-- modules/http.lua - Express-like HTTP server with pure Lua routing

local http = {}

-- Global routing tables (shared across all states)
_G._http_routes = _G._http_routes or {}
_G._http_middleware = _G._http_middleware or {}

-- Request/Response classes
local Request = {}
Request.__index = Request

local Response = {}
Response.__index = Response

-- ======================================================================
-- ROUTER IMPLEMENTATION
-- ======================================================================

local function split_path(path)
	local segments = {}
	for segment in path:gmatch("[^/]+") do
		table.insert(segments, segment)
	end
	return segments
end

local function match_route(method, path)
	local path_segments = split_path(path)
	
	for _, route in ipairs(_G._http_routes) do
		if route.method == method then
			local params = {}
			local route_segments = route.segments
			local match = true
			local i = 1
			
			while i <= #route_segments and match do
				local route_seg = route_segments[i]
				
				if route_seg == "*" then
					-- Wildcard captures everything remaining
					local remaining = {}
					for j = i, #path_segments do
						table.insert(remaining, path_segments[j])
					end
					params["*"] = table.concat(remaining, "/")
					break
				elseif route_seg:sub(1,1) == ":" then
					-- Parameter segment
					if i <= #path_segments then
						local param_name = route_seg:sub(2)
						params[param_name] = path_segments[i]
					else
						match = false
					end
				else
					-- Static segment
					if i > #path_segments or route_seg ~= path_segments[i] then
						match = false
					end
				end
				i = i + 1
			end
			
			-- Must consume all segments unless wildcard
			if match and (i > #path_segments or route_segments[i-1] == "*") then
				return route, params
			end
		end
	end
	return nil, {}
end

function _http_handle_request(req_table, res_table)
	local req = Request.new(req_table)
	local res = Response.new(res_table)
	
	-- Execute middleware chain first
	local function run_middleware(index)
		if index > #_G._http_middleware then
			local route, params = match_route(req.method, req.path)
			req.params = params
			
			if not route then
				res:status(404):send("Not Found")
				return
			end
			
			-- Run route handler
			route.handler(req, res)
			return
		end
		
		local mw = _G._http_middleware[index]
		if mw.path == nil or req.path:match("^" .. mw.path:gsub("([%(%)%.%+%-%*%?%[%]%^%$%%])", "%%%1")) then
			mw.handler(req, res, function()
				run_middleware(index + 1)
			end)
		else
			run_middleware(index + 1)
		end
	end
	
	run_middleware(1)
end

-- Functions for route synchronization
function _http_get_routes()
	return {
		routes = _G._http_routes,
		middleware = _G._http_middleware
	}
end

function _http_sync_worker_routes()
	local data = _G._http_routes_data
	if data and data.routes and data.middleware then
		_G._http_routes = data.routes
		_G._http_middleware = data.middleware
	end
end

-- ======================================================================
-- SERVER CLASS
-- ======================================================================

local Server = {}
Server.__index = Server

function http.server()
	-- Workers should not create servers
	if _G.__IS_WORKER then
		return setmetatable({}, Server)
	end

	local server = setmetatable({
		_server_created = false
	}, Server)
	
	-- Create the fasthttp server immediately
	local success, err = moonshark.http_create_server()
	if not success then
		error("Failed to create HTTP server: " .. (err or "unknown error"))
	end
	server._server_created = true
	
	return server
end

function Server:use(...)
	local args = {...}
	if #args == 1 and type(args[1]) == "function" then
		table.insert(_G._http_middleware, {path = nil, handler = args[1]})
	elseif #args == 2 and type(args[1]) == "string" and type(args[2]) == "function" then
		table.insert(_G._http_middleware, {path = args[1], handler = args[2]})
	else
		error("Invalid arguments to use()")
	end
	
	-- Only sync in main state
	if not _G.__IS_WORKER then
		self:_sync_routes()
	end
	return self
end

function Server:_add_route(method, path, handler)
	-- Ensure path starts with /
	if path:sub(1,1) ~= "/" then
		path = "/" .. path
	end
	
	local segments = split_path(path)
	
	table.insert(_G._http_routes, {
		method = method,
		path = path,
		segments = segments,
		handler = handler
	})
	
	-- Only sync in main state
	if not _G.__IS_WORKER then
		self:_sync_routes()
	end
	return self
end

function Server:_sync_routes()
	-- No-op - routes are in global Lua tables, workers inherit them automatically
end

