package command

import (
	"fmt"
	"os"
	"path/filepath"

	"github.com/hashicorp/terraform/plugin/discovery"
)

// mockProviderInstaller is a discovery.PluginInstaller implementation that
// is a mock for discovery.ProviderInstaller.
type mockProviderInstaller struct {
	// A map of provider names to available versions.
	// The tests expect the versions to be in order from newest to oldest.
	Providers map[string][]string

	Dir               string
	PurgeUnusedCalled bool
}

func (i *mockProviderInstaller) FileName(provider, version string) string {
	return fmt.Sprintf("terraform-provider-%s_v%s_x4", provider, version)
}

func (i *mockProviderInstaller) Get(provider string, req discovery.Constraints) (discovery.PluginMeta, error) {
	noMeta := discovery.PluginMeta{}
	versions := i.Providers[provider]
	if len(versions) == 0 {
		return noMeta, fmt.Errorf("provider %q not found", provider)
	}

	err := os.MkdirAll(i.Dir, 0755)
	if err != nil {
		return noMeta, fmt.Errorf("error creating plugins directory: %s", err)
	}

	for _, v := range versions {
		version, err := discovery.VersionStr(v).Parse()
		if err != nil {
			panic(err)
		}

		if req.Allows(version) {
			// provider filename
			name := i.FileName(provider, v)
			path := filepath.Join(i.Dir, name)
			f, err := os.Create(path)
			if err != nil {
				return noMeta, fmt.Errorf("error fetching provider: %s", err)
			}
			f.Close()
			return discovery.PluginMeta{
				Name:    provider,
				Version: discovery.VersionStr(v),
				Path:    path,
			}, nil
		}
	}

	return noMeta, fmt.Errorf("no suitable version for provider %q found with constraints %s", provider, req)
}

func (i *mockProviderInstaller) PurgeUnused(map[string]discovery.PluginMeta) (discovery.PluginMetaSet, error) {
	i.PurgeUnusedCalled = true
	ret := make(discovery.PluginMetaSet)
	ret.Add(discovery.PluginMeta{
		Name:    "test",
		Version: "0.0.0",
		Path:    "mock-test",
	})
	return ret, nil
}

type callbackPluginInstaller func(provider string, req discovery.Constraints) (discovery.PluginMeta, error)

func (cb callbackPluginInstaller) Get(provider string, req discovery.Constraints) (discovery.PluginMeta, error) {
	return cb(provider, req)
}

func (cb callbackPluginInstaller) PurgeUnused(map[string]discovery.PluginMeta) (discovery.PluginMetaSet, error) {
	// does nothing
	return make(discovery.PluginMetaSet), nil
}