package liquidsoap

import (
	"bufio"
	"errors"
	"fmt"
	"io"
	"regexp"
	"strconv"
)

// Output represents a liquidsoap message in a structured form
type Output struct {
	Level     int // lower means more important
	Msg       string
	Component string
}

// Parse needs a reader of the log, and will produce parsed output
func Parse(r io.Reader, parsed chan<- Output, onexit chan interface{}) {
	scanner := bufio.NewScanner(r)
	for scanner.Scan() {
		out, err := outParseLine(scanner.Text())
		if err == nil {
			parsed <- out
		}
	}
	onexit <- struct{}{}
}

var lineRegex = regexp.MustCompile(`^([0-9]{4}/[0-9]{2}/[0-9]{2}) ([0-9:]{8}) \[([^:\[\]]*):([0-9])\] (.*)$`)

func outParseLine(line string) (Output, error) {
	res := lineRegex.FindStringSubmatch(line)
	if res == nil {
		return Output{}, errors.New("Invalid line")
	}
	if len(res) != 6 {
		return Output{}, errors.New("Invalid line: missing parts")
	}
	level, err := strconv.Atoi(res[4])
	if err != nil {
		return Output{}, fmt.Errorf("Invalid line: invalid level `%s`", res[4])
	}
	return Output{Level: level, Msg: res[5], Component: res[3]}, nil
}