using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using FinlyticCore.Clients;
using FinlyticCore.Dtos.Fundamentals;
using FinlyticCore.Dtos.Yahoo;
using FinlyticCore.Services;
using FinlyticCore.Services.Yahoo;
using FinlyticFundamentals.Database;
using FinlyticFundamentals.Util;
using Microsoft.Extensions.Logging;

namespace FinlyticFundamentals.Services;

public interface IYahooFinanceScraper
{
    /// <summary>
    /// Ermittelt den primären Börsenticker zu einer ISIN anhand von Börsenplatz-Prioritäten.
    /// </summary>
    Task<TickerInfoDto?> ResolveTickerFromIsinAsync(string isin, CancellationToken cancellationToken = default);

    /// <summary>
    /// Ermittelt alle gefundenen Börsenticker zu einer ISIN, sortiert nach Priorität.
    /// </summary>
    Task<List<TickerInfoDto>> ResolveAllTickersFromIsinAsync(string isin, CancellationToken cancellationToken = default);

    /// <summary>
    /// Ruft Fundamental- und Unternehmensdaten primär über die Yahoo Finance API ab
    /// und fällt automatisch auf den Playwright HTML Scraper zurück, falls keine Daten vorhanden sind.
    /// </summary>
    /// <param name="symbolOrIsin">Das Tickersymbol (z. B. "MSFT") oder die ISIN.</param>
    /// <param name="forceHtmlScrape">Erzwingt sofortiges HTML-Scraping ohne API-Vorprüfung.</param>
    /// <param name="cancellationToken">Abbruch-Token.</param>
    /// <returns>Das aggregierte <see cref="YahooQuoteSummaryModulesDto"/> oder <c>null</c>.</returns>
    Task<YahooQuoteSummaryModulesDto?> GetQuoteSummaryModulesAsync(
        string symbolOrIsin,
        bool forceHtmlScrape = false,
        CancellationToken cancellationToken = default);
}

public class YahooFinanceScraper : IYahooFinanceScraper
{
    private readonly YahooFinanceClient _yahooApiClient;
    private readonly IYahooFinanceHtmlClient _htmlScraperClient;
    private readonly IFinlyticLogger<YahooFinanceScraper, FundamentalsDbContext> _finlyticLogger;

    public YahooFinanceScraper(
        YahooFinanceClient yahooApiClient,
        IYahooFinanceHtmlClient htmlScraperClient,
        IFinlyticLogger<YahooFinanceScraper, FundamentalsDbContext> finlyticLogger)
    {
        _yahooApiClient = yahooApiClient;
        _htmlScraperClient = htmlScraperClient;
        _finlyticLogger = finlyticLogger;
    }

    /// <inheritdoc />
    public async Task<TickerInfoDto?> ResolveTickerFromIsinAsync(string isin, CancellationToken cancellationToken = default)
    {
        var tickers = await ResolveAllTickersFromIsinAsync(isin, cancellationToken);
        return tickers.FirstOrDefault();
    }

    /// <inheritdoc />
    public async Task<List<TickerInfoDto>> ResolveAllTickersFromIsinAsync(string isin, CancellationToken cancellationToken = default)
    {
        if (string.IsNullOrWhiteSpace(isin)) return new List<TickerInfoDto>();

        var cleanIsin = isin.Trim().ToUpperInvariant();
        var symbols = new List<(string symbol, string exchange, int priority)>();

        try
        {
            // 1. Suche via ISIN
            var primary = await _yahooApiClient.SearchAsync(cleanIsin, quotesCount: 20, cancellationToken: cancellationToken);
            var quotes = primary?.Quotes ?? new List<YahooSearchQuoteDto>();

            foreach (var q in quotes.Where(q => !string.IsNullOrEmpty(q.Symbol)))
            {
                symbols.Add((q.Symbol, q.Exchange ?? string.Empty, GetExchangePriority(q.Symbol, cleanIsin)));
            }

