// Copyright 2022 Princess B33f Heavy Industries / Dave Shanley
// SPDX-License-Identifier: MIT

package what_changed

import (
	"github.com/pb33f/libopenapi/datamodel/low"
	"strings"
)

// ExtensionChanges represents any changes to custom extensions defined for an OpenAPI object.
type ExtensionChanges struct {
	PropertyChanges[any]
}

func (e *ExtensionChanges) TotalChanges() int {
	return e.PropertyChanges.TotalChanges()
}

// TotalBreakingChanges always returns 0 for Extension objects, they are non-binding.
func (e *ExtensionChanges) TotalBreakingChanges() int {
	return 0
}

// CompareExtensions will compare a left and right map of Key/ValueReference models for any changes to
// anything. This function does not try and cast the value of an extension to perform checks, it
// will perform a basic value check.
//
// A current limitation relates to extensions being objects and a property of the object changes,
// there is currently no support for knowing anything changed - so it is ignored.
func CompareExtensions(l, r map[low.KeyReference[string]]low.ValueReference[any]) *ExtensionChanges {

	// look at the original and then look through the new.
	seenLeft := make(map[string]*low.ValueReference[any])
	seenRight := make(map[string]*low.ValueReference[any])
	for i := range l {
		h := l[i]
		seenLeft[strings.ToLower(i.Value)] = &h
	}
	for i := range r {
		h := r[i]
		seenRight[strings.ToLower(i.Value)] = &h
	}

	var changes []*Change[any]
	for i := range seenLeft {

		CheckForObjectAdditionOrRemoval[any](seenLeft, seenRight, i, &changes, false, true)

		if seenRight[i] != nil {
			var props []*PropertyCheck[any]

			props = append(props, &PropertyCheck[any]{
				LeftNode:  seenLeft[i].ValueNode,
				RightNode: seenRight[i].ValueNode,
				Label:     i,
				Changes:   &changes,
				Breaking:  false,
				Original:  seenLeft[i].Value,
				New:       seenRight[i].Value,
			})

			// check properties
			CheckProperties(props)
		}
	}
	for i := range seenRight {
		if seenLeft[i] == nil {
			CheckForObjectAdditionOrRemoval[any](seenLeft, seenRight, i, &changes, false, true)
		}
	}
	ex := new(ExtensionChanges)
	ex.Changes = changes
	if ex.TotalChanges() <= 0 {
		return nil
	}
	return ex
}