using System.Globalization;
using System.Text.Json;
using Domain.Entities.Stocks.ValueObject;

namespace Infrastructure.StockData;

/// <summary>
/// KRX OpenAPI(data-dbg.krx.co.kr) 일반상품(석유/금/배출권) 일별매매 응답 파서 — 순수 C# (System.Text.Json).
/// 응답 골격: { "OutBlock_1": [ { ...string values }, ... ] }. 모든 값은 문자열, 천단위 콤마 가능, 결측치는 "" 또는 "-".
/// 시장별 응답 shape 이 다르다:
///  - 금(gold)/배출권(ets): ISU_CD/ISU_NM + TDD_CLSPRC/OPNPRC/HGPRC/LWPRC(주식형 OHLC) + CMPPREVDD_PRC(전일대비)·FLUC_RT(등락률).
///  - 석유(oil): ISU_CD 없음 → OIL_NM(유종구분)을 Code·Name 으로 사용. OHLC 미제공(0), 전일대비·등락률 없음(null).
///    가격은 WT_AVG_PRC(가중평균가격_경쟁)를 Close 로, WT_DIS_AVG_PRC(가중평균가격_협의)를 WeightedDiscussionPrice 로.
/// 시장은 호출 엔드포인트(commodityMarket)로 결정.
/// </summary>
public static class KrxCommodityParser
{
    /// <summary>일반상품 일별매매 1행 (등락은 금/배출권만, 협의가격은 석유만 — 나머지는 null)</summary>
    public sealed record CommodityRow(
        CommodityMarket CommodityMarket,
        string Code,
        string Name,
        DateOnly TradeDate,
        decimal Close,
        decimal Open,
        decimal High,
        decimal Low,
        decimal? ChangeAmount,
        decimal? ChangeRate,
        decimal? WeightedDiscussionPrice,
        long Volume,
        long TradeValue
    );

    /// <summary>oil/gold/ets_bydd_trd 파싱. commodityMarket 은 호출 엔드포인트로 결정, 석유 전용/금·배출권 전용 필드는 조건 분기.</summary>
    public static IReadOnlyList<CommodityRow> ParseDaily(string json, CommodityMarket commodityMarket)
    {
        using var doc = JsonDocument.Parse(json);
        var rows = new List<CommodityRow>();

        if (!doc.RootElement.TryGetProperty("OutBlock_1", out var block) || block.ValueKind != JsonValueKind.Array)
        {
            return rows;
        }

        foreach (var item in block.EnumerateArray())
        {
            var tradeDate = ParseDate(GetString(item, "BAS_DD"));
            if (tradeDate is null)
            {
                continue;
            }

            if (commodityMarket == CommodityMarket.Oil)
            {
                var oilName = ToNull(GetString(item, "OIL_NM"));
                if (oilName is null)
                {
                    continue;
                }

                rows.Add(new CommodityRow(
                    commodityMarket,
                    oilName,
                    oilName,
                    tradeDate.Value,
                    ParseDecimal(GetString(item, "WT_AVG_PRC")),
                    0m,
                    0m,
                    0m,
                    null,
                    null,
                    ParseNullableDecimal(GetString(item, "WT_DIS_AVG_PRC")),
                    ParseLong(GetString(item, "ACC_TRDVOL")),
                    ParseLong(GetString(item, "ACC_TRDVAL"))
                ));
            }
            else
            {
                var code = ToNull(GetString(item, "ISU_CD"));
                var name = GetString(item, "ISU_NM");

                if (code is null || name.Length == 0)
                {
                    continue;
                }

                rows.Add(new CommodityRow(
                    commodityMarket,
                    code,
                    name,
                    tradeDate.Value,
                    ParseDecimal(GetString(item, "TDD_CLSPRC")),
                    ParseDecimal(GetString(item, "TDD_OPNPRC")),
                    ParseDecimal(GetString(item, "TDD_HGPRC")),
                    ParseDecimal(GetString(item, "TDD_LWPRC")),
                    ParseNullableDecimal(GetString(item, "CMPPREVDD_PRC")),
                    ParseNullableDecimal(GetString(item, "FLUC_RT")),
                    null,
                    ParseLong(GetString(item, "ACC_TRDVOL")),
                    ParseLong(GetString(item, "ACC_TRDVAL"))
                ));
            }
        }

        return rows;
    }

    private static string GetString(JsonElement element, string name)
    {
        if (!element.TryGetProperty(name, out var value))
        {
            return string.Empty;
        }

        return value.ValueKind switch
        {
            JsonValueKind.String => value.GetString()?.Trim() ?? string.Empty,
            JsonValueKind.Number => value.GetRawText(),
            _ => string.Empty
        };
    }

    /// <summary>빈 문자열/"-" 은 null, 나머지는 trim 값</summary>
    private static string? ToNull(string raw)
    {
        return raw.Length == 0 || raw == "-" ? null : raw;
    }

    private static DateOnly? ParseDate(string raw)
    {
        return DateOnly.TryParseExact(raw, "yyyyMMdd", CultureInfo.InvariantCulture, DateTimeStyles.None, out var date) ? date : null;
    }

    private static long ParseLong(string raw)
    {
        return long.TryParse(raw, NumberStyles.Integer | NumberStyles.AllowThousands, CultureInfo.InvariantCulture, out var value) ? value : 0L;
    }

    /// <summary>가격 문자열 → decimal 그대로. "" 나 "-" 등 파싱 실패는 0.</summary>
    private static decimal ParseDecimal(string raw)
    {
        return decimal.TryParse(raw, NumberStyles.Float | NumberStyles.AllowThousands, CultureInfo.InvariantCulture, out var value) ? value : 0m;
    }

    /// <summary>전일대비/등락률/협의가격 — "" 나 "-" 등 파싱 실패는 null (0 과 구분, 미제공은 값 없음)</summary>
    private static decimal? ParseNullableDecimal(string raw)
    {
        return decimal.TryParse(raw, NumberStyles.Float | NumberStyles.AllowThousands, CultureInfo.InvariantCulture, out var value) ? value : null;
    }
}