// Copyright 2024 Matthew Rich <matthewrich.conf@gmail.com>. All rights reserved.

package folio

import (
	"decl/internal/data"
	"errors"
	"log/slog"
)

// Dependencies describe a requirement on a given system property

// system properties:
//   loaded from config
//   
// deps assigned to decl
// match values in document configurations
// match values in all configurations?
//
// documents/facter.jx.yaml -> facts -> Get(key)
//
// ConfigMapper? -> DocumentRegistry

// system:
//   arch: amd64
//   foo: bar

var (
	ErrConstraintFailure = errors.New("Constraint failure")
)

type Constraint map[string]any

//func Compare[aV, bV map[K]V, K, V comparable](a aV, b bV) (matched bool) {
func CompareMap(a, b any) (matched bool) {
	for k,v := range a.(Constraint) {
		if bv, exists := b.(map[string]any)[k]; exists && bv == v {
			matched = true
		} else {
			matched = false
		}
	}
	return
}

func (c Constraint) CompareValues(a, b any) (matched bool) {
	matched = true
	slog.Info("Constraint.CompareValues()", "a", a, "b", b)
	switch btype := b.(type) {
	case map[string]string:
		return CompareMap(a, b)
	case map[string]any:
		return CompareMap(a, b)
	case []string:
		acmp := a.([]string)
		if len(acmp) > len(btype) {
			return false
		}
		for i,v := range acmp {
			if v != btype[i] {
				return false
			}
		}
	default:
		return a == b
	}
	return
}

func (c Constraint) Check(configs data.ConfigurationValueGetter) (matched bool) {
	matched = true
	for k,v := range c {
		slog.Info("Constraint.Check()", "constraint", c, "config", configs)
		
		if configValue, err := configs.GetValue(k); err != nil || ! c.CompareValues(v, configValue) {
			slog.Info("Constraint.Check() - FAILURE", "configvalue", configValue, "constraint", v, "error", err)
			matched = false
		}
	}
	return
}