            // 2. Falls Ticker gefunden, aber mit Unternehmensname noch mehr Exchangeticker auffindbar sind
            if (quotes.Count > 0)
            {
                var companyName = quotes[0].LongName ?? quotes[0].ShortName;
                if (!string.IsNullOrWhiteSpace(companyName))
                {
                    var secondary = await _yahooApiClient.SearchAsync(companyName, quotesCount: 20, cancellationToken: cancellationToken);
                    foreach (var q in secondary?.Quotes ?? new List<YahooSearchQuoteDto>())
                    {
                        if (!string.IsNullOrEmpty(q.Symbol) &&
                            !symbols.Any(s => s.symbol.Equals(q.Symbol, StringComparison.OrdinalIgnoreCase)))
                        {
                            symbols.Add((q.Symbol, q.Exchange ?? string.Empty, GetExchangePriority(q.Symbol, cleanIsin)));
                        }
                    }
                }
            }
        }
        catch (Exception ex)
        {
            await _finlyticLogger.LogWarningAsync(SettingKeys.YahooClientChannel, ex,
                "[YahooFinanceScraper] Fehler beim Auflösen des Tickers für ISIN '{Isin}'", cleanIsin);
        }

        return symbols
            .OrderBy(s => s.priority)
            .Select(s => new TickerInfoDto(){Ticker = s.symbol, Exchange = s.exchange})
            .ToList();
    }

    /// <inheritdoc />
    public async Task<YahooQuoteSummaryModulesDto?> GetQuoteSummaryModulesAsync(
        string symbolOrIsin,
        bool forceHtmlScrape = false,
        CancellationToken cancellationToken = default)
    {
        if (string.IsNullOrWhiteSpace(symbolOrIsin)) return null;

        var symbol = symbolOrIsin.Trim().ToUpperInvariant();

        // Falls eine ISIN übergeben wurde, zuerst Ticker auflösen
        if (IsIsin(symbol))
        {
            var resolvedTicker = await ResolveTickerFromIsinAsync(symbol, cancellationToken);
            if (resolvedTicker != null)
            {
                symbol = resolvedTicker.Ticker;
            }
        }

        YahooQuoteSummaryModulesDto? apiModules = null;

        // -------------------------------------------------------------
        // 1. PRIMÄRE DATENQUELLE: Yahoo Finance API (Cookie/Crumb)
        // -------------------------------------------------------------
        if (!forceHtmlScrape)
        {
            try
            {
                await _finlyticLogger.LogInfoAsync(SettingKeys.YahooClientChannel,
                    "[YahooFinanceScraper] Starte primären API-Abruf für '{Symbol}'...", symbol);

                var apiResponse = await _yahooApiClient.GetFullQuoteSummaryAsync(symbol, cancellationToken);
                apiModules = apiResponse?.QuoteSummary?.Result?.FirstOrDefault();

                if (apiModules != null && HasSufficientData(apiModules))
                {
                    await _finlyticLogger.LogInfoAsync(SettingKeys.YahooClientChannel,
                        "[YahooFinanceScraper] Erfolgreich Daten über API bezogen für '{Symbol}'.", symbol);
                    return apiModules;
                }

                await _finlyticLogger.LogWarningAsync(SettingKeys.YahooClientChannel,
                    "[YahooFinanceScraper] API lieferte unvollständige Daten für '{Symbol}'. Initiiere Fallback...", symbol);
            }
            catch (Exception ex)
            {
                await _finlyticLogger.LogWarningAsync(SettingKeys.YahooClientChannel, ex,
                    "[YahooFinanceScraper] API-Abruf fehlgeschlagen für '{Symbol}'. Wechsle zu Scraper...", symbol);
            }
        }

        // -------------------------------------------------------------
        // 2. FALLBACK DATENQUELLE: Playwright HTML Scraper
        // -------------------------------------------------------------
        YahooQuoteSummaryModulesDto? htmlModules = null;
        try
        {
            await _finlyticLogger.LogInfoAsync(SettingKeys.YahooClientChannel,
                "[YahooFinanceScraper] Starte HTML-Scraper Fallback für '{Symbol}'...", symbol);

            htmlModules = await _htmlScraperClient.ScrapeQuoteSummaryModulesAsync(symbol, cancellationToken);
        }
        catch (Exception ex)
        {
            await _finlyticLogger.LogErrorAsync(SettingKeys.YahooClientChannel, ex,
                "[YahooFinanceScraper] HTML-Scraper Fallback ebenfalls fehlgeschlagen für '{Symbol}'.", symbol);
        }

