package resolution

import (
	"sort"

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

// meshWords are the settings keys the mesh reads itself; a module declares none of them.
var meshWords = map[string]bool{mcat.PortsSetting: true, mcat.ExposeSetting: true, mcat.ReachSetting: true, mcat.EndpointsSetting: true, mcat.PlacesSetting: true, mcat.AccessesSetting: true, mcat.NetworksSetting: true}

// Defaults is the layer a module's own defaults make, or nothing when it gives none.
func Defaults(m mcat.Manifest) (mcat.Layer, bool) {
	if len(m.Settings) == 0 {
		return mcat.Layer{}, false
	}
	values := map[string]any{}
	for key, d := range m.Settings {
		if d.Default != nil {
			values[key] = d.Default
		}
	}
	return mcat.Layer{From: mcat.DefaultLayer, Values: values, Default: true}, len(values) > 0
}

// WithDefaults is a module's layers with its defaults under them, for filling `${setting:<key>}`.
func WithDefaults(m mcat.Manifest, layers []mcat.Layer) []mcat.Layer {
	d, has := Defaults(m)
	if !has {
		return layers
	}
	return append([]mcat.Layer{d}, layers...)
}

// Effective is every key a module gives a default or a layer sets, with its value and where it came
// from: the default, then the mesh's layer, then the node's — later wins.
func Effective(m mcat.Manifest, layers []mcat.Layer) []mcat.SettingSource {
	byKey := map[string]*mcat.SettingSource{}
	for key, d := range m.Settings {
		if d.Default == nil {
			// A required config value has no default (ADR 0348 §4); a settings declaration always has one.
			continue
		}
		byKey[key] = &mcat.SettingSource{Key: key, Value: d.Default, From: mcat.DefaultLayer, FromDefault: true,
			Default: d.Default, HasDefault: true}
	}
	for _, layer := range layers {
		// As the layer is said, placement too: `settings` answers it as a person set it.
		for key, v := range layer.Whole() {
			s, ok := byKey[key]
			if !ok {
				s = &mcat.SettingSource{Key: key}
				byKey[key] = s
			}
			s.Value, s.From, s.FromDefault = v, layer.From, layer.Default
		}
	}
	out := make([]mcat.SettingSource, 0, len(byKey))
	for _, s := range byKey {
		out = append(out, *s)
	}
	sort.Slice(out, func(i, j int) bool { return out[i].Key < out[j].Key })
	return out
}