#pragma once

#include <string>
#include <string_view>
#include <unordered_map>
#include <array>

using std::string_view;

struct HttpResponse {
	int status = 200;
	std::string body;
	std::string content_type = "text/plain";
	std::unordered_map<std::string, std::string> headers;

	void set_json(const std::string& json) {
		body = json;
		content_type = "application/json";
	}

	void set_text(const std::string& text) {
		body = text;
		content_type = "text/plain";
	}

	void set_html(const std::string& html) {
		body = html;
		content_type = "text/html";
	}
};

class HttpResponseBuilder {
private:
	static constexpr size_t BUFFER_SIZE = 4096;
	static constexpr const char* STATUS_LINES[] = {
		"HTTP/1.1 200 OK\r\n",
		"HTTP/1.1 201 Created\r\n", 
		"HTTP/1.1 400 Bad Request\r\n",
		"HTTP/1.1 404 Not Found\r\n",
		"HTTP/1.1 500 Internal Server Error\r\n"
	};

	static int get_status_index(int status) {
		switch (status) {
			case 200: return 0;
			case 201: return 1;
			case 400: return 2;
			case 404: return 3;
			case 500: return 4;
			default: return -1;
		}
	}

public:
	static std::string build_response(const HttpResponse& response, string_view version = "HTTP/1.1") {
		std::string result;
		result.reserve(BUFFER_SIZE);

		// Status line
		int status_idx = get_status_index(response.status);
		if (status_idx >= 0) {
			result += STATUS_LINES[status_idx];
		} else {
			result += version;
			result += " ";
			result += std::to_string(response.status);
			result += " Unknown\r\n";
		}

		// Content headers
		result += "Content-Type: ";
		result += response.content_type;
		result += "\r\nContent-Length: ";
		result += std::to_string(response.body.size());
		result += "\r\n";

		// Custom headers
		for (const auto& [key, value] : response.headers) {
			result += key;
			result += ": ";
			result += value;
			result += "\r\n";
		}

		// Connection handling
		bool keep_alive = version != "HTTP/1.0";
		if (response.headers.find("Connection") == response.headers.end()) {
			result += keep_alive ? "Connection: keep-alive\r\n" : "Connection: close\r\n";
		}

		result += "\r\n";
		result += response.body;

		return result;
	}

	// Fast path for common responses
	static std::string build_error_response(int status, string_view message, string_view version = "HTTP/1.1") {
		std::string result;
		result.reserve(256);

		int status_idx = get_status_index(status);
		if (status_idx >= 0) {
			result += STATUS_LINES[status_idx];
		} else {
			result += version;
			result += " ";
			result += std::to_string(status);
			result += " Error\r\n";
		}

		result += "Content-Type: text/plain\r\nContent-Length: ";
		result += std::to_string(message.size());
		result += "\r\nConnection: close\r\n\r\n";
		result += message;

		return result;
	}
};