namespace Core.Parsers.EventOccurrence;

/// <summary>
/// Shared regex patterns for time parsing.
/// </summary>
internal static class TimePatterns
{
    /// <summary>
    /// AM/PM pattern (case-insensitive via IgnoreCase flag).
    /// Matches: "a.m.", "am", "A.M.", "AM", "p.m.", "pm", "P.M.", "PM"
    /// </summary>
    public const string AmPm = @"(?:a|p)\.?m\.?";

    /// <summary>
    /// Hour pattern: matches 1-2 digits (1-12 or 1-23).
    /// </summary>
    public const string Hour = @"\d{1,2}";

    /// <summary>
    /// Minute pattern with named group for parsing: matches exactly 2 digits if present.
    /// Used when parsing to TimeOnly objects where minutes must be valid.
    /// </summary>
    public const string MinuteWithGroup = @"(?<Minute>\d{2})?";

    /// <summary>
    /// Minute pattern for matching: matches 0-2 digits.
    /// Used when extracting time strings (more lenient for location parsing).
    /// </summary>
    public const string MinuteFlexible = @"\d{0,2}";

    /// <summary>
    /// Time value pattern: matches either NOON or a time with AM/PM.
    /// Used for matching time strings in location parsing (more lenient minute format).
    /// </summary>
    public static string TimeValue => $@"(?:NOON|{Hour}:?{MinuteFlexible}\s*{AmPm})";

    /// <summary>
    /// Time pattern with named groups for parsing hour, minute, and AM/PM.
    /// Used when parsing to TimeOnly objects (requires 2-digit minutes if present).
    /// </summary>
    public static string TimeWithGroups => $@"(?<Hour>{Hour}):?{MinuteWithGroup}\s?(?<APM>{AmPm})";
}