using QuestionsApi.Models;
using System.Text.Json;

namespace QuestionsApi.Services;

public static class DynamicBlueprintResolver
{
    private static readonly JsonSerializerOptions Json = new(JsonSerializerDefaults.Web);

    public static List<DynamicQuestionBlueprint> ResolveAll(IEnumerable<DynamicQuestionBlueprint> source)
    {
        var all = source.ToList();
        var resolved = new List<DynamicQuestionBlueprint>();
        foreach (var blueprint in all.OrderBy(value => value.Version))
        {
            if (blueprint.BaseBlueprintVersion <= 0)
            {
                resolved.Add(blueprint);
                continue;
            }
            var baseBlueprint = resolved.FirstOrDefault(value =>
                value.ExternalId == blueprint.ExternalId
                && value.Version == blueprint.BaseBlueprintVersion)
                ?? throw new InvalidDataException(
                    $"{blueprint.ExternalId} v{blueprint.Version} base version {blueprint.BaseBlueprintVersion} not found");
            var materialized = Clone(baseBlueprint);
            materialized.Id = null;
            materialized.Version = blueprint.Version;
            materialized.BaseBlueprintVersion = blueprint.BaseBlueprintVersion;
            materialized.QualityStandardVersion = blueprint.QualityStandardVersion;
            materialized.IsPublished = blueprint.IsPublished;
            materialized.EncounterFrame = blueprint.EncounterFrame;
            materialized.SiteOfCare = blueprint.SiteOfCare;
            materialized.BlueprintWeight = blueprint.BlueprintWeight;
            materialized.ConceptIds = blueprint.ConceptIds;
            materialized.PrerequisiteConceptIds = blueprint.PrerequisiteConceptIds;
            materialized.MedicallyReviewedUtc = blueprint.MedicallyReviewedUtc;
            materialized.MedicalReviewExpiresUtc = blueprint.MedicalReviewExpiresUtc;
            materialized.MedicalReviewer = blueprint.MedicalReviewer;
            if (blueprint.Distractors.Count > 0)
                materialized.Distractors = blueprint.Distractors;
            if (blueprint.CaseFamilies.Count > 0)
                materialized.CaseFamilies = blueprint.CaseFamilies.Select(overlay =>
            {
                var baseFamily = baseBlueprint.CaseFamilies.FirstOrDefault(value => value.Id == overlay.BaseFamilyId)
                    ?? throw new InvalidDataException(
                        $"{blueprint.ExternalId} v{blueprint.Version} base family {overlay.BaseFamilyId} not found");
                var family = Clone(baseFamily);
                family.Id = overlay.Id;
                family.BaseFamilyId = overlay.BaseFamilyId;
                family.DifficultyTier = overlay.DifficultyTier;
                family.NominalElo = overlay.NominalElo;
                if (!string.IsNullOrWhiteSpace(family.LeadIn)
                    && family.StemTemplate.EndsWith(family.LeadIn, StringComparison.Ordinal))
                    family.StemTemplate = family.StemTemplate[..^family.LeadIn.Length].TrimEnd();
                if (!string.IsNullOrWhiteSpace(overlay.StemTemplate))
                    family.StemTemplate = $"{family.StemTemplate} {overlay.StemTemplate}".Trim();
                if (!string.IsNullOrWhiteSpace(overlay.LeadIn))
                    family.LeadIn = overlay.LeadIn;
                if (overlay.Distractors.Count > 0)
                    family.Distractors = overlay.Distractors;
                return family;
            }).ToList();
            resolved.Add(materialized);
        }
        return resolved;
    }

    private static T Clone<T>(T value) =>
        JsonSerializer.Deserialize<T>(JsonSerializer.Serialize(value, Json), Json)
        ?? throw new InvalidOperationException("Blueprint clone failed.");
}