using Strata.SqlTools.SqlBreakdown.Interfaces.Core;

using System.Collections;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace Strata.SqlTools.SqlBreakdown.Expressions;

/// <summary>
/// Represents a reference to a property from an input data source, typically used for
/// dynamic data binding in query construction. Used when building queries that reference
/// external data sources by GUID identifiers.
/// </summary>
/// <remarks>
/// This expression type is used in scenarios where data comes from registered data
/// sources (like data tables or dimensions) that are identified by GUIDs. The
/// expression can reference a primary data source and optionally a secondary data source
/// for hierarchical or relational lookups.
/// </remarks>
/// <example>
/// <code language="csharp">
/// // Reference a simple property from a data source
/// var patientName = new InputPropertyExpression(
///     dataSourceGuid: Guid.Parse("41639c8f-fecf-4449-b6e6-53f796c0c3e4"),
///     dataKeyLookup: "PatientName"
/// );
///
/// // Reference a property with a secondary data source (dimension lookup)
/// var patientType = new InputPropertyExpression(
///     dataSourceGuid: Guid.Parse("41639c8f-fecf-4449-b6e6-53f796c0c3e4"),
///     secondaryDataSource: Guid.Parse("6ef6b1f7-a50c-4198-8866-140bb82e2dda"),
///     dataKeyLookup: "PatientTypeRollupName"
/// );
/// </code>
/// </example>
public class InputPropertyExpression : Expression
{
    /// <summary>
    /// Gets the GUID identifier of the primary data source.
    /// </summary>
    /// <value>
    /// The data source GUID, typically representing a data table or primary data entity.
    /// </value>
    /// <example>
    /// 41639c8f-fecf-4449-b6e6-53f796c0c3e4 - the data table id of PES
    /// </example>
    public Guid DataSourceGuid { get; }

    /// <summary>
    /// Gets the optional GUID identifier of a secondary data source.
    /// </summary>
    /// <value>
    /// The secondary data source GUID, typically representing a dimension or lookup table.
    /// Null if no secondary source is required.
    /// </value>
    /// <example>
    /// 6ef6b1f7-a50c-4198-8866-140bb82e2dda - the dimension id of the Patient Type
    /// Rollup dimension
    /// </example>
    public Guid? SecondaryDataSource { get; }

    /// <summary>
    /// Gets the key name used to look up the data value.
    /// </summary>
    /// <value>
    /// The property or column name within the data source.
    /// </value>
    /// <example>"PatientTypeRollupName"</example>
    public string DataKeyLookup { get; }

    /// <summary>
    /// Initializes a new instance of the <see cref="InputPropertyExpression"/> class
    /// with a primary data source.
    /// </summary>
    /// <param name="dataSourceGuid">The GUID of the primary data source.</param>
    /// <param name="dataKeyLookup">The key name for data lookup.</param>
    /// <remarks>
    /// Example:
    /// <code language="csharp">
    /// var property = new InputPropertyExpression(
    ///     Guid.Parse("41639c8f-fecf-4449-b6e6-53f796c0c3e4"),
    ///     "PatientName");
    /// </code>
    /// </remarks>
    public InputPropertyExpression(Guid dataSourceGuid, string dataKeyLookup) : this(dataSourceGuid, null, dataKeyLookup)
    {

    }

    /// <summary>
    /// Initializes a new instance of the <see cref="InputPropertyExpression"/> class
    /// with primary and optional secondary data sources.
    /// </summary>
    /// <param name="dataSourceGuid">The GUID of the primary data source.</param>
    /// <param name="secondaryDataSource">
    /// The optional GUID of the secondary data source.
    /// </param>
    /// <param name="dataKeyLookup">The key name for data lookup.</param>
    /// <remarks>
    /// Example with secondary data source:
    /// <code language="csharp">
    /// var property = new InputPropertyExpression(
    ///     Guid.Parse("41639c8f-fecf-4449-b6e6-53f796c0c3e4"),
    ///     Guid.Parse("6ef6b1f7-a50c-4198-8866-140bb82e2dda"),
    ///     "PatientTypeRollupName");
    /// </code>
    /// </remarks>
    public InputPropertyExpression(Guid dataSourceGuid, Guid? secondaryDataSource, string dataKeyLookup)
    {
        DataSourceGuid = dataSourceGuid;
        SecondaryDataSource = secondaryDataSource;
        DataKeyLookup = dataKeyLookup;
    }

    public override T Accept<T>(IVisitor<T> visitor)
    {
        return visitor.VisitInputPropertyExpression(this);
    }
}

public class CollectionInputPropertyExpression : InputPropertyExpression
{
    public CollectionInputPropertyExpression(Guid dataSourceGuid, Guid secondaryDataSource, string dataKeyLookup)
        : base(dataSourceGuid, secondaryDataSource, dataKeyLookup)
    {

