using System.Reflection;
using SessionZero.SzfLib.Objects;
using SessionZero.SzfLib.Parser;

namespace SessionZero.SzfLib.Helpers;

public static class SzfHelper
{
    /// <summary>
    /// Gets the SzfObject type by its type identifier attribute.
    /// </summary>
    /// <param name="szfType"></param>
    /// <returns></returns>
    public static Type? FindSzfObjectTypeByAttributeType(string szfType)
    {
        var obj = Assembly
            .GetExecutingAssembly()
            .GetTypes()
            .FirstOrDefault(t => t.GetCustomAttribute(typeof(SzfObjectAttribute)) is not null && t.GetCustomAttribute<SzfObjectAttribute>()?.TypeIdentifier == szfType);
        
        if (obj is null) return null;
        
        return obj.IsAbstract || obj.IsInterface ? null : obj;
    }

    /// <summary>
    /// Does basic validation of a SzfObject.
    /// </summary>
    /// <param name="obj"></param>
    /// <param name="canHaveEmptyFieldValues"></param>
    /// <returns></returns>
    public static SzfError BasicSzfValidation(ISzfObject obj, bool canHaveEmptyFieldValues = false)
    {
        SzfError result = new SzfError();
        
        var metadataSection = obj.Sections.FirstOrDefault(s => s.Name == "Metadata");
        if (metadataSection is null) result.AddError("No metadata section found");
        
        if (obj.GetMetadataField("Name") == string.Empty) result.AddError("No metadata field name found");
        
        foreach (var field in GetAllFields(obj))
        {
            var fieldValidation = field.Validate(canHaveEmptyFieldValues);
            if (!fieldValidation.IsValid) result.AddError(fieldValidation.Message);
        }
        
        return result;
    }
    
    
    /// <summary>
    /// Gets all sections and subsections of a SzfObject.
    /// </summary>
    /// <param name="obj"></param>
    /// <returns></returns>
    public static IEnumerable<SzfSection> GetAllSectionsAndSubsections(ISzfObject obj)
    {
        List<SzfSection> allSections = new List<SzfSection>();
        
        foreach (var section in obj.Sections)
        {
            allSections.Add(section);
            allSections.AddRange(GetAllSubsections(section));
        }
        
        return allSections;
    }

    /// <summary>
    /// Gets all subsections of a given section recursively.
    /// </summary>
    /// <param name="section"></param>
    /// <returns></returns>
    public static IEnumerable<SzfSection> GetAllSubsections(SzfSection section)
    {
        List<SzfSection> subsections = new List<SzfSection>();
        
        foreach (var subsection in section.Subsections.Values)
        {
            subsections.Add(subsection);
            subsections.AddRange(GetAllSubsections(subsection));
        }
        
        return subsections;
    }
    
    /// <summary>
    /// Gets all fields from all sections and subsections of an SzfObject.
    /// </summary>
    /// <param name="obj"></param>
    /// <returns></returns>
    public static IEnumerable<SzfField> GetAllFields(ISzfObject obj)
    {
        List<SzfField> allFields = new List<SzfField>();
        
        foreach (var section in GetAllSectionsAndSubsections(obj))
        {
            allFields.AddRange(section.Fields.Values);
        }
        
        return allFields;
    }
}