using Newtonsoft.Json;
using NJsonSchema;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Text.Json.Nodes;
using System.Threading.Tasks;

namespace Elwig.Helpers.Billing {
    public class BillingData {

        public enum CalculationMode { Elwig, WgMaster }
        public enum CurveMode { Oe, Kmw }
        public record struct Curve(CurveMode Mode, Dictionary<double, decimal> Normal, Dictionary<double, decimal>? Gebunden);

        public static JsonSchema? Schema { get; private set; }

        public static async Task Init() {
            var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream("Elwig.Resources.Schemas.PaymentVariantData.json");
            Schema = await JsonSchema.FromJsonAsync(stream ?? throw new ArgumentException("JSON schema not found"));
        }

        public readonly JsonObject Data;
        public readonly CalculationMode Mode;

        public bool ConsiderDelieryModifiers {
            get => GetConsider("consider_delivery_modifiers");
            set => SetConsider(value, "consider_delivery_modifiers");
        }
        public bool ConsiderContractPenalties {
            get => GetConsider("consider_contract_penalties");
            set => SetConsider(value, "consider_contract_penalties");
        }
        public bool ConsiderTotalPenalty {
            get => GetConsider("consider_total_penalty");
            set => SetConsider(value, "consider_total_penalty");
        }
        public bool ConsiderAutoBusinessShares {
            get => GetConsider("consider_auto_business_shares");
            set => SetConsider(value, "consider_auto_business_shares");
        }

        private bool GetConsider(string name, string? wgMasterName = null) {
            return ((Mode == CalculationMode.Elwig) ? Data[name] : Data[wgMasterName ?? ""])?.AsValue().GetValue<bool>() ?? false;
        }

        private void SetConsider(bool value, string name, string? wgMasterName = null) {
            if (Mode == CalculationMode.WgMaster && wgMasterName == null) {
                return;
            } else if (value) {
                Data[(Mode == CalculationMode.Elwig) ? name : wgMasterName ?? ""] = value;
            } else {
                Data.Remove((Mode == CalculationMode.Elwig) ? name : wgMasterName ?? "");
            }
        }

        public BillingData(JsonObject data) {
            Data = data;
            var mode = Data["mode"]?.GetValue<string>();
            Mode = (mode == "elwig") ? CalculationMode.Elwig : CalculationMode.WgMaster;
        }

        protected static JsonObject ParseJson(string json) {
            if (Schema == null) throw new InvalidOperationException("Schema has to be initialized first");
            try {
                var errors = Schema.Validate(json);
                if (errors.Count != 0) throw new ArgumentException("Invalid JSON data");
                return JsonNode.Parse(json)?.AsObject() ?? throw new ArgumentException("Invalid JSON data");
            } catch (JsonReaderException) {
                throw new ArgumentException("Invalid JSON data");
            }
        }

        public static BillingData FromJson(string json) {
            return new(ParseJson(json));
        }

        protected JsonArray GetCurvesEntry() {
            return Data[Mode == CalculationMode.Elwig ? "curves" : "Kurven"]?.AsArray() ?? throw new InvalidOperationException();
        }

        protected JsonNode GetPaymentEntry() {
            return Data[Mode == CalculationMode.Elwig ? "payment" : "AuszahlungSorten"] ?? throw new InvalidOperationException();
        }

        protected JsonObject? GetQualityEntry() {
            return Data[Mode == CalculationMode.Elwig ? "quality" : "AuszahlungSortenQualitätsstufe"]?.AsObject();
        }

        private static Dictionary<double, decimal> GetCurveData(JsonObject data, CurveMode mode) {
            var dict = new Dictionary<double, decimal>();
            foreach (var (index, price) in data) {
                double idx;
                bool? gtlt = index.StartsWith('>') ? true : index.StartsWith('<') ? false : null;
                if (index.EndsWith("kmw")) {
                    idx = double.Parse(index[(gtlt != null ? 1 : 0)..^3], CultureInfo.InvariantCulture);
                    if (mode == CurveMode.Oe) {
                        idx = Utils.KmwToOe(idx);
                    }
                } else if (index.EndsWith("oe")) {
                    idx = double.Parse(index[(gtlt != null ? 1 : 0)..^2], CultureInfo.InvariantCulture);
                    if (mode == CurveMode.Kmw) {
                        idx = Utils.OeToKmw(idx);
                    }
                } else {
                    throw new InvalidOperationException();
                }
                if (gtlt == true) {
                    idx = Math.BitIncrement(idx);
                } else if (gtlt == false) {
                    idx = Math.BitDecrement(idx);
                }
                dict[idx] = price?.AsValue().GetValue<decimal>() ?? throw new InvalidOperationException();
            }
            return dict;
        }

        protected Dictionary<int, Curve> GetCurves() {
            var dict = new Dictionary<int, Curve>();
            var curves = GetCurvesEntry();
            foreach (var c in curves) {
                var obj = c?.AsObject() ?? throw new InvalidOperationException();
                var id = obj["id"]?.GetValue<int>() ?? throw new InvalidOperationException();
                var cMode = (obj["mode"]?.GetValue<string>() == "kmw") ? CurveMode.Kmw : CurveMode.Oe;
                double quw = cMode == CurveMode.Oe ? 73 : 15;

