package manager

import (
	"context"
	"fmt"

	"github.com/grafana/grafana/pkg/plugins"
	"github.com/grafana/grafana/pkg/plugins/repo"
)

func (m *PluginManager) Plugin(ctx context.Context, pluginID string) (plugins.PluginDTO, bool) {
	p, exists := m.plugin(ctx, pluginID)
	if !exists {
		return plugins.PluginDTO{}, false
	}

	return p.ToDTO(), true
}

func (m *PluginManager) Plugins(ctx context.Context, pluginTypes ...plugins.Type) []plugins.PluginDTO {
	// if no types passed, assume all
	if len(pluginTypes) == 0 {
		pluginTypes = plugins.PluginTypes
	}

	var requestedTypes = make(map[plugins.Type]struct{})
	for _, pt := range pluginTypes {
		requestedTypes[pt] = struct{}{}
	}

	pluginsList := make([]plugins.PluginDTO, 0)
	for _, p := range m.availablePlugins(ctx) {
		if _, exists := requestedTypes[p.Type]; exists {
			pluginsList = append(pluginsList, p.ToDTO())
		}
	}
	return pluginsList
}

// plugin finds a plugin with `pluginID` from the registry that is not decommissioned
func (m *PluginManager) plugin(ctx context.Context, pluginID string) (*plugins.Plugin, bool) {
	p, exists := m.pluginRegistry.Plugin(ctx, pluginID)
	if !exists || p.IsDecommissioned() {
		return nil, false
	}

	return p, true
}

// availablePlugins returns all non-decommissioned plugins from the registry
func (m *PluginManager) availablePlugins(ctx context.Context) []*plugins.Plugin {
	var res []*plugins.Plugin
	for _, p := range m.pluginRegistry.Plugins(ctx) {
		if !p.IsDecommissioned() {
			res = append(res, p)
		}
	}
	return res
}

// registeredPlugins returns all registered plugins from the registry
func (m *PluginManager) registeredPlugins(ctx context.Context) map[string]struct{} {
	pluginsByID := make(map[string]struct{})
	for _, p := range m.pluginRegistry.Plugins(ctx) {
		pluginsByID[p.ID] = struct{}{}
	}

	return pluginsByID
}

func (m *PluginManager) Add(ctx context.Context, pluginID, version string, opts plugins.CompatOpts) error {
	compatOpts := repo.NewCompatOpts(opts.GrafanaVersion, opts.OS, opts.Arch)

	var pluginArchive *repo.PluginArchive
	if plugin, exists := m.plugin(ctx, pluginID); exists {
		if !plugin.IsExternalPlugin() {
			return plugins.ErrInstallCorePlugin
		}

		if plugin.Info.Version == version {
			return plugins.DuplicateError{
				PluginID:          plugin.ID,
				ExistingPluginDir: plugin.PluginDir,
			}
		}

		// get plugin update information to confirm if target update is possible
		dlOpts, err := m.pluginRepo.GetPluginDownloadOptions(ctx, pluginID, version, compatOpts)
		if err != nil {
			return err
		}

		// if existing plugin version is the same as the target update version
		if dlOpts.Version == plugin.Info.Version {
			return plugins.DuplicateError{
				PluginID:          plugin.ID,
				ExistingPluginDir: plugin.PluginDir,
			}
		}

		if dlOpts.PluginZipURL == "" && dlOpts.Version == "" {
			return fmt.Errorf("could not determine update options for %s", pluginID)
		}

		// remove existing installation of plugin
		err = m.Remove(ctx, plugin.ID)
		if err != nil {
			return err
		}

		if dlOpts.PluginZipURL != "" {
			pluginArchive, err = m.pluginRepo.GetPluginArchiveByURL(ctx, dlOpts.PluginZipURL, compatOpts)
			if err != nil {
				return err
			}
		} else {
			pluginArchive, err = m.pluginRepo.GetPluginArchive(ctx, pluginID, dlOpts.Version, compatOpts)
			if err != nil {
				return err
			}
		}
	} else {
		var err error
		pluginArchive, err = m.pluginRepo.GetPluginArchive(ctx, pluginID, version, compatOpts)
		if err != nil {
			return err
		}
	}

	extractedArchive, err := m.pluginStorage.Add(ctx, pluginID, pluginArchive.File)
	if err != nil {
		return err
	}

	// download dependency plugins
	pathsToScan := []string{extractedArchive.Path}
	for _, dep := range extractedArchive.Dependencies {
		m.log.Info("Fetching %s dependencies...", dep.ID)
		d, err := m.pluginRepo.GetPluginArchive(ctx, dep.ID, dep.Version, compatOpts)
		if err != nil {
			return fmt.Errorf("%v: %w", fmt.Sprintf("failed to download plugin %s from repository", dep.ID), err)
		}

		depArchive, err := m.pluginStorage.Add(ctx, dep.ID, d.File)
		if err != nil {
			return err
		}

		pathsToScan = append(pathsToScan, depArchive.Path)
	}

	err = m.loadPlugins(context.Background(), plugins.External, pathsToScan...)
	if err != nil {
		m.log.Error("Could not load plugins", "paths", pathsToScan, "err", err)
		return err
	}

	return nil
}

func (m *PluginManager) Remove(ctx context.Context, pluginID string) error {
	plugin, exists := m.plugin(ctx, pluginID)
	if !exists {
		return plugins.ErrPluginNotInstalled
	}

	if !plugin.IsExternalPlugin() {
		return plugins.ErrUninstallCorePlugin
	}

	if err := m.unregisterAndStop(ctx, plugin); err != nil {
		return err
	}

	return m.pluginStorage.Remove(ctx, plugin.ID)
}