package s3

import (
	"context"
	"errors"
	"fmt"
	neturl "net/url"
	"os"
	"time"

	"github.com/minio/minio-go/v7"
	"github.com/minio/minio-go/v7/pkg/credentials"
	"github.com/spf13/afero"
)

var (
	ErrUnsupported     = errors.New("unsupported operation")
	ErrInvalidProtocol = errors.New("invalid protocol")
)

type Fs struct {
	client *minio.Client
	bucket string

	// Configurables
	Timeout time.Duration
}

func NewFs(endpoint, bucket, accessKeyID, secretAccessKey string, useSSL bool) (*Fs, error) {
	// Initialize minio client object.
	client, err := minio.New(endpoint, &minio.Options{
		Creds:  credentials.NewStaticV4(accessKeyID, secretAccessKey, ""),
		Secure: useSSL,
	})
	if err != nil {
		return nil, err
	}

	return &Fs{
		client: client,
		bucket: bucket,

		Timeout: 10 * time.Second,
	}, nil
}

func NewFsFromURL(url string) (*Fs, error) {
	r, err := neturl.ParseRequestURI(url)
	if err != nil {
		return nil, fmt.Errorf("failed to parse url: %w", err)
	}
	useSSL := false
	switch r.Scheme {
	case "http":
	case "https":
		useSSL = true
	default:
		return nil, ErrInvalidProtocol

	}

	endpoint := r.Host
	bucket := r.Path[1:]
	accessKeyId := r.User.Username()
	secretAccessKey, _ := r.User.Password()
	return NewFs(endpoint, bucket, accessKeyId, secretAccessKey, useSSL)
}

// The name of this FileSystem
func (fs *Fs) Name() string {
	return "s3"
}

// Create creates a file in the filesystem, returning the file and an
// error, if any happens.
func (fs *Fs) Create(name string) (File, error) {
	panic("not implemented")
}

// Mkdir creates a directory in the filesystem, return an error if any
// happens.
func (fs *Fs) Mkdir(name string, perm os.FileMode) error {
	return ErrUnsupported
}

// MkdirAll creates a directory path and all parents that does not exist
// yet.
func (fs *Fs) MkdirAll(path string, perm os.FileMode) error {
	return ErrUnsupported
}

// Open opens a file, returning it or an error, if any happens.
func (fs *Fs) Open(name string) (File, error) {
	panic("not implemented")
}

// OpenFile opens a file using the given flags and the given mode.
func (fs *Fs) OpenFile(name string, flag int, perm os.FileMode) (File, error) {
	panic("not implemented")
}

// Remove removes a file identified by name, returning an error, if any
// happens.
func (fs *Fs) Remove(name string) error {
	panic("not implemented")
}

// RemoveAll removes a directory path and any children it contains. It
// does not fail if the path does not exist (return nil).
func (fs *Fs) RemoveAll(path string) error {
	panic("not implemented")
}

// Rename renames a file.
func (fs *Fs) Rename(oldname, newname string) error {
	panic("not implemented")
}

// Stat returns a FileInfo describing the named file, or an error, if any
// happens.
func (fs *Fs) Stat(name string) (os.FileInfo, error) {
	ctx, cancel := fs.contextWithTimeout()
	defer cancel()
	info, err := fs.client.StatObject(ctx, fs.bucket, name, minio.GetObjectOptions{})
	if err != nil {
		return nil, transformError(err)
	}
	return transformObjectInfo(info), nil
}

// Chmod changes the mode of the named file to mode.
func (fs *Fs) Chmod(name string, mode os.FileMode) error {
	return ErrUnsupported
}

// Chown changes the uid and gid of the named file.
func (fs *Fs) Chown(name string, uid, gid int) error {
	return ErrUnsupported
}

// Chtimes changes the access and modification times of the named file
func (fs *Fs) Chtimes(name string, atime time.Time, mtime time.Time) error {
	return ErrUnsupported
}

func (fs *Fs) contextWithTimeout() (context.Context, context.CancelFunc) {
	return context.WithTimeout(context.Background(), fs.Timeout)
}

func transformError(err error) error {
	resp, ok := err.(minio.ErrorResponse)
	if !ok {
		return err
	}

	switch resp.Code {
	case "NoSuchKey":
		return afero.ErrFileNotFound
	case "EntityTooLarge":
		return afero.ErrTooLarge
	}
	return err
}