package stateobjects

import (
	"encoding/json"
	"errors"

	stdio "git.novox.be/novox/mesh-sdk/go"
	"git.novox.be/novox/mesh-sdk/go/busstate"
	"git.novox.be/novox/mesh-sdk/go/catalogue"
)

// ForState is a state of this module, kept through its runtime: the state by its local name, and its object store
// `<state>-objects` (catalogue.StateObjectsName).
func ForState(state string) Values {
	store := catalogue.StateObjectsName(state)
	return Values{KV: BundleKV{State: stdio.State(state)}, Objects: BundleObjects{Store: busstate.ObjectsOf(store)}, Store: store}
}

// BundleKV is a state as a bundle reaches it.
type BundleKV struct{ State stdio.KeptState }

func (b BundleKV) Get(key string) (*Entry, error) {
	e, err := b.State.Get(key)
	if err != nil || e == nil {
		return nil, err
	}
	return &Entry{Value: e.Value, Revision: e.Revision}, nil
}

func changed(err error) error {
	if errors.Is(err, stdio.ErrChanged) {
		return ErrChanged
	}
	return err
}

func (b BundleKV) Create(key string, value []byte) error {
	_, err := b.State.Create(key, json.RawMessage(value))
	return changed(err)
}

func (b BundleKV) Update(key string, value []byte, revision uint64) error {
	_, err := b.State.Update(key, json.RawMessage(value), revision)
	return changed(err)
}

func (b BundleKV) Delete(key string) error { return b.State.Delete(key) }
func (b BundleKV) Keys() ([]string, error) { return b.State.Keys() }

// BundleObjects is an object store as a bundle reaches it.
type BundleObjects struct{ Store busstate.Objects }

// MostBytes is zero: a bundle's value of any size is put by a session of chunks, bounded by its store's cap, which the tool
// runner refuses at the chunk that passes it (design 47 G §518).
func (BundleObjects) MostBytes() int { return 0 }

func (b BundleObjects) Put(name string, data []byte) error {
	_, err := b.Store.Put(name, data, "a value kept beside its key")
	return err
}

func (b BundleObjects) Get(name string) ([]byte, error) {
	d, err := b.Store.Get(name)
	return d.Data, err
}

func (b BundleObjects) Delete(name string) error { return b.Store.Delete(name) }

func (b BundleObjects) List() ([]Object, error) {
	l, err := b.Store.List()
	out := make([]Object, 0, len(l))
	for _, o := range l {
		if !o.Deleted {
			out = append(out, Object{Name: o.Name, Size: int64(o.Size), Modified: o.Modified})
		}
	}
	return out, err
}