package main

import (
	"fmt"
	"log"
	"net/http"
	"os"

	"github.com/gin-gonic/gin"
)

const ADDRESS = "0.0.0.0"
const PORT = "3000"
const LOG_FILE = "./log/api-server.log"

var containerName string

type HelloResponseDto struct {
	Message string `json:"message"`
}

func handleHello(ctx *gin.Context) {
	log.Println("Request received to handleHello")
	ctx.JSON(
		http.StatusOK,
		HelloResponseDto{
			Message: fmt.Sprintf("Hello world from %s", containerName),
		},
	)
}

func openLogFile(path string) (*os.File, error) {
	logFile, err := os.OpenFile(path, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0644)
	if err != nil {
		return nil, err
	}
	return logFile, nil
}

func initLogging() {
	file, err := openLogFile(LOG_FILE)
	if err != nil {
		log.Fatal(err)
	}
	log.SetOutput(file)
	log.SetFlags(log.LstdFlags | log.Lshortfile | log.Lmicroseconds)
}

func main() {
	// get container name from environment
	containerName = os.Getenv("CONTAINER_NAME")
	if len(containerName) == 0 {
		containerName = "Unknown"
	}

	// get port from environment
	port := os.Getenv("PORT")
	if len(port) == 0 {
		port = PORT
	}

	initLogging()

	serverAddr := fmt.Sprintf("%s:%s", ADDRESS, port)

	// init gin
	gin.SetMode(gin.ReleaseMode)
	router := gin.Default()
	router.GET("/hello", handleHello)

	msg := fmt.Sprintf("Running server on %s as %s", serverAddr, containerName)
	log.Println(msg)
	fmt.Printf("%s\n", msg)

	// finally, start server
	router.Run(serverAddr)
}