package ytdlp

import (
	"context"
	"encoding/json"
	"fmt"
	"path"
	"sync"

	"git.kmsign.ru/royalcat/tstor/pkg/ctxbilly"
	"git.kmsign.ru/royalcat/tstor/src/vfs"
	"github.com/go-git/go-billy/v5/osfs"
	"github.com/royalcat/ctxio"
)

func NewService(dataDir string) *Service {
	return &Service{
		dataDir: dataDir,
		sources: make(map[string]ytdlpSource, 0),
	}
}

type Service struct {
	mu sync.Mutex

	dataDir string
	sources map[string]ytdlpSource
}

func (c *Service) AddSource(s ytdlpSource) {
	c.mu.Lock()
	defer c.mu.Unlock()

	c.sources[s.Name()] = s
}

func (c *Service) sourceDir(s ytdlpSource) string {
	return path.Join(c.dataDir, s.Name())
}

func (c *Service) Update(ctx context.Context) error {
	for name, s := range c.sources {
		if ctx.Err() != nil {
			return ctx.Err()
		}

		dir := c.sourceDir(s)
		err := s.Download(ctx, nil, dir)
		if err != nil {
			return fmt.Errorf("failed to fetch source %s: %w", name, err)
		}
	}
	return nil
}

func (c *Service) BuildFS(ctx context.Context, f vfs.File) (vfs.Filesystem, error) {
	data, err := ctxio.ReadAll(ctx, f)
	if err != nil {
		return nil, fmt.Errorf("failed to read source file: %w", err)
	}

	var s ytdlpSource
	err = json.Unmarshal(data, &s)
	if err != nil {
		return nil, err
	}

	c.AddSource(s)

	downloadFS := ctxbilly.WrapFileSystem(osfs.New(c.sourceDir(s)))

	return newSourceFS(s.Name(), downloadFS, c, s), nil
}