using Core.Entities;
using Core.Models;

namespace GoogleSheetsScheduleImport;

/// <summary>
/// For grouped output, occurrence lines should look like the PDF schedule: activity text only, not
/// <c>MS EventName Activity</c> when the section is already <c>EventName - MS</c>.
/// </summary>
public static class OccurrenceDisplayNameReducer
{
    public static string ReduceForSection(string occurrenceName, EventDefinition matched, SchoolLevel level)
    {
        var (remainder, lvl) = SchoolLevelPrefixParser.StripLeadingSchoolPrefix(occurrenceName);
        if (!lvl.HasValue || lvl.Value != level)
            return TextNormalization.ForEmitLine(occurrenceName);

        var r = remainder.Trim();
        var eventName = matched.Name.Trim();
        if (r.StartsWith(eventName, StringComparison.OrdinalIgnoreCase))
        {
            r = r[eventName.Length..].TrimStart();
            r = TrimLeadingJoiners(r);
        }

        r = TextNormalization.ForEmitLine(r);
        if (string.IsNullOrWhiteSpace(r))
            return TextNormalization.ForEmitLine(remainder.Trim());

        return r;
    }

    private static string TrimLeadingJoiners(string s)
    {
        var r = s;
        while (r.Length > 0)
        {
            var c = r[0];
            if (c is '/' or '-' or ':' or '&' or '–' or '—' or ',' or '.')
            {
                r = r[1..].TrimStart();
                continue;
            }

            break;
        }

        return r;
    }
}