using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;

namespace Elwig.Models.Dtos {
    public class DataTable<T> {

        public string Name { get; set; }
        public string FullName { get; set; }
        public string? Subtitle { get; set; }
        public IEnumerable<(string? Name, IEnumerable<T> Rows)> Sections { get; private set; }
        public IEnumerable<T> Rows => Sections.SelectMany(s => s.Rows);
        public int RowNum => Rows.Count();
        public int ColNum => ColumnNames.Count();

        public IEnumerable<(string Name, Type? Type)> ColumnDefs => _map.Select(m => (m.Name, m.PInfo?.PropertyType ?? m.FInfo?.FieldType));
        public IEnumerable<string> ColumnNames => ColumnDefs.Select(m => m.Name);
        public IEnumerable<Type?> ColumnTypes => ColumnDefs.Select(m => m.Type);
        public IEnumerable<Type?> ColumnFlatTypes { get; private set; }
        public IEnumerable<int> ColumnSpans { get; private set; }
        public IEnumerable<int?> ColumnWidths { get; private set; }
        public IEnumerable<string?[]> ColumnUnits { get; private set; }

        private readonly PropertyInfo[] _properties;
        private readonly FieldInfo[] _fields;
        private readonly (string Name, PropertyInfo? PInfo, FieldInfo? FInfo)[] _map;

        public DataTable(string name, string fullName, string subtitle, IEnumerable<(string? Name, IEnumerable<T> Rows)> sections, IEnumerable<(string Property, string Name, string? Unit, int? Width)>? colNames = null) :
            this(name, fullName, sections, colNames) {
            Subtitle = subtitle;
        }

        public DataTable(string name, string fullName, string subtitle, IEnumerable<T> rows, IEnumerable<(string Property, string Name, string? Unit, int? Width)>? colNames = null) :
            this(name, fullName, subtitle, [(null, rows)], colNames) {
        }

        public DataTable(string name, string fullName, IEnumerable<(string? Name, IEnumerable<T> Rows)> sections, IEnumerable<(string Property, string Name, string? Unit, int? Width)>? colNames = null) {
            _fields = typeof(T).GetFields();
            _properties = typeof(T).GetProperties();
            colNames ??= [.. _properties.Select(p => p.Name).Union(_fields.Select(f => f.Name)).Select(i => (i, i, (string?)null, (int?)null))];
            _map = [.. colNames.Select(n => (n.Name, _properties.FirstOrDefault(p => p?.Name == n.Property, null), _fields.FirstOrDefault(f => f?.Name == n.Property, null)))];
            Name = name;
            FullName = fullName;
            Sections = sections;
            ColumnFlatTypes = [.. ColumnTypes.SelectMany(type => {
                var elType = type?.GetElementType();
                return type != null && type.IsValueType && type.Name.StartsWith("ValueTuple") ? type.GetFields().Select(f => (Type?)f.FieldType) :
                       type != null && elType != null && type.IsArray && elType.IsValueType && elType.Name.StartsWith("ValueTuple") ? elType.GetFields().Select(f => (Type?)f.FieldType) :
                       [type];
            })];
            ColumnSpans = [.. ColumnTypes.Select(type => {
                var elType = type?.GetElementType();
                return type != null && type.IsValueType && type.Name.StartsWith("ValueTuple") ? type.GetFields().Length :
                       type != null && elType != null && type.IsArray && elType.IsValueType && elType.Name.StartsWith("ValueTuple") ? elType.GetFields().Length :
                       1;
            })];
            ColumnWidths = [.. colNames.Select(c => c.Width)];
            ColumnUnits = [.. colNames.Select(c => c.Unit?.Split("|").Select(p => p.Length == 0 ? null : p).ToArray() ?? [])];
        }

        public DataTable(string name, string fullName, IEnumerable<T> rows, IEnumerable<(string Property, string Name, string? Unit, int? Width)>? colNames = null) :
            this(name, fullName, [(null, rows)], colNames) {
        }

        public DataTable(string name, string fullName, IEnumerable<T> rows, IEnumerable<(string Property, string Name, string? Unit)>? colNames = null) :
            this(name, fullName, rows, colNames?.Select(c => (c.Property, c.Name, c.Unit, (int?)null))) {
        }

        public DataTable(string name, string fullName, IEnumerable<T> rows, IEnumerable<(string Property, string Name, string? Unit, int Width)>? colNames = null) :
            this(name, fullName, rows, colNames?.Select(c => (c.Property, c.Name, c.Unit, (int?)c.Width))) {
        }

        public DataTable(string name, IEnumerable<T> rows, IEnumerable<(string Property, string Name, string? Unit, int? Width)>? colNames = null) :
            this(name, name, rows, colNames) {
        }

        public DataTable(string name, IEnumerable<T> rows, IEnumerable<(string Property, string Name, string? Unit)>? colNames = null) :
            this(name, name, rows, colNames) {
        }

        public DataTable(string name, IEnumerable<T> rows, IEnumerable<(string Property, string Name, string? Unit, int Width)>? colNames = null) :
            this(name, name, rows, colNames) {
        }

        public DataTable(string name, string fullName, IEnumerable<(string? Name, IEnumerable<T> Rows)> sections, IEnumerable<(string Property, string Name, string? Unit)>? colNames = null) :
            this(name, fullName, sections, colNames?.Select(c => (c.Property, c.Name, c.Unit, (int?)null))) {
        }

        public DataTable(string name, string fullName, IEnumerable<(string? Name, IEnumerable<T> Rows)> sections, IEnumerable<(string Property, string Name, string? Unit, int Width)>? colNames = null) :
            this(name, fullName, sections, colNames?.Select(c => (c.Property, c.Name, c.Unit, (int?)c.Width))) {
        }

        protected IEnumerable<(string Name, object? Value)> GetNamedRowValues(T row) {
            return _map.Select(i => (i.Name, i.PInfo?.GetValue(row) ?? i.FInfo?.GetValue(row)));
        }

        protected IEnumerable<object?> GetRowValues(T row) {
            return GetNamedRowValues(row).Select(i => i.Value);
        }

        public IEnumerable<(string? Name, IEnumerable<IEnumerable<object?>> Rows)> GetData() {
            return Sections.Select(s => (s.Name, s.Rows.Select(GetRowValues)));
        }

        public IEnumerable<(string? Name, IEnumerable<IEnumerable<(string Name, object? Value)>> Rows)> GetNamedData() {
            return Sections.Select(s => (s.Name, s.Rows.Select(GetNamedRowValues)));
        }
    }
}