using Microsoft.AspNetCore.Mvc.Testing;
using NeonSprawl.Server.Game.Encounters;

namespace NeonSprawl.Server.Tests.Game.Encounters;

public class EncounterDefinitionCatalogLoaderTests
{
    private const string ValidPrototypeCatalogJson =
        """
        {
          "schemaVersion": 1,
          "encounters": [
            {
              "id": "prototype_combat_pocket",
              "displayName": "Prototype Combat Pocket",
              "completionCriteria": { "kind": "defeat_all_targets" },
              "requiredNpcInstanceIds": [
                "prototype_npc_melee",
                "prototype_npc_ranged",
                "prototype_npc_elite"
              ],
              "rewardTableId": "prototype_combat_pocket_clear"
            }
          ]
        }
        """;

    private static readonly HashSet<string> KnownRewardTableIds =
        ["prototype_combat_pocket_clear"];

    private static (string Root, string EncountersDir, string SchemaPath) CreateTempContentLayout()
    {
        var root = Directory.CreateTempSubdirectory("neon-sprawl-encountercat-");
        var encountersDir = Path.Combine(root.FullName, "content", "encounters");
        var schemaDir = Path.Combine(root.FullName, "content", "schemas");
        Directory.CreateDirectory(encountersDir);
        Directory.CreateDirectory(schemaDir);
        var schemaPath = Path.Combine(schemaDir, "encounter-def.schema.json");
        File.Copy(EncounterCatalogTestPaths.DiscoverRepoEncounterDefSchemaPath(), schemaPath, overwrite: true);
        return (root.FullName, encountersDir, schemaPath);
    }

    private static void WriteCatalog(string encountersDir, string catalogJson) =>
        File.WriteAllText(Path.Combine(encountersDir, "prototype_encounters.json"), catalogJson, Encoding.UTF8);

    private static EncounterDefinitionCatalog LoadCatalog(
        string encountersDir,
        string schemaPath,
        IReadOnlySet<string>? knownRewardTableIds = null) =>
        EncounterDefinitionCatalogLoader.Load(
            encountersDir,
            schemaPath,
            knownRewardTableIds ?? KnownRewardTableIds,
            NullLogger.Instance);

    [Fact]
    public void Load_ShouldSucceed_WhenCatalogMatchesPrototypeContract()
    {
        // Arrange
        var (_, encountersDir, schemaPath) = CreateTempContentLayout();
        WriteCatalog(encountersDir, ValidPrototypeCatalogJson);
        // Act
        var catalog = LoadCatalog(encountersDir, schemaPath);
        // Assert
        Assert.Equal(1, catalog.DistinctEncounterCount);
        Assert.Equal(1, catalog.CatalogJsonFileCount);
        Assert.True(catalog.TryGetEncounter("prototype_combat_pocket", out var encounter));
        Assert.NotNull(encounter);
        Assert.Equal("Prototype Combat Pocket", encounter!.DisplayName);
        Assert.Equal("defeat_all_targets", encounter.CompletionCriteriaKind);
        Assert.Equal("prototype_combat_pocket_clear", encounter.RewardTableId);
        Assert.Equal(3, encounter.RequiredNpcInstanceIds.Count);
    }

    [Fact]
    public void Load_ShouldThrow_WhenEncountersIsNotArray()
    {
        // Arrange
        var (_, encountersDir, schemaPath) = CreateTempContentLayout();
        File.WriteAllText(
            Path.Combine(encountersDir, "bad_encounters.json"),
            """{"schemaVersion": 1, "encounters": "nope"}""",
            Encoding.UTF8);
        // Act
        var ex = Record.Exception(() => LoadCatalog(encountersDir, schemaPath));
        // Assert
        var ioe = Assert.IsType<InvalidOperationException>(ex);
        Assert.Contains("bad_encounters.json", ioe.Message, StringComparison.Ordinal);
        Assert.Contains("expected top-level 'encounters' array", ioe.Message, StringComparison.Ordinal);
    }

    [Fact]
    public void Load_ShouldThrow_WhenSchemaVersionIsNotOne()
    {
        // Arrange
        var (_, encountersDir, schemaPath) = CreateTempContentLayout();
        File.WriteAllText(
            Path.Combine(encountersDir, "bad_encounters.json"),
            """{"schemaVersion": 2, "encounters": []}""",
            Encoding.UTF8);
        // Act
        var ex = Record.Exception(() => LoadCatalog(encountersDir, schemaPath));
        // Assert
        var ioe = Assert.IsType<InvalidOperationException>(ex);
        Assert.Contains("expected schemaVersion 1", ioe.Message, StringComparison.Ordinal);
    }