    }

    public InputPropertyExpression? ItemProperty { get; }

    public override T Accept<T>(IVisitor<T> visitor)
    {
        throw new NotImplementedException();
    }
}

public interface IFlatData : IDictionary<string, object>
{
    string RowIdKey { get; }

    long RowId { get; }
}

public class MyFlatData : Dictionary<string, object>, IFlatData
{
    private readonly Lazy<long> _rowId;

    public MyFlatData() : this(new Dictionary<string, object>())
    {

    }

    public MyFlatData(IDictionary<string, object> rawData) : this(rawData, "RowID")
    {

    }

    public MyFlatData(IDictionary<string, object> rawData, string rowIdKey) : base(rawData)
    {
        RowIdKey = rowIdKey;
        _rowId = new Lazy<long>(() => this.GetValue<long>(RowIdKey), false);
    }

    public string RowIdKey { get; }

    public long RowId => _rowId.Value;
}

public class FlatData : IFlatData
{
    private readonly IDictionary<string, object> _data;

    private readonly Lazy<long> _rowId;

    public FlatData() : this(new Dictionary<string, object>(), "RowID")
    {
    }

    public FlatData(IDictionary<string, object> rawData, string rowIdKey)
    {
        _data = rawData;
        RowIdKey = rowIdKey;
        _rowId = new Lazy<long>(() => this.GetValue<long>(RowIdKey), false);
    }

    public string RowIdKey { get; }

    public long RowId => _rowId.Value;

    public IEnumerator<KeyValuePair<string, object>> GetEnumerator()
    {
        return _data.GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return ((IEnumerable)_data).GetEnumerator();
    }

    public void Add(KeyValuePair<string, object> item)
    {
        _data.Add(item);
    }

    public void Clear()
    {
        _data.Clear();
    }

    public bool Contains(KeyValuePair<string, object> item)
    {
        return _data.Contains(item);
    }

    public void CopyTo(KeyValuePair<string, object>[] array, int arrayIndex)
    {
        _data.CopyTo(array, arrayIndex);
    }

    public bool Remove(KeyValuePair<string, object> item)
    {
        return _data.Remove(item);
    }

    public int Count => _data.Count;

    public bool IsReadOnly { get; }

    public void Add(string key, object value)
    {
        _data.Add(key, value);
    }

    public bool ContainsKey(string key)
    {
        return _data.ContainsKey(key);
    }

    public bool Remove(string key)
    {
        throw new NotImplementedException();
    }

    public bool TryGetValue(string key, out object value)
    {
        return _data.TryGetValue(key, out value!);
    }

    public IEnumerable<string> Keys => _data.Keys;

    ICollection<object> IDictionary<string, object>.Values => _data.Values;

    ICollection<string> IDictionary<string, object>.Keys => _data.Keys;

    public IEnumerable<object> Values => _data.Values;

    public object this[string key]
    {
        get => _data[key];
        set => _data[key] = value;
    }
}

public static class FlatDataUtils
{
    private static readonly IFormatProvider _culture = new CultureInfo("en-US");

    public static object GetValue(this IFlatData data, string key)
    {
        ArgumentNullException.ThrowIfNull(data);

        if (!data.TryGetValue(key, out object? rawValue))
        {
            throw new ArgumentException(
                $"The specified key is not available. Requested key: [{key}] Available keys: [{string.Join(", ", data.Keys)}]",
                nameof(key));
        }

        return rawValue;
    }

    public static TValue GetValue<TValue>(this IFlatData data, string key)
    {
        var rawValue = data.GetValue(key);

        var convertedValue = (TValue)Convert.ChangeType(rawValue, typeof(TValue), _culture);

        return convertedValue;
    }

    public static IEnumerable<long> GetRowIds(this IEnumerable<IFlatData> data)
    {
        return data.Select(x => x.RowId);
    }
}

public interface IHierarchicalData
{
    /// <summary>
    /// The DataSource for this level of the Hierarchy
    /// </summary>
    Guid DataSourceGuid { get; }

    /// <summary>
    /// The Data at this level of the Hierarchy
    /// </summary>
    IFlatData Data { get; set; }

    /// <summary>
    /// Returns all Child Data across all DataSources, or an empty collection if there is no Child Data
    /// </summary>
    IEnumerable<IHierarchicalData> AllChildData { get; set; }

    /// <summary>
    /// Checks if this record has Child Data for a particular DataSource
    /// </summary>
    /// <param name="dataSourceGuid">The DataSource to check</param>
    /// <returns>True if any Child Data exists for the DataSource</returns>
    bool HasChildData(Guid dataSourceGuid);

    /// <summary>
    /// Returns the Child Data for the given DataSource
    /// </summary>
    /// <param name="dataSourceGuid">DataSource identifier for the child data</param>
    /// <returns>The Child Data or an empty collection if no child data is set for the DataSource</returns>
    IEnumerable<IHierarchicalData> GetChildData(Guid dataSourceGuid);

