// Migration 2 — add fields present in code but absent from pb-init-v3.sh.
//
// Discovered by auditing every PocketBase field access in the Go backend
// and SvelteKit UI against the collection definitions in pb-init-v3.sh:
//
//   books.rating              (number) — written by WriteMetadata but never defined.
//   app_users.notify_new_chapters_push (bool) — used in UI push-notification opt-in.
//   book_comments.chapter     (number) — used to scope comments to a chapter (0 = book-level).
//
// The check for field existence makes this migration safe to re-apply on
// a fresh install where migration 1 already created the collections without
// these fields.
package migrations

import (
	"github.com/pocketbase/pocketbase/core"
	m "github.com/pocketbase/pocketbase/migrations"
)

func init() {
	m.Register(func(app core.App) error {
		type addition struct {
			collection string
			field      core.Field
		}
		additions := []addition{
			{"books", &core.NumberField{Name: "rating"}},
			{"app_users", &core.BoolField{Name: "notify_new_chapters_push"}},
			{"book_comments", &core.NumberField{Name: "chapter"}},
		}
		for _, a := range additions {
			coll, err := app.FindCollectionByNameOrId(a.collection)
			if err != nil {
				return err
			}
			if coll.Fields.GetByName(a.field.GetName()) != nil {
				continue // already present — idempotent
			}
			coll.Fields.Add(a.field)
			if err := app.Save(coll); err != nil {
				return err
			}
		}
		return nil
	}, func(app core.App) error {
		type removal struct {
			collection string
			field      string
		}
		removals := []removal{
			{"books", "rating"},
			{"app_users", "notify_new_chapters_push"},
			{"book_comments", "chapter"},
		}
		for _, r := range removals {
			coll, err := app.FindCollectionByNameOrId(r.collection)
			if err != nil {
				continue
			}
			f := coll.Fields.GetByName(r.field)
			if f == nil {
				continue
			}
			coll.Fields.RemoveById(f.GetId())
			if err := app.Save(coll); err != nil {
				return err
			}
		}
		return nil
	})
}