package convids

import (
	"errors"
	"fmt"
	"io"
	"os"
	fp "path/filepath"
	"regexp"
	"strings"

	"gopkg.in/yaml.v3"
)

func NewData(path string) (*Data, error) {
	f, err := os.Open(path)
	if err != nil {
		return nil, err
	}
	ydec := yaml.NewDecoder(f)
	var data Data
	err = ydec.Decode(&data)
	return &data, err
}

func ensureExtRe(c *Config) (err error) {
	if c.extRe != nil {
		return nil
	}
	c.extRe, err = regexp.Compile("(" + strings.Join(c.Extensions, "|") + ")$")
	return
}

type ShowWalker func(show *Show, path string) error
type GroupPrinter func(name string, group Shows)

func WalkFiles(d *Data, stopOnError bool, gp GroupPrinter, cb ShowWalker) (err error) {
	err = ensureExtRe(d.Config)
	if err != nil {
		return
	}
	if cb == nil {
		cb = DryRun(os.Stdout)
	}
	var files []os.DirEntry
	files, err = os.ReadDir(d.Config.Source)
	if err != nil {
		return
	}
	for s := range d.AllShows(gp) {
		var found bool
	start:
		for _, file := range files {
			if file.IsDir() {
				continue
			}
			if !d.Config.extRe.MatchString(file.Name()) {
				continue
			}
			found, err = s.Match(file.Name())
			if err != nil {
				return
			}
			if !found {
				continue
			}

			path := fp.Join(d.Config.Source, file.Name())
			for _, ext := range d.Config.Skip {
				if !strings.HasPrefix(ext, ".") {
					ext = "." + ext
				}
				skipper := path + ext
				_, err := os.Stat(skipper)
				if !errors.Is(err, os.ErrNotExist) {
					break start
				}
			}

			err = cb(s, path)
			if err != nil && stopOnError {
				return
			}
			break
		}
	}
	return nil
}

func DryRun(out io.Writer) ShowWalker {
	return func(s *Show, path string) error {
		fmt.Fprintf(out, "Saving %s to %s\n", path, s.Folder)
		return nil
	}
}

func PrintGroupName(out io.Writer) GroupPrinter {
	return func(name string, group Shows) {
		fmt.Fprintf(out, "Checking %s shows\n\n", name)
	}
}