    /// <summary>
    /// Attempts to add Child Data. Will check if child data exists before adding.
    /// </summary>
    /// <param name="datasourceGuid">DataSource identifier for the child data</param>
    /// <param name="data">The Child Data to Add to the Record</param>
    /// <returns>False if child data exists and was not overriden</returns>
    bool TryAddChildData(Guid datasourceGuid, IEnumerable<IHierarchicalData> data);

    /// <summary>
    /// Add Child Data, will override any existing Child Data for the DataSource
    /// </summary>
    /// <param name="datasourceGuid">DataSource identifier for the child data</param>
    /// <param name="data">The Child Data to Add to the Record</param>
    void SetChildData(Guid datasourceGuid, IEnumerable<IHierarchicalData> data);
}

public class HierarchicalData : IHierarchicalData
{
    private Dictionary<Guid, List<IHierarchicalData>> _childDataMap;

    [JsonConstructor]
    public HierarchicalData() : this(Guid.Empty, default!, new List<IHierarchicalData>())
    {

    }

    public HierarchicalData(Guid dataSourceGuid, IFlatData rootData) : this(dataSourceGuid, rootData,
        new List<IHierarchicalData>())
    {
    }

    public HierarchicalData(Guid dataSourceGuid, IFlatData rootData, IEnumerable<IHierarchicalData> childData)
    {
        DataSourceGuid = dataSourceGuid;
        Data = rootData;
        _childDataMap = childData.GroupBy(x => x.DataSourceGuid).ToDictionary(x => x.Key, x => x.ToList());
    }

    public Guid DataSourceGuid { get; set; }

    public IFlatData Data { get; set; }

    [SuppressMessage("Major Code Smell", "S2365:Properties should not make collection or array copies", Justification = "AllChildData is part of the IHierarchicalData interface contract and is JSON-serialized (see Data.json). The flatten-on-get / group-on-set transformation is the deliberate purpose of the property — _childDataMap is the storage form, the property is the wire form.")]
    public IEnumerable<IHierarchicalData> AllChildData
    {
        get => _childDataMap.SelectMany(x => x.Value).ToList();
        set => _childDataMap = value.GroupBy(x => x.DataSourceGuid).ToDictionary(x => x.Key, x => x.ToList());
    }

    public bool HasChildData(Guid dataSourceGuid)
    {
        return _childDataMap.ContainsKey(dataSourceGuid);
    }

    public IEnumerable<IHierarchicalData> GetChildData(Guid dataSourceGuid)
    {
        if (HasChildData(dataSourceGuid))
        {
            return _childDataMap[dataSourceGuid];
        }

        return new List<IHierarchicalData>();
    }

    public bool TryAddChildData(Guid datasourceGuid, IEnumerable<IHierarchicalData> data)
    {
        if (_childDataMap.ContainsKey(datasourceGuid))
        {
            return false;
        }

        _childDataMap[datasourceGuid] = data.ToList();

        return true;
    }

    public void SetChildData(Guid datasourceGuid, IEnumerable<IHierarchicalData> data)
    {
        _childDataMap[datasourceGuid] = data.ToList();
    }

    public override string? ToString()
    {
        if (Data?.ContainsKey("DimPatientEnEncounterID") ?? false)
        {
            return Data["DimPatientEnEncounterID"].ToString();
        }
        return base.ToString();
    }
}

#region Json Converters
public class HierarchicalDataConverter : JsonConverter<IHierarchicalData>
{
    public override IHierarchicalData? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
    {
        return JsonSerializer.Deserialize<HierarchicalData>(ref reader, options);
    }

    public override void Write(Utf8JsonWriter writer, IHierarchicalData value, JsonSerializerOptions options)
    {
        throw new NotImplementedException();
    }
}

public class FlatDataConverter : JsonConverter<IFlatData>
{
    public override IFlatData? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
    {
        return JsonSerializer.Deserialize<MyFlatData>(ref reader, options);
    }

    public override void Write(Utf8JsonWriter writer, IFlatData value, JsonSerializerOptions options)
    {
        throw new NotImplementedException();
    }
}

public class ObjectToInferredTypesConverter : JsonConverter<object>
{
    public override object Read(
        ref Utf8JsonReader reader,
        Type typeToConvert,
        JsonSerializerOptions options) => reader.TokenType switch
        {
            JsonTokenType.True => true,
            JsonTokenType.False => false,
            JsonTokenType.Number when reader.TryGetInt64(out long l) => l,
            JsonTokenType.Number => reader.GetDouble(),
            JsonTokenType.String when reader.TryGetDateTime(out DateTime datetime) => datetime,
            JsonTokenType.String => reader.GetString()!,
            _ => JsonDocument.ParseValue(ref reader).RootElement.Clone()
        };

    public override void Write(
        Utf8JsonWriter writer,
        object objectToWrite,
        JsonSerializerOptions options) =>
        JsonSerializer.Serialize(writer, objectToWrite, objectToWrite.GetType(), options);
}
#endregion