package frpLogger

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

func (s *InstanceLogStreamer) streamLogFile(logFilePath string) {
	s.streamLogFileSince(logFilePath, time.Time{})
}

func (s *InstanceLogStreamer) streamLogFileSince(logFilePath string, sinceTime time.Time) {
	s.sendInfo(fmt.Sprintf("Streaming log file: %s", logFilePath))

	if _, err := os.Stat(logFilePath); os.IsNotExist(err) {
		s.sendError(fmt.Sprintf("Log file not found: %s", logFilePath))
		return
	}

	file, err := os.Open(logFilePath)
	if err != nil {
		s.sendError(fmt.Sprintf("Failed to open log file: %v", err))
		return
	}
	defer file.Close()

	if !sinceTime.IsZero() {
		s.sendInfo(fmt.Sprintf("Filtering logs since: %s", sinceTime.Format("2006-01-02 15:04:05")))
	}
	s.streamLogFileFromBeginning(file, sinceTime)
}

func (s *InstanceLogStreamer) streamLogFileFromBeginning(file *os.File, sinceTime time.Time) {
	reader := bufio.NewReader(file)

	for {
		select {
		case <-s.stopChan:
			s.sendInfo("Log streaming stopped")
			return
		default:
			line, err := reader.ReadString('\n')
			if err != nil {
				if err == io.EOF {
					time.Sleep(100 * time.Millisecond)
					continue
				}
				s.sendError(fmt.Sprintf("Error reading log file: %v", err))
				return
			}

			line = strings.TrimSpace(line)
			if line != "" {
				lineTime := s.parseLogLineTime(line)
				if lineTime.IsZero() || lineTime.After(sinceTime) || lineTime.Equal(sinceTime) {
					s.sendLog(s.parseLogLevel(line), line)
				}
			}
		}
	}
}

func (s *InstanceLogStreamer) parseLogLineTime(line string) time.Time {
	layouts := []string{
		"2006/01/02 15:04:05",
		"2006-01-02 15:04:05",
		"2006-01-02T15:04:05",
		time.RFC3339,
		time.RFC3339Nano,
	}

	for _, layout := range layouts {
		minLen := len(layout)
		if len(line) >= minLen {
			t, err := time.Parse(layout, strings.TrimSpace(line[:minLen]))
			if err == nil {
				return t
			}
		}
	}

	return time.Time{}
}

func (s *InstanceLogStreamer) parseLogLevel(line string) string {
	lowerLine := strings.ToLower(line)
	if strings.Contains(lowerLine, "error") || strings.Contains(lowerLine, "err") {
		return "ERROR"
	}
	if strings.Contains(lowerLine, "warn") || strings.Contains(lowerLine, "warning") {
		return "WARN"
	}
	if strings.Contains(lowerLine, "debug") {
		return "DEBUG"
	}
	if strings.Contains(lowerLine, "info") {
		return "INFO"
	}
	return "INFO"
}