package catalog

import "context"

// Client composes signed loading, protocol validation and target filtering.
type Client struct {
	loader *Loader
	parser Parser
	target Target
}

// NewClient creates the formal Catalog loading path. Protocol validation is
// installed on Loader so invalid remote data cannot replace the usable cache.
func NewClient(
	verifier Verifier,
	fetcher Fetcher,
	cache Cache,
	target Target,
) *Client {
	parser := Parser{ExpectedChannel: target.Channel}
	return &Client{
		loader: NewLoader(verifier, fetcher, cache, parser),
		parser: parser,
		target: target,
	}
}

// Load returns a verified, validated and target-filtered Catalog.
func (client *Client) Load(ctx context.Context) (Catalog, error) {
	result, err := client.loader.Load(ctx)
	if err != nil {
		return Catalog{}, err
	}
	manifest, err := client.parser.Parse(result.Document)
	if err != nil {
		return Catalog{}, err
	}
	entries, err := Filter(manifest, client.target)
	if err != nil {
		return Catalog{}, err
	}
	return Catalog{
		Manifest: manifest,
		Entries:  entries,
		Source:   result.Source,
		Warning:  result.Warning,
	}, nil
}