package server

import (
	"net/http"
	"os"
	"strings"

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

const maxLogLines = 20

// handleLogsTail returns the last 20 lines of the server log file as plain text.
func (s *Server) handleLogsTail(c *gin.Context) {
	if s.Config.LogFile == "" {
		c.String(http.StatusOK, "KAOS_LOG_FILE nije podešen. Podesi env varijablu za prikaz logova.")
		return
	}

	data, err := os.ReadFile(s.Config.LogFile)
	if err != nil {
		if os.IsNotExist(err) {
			c.String(http.StatusOK, "Log fajl ne postoji: "+s.Config.LogFile)
			return
		}
		c.String(http.StatusInternalServerError, "Greška pri čitanju loga: "+err.Error())
		return
	}

	lines := tailLines(string(data), maxLogLines)
	c.String(http.StatusOK, strings.Join(lines, "\n"))
}

// tailLines returns the last n non-empty lines from text.
func tailLines(text string, n int) []string {
	allLines := strings.Split(strings.TrimRight(text, "\n"), "\n")
	if len(allLines) <= n {
		return allLines
	}
	return allLines[len(allLines)-n:]
}