package main

import (
	"flag"
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"time"

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

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()


	cyutils.WithWorkers(10, files, func(worker int, _ int, file string) {
		workerlog := logger.Default.WithPrefix(fmt.Sprintf("worker=%d", worker))
		filelog := workerlog.WithPrefix(fmt.Sprintf("file=%q", file))
		filelog.Info("processing file")
		date, err := parseDate(file, parsers)
		if err != nil {
			filelog.Error("error parsing date: %s", err)
			return
		}
		filelog.Info("date: %s", date)
		
		datedir := fmt.Sprintf("%04d-%02d-%02d", date.Year(), date.Month(), date.Day())
		dest := filepath.Join(datedir, file)
		filelog.Info("dest: %s", dest)
		err = os.MkdirAll(datedir, 0755)
		if err != nil {
			filelog.Error("error creating directory: %s", err)
			return
		}
		// Make sure file doesn't exist
		destfile, err := os.Stat(dest)
		if err == nil {
			filelog.Info("dest file already exists: %s", destfile.Name())
			return
		} else {
			if !os.IsNotExist(err) {
				filelog.Error("error checking dest file: %s", err)
				return
			}
		}
		err = os.Rename(file, dest)
		if err != nil {
			filelog.Error("error renaming file: %s", err)
			return
		}
		filelog.Info("moved to %q", dest)
	})
}

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")
}