package main

import (
	"encoding/json"
	"fmt"
	"io"
	"net"
	"net/http"
	"regexp"
	// "strconv"
	"strings"
	"time"
)

// Example:
// curl 'http://localhost:8080/v1/auth/login' -X POST -H 'Content-Type: application/json' --data-raw $'{}}\n{"king": 5'

const log_length = 100

type accessLog struct {
	ClientAddr    string    `json:"clientAddr"`
	RequestedPath string    `json:"requestedPath"`
	RequestTime   time.Time `json:"requestTime"`
	HttpMethod    string    `json:"httpMethod"`
}

type loginAttemptLog struct {
	Email      string    `json:"email"`
	Password   string    `json:"password"`
	LoginTime  time.Time `json:"loginTime"`
	Success    bool      `json:"success"`
	RememberMe bool      `json:"rememberMe"`
}

func main() {
	fs := http.FileServer(http.Dir("static"))

	var logs [log_length]string
	n := 0

	// Define a handler function for the root path
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		jsonData, _ := json.Marshal(accessLog{
			ClientAddr:    RedactIP(r.RemoteAddr),
			RequestedPath: r.URL.Path,
			RequestTime:   time.Now().UTC(),
			HttpMethod:    r.Method,
		})
		addRotLog(&logs, &n, string(jsonData))
		// Serve the index.html file from the static directory
		http.StripPrefix("/", fs).ServeHTTP(w, r)
	})

	http.HandleFunc("/logs", createGetLogs(&logs))

	http.HandleFunc("/v1/auth/login", func(w http.ResponseWriter, r *http.Request) {
		body, err := io.ReadAll(r.Body)
		if err != nil {
			http.Error(w, "Bad Request", http.StatusBadRequest)
			return
		}
		defer r.Body.Close()

		var data map[string]any
		if json.Unmarshal(body, &data) != nil {
			addRotLog(&logs, &n, fmt.Sprintf(`{"authRequest": %s}`, string(body)))
			http.Error(w, "Forbidden", http.StatusForbidden)
			return
		}

		if email, ok := data["email"].(string); ok {
			if rememberMe, ok := data["rememberMe"].(bool); ok {
				addRotLog(&logs, &n, fmt.Sprintf(`{"authRequest": {"email": "%s", "password": "XXXXXXXX", "loginTime": "%s", "success": false, "rememberMe": %t}}`, email, time.Now().UTC(), rememberMe))
			}
		}
		http.Error(w, "Forbidden", http.StatusForbidden)
	})

	// Start the server on port 8080
	fmt.Println("Server is listening on port 8080...")
	err := http.ListenAndServe(":8080", nil)
	if err != nil {
		fmt.Printf("Error starting server: %s\n", err)
	}
}

func createGetLogs(logs *[log_length]string) func(http.ResponseWriter, *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		for _, s := range logs {
			fmt.Fprintln(w, s)
		}
	}
}

func addRotLog(logs *[log_length]string, last *int, value string) {
	if strings.Contains(value, "\n") {
		for _, v := range strings.Split(value, "\n") {
			addRotLog(logs, last, v)
		}
	} else {
		if *last == log_length {
			for i := 0; i < log_length-1; i++ {
				logs[i] = logs[i+1]
			}
			logs[log_length-1] = value
		} else {
			logs[*last] = value
			*last++
		}
	}
}

// RedactIP partially redacts an IP address by replacing the last octet with 'xxx'
func RedactIP(input string) string {
	ipRegex := `\b(?:\d{1,3}\.){3}\d{1,3}\b`
	re := regexp.MustCompile(ipRegex)

	return re.ReplaceAllStringFunc(input, func(match string) string {
		if ip := net.ParseIP(match); ip != nil {
			parts := strings.Split(match, ".")
			if len(parts) == 4 {
				parts[3] = "XXX"
				return strings.Join(parts, ".")
			}
		}
		return match
	})
}