairs(t) do
		table.insert(result, v)
	end
	
	return result
end

-- ======================================================================
-- STATISTICAL FUNCTIONS
-- ======================================================================

-- Sum all values (like array_sum)
function table_ext.sum(t)
	if type(t) ~= "table" then return 0 end
	
	local sum = 0
	
	for _, v in pairs(t) do
		if type(v) == "number" then
			sum = sum + v
		end
	end
	
	return sum
end

-- Multiply all values (like array_product)
function table_ext.product(t)
	if type(t) ~= "table" then return 0 end
	
	local product = 1
	local has_number = false
	
	for _, v in pairs(t) do
		if type(v) == "number" then
			product = product * v
			has_number = true
		end
	end
	
	return has_number and product or 0
end

-- Count value occurrences (like array_count_values)
function table_ext.count_values(t)
	if type(t) ~= "table" then return {} end
	
	local result = {}
	
	for _, v in pairs(t) do
		if type(v) == "string" or type(v) == "number" then
			result[v] = (result[v] or 0) + 1
		end
	end
	
	return result
end

-- ======================================================================
-- CREATION HELPERS
-- ======================================================================

-- Create a table with a range of values (like range)
function table_ext.range(start, stop, step)
	if type(start) ~= "number" then return {} end
	
	step = step or 1
	
	local result = {}
	
	if not stop then
		stop = start
		start = 1
	end
	
	if (step > 0 and start > stop) or (step < 0 and start < stop) then
		return {}
	end
	
	local i = start
	while (step > 0 and i <= stop) or (step < 0 and i >= stop) do
		table.insert(result, i)
		i = i + step
	end
	
	return result
end

-- Fill a table with a value (like array_fill)
function table_ext.fill(start_index, count, value)
	if type(start_index) ~= "number" or type(count) ~= "number" or count < 0 then 
		return {}
	end
	
	local result = {}
	
	for i = 0, count - 1 do
		result[start_index + i] = value
	end
	
	return result
end

-- ======================================================================
-- ADDITIONAL USEFUL FUNCTIONS
-- ======================================================================

-- Reverse a table (array part only)
function table_ext.reverse(t)
	if type(t) ~= "table" then return {} end
	
	local result = {}
	local count = #t
	
	for i = count, 1, -1 do
		table.insert(result, t[i])
	end
	
	return result
end

-- Get the max value in a table
function table_ext.max(t)
	if type(t) ~= "table" or #t == 0 then return nil end
	
	local max = t[1]
	
	for i = 2, #t do
		if t[i] > max then
			max = t[i]
		end
	end
	
	return max
end

-- Get the min value in a table
function table_ext.min(t)
	if type(t) ~= "table" or #t == 0 then return nil end
	
	local min = t[1]
	
	for i = 2, #t do
		if t[i] < min then
			min = t[i]
		end
	end
	
	return min
end

-- Check if all elements satisfy a condition
function table_ext.all(t, func)
	if type(t) ~= "table" or type(func) ~= "function" then return false end
	
	for k, v in pairs(t) do
		if not func(v, k) then
			return false
		end
	end
	
	return true
end

-- Check if any element satisfies a condition
function table_ext.any(t, func)
	if type(t) ~= "table" or type(func) ~= "function" then return false end
	
	for k, v in pairs(t) do
		if func(v, k) then
			return true
		end
	end
	
	return false
end

-- ======================================================================
-- TABLE UTILITIES
-- ======================================================================

-- Check if table is empty
function table_ext.is_empty(t)
	if type(t) ~= "table" then return true end
	return next(t) == nil
end

-- Get table length (works for both array and hash parts)
function table_ext.size(t)
	if type(t) ~= "table" then return 0 end
	
	local count = 0
	for _ in pairs(t) do
		count = count + 1
	end
	
	return count
end

-- Get a slice of a table
function table_ext.slice(t, start, stop)
	if type(t) ~= "table" then return {} end
	
	local len = #t
	start = start or 1
	stop = stop or len
	
	-- Convert negative indices
	if start < 0 then start = len + start + 1 end
	if stop < 0 then stop = len + stop + 1 end
	
	-- Ensure bounds
	start = math.max(1, math.min(start, len + 1))
	stop = math.max(0, math.min(stop, len))
	
	local result = {}
	for i = start, stop do
		table.insert(result, t[i])
	end
	
	return result
end

-- ======================================================================
-- SORTING FUNCTIONS
-- ======================================================================

