using System;
using System.Globalization;

namespace JobTrackerApi.Services.JobImport;

public static class LanguageDetector
{
    // Lightweight heuristic: good enough to distinguish Norwegian vs English for job ads.
    public static string Detect(string? text)
    {
        if (string.IsNullOrWhiteSpace(text)) return "en";
        var t = text.AsSpan();

        // Norwegian characters strongly indicate "no".
        for (var i = 0; i < t.Length; i++)
        {
            var ch = char.ToLowerInvariant(t[i]);
            if (ch is 'æ' or 'ø' or 'å') return "no";
        }

        var lower = text.ToLower(CultureInfo.InvariantCulture);
        var hits = 0;
        hits += lower.Contains(" stilling ") || lower.Contains(" stillingen ") ? 2 : 0;
        hits += lower.Contains(" søker ") || lower.Contains(" s\u00F8ker ") ? 2 : 0;
        hits += lower.Contains(" arbeidsoppgaver") ? 2 : 0;
        hits += lower.Contains(" kvalifikasjoner") ? 2 : 0;
        hits += lower.Contains(" vi tilbyr") ? 2 : 0;
        hits += lower.Contains(" krav ") ? 1 : 0;
        hits += lower.Contains(" og ") ? 1 : 0;
        hits += lower.Contains(" ikke ") ? 1 : 0;
        hits += lower.Contains(" du ") || lower.Contains(" deg ") ? 1 : 0;

        return hits >= 4 ? "no" : "en";
    }
}