package nix

import (
	"fmt"
	"strings"
)

type Store interface {
	// Environ returns extra environment variables specified by Store.
	Environ() []string

	fmt.Stringer
}

// Local points to a local filesystem path containing a nix store.
type Local string

func (Local) Environ() []string    { return nil }
func (store Local) String() string { return string(store) }

const (
	EnvAwsSharedCredentialsFile = "AWS_SHARED_CREDENTIALS_FILE"
)

// A BinaryCache holds credentials and parameters to a s3 binary cache.
type BinaryCache struct {
	// Compression is the name of the compression algorithm to use. Example: "zstd".
	Compression string `json:"compression"`
	// ParallelCompression determines whether parallel compression is enabled.
	ParallelCompression bool `json:"parallel_compression,omitempty"`

	// Bucket is the s3 bucket name.
	Bucket string `json:"bucket"`
	// Endpoint is the s3 endpoint. Example: "s3.example.org".
	Endpoint string `json:"endpoint,omitempty"`
	// Region is the s3 region. Example: "ap-northeast-1".
	Region string `json:"region"`
	// Scheme is the s3 protocol. Example: "https".
	Scheme string `json:"scheme"`
	// CredentialsPath is the path to the s3 shared credentials file.
	CredentialsPath string `json:"credentials_path"`

	// KeyPath is the path to the nix secret key for signing all newly copied paths.
	KeyPath string `json:"key_path"`
}

func (store *BinaryCache) Environ() []string {
	return []string{EnvAwsSharedCredentialsFile + "=" + strings.TrimSpace(store.CredentialsPath)}
}

func (store *BinaryCache) String() string {
	return fmt.Sprintf(
		"s3://%s?compression=%s&parallel-compression=%t&region=%s&scheme=%s&endpoint=%s&secret-key=%s",
		store.Bucket, store.Compression, store.ParallelCompression, store.Region, store.Scheme, store.Endpoint, store.KeyPath,
	)
}