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"
)

// FireSubjectEvent fires ev through the application's event bus at once, so
// the MCP endpoint re-lists the subject's tools or ends its sessions. A
// revoked event may carry TokenID (only the sessions one personal token
// opened end) or ClientID with UserID (only that OAuth client's sessions
// end). A missing application or bus, a zero UserID or an empty Kind 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 FireSubjectEvent(ctx context.Context, app *backpack.App, ev pact.MCPSubjectChanged) {
	if app == nil || app.Events == nil || ev.UserID == 0 || ev.Kind == "" {
		return
	}
	if ctx == nil {
		ctx = context.Background()
	}
	event := ev
	if err := app.Events.Fire(ctx, &event); err != nil {
		pluginLog.WarnContext(ctx, "golem15.user: subject changed listener failed", "guard", ev.Guard, "user_id", ev.UserID, "kind", ev.Kind, "token_id", ev.TokenID, "client_id", ev.ClientID, "err", err)
	}
}

// FireSubjectEventAfterCommit is FireSubjectEvent 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 FireSubjectEventAfterCommit(ctx context.Context, app *backpack.App, tx *gorm.DB, ev pact.MCPSubjectChanged) {
	if app == nil || app.Events == nil || ev.UserID == 0 || ev.Kind == "" {
		return
	}
	if tx == nil {
		FireSubjectEvent(ctx, app, ev)
		return
	}
	lagoon.AfterCommit(ctx, tx, func(ctx context.Context, _ *gorm.DB) {
		FireSubjectEvent(ctx, app, ev)
	})
}

// FireSubjectChanged fires one *pact.MCPSubjectChanged (guard, user id,
// kind) at once: FireSubjectEvent for the whole subject.
func FireSubjectChanged(ctx context.Context, app *backpack.App, guard string, userID uint, kind string) {
	FireSubjectEvent(ctx, app, pact.MCPSubjectChanged{Guard: guard, UserID: userID, Kind: kind})
}

// FireSubjectChangedAfterCommit is FireSubjectChanged once the write
// transaction tx commits: FireSubjectEventAfterCommit for the whole subject.
func FireSubjectChangedAfterCommit(ctx context.Context, app *backpack.App, tx *gorm.DB, guard string, userID uint, kind string) {
	FireSubjectEventAfterCommit(ctx, app, tx, pact.MCPSubjectChanged{Guard: guard, UserID: userID, Kind: kind})
}