using Core.Entities;
using FuzzySharp;

namespace Core.Parsers.EventOccurrence;

/// <summary>
/// Matches section headers to event definitions using fuzzy matching.
/// </summary>
public static class SectionHeaderMatcher
{
    /// <summary>
    /// Checks if a line is a general schedule header.
    /// </summary>
    public static bool IsGeneralSchedule(string line)
    {
        return EventOccurrenceGrammar.IsGeneralSchedule(line);
    }

    /// <summary>
    /// Checks if a line contains school level markers (MS or HS).
    /// </summary>
    public static bool HasSchoolLevel(string line)
    {
        return line.Contains("MS", StringComparison.Ordinal) || 
               line.Contains("HS", StringComparison.Ordinal);
    }

    /// <summary>
    /// Matches a section header to the best matching event definition using fuzzy matching.
    /// </summary>
    /// <param name="sectionHeader">The section header text to match.</param>
    /// <param name="events">The collection of available event definitions.</param>
    /// <returns>The best matching EventDefinition, or null if no match is found (ratio > 50).</returns>
    public static EventDefinition? MatchEventDefinition(string sectionHeader, ICollection<EventDefinition> events)
    {
        var evt =
            (from e in events
                let rat = Fuzz.Ratio(e.Name, sectionHeader)
                where rat > 50
                orderby rat descending
                select e).FirstOrDefault();
        
        return evt;
    }

    /// <summary>
    /// Gets the best match ratio for a section header against events.
    /// Useful for error messages when no match is found.
    /// </summary>
    /// <param name="sectionHeader">The section header text.</param>
    /// <param name="events">The collection of available event definitions.</param>
    /// <returns>The best match ratio, or 0 if no events are available.</returns>
    public static int GetBestMatchRatio(string sectionHeader, ICollection<EventDefinition> events)
    {
        if (events.Count == 0)
            return 0;

        var bestEvent = events.FirstOrDefault();
        return bestEvent != null ? Fuzz.Ratio(sectionHeader, bestEvent.Name) : 0;
    }
}