package main

import (
	"crypto/sha256"
	"fmt"
	"net/http"
	"log"
	"os"
	"os/signal"
	"strings"
	"syscall"

	"httpfromtcp/internal/headers"
	"httpfromtcp/internal/server"
	"httpfromtcp/internal/request"
	"httpfromtcp/internal/response"
)

const port = 42069

func respond200() []byte{
	return []byte(`
	<html>
	<head>
	<title>200 OK</title>
	</head>
	<body>
	<h1>Success!</h1>
	<p>Your request was an absolute banger.</p>
	</body>
	</html>	
	`)
}

func respond400() []byte{
	return []byte(`
	<html>
	<head>
	<title>400 Bad Request</title>
	</head>
	<body>
	<h1>Bad Request</h1>
	<p>Your request honestly kinda sucked.</p>
	</body>
	</html>
	`)
}

func respond500() []byte{
	return []byte(`
	<html>
	<head>
	<title>500 Internal Server Error</title>
	</head>
	<body>
	<h1>Internal Server Error</h1>
	<p>Okay, you know what? This one is on me.</p>
	</body>
	</html>
	`)
}

func toStr(bytes []byte) string{
	out := ""
	for _,b := range bytes {
		out += fmt.Sprintf("%02x",b)
	}
	return out
}

func main() {
	s, err := server.Serve(port, func(w *response.Writer, req *request.Request){
		h := response.GetDefaultHeaders(0)
		body := respond200()
		status := response.StatusOK

		if req.RequestLine.RequestTarget == "/yourproblem"{
			body = respond400()
			status = response.StatusBadRequest
		}else if req.RequestLine.RequestTarget == "/myproblem"{
			body = respond500()
			status = response.StatusInternalServerError
		}else if req.RequestLine.RequestTarget == "/video"{
			f, _ := os.ReadFile("assets/vim.mp4")
			h.Replace("content-type","video/mp4")
			h.Replace("content-length", fmt.Sprintf("%d",len(f)))
			w.WriteStatusLine(response.StatusOK)
			w.WriteHeaders(*h)
			w.WriteBody(f)
		}else if strings.HasPrefix(req.RequestLine.RequestTarget, "/httpbin/"){
			target := req.RequestLine.RequestTarget

			res,err := http.Get("https://httpbin.org/" +target[len("/httpbin/"):])
			if err != nil{
				body = respond500()
				status = response.StatusInternalServerError
			}else {
				w.WriteStatusLine(response.StatusOK)
				h.Delete("Content-length")
				h.Set("Transfer-Encoding","chunked")
				h.Replace("Content-Type","text/plain")
				h.Set("Trailer","X-Content-SHA256")
				h.Set("Trailer","X-Content-Length")
				w.WriteHeaders(*h)

				fullBody := []byte{}
				for {
					data := make([]byte,32)
					n,err := res.Body.Read(data)
					if err != nil {
						break
					}
					fullBody = append(fullBody, data[:n]...)
					w.WriteBody([]byte(fmt.Sprintf("%x\r\n",n)))
					w.WriteBody(data[:n])
					w.WriteBody([]byte("\r\n"))
				}
				w.WriteBody([]byte("0\r\n"))
				trailers := headers.NewHeaders()
				out := sha256.Sum256(fullBody)
				trailers.Set("X-Content-SHA256",toStr(out[:]))
				trailers.Set("X-Content-Length",fmt.Sprintf("%d",len(fullBody)))
				w.WriteHeaders(*trailers)
				return
			}
		}

		h.Replace("Content-length",fmt.Sprintf("%d",len(body)))
		h.Replace("Content-Type","text/html")
		w.WriteStatusLine(status)
		w.WriteHeaders(*h)
		w.WriteBody(body)
	})
	
	if err != nil {
		log.Fatalf("Error starting server: %v", err)
	}
	defer s.Close()
	log.Println("Server started on port", port)

	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
	<-sigChan
	log.Println("Server gracefully stopped")
}