using System.Text.Json.Serialization;

namespace GoogleSheetsScheduleImport;

/// <summary>
/// JSON config: sheet tab titles mapped to calendar days plus optional defaults.
/// </summary>
public sealed class MappingConfig
{
    /// <summary>Calendar year for occurrence dates (overridden by CLI --year).</summary>
    public int? Year { get; set; }

    /// <summary>
    /// Emitted before occurrence lines for each sheet (unless overridden per sheet).
    /// Use "General Schedule" when grid cells are generic schedule items.
    /// </summary>
    public string? DefaultSectionHeader { get; set; }

    /// <summary>Per-sheet overrides and day mapping.</summary>
    public List<SheetDayMapping>? Sheets { get; set; }

    /// <summary>
    /// Event titles (cell text) to treat as site-wide: one output line per date+time, no location.
    /// If omitted, built-in rules still include CURFEW.
    /// </summary>
    public List<string>? SiteWideEventNames { get; set; }

    /// <summary>
    /// Path to event definitions CSV (column <c>Event</c>), relative to this mapping file or absolute.
    /// When set (or when <c>--events-csv</c> is passed), output is grouped into <c>Event - MS/HS</c> sections when possible.
    /// </summary>
    public string? EventDefinitionsCsv { get; set; }
}

public sealed class SheetDayMapping
{
    /// <summary>Exact tab title as it appears in Google Sheets.</summary>
    public string Title { get; set; } = "";

    /// <summary>Month name matching EventOccurrenceGrammar (e.g. "April").</summary>
    public string Month { get; set; } = "";

    /// <summary>Day of month (1-31).</summary>
    public int Day { get; set; }

    /// <summary>Optional section header line for this tab only (e.g. "General Schedule" or "Biotechnology - MS").</summary>
    public string? SectionHeader { get; set; }

    [JsonIgnore]
    public string? NormalizedMonth => string.IsNullOrWhiteSpace(Month) ? null : Month.Trim();

    public void Validate()
    {
        if (string.IsNullOrWhiteSpace(Title))
            throw new InvalidOperationException("Mapping entry must include a non-empty Title (sheet tab name).");
        if (string.IsNullOrWhiteSpace(Month))
            throw new InvalidOperationException($"Sheet '{Title}': Month is required.");
        if (Day is < 1 or > 31)
            throw new InvalidOperationException($"Sheet '{Title}': Day must be between 1 and 31.");
    }
}