using BlueLaminate.Core.Tradeups;
using BlueLaminate.EFCore.Data;
using BlueLaminate.EFCore.Entities;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging.Abstractions;
using Xunit;

namespace BlueLaminate.Tests.Tradeups;

/// <summary>
/// Graph-derivation rules verified against a synthetic in-memory catalogue — never the
/// live database (see the no-live-DB-perturbation rule). Each test seeds the minimal
/// catalogue shape it needs.
/// </summary>
public class TradeupGraphBuilderTests
{
    private static SkinTrackerDbContext NewContext()
    {
        var options = new DbContextOptionsBuilder<SkinTrackerDbContext>()
            .UseInMemoryDatabase($"tradeups-{Guid.NewGuid()}")
            .Options;
        return new SkinTrackerDbContext(options);
    }

    private static async Task<TradeupGraph> BuildAsync(SkinTrackerDbContext db)
    {
        await db.SaveChangesAsync();
        var builder = new TradeupGraphBuilder(db, NullLogger<TradeupGraphBuilder>.Instance);
        return await builder.BuildAsync();
    }

    private sealed class Catalogue
    {
        private int _nextId = 1;
        public Weapon Rifle { get; } = new() { Id = 1000, Name = "AK-47", Type = "Rifle", Team = "Both" };
        public Weapon Knife { get; } = new() { Id = 1001, Name = "Karambit", Type = "Knives", Team = "Both" };
        public Weapon Glove { get; } = new() { Id = 1002, Name = "Sport Gloves", Type = "Gloves", Team = "Both" };

        public List<Skin> Skins { get; } = new();

        public Skin Add(
            Collection collection,
            string rarity,
            Weapon? weapon = null,
            decimal? floatMin = 0.0m,
            decimal? floatMax = 1.0m)
        {
            var skin = new Skin
            {
                Id = _nextId,
                Slug = $"skin-{_nextId}",
                Name = $"Skin {_nextId}",
                Rarity = rarity,
                Weapon = weapon ?? Rifle,
                FloatMin = floatMin,
                FloatMax = floatMax,
                Collections = new List<Collection> { collection },
            };
            _nextId++;
            Skins.Add(skin);
            return skin;
        }
    }

    private static Collection NewCollection(string name, string type = "Collection")
        => new() { Name = name, Slug = $"col-{name}", Type = type };

    [Fact]
    public async Task Resolves_across_a_rarity_gap()
    {
        // MilSpec + Classified present, Restricted absent → MilSpec must resolve to Classified.
        await using var db = NewContext();
        var cat = new Catalogue();
        var col = NewCollection("Gap");
        cat.Add(col, "Mil-Spec Grade");
        cat.Add(col, "Classified");
        db.Skins.AddRange(cat.Skins);

        var graph = await BuildAsync(db);

        var group = Assert.Single(graph.Groups);
        Assert.Equal(WeaponRarity.MilSpec, group.InputRarity);
        Assert.Equal(WeaponRarity.Classified, group.OutputRarity);
    }

    [Fact]
    public async Task Covert_is_an_output_but_never_an_input()
    {
        await using var db = NewContext();
        var cat = new Catalogue();
        var col = NewCollection("Tops at Covert");
        cat.Add(col, "Restricted");
        cat.Add(col, "Classified");
        cat.Add(col, "Covert"); // a weapon Covert (eligible output)
        db.Skins.AddRange(cat.Skins);

        var graph = await BuildAsync(db);

        Assert.Contains(graph.Groups, g => g.InputRarity == WeaponRarity.Restricted && g.OutputRarity == WeaponRarity.Classified);
        Assert.Contains(graph.Groups, g => g.InputRarity == WeaponRarity.Classified && g.OutputRarity == WeaponRarity.Covert);
        Assert.DoesNotContain(graph.Groups, g => g.InputRarity == WeaponRarity.Covert);
    }

    [Fact]
    public async Task Knife_with_covert_rarity_is_excluded_as_output()
    {
        // The only "Covert" in the collection is a knife → the Covert tier has no eligible
        // output, so Classified resolves to nothing and yields no group.
        await using var db = NewContext();
        var cat = new Catalogue();
        var col = NewCollection("Knife Covert");
        cat.Add(col, "Classified");
        cat.Add(col, "Covert", weapon: cat.Knife);
        db.Skins.AddRange(cat.Skins);

        var graph = await BuildAsync(db);

        Assert.Empty(graph.Groups);
    }

    [Fact]
    public async Task Contraband_and_gloves_are_not_weapon_tiers()
    {
        await using var db = NewContext();
        var cat = new Catalogue();
        var col = NewCollection("Howl");
        cat.Add(col, "Classified");
        cat.Add(col, "Contraband");                       // The Howl
        cat.Add(col, "Extraordinary", weapon: cat.Glove); // a glove
        db.Skins.AddRange(cat.Skins);

        var graph = await BuildAsync(db);

        // Classified has no higher weapon tier present → no tradeup.
        Assert.Empty(graph.Groups);
    }

    [Fact]
    public async Task Skins_without_float_bounds_are_excluded()
    {
        await using var db = NewContext();
        var cat = new Catalogue();
        var col = NewCollection("No Float");
        cat.Add(col, "Mil-Spec Grade", floatMin: null, floatMax: null); // floatless → not a tier
        cat.Add(col, "Classified");
        db.Skins.AddRange(cat.Skins);

        var graph = await BuildAsync(db);

        // The only would-be input tier is excluded, so nothing resolves.
        Assert.Empty(graph.Groups);
    }

    [Fact]
    public async Task Limited_edition_pseudo_collection_is_skipped()
    {
        await using var db = NewContext();
        var cat = new Catalogue();
        var col = NewCollection("Limited Edition Item");
        cat.Add(col, "Mil-Spec Grade");
        cat.Add(col, "Classified");
        db.Skins.AddRange(cat.Skins);

        var graph = await BuildAsync(db);

        Assert.Empty(graph.Groups);
    }

    [Fact]
    public async Task Containers_are_not_treated_as_collections()
    {
        await using var db = NewContext();
        var cat = new Catalogue();
        var crate = NewCollection("Some Case", type: "Container");
        cat.Add(crate, "Mil-Spec Grade");
        cat.Add(crate, "Classified");
        db.Skins.AddRange(cat.Skins);

        var graph = await BuildAsync(db);

        // Grouping is by Type='Collection' only; case weapons carry a separate Collection
        // source in reality, but a Container source on its own yields nothing.
        Assert.Empty(graph.Groups);
    }

    [Fact]
    public async Task Output_skins_carry_float_bounds_and_stattrak_flag()
    {
        await using var db = NewContext();
        var cat = new Catalogue();
        var col = NewCollection("Bounds");
        cat.Add(col, "Classified");
        var covert = cat.Add(col, "Covert", floatMin: 0.0m, floatMax: 0.8m);
        covert.StatTrakAvailable = true;
        db.Skins.AddRange(cat.Skins);

        var graph = await BuildAsync(db);

        var group = Assert.Single(graph.Groups);
        var output = Assert.Single(group.OutputSkins);
        Assert.Equal(0.0m, output.FloatMin);
        Assert.Equal(0.8m, output.FloatMax);
        Assert.True(output.StatTrakAvailable);
    }
}