package storage

import (
	"context"
	"fmt"
	"strings"

	"go.uber.org/fx"
	"sneak.berlin/go/vaultik/internal/config"
	"sneak.berlin/go/vaultik/internal/s3"
)

// defaultS3Region is used when neither the URL nor the config specify one.
const defaultS3Region = "us-east-1"

// defaultS3Endpoint is the AWS endpoint used when none is configured.
const defaultS3Endpoint = "s3.amazonaws.com"

// Module exports storage functionality as an fx module.
// It provides a Storer implementation based on the configured storage URL
// or falls back to legacy S3 configuration.
//
//nolint:gochecknoglobals // fx module definitions are package globals
var Module = fx.Module("storage",
	fx.Provide(NewStorer),
)

// NewStorer creates a Storer based on configuration.
// If StorageURL is set, it uses URL-based configuration.
// Otherwise, it falls back to legacy S3 configuration.
//
//nolint:ireturn // fx provider intentionally returns the Storer interface
func NewStorer(cfg *config.Config) (Storer, error) {
	if cfg.StorageURL != "" {
		return storerFromURL(cfg.StorageURL, cfg)
	}

	return storerFromLegacyS3Config(cfg)
}

//nolint:ireturn // factory intentionally returns the Storer interface
func storerFromURL(rawURL string, cfg *config.Config) (Storer, error) {
	parsed, err := ParseStorageURL(rawURL)
	if err != nil {
		return nil, fmt.Errorf("parsing storage URL: %w", err)
	}

	switch parsed.Scheme {
	case schemeFile:
		return NewFileStorer(parsed.Prefix)

	case schemeS3:
		return storerFromParsedS3URL(parsed, cfg)

	case schemeRclone:
		return NewRcloneStorer(
			context.Background(), parsed.RcloneRemote, parsed.Prefix)

	default:
		return nil, fmt.Errorf("%w: %s", ErrUnsupportedStorage, parsed.Scheme)
	}
}

// storerFromParsedS3URL builds an S3 storer from a parsed s3:// URL,
// filling endpoint protocol and region defaults from the config.
//
//nolint:ireturn // factory intentionally returns the Storer interface
func storerFromParsedS3URL(parsed *URL, cfg *config.Config) (Storer, error) {
	// Build endpoint URL
	endpoint := parsed.Endpoint
	if endpoint == "" {
		endpoint = defaultS3Endpoint
	}

	// Add protocol if not present
	hasProtocol := strings.HasPrefix(endpoint, "https://") ||
		strings.HasPrefix(endpoint, "http://")
	if !hasProtocol {
		if parsed.UseSSL {
			endpoint = "https://" + endpoint
		} else {
			endpoint = "http://" + endpoint
		}
	}

	region := parsed.Region
	if region == "" {
		region = cfg.S3.Region
		if region == "" {
			region = defaultS3Region
		}
	}

	// Credentials come from config (not URL for security)
	client, err := s3.NewClient(context.Background(), s3.Config{
		Endpoint:        endpoint,
		Bucket:          parsed.Bucket,
		Prefix:          parsed.Prefix,
		AccessKeyID:     cfg.S3.AccessKeyID,
		SecretAccessKey: cfg.S3.SecretAccessKey,
		Region:          region,
	})
	if err != nil {
		return nil, fmt.Errorf("creating S3 client: %w", err)
	}

	return NewS3Storer(client), nil
}

//nolint:ireturn // factory intentionally returns the Storer interface
func storerFromLegacyS3Config(cfg *config.Config) (Storer, error) {
	endpoint := cfg.S3.Endpoint

	// Ensure protocol is present
	if !strings.HasPrefix(endpoint, "http://") &&
		!strings.HasPrefix(endpoint, "https://") {
		if cfg.S3.UseSSL {
			endpoint = "https://" + endpoint
		} else {
			endpoint = "http://" + endpoint
		}
	}

	region := cfg.S3.Region
	if region == "" {
		region = defaultS3Region
	}

	client, err := s3.NewClient(context.Background(), s3.Config{
		Endpoint:        endpoint,
		Bucket:          cfg.S3.Bucket,
		Prefix:          cfg.S3.Prefix,
		AccessKeyID:     cfg.S3.AccessKeyID,
		SecretAccessKey: cfg.S3.SecretAccessKey,
		Region:          region,
	})
	if err != nil {
		return nil, fmt.Errorf("creating S3 client: %w", err)
	}

	return NewS3Storer(client), nil
}