package filestorage

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"

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

type S3Storage struct {
	client *s3.Client
	bucket string
}

func NewS3FromEnv() (*S3Storage, error) {
	bucket := strings.TrimSpace(os.Getenv("S3_BUCKET"))
	accessKey := strings.TrimSpace(os.Getenv("S3_ACCESS_KEY"))
	secretKey := strings.TrimSpace(os.Getenv("S3_SECRET_KEY"))
	if bucket == "" || accessKey == "" || secretKey == "" {
		return nil, errors.New("S3_BUCKET, S3_ACCESS_KEY, and S3_SECRET_KEY are required for FILE_STORAGE_PROVIDER=s3")
	}

	region := strings.TrimSpace(os.Getenv("S3_REGION"))
	if region == "" {
		region = "us-east-1"
	}
	endpoint := strings.TrimSpace(os.Getenv("S3_ENDPOINT"))
	usePathStyle, _ := strconv.ParseBool(strings.TrimSpace(os.Getenv("S3_USE_PATH_STYLE")))

	cfg := aws.Config{
		Region:      region,
		Credentials: aws.NewCredentialsCache(credentials.NewStaticCredentialsProvider(accessKey, secretKey, "")),
	}
	client := s3.NewFromConfig(cfg, func(options *s3.Options) {
		options.UsePathStyle = usePathStyle
		if endpoint != "" {
			options.BaseEndpoint = aws.String(endpoint)
		}
	})
	return &S3Storage{client: client, bucket: bucket}, nil
}

func (s *S3Storage) Provider() string {
	return "s3"
}

func (s *S3Storage) Probe(ctx context.Context) error {
	_, err := s.client.HeadBucket(ctx, &s3.HeadBucketInput{Bucket: aws.String(s.bucket)})
	return err
}

func (s *S3Storage) Put(ctx context.Context, key string, reader io.Reader, contentType string, size int64) error {
	_, err := s.client.PutObject(ctx, &s3.PutObjectInput{
		Bucket:        aws.String(s.bucket),
		Key:           aws.String(key),
		Body:          reader,
		ContentType:   aws.String(contentType),
		ContentLength: aws.Int64(size),
	})
	return err
}

func (s *S3Storage) Get(ctx context.Context, key string) (Object, error) {
	response, err := s.client.GetObject(ctx, &s3.GetObjectInput{
		Bucket: aws.String(s.bucket),
		Key:    aws.String(key),
	})
	if err != nil {
		if isS3NotFoundError(err) {
			return Object{}, ErrNotFound
		}
		return Object{}, err
	}

	contentType := ""
	if response.ContentType != nil {
		contentType = *response.ContentType
	}
	size := int64(0)
	if response.ContentLength != nil {
		size = *response.ContentLength
	}
	return Object{
		Body:        response.Body,
		ContentType: contentType,
		Size:        size,
	}, nil
}

func (s *S3Storage) Delete(ctx context.Context, key string) error {
	_, err := s.client.DeleteObject(ctx, &s3.DeleteObjectInput{
		Bucket: aws.String(s.bucket),
		Key:    aws.String(key),
	})
	if err != nil {
		if isS3NotFoundError(err) {
			return nil
		}
		return fmt.Errorf("delete s3 object: %w", err)
	}
	return nil
}

func isS3NotFoundError(err error) bool {
	var noSuchKey *types.NoSuchKey
	if errors.As(err, &noSuchKey) {
		return true
	}
	var apiErr smithy.APIError
	if errors.As(err, &apiErr) {
		switch apiErr.ErrorCode() {
		case "NoSuchKey", "NotFound", "NoSuchBucket":
			return true
		}
	}
	return false
}