-- HTTP method helpers
function Server:get(path, handler)
	return self:_add_route("GET", path, handler)
end

function Server:post(path, handler)
	return self:_add_route("POST", path, handler)
end

function Server:put(path, handler)
	return self:_add_route("PUT", path, handler)
end

function Server:delete(path, handler)
	return self:_add_route("DELETE", path, handler)
end

function Server:patch(path, handler)
	return self:_add_route("PATCH", path, handler)
end

function Server:head(path, handler)
	return self:_add_route("HEAD", path, handler)
end

function Server:options(path, handler)
	return self:_add_route("OPTIONS", path, handler)
end

function Server:all(path, handler)
	local methods = {"GET", "POST", "PUT", "DELETE", "PATCH", "HEAD", "OPTIONS"}
	for _, method in ipairs(methods) do
		self:_add_route(method, path, handler)
	end
	return self
end

function Server:listen(port, host, callback)
	-- Workers should not listen
	if _G.__IS_WORKER then
		if callback then callback() end
		return self
	end
	
	if type(host) == "function" then
		callback = host
		host = "localhost"
	end
	
	host = host or "localhost"
	local addr = host .. ":" .. tostring(port)
	
	-- Spawn workers first
	local success, err = moonshark.http_spawn_workers()
	if not success then
		error("Failed to spawn workers: " .. (err or "unknown error"))
	end
	
	-- Then start listening
	success, err = moonshark.http_listen(addr)
	if not success then
		error("Failed to start server: " .. (err or "unknown error"))
	end
	
	if callback then
		callback()
	end
	
	return self
end

function Server:close()
	if _G.__IS_WORKER then
		return true
	end
	return moonshark.http_close_server()
end

-- ======================================================================
-- REQUEST OBJECT
-- ======================================================================

function Request.new(req_table)
	local req = setmetatable({
		method = req_table.method,
		path = req_table.path,
		query = req_table.query or {},
		headers = req_table.headers or {},
		params = {},
		body = req_table.body or ""
	}, Request)
	
	return req
end

function Request:get(header_name)
	return self.headers[header_name] or self.headers[header_name:lower()]
end

function Request:header(header_name)
	return self:get(header_name)
end

function Request:param(name, default_value)
	return self.params[name] or default_value
end

function Request:query_param(name, default_value)
	return self.query[name] or default_value
end

function Request:json()
	if self.body == "" then
		return nil
	end
	
	local success, result = pcall(function()
		return moonshark.json_decode(self.body)
	end)
	
	if success then
		return result
	else
		error("Invalid JSON in request body")
	end
end

function Request:is_json()
	local content_type = self:get("content-type") or ""
	return content_type:find("application/json") ~= nil
end

function Request:is_form()
	local content_type = self:get("content-type") or ""
	return content_type:find("application/x-www-form-urlencoded") ~= nil
end

-- ======================================================================
-- RESPONSE OBJECT
-- ======================================================================

function Response.new(res_table)
	local res = setmetatable({
		_table = res_table,
		_sent = false
	}, Response)
	
	return res
end

function Response:status(code)
	if self._sent then
		error("Cannot set status after response has been sent")
	end
	self._table.status = code
	return self
end

function Response:header(name, value)
	if self._sent then
		error("Cannot set headers after response has been sent")
	end
	self._table.headers[name] = value
	return self
end

function Response:set(name, value)
	return self:header(name, value)
end

function Response:type(content_type)
	return self:header("Content-Type", content_type)
end

function Response:send(data)
	if self._sent then
		error("Response already sent")
	end
	
	if type(data) == "table" then
		self:json(data)
	elseif type(data) == "number" then
		self._table.status = data
		self._table.body = ""
	else
		self._table.body = tostring(data or "")
	end
	
	self._sent = true
	return self
end

function Response:json(data)
	if self._sent then
		error("Response already sent")
	end
	
	self:type("application/json")
	
	local success, json_str = pcall(function()
		return moonshark.json_encode(data)
	end)
	
	if success then
		self._table.body = json_str
	else
		error("Failed to encode JSON response")
	end
	
	self._sent = true
	return self
end

function Response:text(text)
	if self._sent then
		error("Response already sent")
	end
	
	self:type("text/plain")
	self._table.body = tostring(text or "")
	self._sent = true
	return self
end

function Response:html(html)
	if self._sent then
		error("Response already sent")
	end
	
	self:type("text/html")
	self._table.body = tostring(html or "")
	self._sent = true
	return self
end

