package plugincheck

import (
	"context"
	"fmt"
	sysruntime "runtime"

	"github.com/Masterminds/semver/v3"
	advisor "github.com/grafana/grafana/apps/advisor/pkg/apis/advisor/v0alpha1"
	"github.com/grafana/grafana/apps/advisor/pkg/app/checks"
	"github.com/grafana/grafana/pkg/cmd/grafana-cli/services"
	"github.com/grafana/grafana/pkg/plugins/repo"
	"github.com/grafana/grafana/pkg/services/pluginsintegration/managedplugins"
	"github.com/grafana/grafana/pkg/services/pluginsintegration/plugininstaller"
	"github.com/grafana/grafana/pkg/services/pluginsintegration/pluginstore"
)

func New(
	pluginStore pluginstore.Store,
	pluginRepo repo.Service,
	pluginPreinstall plugininstaller.Preinstall,
	managedPlugins managedplugins.Manager,
) checks.Check {
	return &check{
		PluginStore:      pluginStore,
		PluginRepo:       pluginRepo,
		PluginPreinstall: pluginPreinstall,
		ManagedPlugins:   managedPlugins,
	}
}

type check struct {
	PluginStore      pluginstore.Store
	PluginRepo       repo.Service
	PluginPreinstall plugininstaller.Preinstall
	ManagedPlugins   managedplugins.Manager
}

func (c *check) ID() string {
	return "plugin"
}

func (c *check) Items(ctx context.Context) ([]any, error) {
	ps := c.PluginStore.Plugins(ctx)
	res := make([]any, len(ps))
	for i, p := range ps {
		res[i] = p
	}
	return res, nil
}

func (c *check) Steps() []checks.Step {
	return []checks.Step{
		&deprecationStep{
			PluginRepo: c.PluginRepo,
		},
		&updateStep{
			PluginRepo:       c.PluginRepo,
			PluginPreinstall: c.PluginPreinstall,
			ManagedPlugins:   c.ManagedPlugins,
		},
	}
}

type deprecationStep struct {
	PluginRepo repo.Service
}

func (s *deprecationStep) Title() string {
	return "Deprecation check"
}

func (s *deprecationStep) Description() string {
	return "Check if any installed plugins are deprecated."
}

func (s *deprecationStep) ID() string {
	return "deprecation"
}

func (s *deprecationStep) Run(ctx context.Context, _ *advisor.CheckSpec, items []any) ([]advisor.CheckReportError, error) {
	errs := []advisor.CheckReportError{}
	for _, i := range items {
		p, ok := i.(pluginstore.Plugin)
		if !ok {
			return nil, fmt.Errorf("invalid item type %T", i)
		}

		// Skip if it's a core plugin
		if p.IsCorePlugin() {
			continue
		}

		// Check if plugin is deprecated
		i, err := s.PluginRepo.PluginInfo(ctx, p.ID)
		if err != nil {
			continue
		}
		if i.Status == "deprecated" {
			errs = append(errs, advisor.CheckReportError{
				Severity: advisor.CheckReportErrorSeverityHigh,
				Reason:   fmt.Sprintf("Plugin deprecated: %s", p.ID),
				Action:   "Check the <a href='https://grafana.com/legal/plugin-deprecation/#a-plugin-i-use-is-deprecated-what-should-i-do' target=_blank>documentation</a> for recommended steps.",
			})
		}
	}
	return errs, nil
}

type updateStep struct {
	PluginRepo       repo.Service
	PluginPreinstall plugininstaller.Preinstall
	ManagedPlugins   managedplugins.Manager
}

func (s *updateStep) Title() string {
	return "Update check"
}

func (s *updateStep) Description() string {
	return "Check if any installed plugins have a newer version available."
}

func (s *updateStep) ID() string {
	return "update"
}

func (s *updateStep) Run(ctx context.Context, _ *advisor.CheckSpec, items []any) ([]advisor.CheckReportError, error) {
	errs := []advisor.CheckReportError{}
	for _, i := range items {
		p, ok := i.(pluginstore.Plugin)
		if !ok {
			return nil, fmt.Errorf("invalid item type %T", i)
		}

		// Skip if it's a core plugin
		if p.IsCorePlugin() {
			continue
		}

		// Skip if it's managed or pinned
		if s.isManaged(ctx, p.ID) || s.PluginPreinstall.IsPinned(p.ID) {
			continue
		}

		// Check if plugin has a newer version available
		compatOpts := repo.NewCompatOpts(services.GrafanaVersion, sysruntime.GOOS, sysruntime.GOARCH)
		info, err := s.PluginRepo.GetPluginArchiveInfo(ctx, p.ID, "", compatOpts)
		if err != nil {
			continue
		}
		if hasUpdate(p, info) {
			errs = append(errs, advisor.CheckReportError{
				Severity: advisor.CheckReportErrorSeverityLow,
				Reason:   fmt.Sprintf("New version available for %s", p.ID),
				Action: fmt.Sprintf(
					"Go to the <a href='/plugins/%s?page=version-history'>plugin admin page</a>"+
						" and upgrade to the latest version.", p.ID),
			})
		}
	}

	return errs, nil
}

func hasUpdate(current pluginstore.Plugin, latest *repo.PluginArchiveInfo) bool {
	// If both versions are semver-valid, compare them
	v1, err1 := semver.NewVersion(current.Info.Version)
	v2, err2 := semver.NewVersion(latest.Version)
	if err1 == nil && err2 == nil {
		return v1.LessThan(v2)
	}
	// In other case, assume that a different latest version will always be newer
	return current.Info.Version != latest.Version
}

func (s *updateStep) isManaged(ctx context.Context, pluginID string) bool {
	for _, managedPlugin := range s.ManagedPlugins.ManagedPlugins(ctx) {
		if managedPlugin == pluginID {
			return true
		}
	}
	return false
}