                Dictionary<double, decimal> c1;
                Dictionary<double, decimal>? c2 = null;
                var norm = obj["data"];
                if (norm is JsonObject) {
                    c1 = GetCurveData(norm.AsObject(), cMode);
                } else if (norm?.AsValue().TryGetValue(out decimal v) == true) {
                    c1 = new() { { quw, v } };
                } else {
                    throw new InvalidOperationException();
                }
                var geb = obj["geb"];
                if (geb is JsonObject) {
                    c2 = GetCurveData(geb.AsObject(), cMode);
                } else if (geb?.AsValue().TryGetValue(out decimal v) == true) {
                    var splitVal = GetCurveValueAt(c1, quw);
                    c2 = c1.ToDictionary(e => e.Key, e => e.Value + (e.Key >= quw ? v : 0));
                    c2[quw] = splitVal + v;
                    c2[Math.BitDecrement(quw)] = splitVal;
                }
                dict.Add(id, new(cMode, c1, c2));
            }
            return dict;
        }

        protected static Dictionary<string, JsonValue> GetSelection(JsonNode value, IEnumerable<string> attributeVariants) {
            if (value is JsonValue flatRate) {
                return attributeVariants.ToDictionary(e => e, _ => flatRate);
            } if (value is not JsonObject data) {
                throw new InvalidOperationException();
            }
            Dictionary<string, JsonValue> dict;
            if (data["default"] is JsonValue def) {
                dict = attributeVariants.ToDictionary(e => e, _ => def);
            } else {
                dict = [];
            }

            var variants = data.Where(p => !p.Key.StartsWith('/') && p.Key.Length == 2);
            var attributes = data.Where(p => p.Key.StartsWith('/'));
            var others = data.Where(p => !p.Key.StartsWith('/') && p.Key.Length > 2 && p.Key != "default");
            foreach (var (idx, v) in variants) {
                var curve = v?.AsValue() ?? throw new InvalidOperationException();
                foreach (var i in attributeVariants.Where(e => e.StartsWith(idx[..^1]))) {
                    dict[i] = curve;
                }
            }
            foreach (var (idx, v) in attributes) {
                var curve = v?.AsValue() ?? throw new InvalidOperationException();
                foreach (var i in attributeVariants.Where(e => e[2..] == idx[1..])) {
                    dict[i] = curve;
                }
            }
            foreach (var (idx, v) in others) {
                var curve = v?.AsValue() ?? throw new InvalidOperationException();
                dict[idx.Replace("/", "")] = curve;
            }

            return dict;
        }

        public static decimal GetCurveValueAt(Dictionary<double, decimal> curve, double key) {
            if (curve.Count == 1) return curve.First().Value;

            var lt = curve.Keys.Where(v => v <= key);
            var gt = curve.Keys.Where(v => v >= key);
            if (!lt.Any()) {
                return curve[gt.Min()];
            } else if (!gt.Any()) {
                return curve[lt.Max()];
            }

            var max = lt.Max();
            var min = gt.Min();
            if (max == min) return curve[key];

            var p1 = ((decimal)key - (decimal)min) / ((decimal)max - (decimal)min);
            var p2 = 1 - p1;
            return curve[min] * p2 + curve[max] * p1;
        }

        protected static JsonNode GraphToJson(Graph graph, string mode) {
            var x = graph.DataX;
            var y = graph.DataY;
            if (y.Distinct().Count() == 1) {
                return JsonValue.Create(graph.DataY[0]);
            }

            var data = new JsonObject();

            if (y[0] != y[1]) {
                data.Add(new KeyValuePair<string, JsonNode?>(x[0] + mode, Math.Round(y[0], graph.Precision)));
            }
            for (int i = 1; i < x.Length - 1; i++) {
                if (Math.Round(y[i] - y[i - 1], 10) != Math.Round(y[i + 1] - y[i], 10)) {
                    data.Add(new KeyValuePair<string, JsonNode?>(x[i] + mode, Math.Round(y[i], graph.Precision)));
                }
            }
            if (y[^1] != y[^2]) {
                data.Add(new KeyValuePair<string, JsonNode?>(x[^1] + mode, Math.Round(y[^1], graph.Precision)));
            }
            return data;
        }

        protected static JsonObject GraphEntryToJson(GraphEntry entry) {
            var curve = new JsonObject {
                ["id"] = entry.Id,
                ["mode"] = entry.Mode.ToString().ToLower(),
            };

            curve["data"] = GraphToJson(entry.DataGraph, entry.Mode.ToString().ToLower());

            if (entry.GebundenFlatBonus != null) {
                curve["geb"] = entry.GebundenFlatBonus;
            } else if (entry.GebundenGraph != null) {
                curve["geb"] = GraphToJson(entry.GebundenGraph, entry.Mode.ToString().ToLower());
            }

            return curve;
        }

        public JsonObject FromGraphEntries(IEnumerable<GraphEntry> graphEntries) {
            var payment = new JsonObject();
            var curves = new JsonArray();

            foreach (var entry in graphEntries) {
                curves.Add(GraphEntryToJson(entry));
                foreach (var contract in entry.Contracts) {
                    payment[$"{contract.Variety?.SortId}/{contract.Attribute?.AttrId}"] = $"curve:{entry.Id}";
                }
            }

            var data = new JsonObject {
                ["mode"] = "elwig",
                ["version"] = 1,
            };
            if (ConsiderDelieryModifiers)
                data["consider_delivery_modifiers"] = true;
            if (ConsiderContractPenalties)
                data["consider_contract_penalties"] = true;
            if (ConsiderTotalPenalty)
                data["consider_total_penalty"] = true;
            if (ConsiderAutoBusinessShares)
                data["consider_auto_business_shares"] = true;

            data["payment"] = payment;
            data["curves"] = curves;

            return data;
        }
    }
}