package saggytrousers

import (
	"fmt"
	"os"
	"time"
)

type LogInfo struct {
	Fp		*os.File
	Prog	string
	Valid	bool	/* Did the log file open successfully. If not, simply don't log */
}

var logInfo LogInfo

func LogFree() {
	err := logInfo.Fp.Close()
	if err != nil {
		fmt.Printf("That's not great. We can't close the log file!\n")
	}
}

func LogInit(file, prog string) {
	logging := true /* are we logging? Set to false on error. */
	fp, err := os.OpenFile(file, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0755)
	if err != nil {
		fmt.Printf("The log file at [%v] cannot be opened.\n", file)
		choices := make([]string, 3)
		choices[0] = "Exit Application"
		choices[1] = "Continue without Logging"
		choices[2] = "View error message"
		for true {
			v := SelectIndexFromArray(choices, "What would you like to do? ", /* each on new line: */ true)
			switch v {
			case 0: /* Exit Application */
				os.Exit(-1)
			case 1: /* Continue without Logging */
				logging = false /* execution just continues from here */
				break
			case 2: /* View error message */
				fmt.Printf("The error message is:\n%v\n", err)
			}
		}
	}
	logInfo = LogInfo { 
		fp,
		prog,
		logging,
	}
	
}

func WriteLogFile(s string) {
	/* TODO: implement. This should just write to the log file in logInfo.Fp */
	_, err := logInfo.Fp.WriteString(fmt.Sprintf("[%v] %v -- %v", 
                  time.Now().Format("2006-01-02 15:04:05"),
                  logInfo.Prog,
				  s))
	if err != nil {
		fmt.Printf("WriteLogFile log failed with %v\n", err)
	}
}

func Log(stdout bool, format string, a ...any) {
	s := fmt.Sprintf(format, a...)

	if stdout {
		fmt.Printf(s)
	} 

	// Regardless, we write to the log file. 
	WriteLogFile(s)
}

func ErrLog(stderr bool, format string, a ...any) {
	s := fmt.Sprintf(format, a...)

	if stderr {
		fmt.Printf("[ERROR] %v", s)
	}

	WriteLogFile(s)
}