package main

import (
	"fmt"
	"io"
	"mime"
	"path/filepath"
	"regexp"
	"strings"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/service/s3"
)

type s3Provider struct {
	conn *s3.S3
}

func newS3Provider() (*s3Provider, error) {
	return &s3Provider{
		conn: s3.New(&aws.Config{}),
	}, nil
}

func (s *s3Provider) getBucketPath(prefix string) (bucket string, path string, err error) {
	rex := regexp.MustCompile(`^s3://?([^/]+)/(.*)$`)
	matches := rex.FindStringSubmatch(prefix)
	if len(matches) != 3 {
		err = fmt.Errorf("prefix did not match requirements")
		return
	}

	bucket = matches[1]
	path = matches[2]

	return
}

func (s *s3Provider) ListFiles(prefix string) ([]file, error) {
	out := []file{}

	bucket, path, err := s.getBucketPath(prefix)
	if err != nil {
		return out, err
	}

	in := &s3.ListObjectsInput{
		Bucket: aws.String(bucket),
		Marker: nil,
		Prefix: aws.String(path),
	}
	for {
		o, err := s.conn.ListObjects(in)
		if err != nil {
			return out, err
		}

		for _, v := range o.Contents {
			out = append(out, file{
				Filename: *v.Key,
				Size:     *v.Size,
				MD5:      strings.Trim(*v.ETag, "\""), // Wat?
			})
		}

		if o.NextMarker == nil {
			break
		}
		in.Marker = o.NextMarker
	}

	return out, nil
}

func (s *s3Provider) WriteFile(path string, content io.ReadSeeker, public bool) error {
	bucket, path, err := s.getBucketPath(path)
	if err != nil {
		return err
	}

	ext := filepath.Ext(path)
	mimeType := mime.TypeByExtension(ext)
	if mimeType == "" {
		mimeType = "application/octet-stream"
	}

	params := &s3.PutObjectInput{
		Bucket:      aws.String(bucket),
		Key:         aws.String(path),
		Body:        content,
		ContentType: aws.String(mimeType),
	}
	if public {
		params.ACL = aws.String("public-read")
	}
	_, err = s.conn.PutObject(params)

	return err
}

func (s *s3Provider) ReadFile(path string) (io.ReadCloser, error) {
	bucket, path, err := s.getBucketPath(path)
	if err != nil {
		return nil, err
	}

	o, err := s.conn.GetObject(&s3.GetObjectInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(path),
	})

	if err != nil {
		return nil, err
	}

	return o.Body, nil
}

func (s *s3Provider) DeleteFile(path string) error {
	bucket, path, err := s.getBucketPath(path)
	if err != nil {
		return err
	}

	_, err = s.conn.DeleteObject(&s3.DeleteObjectInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(path),
	})

	return err
}

func (s *s3Provider) GetAbsolutePath(path string) (string, error) {
	return path, nil
}