package classes

import (
	"context"

	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/lagoon"
	"git.golem15.com/golem15/summercms/modules/pact"
	"gorm.io/gorm"
)

// Guard names the plugin's pact.MCPSubjectChanged events carry: the frontend
// user guard this plugin provides and the admin's guard (for the backend
// side of an account link).
const (
	SubjectGuardUser    = "user"
	SubjectGuardBackend = "backend"
)

// FireSubjectChanged fires one *pact.MCPSubjectChanged (guard, user id,
// kind) through the application's event bus at once, so the MCP endpoint
// re-lists the subject's tools or ends its sessions. A missing application
// or bus, or a zero id, is a no-op; a listener's error is logged and never
// returned, so the write that caused the event never fails because of it
// (every MCP request re-checks anyway).
func FireSubjectChanged(ctx context.Context, app *backpack.App, guard string, userID uint, kind string) {
	if app == nil || app.Events == nil || userID == 0 || kind == "" {
		return
	}
	if ctx == nil {
		ctx = context.Background()
	}
	event := &pact.MCPSubjectChanged{Guard: guard, UserID: userID, Kind: kind}
	if err := app.Events.Fire(ctx, event); err != nil {
		pluginLog.WarnContext(ctx, "golem15.user: subject changed listener failed", "guard", guard, "user_id", userID, "kind", kind, "err", err)
	}
}

// FireSubjectChangedAfterCommit is FireSubjectChanged once the write
// transaction tx commits (lagoon.AfterCommit), so a listener that reads the
// database sees the change; nothing is fired when the transaction rolls
// back. A nil tx fires at once. ctx must be the context the transaction
// runs under (the one cabana hands a hook or an action).
func FireSubjectChangedAfterCommit(ctx context.Context, app *backpack.App, tx *gorm.DB, guard string, userID uint, kind string) {
	if app == nil || app.Events == nil || userID == 0 || kind == "" {
		return
	}
	if tx == nil {
		FireSubjectChanged(ctx, app, guard, userID, kind)
		return
	}
	lagoon.AfterCommit(ctx, tx, func(ctx context.Context, _ *gorm.DB) {
		FireSubjectChanged(ctx, app, guard, userID, kind)
	})
}