    [Fact]
    public void Load_ShouldThrow_WhenDuplicateEncounterIdAcrossFiles()
    {
        // Arrange
        var (_, encountersDir, schemaPath) = CreateTempContentLayout();
        WriteCatalog(encountersDir, ValidPrototypeCatalogJson);
        File.WriteAllText(
            Path.Combine(encountersDir, "extra_encounters.json"),
            """
            {
              "schemaVersion": 1,
              "encounters": [
                {
                  "id": "prototype_combat_pocket",
                  "displayName": "Duplicate Encounter",
                  "completionCriteria": { "kind": "defeat_all_targets" },
                  "requiredNpcInstanceIds": [
                    "prototype_npc_melee",
                    "prototype_npc_ranged",
                    "prototype_npc_elite"
                  ],
                  "rewardTableId": "prototype_combat_pocket_clear"
                }
              ]
            }
            """,
            Encoding.UTF8);
        // Act
        var ex = Record.Exception(() => LoadCatalog(encountersDir, schemaPath));
        // Assert
        var ioe = Assert.IsType<InvalidOperationException>(ex);
        Assert.Contains("duplicate encounter id 'prototype_combat_pocket'", ioe.Message, StringComparison.Ordinal);
    }

    [Fact]
    public void Load_ShouldThrow_WhenE5M3AllowlistMismatch()
    {
        // Arrange
        var (_, encountersDir, schemaPath) = CreateTempContentLayout();
        File.WriteAllText(
            Path.Combine(encountersDir, "prototype_encounters.json"),
            """
            {
              "schemaVersion": 1,
              "encounters": [
                {
                  "id": "wrong_encounter_id",
                  "displayName": "Wrong Encounter",
                  "completionCriteria": { "kind": "defeat_all_targets" },
                  "requiredNpcInstanceIds": [
                    "prototype_npc_melee",
                    "prototype_npc_ranged",
                    "prototype_npc_elite"
                  ],
                  "rewardTableId": "prototype_combat_pocket_clear"
                }
              ]
            }
            """,
            Encoding.UTF8);
        // Act
        var ex = Record.Exception(() => LoadCatalog(encountersDir, schemaPath));
        // Assert
        var ioe = Assert.IsType<InvalidOperationException>(ex);
        Assert.Contains("prototype E5M3 expects exactly encounter ids", ioe.Message, StringComparison.Ordinal);
    }

    [Fact]
    public void Load_ShouldThrow_WhenRequiredNpcInstanceIdsMismatch()
    {
        // Arrange
        var (_, encountersDir, schemaPath) = CreateTempContentLayout();
        File.WriteAllText(
            Path.Combine(encountersDir, "prototype_encounters.json"),
            """
            {
              "schemaVersion": 1,
              "encounters": [
                {
                  "id": "prototype_combat_pocket",
                  "displayName": "Prototype Combat Pocket",
                  "completionCriteria": { "kind": "defeat_all_targets" },
                  "requiredNpcInstanceIds": [
                    "prototype_npc_melee",
                    "prototype_npc_ranged",
                    "prototype_npc_unknown"
                  ],
                  "rewardTableId": "prototype_combat_pocket_clear"
                }
              ]
            }
            """,
            Encoding.UTF8);
        // Act
        var ex = Record.Exception(() => LoadCatalog(encountersDir, schemaPath));
        // Assert
        var ioe = Assert.IsType<InvalidOperationException>(ex);
        Assert.Contains("requiredNpcInstanceIds must be exactly", ioe.Message, StringComparison.Ordinal);
    }

    [Fact]
    public void Load_ShouldThrow_WhenRewardTableIdUnknown()
    {
        // Arrange
        var (_, encountersDir, schemaPath) = CreateTempContentLayout();
        File.WriteAllText(
            Path.Combine(encountersDir, "prototype_encounters.json"),
            """
            {
              "schemaVersion": 1,
              "encounters": [
                {
                  "id": "prototype_combat_pocket",
                  "displayName": "Prototype Combat Pocket",
                  "completionCriteria": { "kind": "defeat_all_targets" },
                  "requiredNpcInstanceIds": [
                    "prototype_npc_melee",
                    "prototype_npc_ranged",
                    "prototype_npc_elite"
                  ],
                  "rewardTableId": "missing_reward_table"
                }
              ]
            }
            """,
            Encoding.UTF8);
        // Act
        var ex = Record.Exception(() => LoadCatalog(encountersDir, schemaPath));
        // Assert
        var ioe = Assert.IsType<InvalidOperationException>(ex);
        Assert.Contains("rewardTableId 'missing_reward_table' is not in reward table catalogs", ioe.Message, StringComparison.Ordinal);
    }

