package main

import (
	"bytes"
	"context"
	"errors"

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

var (
	s3Client *s3.Client
	bucket   string
)

func initS3(bucketName string) error {
	cfg, err := config.LoadDefaultConfig(context.Background(), config.WithRegion("us-east-1"))
	if err != nil {
		return err
	}
	s3Client = s3.NewFromConfig(cfg)
	bucket = bucketName
	return nil
}

// s3Exists checks if an object already exists in S3 (for dedup).
func s3Exists(ctx context.Context, key string) (bool, error) {
	_, err := s3Client.HeadObject(ctx, &s3.HeadObjectInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
	})
	if err != nil {
		var notFound *types.NotFound
		if errors.As(err, &notFound) {
			return false, nil
		}
		// NoSuchKey error type
		var nsk *types.NoSuchKey
		if errors.As(err, &nsk) {
			return false, nil
		}
		// Some S3 errors return 404 as a generic error
		if ctx.Err() != nil {
			return false, ctx.Err()
		}
		// Treat other errors as "not found" to avoid blocking uploads
		return false, nil
	}
	return true, nil
}

// s3Upload uploads icon data to S3 with the given key.
func s3Upload(ctx context.Context, key string, data []byte, contentType string) error {
	_, err := s3Client.PutObject(ctx, &s3.PutObjectInput{
		Bucket:      aws.String(bucket),
		Key:         aws.String(key),
		Body:        bytes.NewReader(data),
		ContentType: aws.String(contentType),
	})
	return err
}