package command

import (
	"path/filepath"

	"github.com/hashicorp/terraform/internal/getproviders"
	"github.com/hashicorp/terraform/internal/providercache"
)

// providerLocalCacheDir returns an object representing the
// configuration-specific local cache directory. This is the
// only location consulted for provider plugin packages for Terraform
// operations other than provider installation.
//
// Only the provider installer (in "terraform init") is permitted to make
// modifications to this cache directory. All other commands must treat it
// as read-only.
func (m *Meta) providerLocalCacheDir() *providercache.Dir {
	dir := filepath.Join(m.DataDir(), "plugins")
	if dir == "" {
		return nil // cache disabled
	}
	return providercache.NewDir(dir)
}

// providerGlobalCacheDir returns an object representing the shared global
// provider cache directory, used as a read-through cache when installing
// new provider plugin packages.
//
// This function may return nil, in which case there is no global cache
// configured and new packages should be downloaded directly into individual
// configuration-specific cache directories.
func (m *Meta) providerGlobalCacheDir() *providercache.Dir {
	dir := m.PluginCacheDir
	if dir == "" {
		return nil // cache disabled
	}
	return providercache.NewDir(dir)
}

// providerInstallSource returns an object that knows how to consult one or
// more external sources to determine the availability of and package
// locations for versions of Terraform providers that are available for
// automatic installation.
//
// This returns the standard provider install source that consults a number
// of directories selected either automatically or via the CLI configuration.
// Users may choose to override this during a "terraform init" command by
// specifying one or more -plugin-dir options, in which case the installation
// process will construct its own source consulting only those directories
// and use that instead.
func (m *Meta) providerInstallSource() getproviders.Source {
	// A provider source should always be provided in normal use, but our
	// unit tests might not always populate Meta fully and so we'll be robust
	// by returning a non-nil source that just always answers that no plugins
	// are available.
	if m.ProviderSource == nil {
		// A multi-source with no underlying sources is effectively an
		// always-empty source.
		return getproviders.MultiSource(nil)
	}
	return m.ProviderSource
}