-- Sort array values (like sort)
function table_ext.sort(t)
	if type(t) ~= "table" then return t end
	table.sort(t)
	return t
end

-- Sort array values in reverse order (like rsort)
function table_ext.rsort(t)
	if type(t) ~= "table" then return t end
	table.sort(t, function(a, b) return a > b end)
	return t
end

-- Sort and maintain index association (like asort)
function table_ext.asort(t)
	if type(t) ~= "table" then return t end
	
	local keys, result = {}, {}
	for k in pairs(t) do
		table.insert(keys, k)
	end
	
	table.sort(keys, function(a, b) 
		return t[a] < t[b]
	end)
	
	for _, k in ipairs(keys) do
		result[k] = t[k]
	end
	
	return result
end

-- Sort in reverse order and maintain index association (like arsort)
function table_ext.arsort(t)
	if type(t) ~= "table" then return t end
	
	local keys, result = {}, {}
	for k in pairs(t) do
		table.insert(keys, k)
	end
	
	table.sort(keys, function(a, b) 
		return t[a] > t[b]
	end)
	
	for _, k in ipairs(keys) do
		result[k] = t[k]
	end
	
	return result
end

-- Sort by keys (like ksort)
function table_ext.ksort(t)
	if type(t) ~= "table" then return t end
	
	local keys, result = {}, {}
	for k in pairs(t) do
		table.insert(keys, k)
	end
	
	table.sort(keys)
	
	for _, k in ipairs(keys) do
		result[k] = t[k]
	end
	
	return result
end

-- Sort by keys in reverse order (like krsort)
function table_ext.krsort(t)
	if type(t) ~= "table" then return t end
	
	local keys, result = {}, {}
	for k in pairs(t) do
		table.insert(keys, k)
	end
	
	table.sort(keys, function(a, b) return a > b end)
	
	for _, k in ipairs(keys) do
		result[k] = t[k]
	end
	
	return result
end

-- Sort using custom comparison function (like usort)
function table_ext.usort(t, compare_func)
	if type(t) ~= "table" or type(compare_func) ~= "function" then return t end
	
	table.sort(t, compare_func)
	return t
end

-- Sort maintaining keys using custom comparison function (like uasort)
function table_ext.uasort(t, compare_func)
	if type(t) ~= "table" or type(compare_func) ~= "function" then return t end
	
	local keys, result = {}, {}
	for k in pairs(t) do
		table.insert(keys, k)
	end
	
	table.sort(keys, function(a, b) 
		return compare_func(t[a], t[b])
	end)
	
	for _, k in ipairs(keys) do
		result[k] = t[k]
	end
	
	return result
end

-- Sort by keys using custom comparison function (like uksort)
function table_ext.uksort(t, compare_func)
	if type(t) ~= "table" or type(compare_func) ~= "function" then return t end
	
	local keys, result = {}, {}
	for k in pairs(t) do
		table.insert(keys, k)
	end
	
	table.sort(keys, compare_func)
	
	for _, k in ipairs(keys) do
		result[k] = t[k]
	end
	
	return result
end

-- Natural order sort (like natsort)
function table_ext.natsort(t)
	if type(t) ~= "table" then return t end
	
	local function natural_compare(a, b)
		local function get_chunks(s)
			if type(s) ~= "string" then s = tostring(s) end
			local chunks = {}
			for num, alpha in s:gmatch("(%d+)([^%d]*)") do
				table.insert(chunks, {n=true, val=tonumber(num)})
				if alpha ~= "" then
					table.insert(chunks, {n=false, val=alpha})
				end
			end
			return chunks
		end
		
		local a_chunks = get_chunks(a)
		local b_chunks = get_chunks(b)
		
		for i = 1, math.min(#a_chunks, #b_chunks) do
			if a_chunks[i].n ~= b_chunks[i].n then
				return a_chunks[i].n -- numbers come before strings
			elseif a_chunks[i].val ~= b_chunks[i].val then
				if a_chunks[i].n then
					return a_chunks[i].val < b_chunks[i].val
				else
					return a_chunks[i].val < b_chunks[i].val
				end
			end
		end
		
		return #a_chunks < #b_chunks
	end
	
	table.sort(t, natural_compare)
	return t
end

-- Natural case-insensitive sort (like natcasesort)
function table_ext.natcasesort(t)
	if type(t) ~= "table" then return t end
	
	local function case_insensitive_natural_compare(a, b)
		if type(a) == "string" and type(b) == "string" then
			return table_ext.natural_compare(a:lower(), b:lower())
		else
			return table_ext.natural_compare(a, b)
		end
	end
	
	return table_ext.usort(t, case_insensitive_natural_compare)
end

-- ======================================================================
-- ARRAY MODIFICATION FUNCTIONS
-- ======================================================================

