package station

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

// Close releases the log file. It is safe to call more than once.
func (s *Station) Close() {
	s.mu.Lock()
	defer s.mu.Unlock()
	s.closeLogLocked()
}

func (s *Station) openLog() {
	f, err := os.OpenFile(s.logPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o600)
	if err != nil {
		s.logNotice = "Cannot write " + s.logPath
		if s.state.Talker == "" {
			s.state.Detail = s.logNotice
		}
		return
	}
	s.logFile = f
}

func (s *Station) closeLogLocked() {
	if s.logFile != nil {
		s.logFile.Close()
		s.logFile = nil
	}
}

func (s *Station) writeLog(ts time.Time, msg string) {
	if s.logFile == nil {
		return
	}
	line := ts.Format(time.RFC3339) + " " + msg + "\n"
	if _, err := s.logFile.Write([]byte(line)); err != nil {
		s.closeLogLocked()
		if s.logNotice == "" {
			s.logNotice = "Cannot write " + s.logPath
		}
	}
}

func (s *Station) noteTransmitLocked() {
	s.noteTransmitAt(s.clock.Now())
}

func (s *Station) noteTransmitAt(now time.Time) {
	tx := s.transmitting()
	if tx && !s.sending {
		s.sending = true
		s.sendStart = now
		return
	}
	if !tx && s.sending {
		start := s.sendStart
		s.sending = false
		s.writeLog(start, fmt.Sprintf("sending for %d seconds.", wholeSeconds(start, now)))
	}
}

func (s *Station) closeTalkerLocked(now time.Time) {
	if s.talkCall == "" {
		return
	}
	call := s.talkCall
	start := s.talkStart
	s.talkCall = ""
	s.writeLog(start, fmt.Sprintf("%s talked for %d seconds.", call, wholeSeconds(start, now)))
}

func (s *Station) noteDownLocked(now time.Time, dial bool) {
	s.closeTalkerLocked(now)
	s.state.Connection = "Disconnected"
	s.remoteTalker = ""
	s.roomBusy = false
	s.noteTransmitAt(now)
	switch {
	case s.up:
		s.up = false
		s.outage = true
		s.writeLog(now, "disconnected")
	case dial && !s.outage:
		s.outage = true
		s.writeLog(now, "disconnected")
	}
	s.publish()
}

func (s *Station) endFatal(msg string, log bool) {
	s.mu.Lock()
	defer s.mu.Unlock()
	if s.fatal != "" {
		return
	}
	now := s.clock.Now()
	s.closeTalkerLocked(now)
	s.fatal = msg
	s.remoteTalker = ""
	s.roomBusy = false
	s.noteTransmitAt(now)
	if log {
		s.up = false
		s.outage = true
		s.writeLog(now, oneLine(msg))
	}
	s.publish()
}

func wholeSeconds(start, end time.Time) int {
	d := end.Sub(start)
	if d <= 0 {
		return 0
	}
	return int(d / time.Second)
}

func oneLine(msg string) string {
	return strings.NewReplacer("\r\n", " ", "\n", " ", "\r", " ").Replace(msg)
}