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

package model

import (
	"encoding/json"
	"gopkg.in/yaml.v3"
)

// Definitions of the possible changes between two items
const (

	// Modified means that was a modification of a value was made
	Modified = iota + 1

	// PropertyAdded means that a new property to an object was added
	PropertyAdded

	// ObjectAdded means that a new object was added to a parent object
	ObjectAdded

	// ObjectRemoved means that an object was removed from a parent object
	ObjectRemoved

	// PropertyRemoved means that a property of an object was removed
	PropertyRemoved
)

// WhatChanged is a summary object that contains a high level summary of everything changed.
type WhatChanged struct {
	Added        int `json:"added,omitempty" yaml:"added,omitempty"`
	Removed      int `json:"removed,omitempty" yaml:"removed,omitempty"`
	Modified     int `json:"modified,omitempty" yaml:"modified,omitempty"`
	TotalChanges int `json:"total,omitempty" yaml:"total,omitempty"`
}

// ChangeContext holds a reference to the line and column positions of original and new change.
type ChangeContext struct {
	OriginalLine   *int `json:"originalLine,omitempty" yaml:"originalLine,omitempty"`
	OriginalColumn *int `json:"originalColumn,omitempty" yaml:"originalColumn,omitempty"`
	NewLine        *int `json:"newLine,omitempty" yaml:"newLine,omitempty"`
	NewColumn      *int `json:"newColumn,omitempty" yaml:"newColumn,omitempty"`
}

// HasChanged determines if the line and column numbers of the original and new values have changed.
//
// It's worth noting that there is no guarantee to the positions of anything in either left or right, so
// considering these values as 'changes' is going to add a considerable amount of noise to results.
func (c *ChangeContext) HasChanged() bool {
	if c.NewLine != nil && c.OriginalLine != nil && *c.NewLine != *c.OriginalLine {
		return true
	}
	//if c.NewColumn != nil && c.OriginalColumn != nil && *c.NewColumn != *c.OriginalColumn {
	//    return true
	//}
	if (c.NewLine == nil && c.OriginalLine != nil) || (c.NewLine != nil && c.OriginalLine == nil) {
		return true
	}
	//if (c.NewColumn == nil && c.OriginalColumn != nil) || (c.NewColumn != nil && c.OriginalColumn == nil) {
	//    return true
	//}
	return false
}

// Change represents a change between two different elements inside an OpenAPI specification.
type Change struct {

	// Context represents the lines and column numbers of the original and new values
	// It's worth noting that these values may frequently be different and are not used to calculate
	// a change. If the positions change, but values do not, then no change is recorded.
	Context *ChangeContext `json:"context,omitempty" yaml:"context,omitempty"`

	// ChangeType represents the type of change that occurred. stored as an integer, defined by constants above.
	ChangeType int `json:"change,omitempty" yaml:"change,omitempty"`

	// Property is the property name key being changed.
	Property string `json:"property,omitempty" yaml:"property,omitempty"`

	// Original is the original value represented as a string.
	Original string `json:"original,omitempty" yaml:"original,omitempty"`

	// New is the new value represented as a string.
	New string `json:"new,omitempty" yaml:"new,omitempty"`

	// Breaking determines if the change is a breaking one or not.
	Breaking bool `json:"breaking" yaml:"breaking"`

	// OriginalObject represents the original object that was changed.
	OriginalObject any `json:"-" yaml:"-"`

	// NewObject represents the new object that has been modified.
	NewObject any `json:"-" yaml:"-"`
}

// MarshalJSON is a custom JSON marshaller for the Change object.
func (c *Change) MarshalJSON() ([]byte, error) {
	changeType := ""
	switch c.ChangeType {
	case Modified:
		changeType = "modified"
	case PropertyAdded:
		changeType = "property_added"
	case ObjectAdded:
		changeType = "object_added"
	case ObjectRemoved:
		changeType = "object_removed"
	case PropertyRemoved:
		changeType = "property_removed"
	}
	data := map[string]interface{}{
		"change":     c.ChangeType,
		"changeText": changeType,
		"context":    c.Context,
		"property":   c.Property,
		"original":   c.Original,
		"new":        c.New,
		"breaking":   c.Breaking,
	}
	return json.Marshal(data)
}

// PropertyChanges holds a slice of Change pointers
type PropertyChanges struct {
	//Total *int `json:"total,omitempty" yaml:"total,omitempty"`
	//Breaking *int `json:"breaking,omitempty" yaml:"breaking,omitempty"`
	Changes []*Change `json:"changes,omitempty" yaml:"changes,omitempty"`
}

// TotalChanges returns the total number of property changes made.
func (p PropertyChanges) TotalChanges() int {
	return len(p.Changes)
}

// TotalBreakingChanges returns the total number of property breaking changes made.
func (p PropertyChanges) TotalBreakingChanges() int {
	return CountBreakingChanges(p.Changes)
}

func NewPropertyChanges(changes []*Change) *PropertyChanges {
	return &PropertyChanges{Changes: changes}
}

// PropertyCheck is used by functions to check the state of left and right values.
type PropertyCheck struct {

	// Original is the property we're checking on the left
	Original any

	// New is s the property we're checking on the right
	New any

	// Label is the identifier we're looking for on the left and right hand sides
	Label string

	// LeftNode is the yaml.Node pointer that holds the original node structure of the value
	LeftNode *yaml.Node

	// RightNode is the yaml.Node pointer that holds the new node structure of the value
	RightNode *yaml.Node

	// Breaking determines if the check is a breaking change (modifications or removals etc.)
	Breaking bool

	// Changes represents a pointer to the slice to contain all changes found.
	Changes *[]*Change
}
