// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Collections.Generic;
using System.Text.Json;
using System.Text.Json.Nodes;
using Microsoft.AspNetCore.JsonPatch.SystemTextJson.Helpers;
 
namespace Microsoft.AspNetCore.JsonPatch.SystemTextJson.Internal;
 
internal class DictionaryAdapter<TKey, TValue> : IAdapter
{
    public virtual bool TryAdd(
        object target,
        string segment,
        JsonSerializerOptions serializerOptions,
        object value,
        out string errorMessage)
    {
        var key = segment;
        var dictionary = (IDictionary<TKey, TValue>)target;
 
        // As per JsonPatch spec, if a key already exists, adding should replace the existing value
        if (!TryConvertKey(key, out var convertedKey, out errorMessage))
        {
            return false;
        }
 
        if (!TryConvertValue(value, serializerOptions, out var convertedValue, out errorMessage))
        {
            return false;
        }
 
        dictionary[convertedKey] = convertedValue;
        errorMessage = null;
        return true;
    }
 
    public virtual bool TryGet(
        object target,
        string segment,
        JsonSerializerOptions serializerOptions,
        out object value,
        out string errorMessage)
    {
        var key = segment;
        var dictionary = (IDictionary<TKey, TValue>)target;
 
        if (!TryConvertKey(key, out var convertedKey, out errorMessage))
        {
            value = null;
            return false;
        }
 
        if (!dictionary.TryGetValue(convertedKey, out var valueAsT))
        {
            value = null;
            errorMessage = Resources.FormatTargetLocationAtPathSegmentNotFound(segment);
            return false;
        }
 
        value = valueAsT;
        errorMessage = null;
        return true;
    }
 
    public virtual bool TryRemove(
        object target,
        string segment,
        JsonSerializerOptions serializerOptions,
        out string errorMessage)
    {
        var key = segment;
        var dictionary = (IDictionary<TKey, TValue>)target;
 
        if (!TryConvertKey(key, out var convertedKey, out errorMessage))
        {
            return false;
        }
 
        // As per JsonPatch spec, the target location must exist for remove to be successful
        if (!dictionary.Remove(convertedKey))
        {
            errorMessage = Resources.FormatTargetLocationAtPathSegmentNotFound(segment);
            return false;
        }
 
        errorMessage = null;
        return true;
    }
 
    public virtual bool TryReplace(
        object target,
        string segment,
        JsonSerializerOptions serializerOptions,
        object value,
        out string errorMessage)
    {
        var key = segment;
        var dictionary = (IDictionary<TKey, TValue>)target;
 
        if (!TryConvertKey(key, out var convertedKey, out errorMessage))
        {
            return false;
        }
 
        // As per JsonPatch spec, the target location must exist for remove to be successful
        if (!dictionary.ContainsKey(convertedKey))
        {
            errorMessage = Resources.FormatTargetLocationAtPathSegmentNotFound(segment);
            return false;
        }
 
        if (!TryConvertValue(value, serializerOptions, out var convertedValue, out errorMessage))
        {
            return false;
        }
 
        dictionary[convertedKey] = convertedValue;
 
        errorMessage = null;
        return true;
    }
 
    public virtual bool TryTest(
        object target,
        string segment,
        JsonSerializerOptions serializerOptions,
        object value,
        out string errorMessage)
    {
        var key = segment;
        var dictionary = (IDictionary<TKey, TValue>)target;
 
        if (!TryConvertKey(key, out var convertedKey, out errorMessage))
        {
            return false;
        }
 
        // As per JsonPatch spec, the target location must exist for test to be successful
        if (!dictionary.TryGetValue(convertedKey, out var currentValue))
        {
            errorMessage = Resources.FormatTargetLocationAtPathSegmentNotFound(segment);
            return false;
        }
 
        if (!TryConvertValue(value, serializerOptions, out var convertedValue, out errorMessage))
        {
            return false;
        }
 
        // The target segment does not have an assigned value to compare the test value with
        if (currentValue == null)
        {
            errorMessage = Resources.FormatValueForTargetSegmentCannotBeNullOrEmpty(segment);
            return false;
        }
 
        if (!JsonUtilities.DeepEquals(currentValue, convertedValue, serializerOptions))
        {
            errorMessage = Resources.FormatValueNotEqualToTestValue(currentValue, value, segment);
            return false;
        }
        else
        {
            errorMessage = null;
            return true;
        }
    }
 
    public virtual bool TryTraverse(
        object target,
        string segment,
        JsonSerializerOptions serializerOptions,
        out object nextTarget,
        out string errorMessage)
    {
        var key = segment;
        var dictionary = (IDictionary<TKey, TValue>)target;
 
        if (!TryConvertKey(key, out var convertedKey, out errorMessage))
        {
            nextTarget = null;
            return false;
        }
 
        if (dictionary.TryGetValue(convertedKey, out var valueAsT))
        {
            nextTarget = valueAsT;
            errorMessage = null;
            return true;
        }
        else
        {
            nextTarget = null;
            errorMessage = null;
            return false;
        }
    }
 
    private static bool TryConvertKey(string key, out TKey convertedKey, out string errorMessage)
    {
        var options = new JsonSerializerOptions() { NumberHandling = System.Text.Json.Serialization.JsonNumberHandling.AllowReadingFromString };
        var conversionResult = ConversionResultProvider.ConvertTo(key, typeof(TKey), options);
        if (conversionResult.CanBeConverted)
        {
            errorMessage = null;
            convertedKey = (TKey)conversionResult.ConvertedInstance;
            return true;
        }
        else
        {
            errorMessage = Resources.FormatInvalidPathSegment(key);
            convertedKey = default(TKey);
            return false;
        }
    }
 
    private static bool TryConvertValue(object value, JsonSerializerOptions serializerOptions, out TValue convertedValue, out string errorMessage)
    {
        var conversionResult = ConversionResultProvider.ConvertTo(value, typeof(TValue), serializerOptions);
        if (conversionResult.CanBeConverted)
        {
            errorMessage = null;
            convertedValue = (TValue)conversionResult.ConvertedInstance;
            return true;
        }
        else
        {
            errorMessage = Resources.FormatInvalidValueForProperty(value);
            convertedValue = default(TValue);
            return false;
        }
    }
}