require("../tests/tests")
local str = require("string")

-- Pure Lua implementations for comparison
local pure_lua = {}

function pure_lua.capitalize(s)
	return s:gsub("(%a)([%w_']*)", function(first, rest)
		return first:upper() .. rest:lower()
	end)
end

function pure_lua.camel_case(s)
	local words = {}
	for word in s:gmatch("%S+") do
		table.insert(words, word:lower())
	end
	if #words == 0 then return s end
	
	local result = words[1]
	for i = 2, #words do
		result = result .. words[i]:gsub("^%l", string.upper)
	end
	return result
end

function pure_lua.template(template, vars)
	vars = vars or {}
	return template:gsub("%${([%w_]+)}", function(var)
		return tostring(vars[var] or "")
	end)
end

function pure_lua.distance(a, b)
	local len_a, len_b = #a, #b
	if len_a == 0 then return len_b end
	if len_b == 0 then return len_a end
	
	local matrix = {}
	for i = 0, len_a do
		matrix[i] = {[0] = i}
	end
	for j = 0, len_b do
		matrix[0][j] = j
	end
	
	for i = 1, len_a do
		for j = 1, len_b do
			local cost = (a:sub(i,i) == b:sub(j,j)) and 0 or 1
			matrix[i][j] = math.min(
				matrix[i-1][j] + 1,
				matrix[i][j-1] + 1,
				matrix[i-1][j-1] + cost
			)
		end
	end
	
	return matrix[len_a][len_b]
end

function pure_lua.wrap(s, width)
	local words = {}
	for word in s:gmatch("%S+") do
		table.insert(words, word)
	end
	
	local lines = {}
	local current_line = ""
	
	for _, word in ipairs(words) do
		if #current_line + #word + 1 <= width then
			if current_line == "" then
				current_line = word
			else
				current_line = current_line .. " " .. word
			end
		else
			if current_line ~= "" then
				table.insert(lines, current_line)
			end
			current_line = word
		end
	end
	
	if current_line ~= "" then
		table.insert(lines, current_line)
	end
	
	return lines
end

function pure_lua.slug(s)
	-- Remove accents (simplified)
	local result = s:lower()
	result = result:gsub("[àáâãäå]", "a")
	result = result:gsub("[èéêë]", "e")
	result = result:gsub("[ìíîï]", "i")
	result = result:gsub("[òóôõö]", "o")
	result = result:gsub("[ùúûü]", "u")
	result = result:gsub("[ñ]", "n")
	result = result:gsub("[ç]", "c")
	result = result:gsub("[^%w%s]", "")
	result = result:gsub("%s+", "-")
	result = result:gsub("^%-+", ""):gsub("%-+$", "")
	return result
end

-- Test data
local test_texts = {
	short = "Hello World",
	medium = "The quick brown fox jumps over the lazy dog. This is a test sentence for benchmarking.",
	long = string.rep("Lorem ipsum dolor sit amet, consectetur adipiscing elit. ", 100),
	template_str = "Hello ${name}, you are ${age} years old and work as a ${job}.",
	template_vars = {name = "John", age = 30, job = "developer"}
}

-- Benchmark function
local function benchmark_comparison(name, go_func, lua_func, test_data, iterations)
	iterations = iterations or 10000
	
	print(string.format("\n=== %s Benchmark (%d iterations) ===", name, iterations))
	
	-- Warmup
	for i = 1, 100 do
		go_func(test_data)
		lua_func(test_data)
	end
	
	-- Benchmark Go version
	local go_start = os.clock()
	for i = 1, iterations do
		go_func(test_data)
	end
	local go_time = os.clock() - go_start
	
	-- Benchmark Lua version
	local lua_start = os.clock()
	for i = 1, iterations do
		lua_func(test_data)
	end
	local lua_time = os.clock() - lua_start
	
	-- Results
	local go_rate = iterations / go_time
	local lua_rate = iterations / lua_time
	local speedup = lua_time / go_time
	
	print(string.format("Go (enhanced):   %.3fs (%.0f ops/sec)", go_time, go_rate))
	print(string.format("Lua (pure):      %.3fs (%.0f ops/sec)", lua_time, lua_rate))
	print(string.format("Speedup: %.2fx %s", math.abs(speedup), speedup > 1 and "(Go faster)" or "(Lua faster)"))
	
	return {
		go_time = go_time,
		lua_time = lua_time,
		speedup = speedup,
		go_rate = go_rate,
		lua_rate = lua_rate
	}
end

-- Benchmark wrapper functions
local function run_benchmarks()
	print("String Operations Performance Comparison")
	print("=" .. string.rep("=", 50))
	
	local results = {}
	
	-- Capitalize benchmark
	results.capitalize = benchmark_comparison(
		"Capitalize",
		function(text) return str.capitalize(text) end,
		function(text) return pure_lua.capitalize(text) end,
		test_texts.medium
	)
	
	-- CamelCase benchmark
	results.camel_case = benchmark_comparison(
		"CamelCase",
		function(text) return str.camel_case(text) end,
		function(text) return pure_lua.camel_case(text) end,
		test_texts.medium
	)
	
	-- Template benchmark
	results.template = benchmark_comparison(
		"Template",
		function(data) return str.template(test_texts.template_str, data) end,
		function(data) return pure_lua.template(test_texts.template_str, data) end,
		test_texts.template_vars
	)
	
	-- Distance benchmark (shorter strings due to O(n²) complexity)
	results.distance = benchmark_comparison(
		"Levenshtein Distance",
		function(texts) return str.distance(texts[1], texts[2]) end,
		function(texts) return pure_lua.distance(texts[1], texts[2]) end,
		{"kitten", "sitting"},
		1000  -- Fewer iterations for expensive operation
	)
	
	-- Wrap benchmark
	results.wrap = benchmark_comparison(
		"Text Wrap",
		function(text) return str.wrap(text, 40) end,
		function(text) return pure_lua.wrap(text, 40) end,
		test_texts.long
	)
	
	-- Slug benchmark
	results.slug = benchmark_comparison(
		"Slug Generation",
		function(text) return str.slug(text) end,
		function(text) return pure_lua.slug(text) end,
		"Café & Restaurant!! Special Characters"
	)
	
	-- Summary
	print("\n" .. string.rep("=", 50))
	print("PERFORMANCE SUMMARY")
	print(string.rep("=", 50))
	
	local go_wins = 0
	local lua_wins = 0
	
	for name, result in pairs(results) do
		local winner = result.speedup > 1 and "Go" or "Lua"
		local margin = string.format("%.2fx", math.abs(result.speedup))
		print(string.format("%-20s: %s wins by %s", name, winner, margin))
		
		if result.speedup > 1 then
			go_wins = go_wins + 1
		else
			lua_wins = lua_wins + 1
		end
	end
	
	print(string.rep("-", 50))
	print(string.format("Go wins: %d, Lua wins: %d", go_wins, lua_wins))
	
	-- Analysis
	print("\nANALYSIS:")
	print("• Go functions benefit from optimized implementations")
	print("• Lua functions avoid CGO overhead for simple operations")
	print("• Choice depends on operation complexity vs call frequency")
	
	return results
end

-- Run the benchmarks
run_benchmarks()