using System.Globalization;
using System.Text.Json;

namespace Infrastructure.StockData;

/// <summary>
/// OpenDART 공시검색(list.json) 응답 파서 — 순수 C# (System.Text.Json).
/// 응답 골격: { "status", "message", "page_no", "page_count", "total_count", "total_page", "list":[ {...} ] }.
/// status: "000" 정상, "013" 조회된 데이터 없음, "020"/"100" 등은 키/파라미터 오류. list 항목의 모든 값은 문자열.
///  - stock_code 는 6자리 단축코드(상장) 또는 "" (비상장) → 빈 값은 null.
///  - rcept_dt 는 YYYYMMDD → DateOnly. rm(비고)은 없거나 "" → null.
/// list.json 이 stock_code 를 이미 포함하므로 corpCode.xml 매핑 없이 종목별 조회가 가능하다.
/// </summary>
public static class DartDisclosureParser
{
    /// <summary>공시 1행 (list.json 항목). stock_code 빈 값은 null, rcept_dt 는 DateOnly.</summary>
    public sealed record DisclosureRow(
        string RceptNo,
        string CorpCode,
        string CorpName,
        string? StockCode,
        string CorpCls,
        string ReportNm,
        string FlrNm,
        DateOnly RceptDt,
        string? Rm
    );

    /// <summary>파싱 결과 — status/총페이지 등 메타와 파싱된 행. status != "000" 이면 Rows 는 빈 목록.</summary>
    public sealed record ParseResult(
        string Status,
        string Message,
        int PageNo,
        int TotalPage,
        int TotalCount,
        IReadOnlyList<DisclosureRow> Rows
    );

    public static ParseResult Parse(string json)
    {
        using var doc = JsonDocument.Parse(json);
        var root = doc.RootElement;

        var status = GetString(root, "status");
        var message = GetString(root, "message");
        var pageNo = GetInt(root, "page_no");
        var totalPage = GetInt(root, "total_page");
        var totalCount = GetInt(root, "total_count");

        var rows = new List<DisclosureRow>();

        if (status != "000" || !root.TryGetProperty("list", out var list) || list.ValueKind != JsonValueKind.Array)
        {
            return new ParseResult(status, message, pageNo, totalPage, totalCount, rows);
        }

        foreach (var item in list.EnumerateArray())
        {
            var rceptNo = GetString(item, "rcept_no");
            var corpCode = GetString(item, "corp_code");
            var reportNm = GetString(item, "report_nm");
            var rceptDt = ParseDate(GetString(item, "rcept_dt"));

            if (rceptNo.Length == 0 || corpCode.Length == 0 || reportNm.Length == 0 || rceptDt is null)
            {
                continue;
            }

            rows.Add(new DisclosureRow(
                rceptNo,
                corpCode,
                GetString(item, "corp_name"),
                ToNull(GetString(item, "stock_code")),
                GetString(item, "corp_cls"),
                reportNm,
                GetString(item, "flr_nm"),
                rceptDt.Value,
                ToNull(GetString(item, "rm"))
            ));
        }

        return new ParseResult(status, message, pageNo, totalPage, totalCount, 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
        };
    }

    private static int GetInt(JsonElement element, string name)
    {
        if (!element.TryGetProperty(name, out var value))
        {
            return 0;
        }

        return value.ValueKind switch
        {
            JsonValueKind.Number => value.TryGetInt32(out var n) ? n : 0,
            JsonValueKind.String => int.TryParse(value.GetString(), NumberStyles.Integer, CultureInfo.InvariantCulture, out var s) ? s : 0,
            _ => 0
        };
    }

    /// <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;
    }
}