-- Push one or more elements onto the end (like array_push)
function table_ext.push(t, ...)
	if type(t) ~= "table" then return 0 end
	
	local count = 0
	for _, v in ipairs({...}) do
		table.insert(t, v)
		count = count + 1
	end
	
	return count
end

-- Pop the element off the end (like array_pop)
function table_ext.pop(t)
	if type(t) ~= "table" or #t == 0 then return nil end
	
	local value = t[#t]
	t[#t] = nil
	return value
end

-- Shift an element off the beginning (like array_shift)
function table_ext.shift(t)
	if type(t) ~= "table" or #t == 0 then return nil end
	
	local value = t[1]
	table.remove(t, 1)
	return value
end

-- Prepend elements to the beginning (like array_unshift)
function table_ext.unshift(t, ...)
	if type(t) ~= "table" then return 0 end
	
	local args = {...}
	for i = #args, 1, -1 do
		table.insert(t, 1, args[i])
	end
	
	return #t
end

-- Pad array to specified length (like array_pad)
function table_ext.pad(t, size, value)
	if type(t) ~= "table" then return {} end
	
	local result = table_ext.deep_copy(t)
	local current_size = #result
	
	if size == current_size then return result end
	
	if size > current_size then
		-- Pad to the right
		for i = current_size + 1, size do
			result[i] = value
		end
	else
		-- Pad to the left (negative size)
		local abs_size = math.abs(size)
		if abs_size < current_size then
			local temp = {}
			for i = 1, abs_size do
				if i <= abs_size - current_size then
					temp[i] = value
				else
					temp[i] = result[i - (abs_size - current_size)]
				end
			end
			result = temp
		else
			-- Fill completely with padding value
			result = {}
			for i = 1, abs_size do
				result[i] = value
			end
		end
	end
	
	return result
end

-- Remove a portion and replace it (like array_splice)
function table_ext.splice(t, offset, length, ...)
	if type(t) ~= "table" then return {} end
	
	local result = table_ext.deep_copy(t)
	local size = #result
	
	-- Handle negative offset
	if offset < 0 then
		offset = size + offset
	end
	
	-- Ensure offset is valid
	offset = math.max(1, math.min(offset, size + 1))
	
	-- Handle negative or nil length
	if length == nil then
		length = size - offset + 1
	elseif length < 0 then
		length = math.max(0, size - offset + length + 1)
	end
	
	-- Extract removed portion
	local removed = {}
	for i = offset, offset + length - 1 do
		if i <= size then
			table.insert(removed, result[i])
		end
	end
	
	-- Remove portion from original
	for i = 1, length do
		table.remove(result, offset)
	end
	
	-- Insert replacement values
	local replacements = {...}
	for i = #replacements, 1, -1 do
		table.insert(result, offset, replacements[i])
	end
	
	return removed, result
end

-- Randomize array order (like shuffle)
function table_ext.shuffle(t)
	if type(t) ~= "table" then return t end
	
	local result = table_ext.deep_copy(t)
	local size = #result
	
	for i = size, 2, -1 do
		local j = math.random(i)
		result[i], result[j] = result[j], result[i]
	end
	
	return result
end

-- Pick random keys from array (like array_rand)
function table_ext.rand(t, num_keys)
	if type(t) ~= "table" then return nil end
	
	local size = #t
	if size == 0 then return nil end
	
	num_keys = num_keys or 1
	num_keys = math.min(num_keys, size)
	
	if num_keys <= 0 then return nil end
	
	if num_keys == 1 then
		return math.random(size)
	else
		local keys = {}
		local result = {}
		
		-- Create a list of all possible keys
		for i = 1, size do
			keys[i] = i
		end
		
		-- Select random keys
		for i = 1, num_keys do
			local j = math.random(#keys)
			table.insert(result, keys[j])
			table.remove(keys, j)
		end
		
		table.sort(result)
		return result
	end
end

-- ======================================================================
-- ARRAY INSPECTION FUNCTIONS
-- ======================================================================

-- Check if key exists (like array_key_exists)
function table_ext.key_exists(key, t)
	if type(t) ~= "table" then return false end
	return t[key] ~= nil
end