        // -------------------------------------------------------------
        // 3. Zusammenführen (Merge API & HTML Fallback)
        // -------------------------------------------------------------
        if (apiModules == null) return htmlModules;
        if (htmlModules == null) return apiModules;

        return MergeModules(apiModules, htmlModules);
    }

    /// <summary>
    /// Prüft, ob das Modul-DTO die wesentlichen Fundamentalblöcke enthält.
    /// </summary>
    private static bool HasSufficientData(YahooQuoteSummaryModulesDto modules)
    {
        return modules.SummaryDetail != null ||
               modules.FinancialData != null ||
               modules.DefaultKeyStatistics != null;
    }

    /// <summary>
    /// Führt API- und Scraper-Daten zusammen, damit Lücken in API-Responses geschlossen werden.
    /// </summary>
    private static YahooQuoteSummaryModulesDto MergeModules(
        YahooQuoteSummaryModulesDto primary,
        YahooQuoteSummaryModulesDto secondary)
    {
        return new YahooQuoteSummaryModulesDto(
            QuoteType: primary.QuoteType ?? secondary.QuoteType,
            AssetProfile: primary.AssetProfile ?? secondary.AssetProfile,
            FinancialData: primary.FinancialData ?? secondary.FinancialData,
            DefaultKeyStatistics: primary.DefaultKeyStatistics ?? secondary.DefaultKeyStatistics,
            SummaryDetail: primary.SummaryDetail ?? secondary.SummaryDetail,
            IncomeStatementHistory: primary.IncomeStatementHistory ?? secondary.IncomeStatementHistory,
            IncomeStatementHistoryQuarterly: primary.IncomeStatementHistoryQuarterly ?? secondary.IncomeStatementHistoryQuarterly,
            BalanceSheetHistory: primary.BalanceSheetHistory ?? secondary.BalanceSheetHistory,
            BalanceSheetHistoryQuarterly: primary.BalanceSheetHistoryQuarterly ?? secondary.BalanceSheetHistoryQuarterly,
            CashflowStatementHistory: primary.CashflowStatementHistory ?? secondary.CashflowStatementHistory,
            CashflowStatementHistoryQuarterly: primary.CashflowStatementHistoryQuarterly ?? secondary.CashflowStatementHistoryQuarterly,
            CalendarEvents: primary.CalendarEvents ?? secondary.CalendarEvents
        );
    }

    private static bool IsIsin(string value)
    {
        return value.Length == 12 &&
               char.IsLetter(value[0]) &&
               char.IsLetter(value[1]) &&
               value.All(char.IsLetterOrDigit);
    }

    private static int GetExchangePriority(string symbol, string isin)
    {
        bool isGermanIsin = isin.StartsWith("DE", StringComparison.OrdinalIgnoreCase);

        if (isGermanIsin)
        {
            if (symbol.EndsWith(".DE", StringComparison.OrdinalIgnoreCase)) return 1;  // Xetra
            if (symbol.EndsWith(".F", StringComparison.OrdinalIgnoreCase)) return 2;   // Frankfurt
            if (symbol.EndsWith(".STU", StringComparison.OrdinalIgnoreCase)) return 3; // Stuttgart
            if (symbol.EndsWith(".SG", StringComparison.OrdinalIgnoreCase)) return 4;  // Stuttgart (alt)
            if (symbol.EndsWith(".HM", StringComparison.OrdinalIgnoreCase)) return 5;  // Hamburg
            if (!symbol.Contains('.')) return 6;                                       // US Primary
        }
        else
        {
            if (!symbol.Contains('.')) return 1;                                       // US Primary (NASDAQ, NYSE)
            if (symbol.EndsWith(".DE", StringComparison.OrdinalIgnoreCase)) return 2;  // Xetra
            if (symbol.EndsWith(".F", StringComparison.OrdinalIgnoreCase)) return 3;   // Frankfurt
            if (symbol.EndsWith(".L", StringComparison.OrdinalIgnoreCase)) return 4;   // London
            if (symbol.EndsWith(".PA", StringComparison.OrdinalIgnoreCase)) return 5;  // Paris
        }

        return 10;
    }
}