    [Fact]
    public void Load_ShouldThrow_WhenRowViolatesSchema()
    {
        // Arrange
        var (_, encountersDir, schemaPath) = CreateTempContentLayout();
        const string bad = """
                  {
                    "schemaVersion": 1,
                    "encounters": [
                      {
                        "id": "prototype_combat_pocket",
                        "displayName": "",
                        "completionCriteria": { "kind": "defeat_all_targets" },
                        "requiredNpcInstanceIds": [
                          "prototype_npc_melee",
                          "prototype_npc_ranged",
                          "prototype_npc_elite"
                        ],
                        "rewardTableId": "prototype_combat_pocket_clear"
                      }
                    ]
                  }
                  """;
        File.WriteAllText(Path.Combine(encountersDir, "bad_encounters.json"), bad, Encoding.UTF8);
        // Act
        var ex = Record.Exception(() => LoadCatalog(encountersDir, schemaPath));
        // Assert
        var ioe = Assert.IsType<InvalidOperationException>(ex);
        Assert.Contains("bad_encounters.json", ioe.Message, StringComparison.Ordinal);
        Assert.Contains("Encounter catalog validation failed", ioe.Message, StringComparison.Ordinal);
    }

    [Fact]
    public void Load_ShouldThrow_WhenSchemaFileMissing()
    {
        // Arrange
        var (_, encountersDir, _) = CreateTempContentLayout();
        WriteCatalog(encountersDir, ValidPrototypeCatalogJson);
        var missingSchema = Path.Combine(encountersDir, "missing-encounter-def.schema.json");
        // Act
        var ex = Record.Exception(() => LoadCatalog(encountersDir, missingSchema));
        // Assert
        var ioe = Assert.IsType<InvalidOperationException>(ex);
        Assert.Contains("missing schema file", ioe.Message, StringComparison.Ordinal);
        Assert.Contains(missingSchema, ioe.Message, StringComparison.Ordinal);
    }

    [Fact]
    public async Task Host_ShouldResolveCatalogsFromDi_WhenStartupSucceeds()
    {
        // Arrange
        await using var factory = new InMemoryWebApplicationFactory();
        using var client = factory.CreateClient();
        // Act
        var response = await client.GetAsync("/health");
        // Assert
        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
        var rewardCatalog = factory.Services.GetRequiredService<RewardTableDefinitionCatalog>();
        Assert.Equal(1, rewardCatalog.DistinctRewardTableCount);
        Assert.True(rewardCatalog.TryGetRewardTable("prototype_combat_pocket_clear", out var rewardTable));
        Assert.NotNull(rewardTable);
        Assert.Equal(10, rewardTable!.FixedGrants.First(g => g.ItemId == "scrap_metal_bulk").Quantity);
        var encounterCatalog = factory.Services.GetRequiredService<EncounterDefinitionCatalog>();
        Assert.Equal(1, encounterCatalog.DistinctEncounterCount);
        Assert.True(encounterCatalog.TryGetEncounter("prototype_combat_pocket", out var encounter));
        Assert.NotNull(encounter);
        Assert.Equal("prototype_combat_pocket_clear", encounter!.RewardTableId);
    }

    [Fact]
    public void Host_ShouldFailStartup_WhenRewardTablesDirectoryInvalid()
    {
        // Arrange
        var badDir = Path.Combine(Path.GetTempPath(), "neon-sprawl-empty-reward-tables-" + Guid.NewGuid().ToString("n"));
        Directory.CreateDirectory(badDir);
        try
        {
            // Act
            var ex = Record.Exception(() =>
            {
                using var factory = new WebApplicationFactory<Program>().WithWebHostBuilder(b =>
                    b.UseSetting("Content:RewardTablesDirectory", badDir));
                factory.CreateClient();
            });
            // Assert
            Assert.NotNull(ex);
            Assert.Contains("Reward table catalog validation failed", ex.ToString(), StringComparison.Ordinal);
        }
        finally
        {
            if (Directory.Exists(badDir))
                Directory.Delete(badDir);
        }
    }

    [Fact]
    public void Host_ShouldFailStartup_WhenEncountersDirectoryInvalid()
    {
        // Arrange
        var badDir = Path.Combine(Path.GetTempPath(), "neon-sprawl-empty-encounters-" + Guid.NewGuid().ToString("n"));
        Directory.CreateDirectory(badDir);
        try
        {
            // Act
            var ex = Record.Exception(() =>
            {
                using var factory = new WebApplicationFactory<Program>().WithWebHostBuilder(b =>
                    b.UseSetting("Content:EncountersDirectory", badDir));
                factory.CreateClient();
            });
            // Assert
            Assert.NotNull(ex);
            Assert.Contains("Encounter catalog validation failed", ex.ToString(), StringComparison.Ordinal);
        }
        finally
        {
            if (Directory.Exists(badDir))
                Directory.Delete(badDir);
        }
    }
}