package main

import (
	"flag"
	"fmt"
	"regexp"
	"time"

	logger "git.site.quack-lab.dev/dave/cylogger"
)

type DateParser interface {
	Parse(s string) (time.Time, error)
}

type DateParser8 struct {
	re *regexp.Regexp
}

func (dp *DateParser8) Parse(s string) (time.Time, error) {
	matches := dp.re.FindStringSubmatch(s)
	if len(matches) == 0 {
		return time.Time{}, fmt.Errorf("no match")
	}
	return time.Parse("20060102", matches[0])
}

type DateParserISO struct {
	re *regexp.Regexp
}

func (dp *DateParserISO) Parse(s string) (time.Time, error) {
	matches := dp.re.FindStringSubmatch(s)
	if len(matches) == 0 {
		return time.Time{}, fmt.Errorf("no match")
	}
	return time.Parse("2006-01-02", matches[0])
}

func main() {
	flag.Parse()
	logger.InitFlag()

	if flag.NArg() == 0 {
		logger.Error("no files provided")
		return
	}

	parsers := []DateParser{
		&DateParser8{re: regexp.MustCompile(`\d{8}`)},
		&DateParserISO{re: regexp.MustCompile(`\d{4}-\d{2}-\d{2}`)},
	}

	files := flag.Args()

	for _, file := range files {
		logger.Info("processing file: %s", file)
		date, err := parseDate(file, parsers)
		if err != nil {
			logger.Error("error parsing date: %s", err)
			continue
		}
		logger.Info("date: %s", date)
	}
}

func parseDate(file string, parsers []DateParser) (time.Time, error) {
	for _, parser := range parsers {
		date, err := parser.Parse(file)
		if err == nil {
			return date, nil
		}
	}
	return time.Time{}, fmt.Errorf("no date found")
}