-- Get the first key (like array_key_first)
function table_ext.key_first(t)
	if type(t) ~= "table" then return nil end
	
	-- For array-like tables
	if #t > 0 then return 1 end
	
	-- For associative tables
	local first_key = nil
	for k in pairs(t) do
		first_key = k
		break
	end
	
	return first_key
end

-- Get the last key (like array_key_last)
function table_ext.key_last(t)
	if type(t) ~= "table" then return nil end
	
	-- For array-like tables
	if #t > 0 then return #t end
	
	-- For associative tables (no guaranteed order, return any key)
	local last_key = nil
	for k in pairs(t) do
		last_key = k
	end
	
	return last_key
end

-- Check if table is a list (like array_is_list)
function table_ext.is_list(t)
	if type(t) ~= "table" then return false end
	
	local count = 0
	for k in pairs(t) do
		count = count + 1
		if type(k) ~= "number" or k <= 0 or math.floor(k) ~= k or k > count then
			return false
		end
	end
	
	return true
end

-- ======================================================================
-- OTHER IMPORTANT FUNCTIONS
-- ======================================================================

-- Create array with keys from one array, values from another (like array_combine)
function table_ext.combine(keys, values)
	if type(keys) ~= "table" or type(values) ~= "table" then return {} end
	
	local result = {}
	local key_count = #keys
	local value_count = #values
	
	for i = 1, math.min(key_count, value_count) do
		result[keys[i]] = values[i]
	end
	
	return result
end

-- Replace elements from one array into another (like array_replace)
function table_ext.replace(t, ...)
	if type(t) ~= "table" then return {} end
	
	local result = table_ext.deep_copy(t)
	
	for _, replacement in ipairs({...}) do
		if type(replacement) == "table" then
			for k, v in pairs(replacement) do
				result[k] = v
			end
		end
	end
	
	return result
end

-- Replace elements recursively (like array_replace_recursive)
function table_ext.replace_recursive(t, ...)
	if type(t) ~= "table" then return {} end
	
	local result = table_ext.deep_copy(t)
	
	for _, replacement in ipairs({...}) do
		if type(replacement) == "table" then
			for k, v in pairs(replacement) do
				if type(v) == "table" and type(result[k]) == "table" then
					result[k] = table_ext.replace_recursive(result[k], v)
				else
					result[k] = v
				end
			end
		end
	end
	
	return result
end

-- Apply function to each element (like array_walk)
function table_ext.walk(t, callback, user_data)
	if type(t) ~= "table" or type(callback) ~= "function" then return t end
	
	for k, v in pairs(t) do
		t[k] = callback(v, k, user_data)
	end
	
	return t
end

-- Apply function recursively (like array_walk_recursive)
function table_ext.walk_recursive(t, callback, user_data)
	if type(t) ~= "table" or type(callback) ~= "function" then return t end
	
	for k, v in pairs(t) do
		if type(v) == "table" then
			table_ext.walk_recursive(v, callback, user_data)
		else
			t[k] = callback(v, k, user_data)
		end
	end
	
	return t
end

-- Sort multiple arrays (simplified array_multisort)
function table_ext.multisort(...)
	local args = {...}
	if #args == 0 then return end
	
	-- First argument is the main table
	local main = args[1]
	if type(main) ~= "table" then return end
	
	-- Create a table of indices
	local indices = {}
	for i = 1, #main do
		indices[i] = i
	end
	
	-- Sort the indices based on the arrays
	table.sort(indices, function(a, b)
		for i = 1, #args do
			local arr = args[i]
			if type(arr) == "table" then
				if arr[a] ~= arr[b] then
					return arr[a] < arr[b]
				end
			end
		end
		return a < b
	end)
	
	-- Reorder all arrays based on sorted indices
	for i = 1, #args do
		local arr = args[i]
		if type(arr) == "table" then
			local temp = table_ext.deep_copy(arr)
			for j = 1, #indices do
				arr[j] = temp[indices[j]]
			end
		end
	end
end

-- Efficient deep copy function
function table_ext.deep_copy(obj)
	if type(obj) ~= 'table' then return obj end
	local res = {}
	for k, v in pairs(obj) do res[k] = table_ext.deep_copy(v) end
	return res
end

-- ======================================================================
-- INSTALL EXTENSIONS INTO TABLE LIBRARY
-- ======================================================================

for name, func in pairs(table) do
	table_ext[name] = func
end

return table_ext