function Response:redirect(url, status)
	if self._sent then
		error("Response already sent")
	end
	
	status = status or 302
	self:status(status)
	self:header("Location", url)
	self._table.body = ""
	self._sent = true
	return self
end

function Response:cookie(name, value, options)
	if self._sent then
		error("Cannot set cookies after response has been sent")
	end
	
	options = options or {}
	local cookie = name .. "=" .. tostring(value)
	
	if options.expires then
		cookie = cookie .. "; Expires=" .. options.expires
	end
	
	if options.max_age then
		cookie = cookie .. "; Max-Age=" .. tostring(options.max_age)
	end
	
	if options.domain then
		cookie = cookie .. "; Domain=" .. options.domain
	end
	
	if options.path then
		cookie = cookie .. "; Path=" .. options.path
	end
	
	if options.secure then
		cookie = cookie .. "; Secure"
	end
	
	if options.http_only then
		cookie = cookie .. "; HttpOnly"
	end
	
	if options.same_site then
		cookie = cookie .. "; SameSite=" .. options.same_site
	end
	
	local existing = self._table.headers["Set-Cookie"]
	if existing then
		if type(existing) == "table" then
			table.insert(existing, cookie)
		else
			self._table.headers["Set-Cookie"] = {existing, cookie}
		end
	else
		self._table.headers["Set-Cookie"] = cookie
	end
	
	return self
end

function Response:clear_cookie(name, options)
	options = options or {}
	options.expires = "Thu, 01 Jan 1970 00:00:00 GMT"
	options.max_age = 0
	return self:cookie(name, "", options)
end

-- ======================================================================
-- MIDDLEWARE HELPERS
-- ======================================================================

function http.cors(options)
	options = options or {}
	local origin = options.origin or "*"
	local methods = options.methods or "GET,HEAD,PUT,PATCH,POST,DELETE"
	local headers = options.headers or "Content-Type,Authorization"
	
	return function(req, res, next)
		res:header("Access-Control-Allow-Origin", origin)
		res:header("Access-Control-Allow-Methods", methods)
		res:header("Access-Control-Allow-Headers", headers)
		
		if options.credentials then
			res:header("Access-Control-Allow-Credentials", "true")
		end
		
		if req.method == "OPTIONS" then
			res:status(204):send("")
		else
			next()
		end
	end
end

function http.static(root_path)
	return function(req, res, next)
		if req.method ~= "GET" and req.method ~= "HEAD" then
			next()
			return
		end
		
		local file_path = moonshark.path_join(root_path, req.path)
		file_path = moonshark.path_clean(file_path)
		
		local abs_root = moonshark.path_abs(root_path)
		local abs_file = moonshark.path_abs(file_path)
		
		if not abs_file or not abs_file:find("^" .. abs_root:gsub("([%(%)%.%+%-%*%?%[%]%^%$%%])", "%%%1")) then
			next()
			return
		end
		
		if moonshark.file_exists(file_path) and not moonshark.file_is_dir(file_path) then
			local content = moonshark.file_read(file_path)
			if content then
				local ext = moonshark.path_ext(file_path):lower()
				local content_types = {
					[".html"] = "text/html",
					[".css"] = "text/css",
					[".js"] = "application/javascript",
					[".json"] = "application/json",
					[".png"] = "image/png",
					[".jpg"] = "image/jpeg",
					[".jpeg"] = "image/jpeg",
					[".gif"] = "image/gif",
					[".svg"] = "image/svg+xml",
					[".webp"] = "image/webp",
					[".txt"] = "text/plain",
				}
				
				local content_type = content_types[ext] or "application/octet-stream"
				res:type(content_type):send(content)
				return
			end
		end
		
		next()
	end
end

function http.json_parser()
	return function(req, res, next)
		if req:is_json() and req.body ~= "" then
			local success, data = pcall(function()
				return req:json()
			end)
			
			if success then
				req.json_body = data
			else
				res:status(400):json({error = "Invalid JSON"})
				return
			end
		end
		next()
	end
end

function http.logger()
	return function(req, res, next)
		local start_time = os.clock()
		
		next()
		
		local duration = (os.clock() - start_time) * 1000
		local status = res._table.status or 200
		print(string.format("%s %s %d %.2fms", req.method, req.path, status, duration))
	end
end

function http.create_server(callback)
	local app = http.server()
	if callback then
		callback(app)
	end
	return app
end

return http