package storage

import (
	"context"
	"fmt"
	"os"
	"path/filepath"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/credentials"
	"github.com/aws/aws-sdk-go-v2/service/s3"

	dcfg "git.misaka.ren/M1saka/docker_backup/internal/config"
)

// S3Backend uploads to S3-compatible storage.
type S3Backend struct {
	cfg    *dcfg.S3Config
	client *s3.Client
}

// NewS3Backend creates a configured S3 backend.
func NewS3Backend(cfg *dcfg.S3Config) (*S3Backend, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	awsCfg, err := config.LoadDefaultConfig(ctx,
		config.WithRegion(cfg.Region),
		config.WithCredentialsProvider(
			credentials.NewStaticCredentialsProvider(cfg.AccessKey, cfg.SecretKey, ""),
		),
	)
	if err != nil {
		return nil, fmt.Errorf("load aws config: %w", err)
	}

	s3Opts := func(o *s3.Options) {
		if cfg.Endpoint != "" {
			o.BaseEndpoint = aws.String(cfg.Endpoint)
			o.UsePathStyle = true
		}
	}

	return &S3Backend{
		cfg:    cfg,
		client: s3.NewFromConfig(awsCfg, s3Opts),
	}, nil
}

// Upload implements Backend.
func (s *S3Backend) Upload(ctx context.Context, projectName, localPath string) error {
	file, err := os.Open(localPath)
	if err != nil {
		return fmt.Errorf("open: %w", err)
	}
	defer file.Close()

	key := filepath.Base(localPath)
	if s.cfg.PathPrefix != "" {
		key = s.cfg.PathPrefix + projectName + "/" + key
	} else {
		key = projectName + "/" + key
	}

	_, err = s.client.PutObject(ctx, &s3.PutObjectInput{
		Bucket:      aws.String(s.cfg.Bucket),
		Key:         aws.String(key),
		Body:        file,
		ContentType: aws.String("application/gzip"),
	})
	if err != nil {
		return fmt.Errorf("s3 put object: %w", err)
	}

	return nil
}