import { Texture } from "three";
import { describe, expect, it, vi } from "vitest";

import { createDefaultWorldSettings } from "../../src/document/world-settings";
import {
  resolveWorldCelestialBodiesState,
  resolveWorldCelestialHorizonVisibility,
  resolveWorldEnvironmentState
} from "../../src/rendering/world-background-renderer";
import type { WorldShaderSkyRenderState } from "../../src/rendering/world-shader-sky";

describe("resolveWorldEnvironmentState", () => {
  it("keeps the authored day environment when no night overlay is active", () => {
    const world = createDefaultWorldSettings();
    const dayTexture = new Texture();
    world.background = {
      mode: "image",
      assetId: "asset-day-sky",
      environmentIntensity: 0.65
    };

    expect(
      resolveWorldEnvironmentState(world.background, dayTexture, null)
    ).toEqual({
      texture: dayTexture,
      intensity: 0.65
    });
  });

  it("keeps environment lighting energy during a day-to-night crossfade", () => {
    const world = createDefaultWorldSettings();
    const dayTexture = new Texture();
    const nightTexture = new Texture();
    world.background = {
      mode: "image",
      assetId: "asset-day-sky",
      environmentIntensity: 0.4
    };

    const earlyTwilight = resolveWorldEnvironmentState(
      world.background,
      dayTexture,
      {
        texture: nightTexture,
        opacity: 0.25,
        environmentIntensity: 0.8
      }
    );
    const lateTwilight = resolveWorldEnvironmentState(
      world.background,
      dayTexture,
      {
        texture: nightTexture,
        opacity: 0.75,
        environmentIntensity: 0.8
      }
    );

    expect(earlyTwilight.texture).toBe(dayTexture);
    expect(earlyTwilight.intensity).toBeCloseTo(0.5);
    expect(lateTwilight.texture).toBe(dayTexture);
    expect(lateTwilight.intensity).toBeCloseTo(0.7);
  });

  it("uses a cached blended environment texture during partial image-image twilight blends", () => {
    const world = createDefaultWorldSettings();
    const dayTexture = new Texture();
    const nightTexture = new Texture();
    const blendedTexture = new Texture();
    const environmentBlendTextureResolver = {
      resolveBlendTexture: vi.fn().mockReturnValue(blendedTexture)
    };
    world.background = {
      mode: "image",
      assetId: "asset-day-sky",
      environmentIntensity: 0.45
    };

    const twilight = resolveWorldEnvironmentState(
      world.background,
      dayTexture,
      {
        texture: nightTexture,
        opacity: 0.5,
        environmentIntensity: 0.85
      },
      environmentBlendTextureResolver
    );

    expect(
      environmentBlendTextureResolver.resolveBlendTexture
    ).toHaveBeenCalledWith(dayTexture, nightTexture, 0.5);
    expect(twilight.texture).toBe(blendedTexture);
    expect(twilight.intensity).toBeCloseTo(0.65);
  });

  it("falls back to the existing single-texture environment while a blended bucket is unavailable", () => {
    const world = createDefaultWorldSettings();
    const dayTexture = new Texture();
    const nightTexture = new Texture();
    const environmentBlendTextureResolver = {
      resolveBlendTexture: vi.fn().mockReturnValue(null)
    };
    world.background = {
      mode: "image",
      assetId: "asset-day-sky",
      environmentIntensity: 0.45
    };

    const twilight = resolveWorldEnvironmentState(
      world.background,
      dayTexture,
      {
        texture: nightTexture,
        opacity: 0.5,
        environmentIntensity: 0.85
      },
      environmentBlendTextureResolver
    );

    expect(twilight.texture).toBe(dayTexture);
    expect(twilight.intensity).toBeCloseTo(0.65);
  });

  it("fades the night environment in when the authored day background has no image environment", () => {
    const world = createDefaultWorldSettings();
    const nightTexture = new Texture();

    expect(
      resolveWorldEnvironmentState(world.background, null, {
        texture: nightTexture,
        opacity: 0.5,
        environmentIntensity: 0.7
      })
    ).toEqual({
      texture: nightTexture,
      intensity: 0.35
    });
  });

  it("uses a shader-derived environment texture when shader mode is active", () => {
    const world = createDefaultWorldSettings();
    const shaderTexture = new Texture();
    const shaderState = {
      presetId: "defaultSky",
      time: {
        dayCount: 0,
        timeOfDayHours: 12,
        dayPhase: "day",
        daylightFactor: 1,
        twilightFactor: 0,
        phaseWeights: {
          day: 1,
          dawn: 0,
          dusk: 0,
          night: 0
        }
      }
    } as unknown as WorldShaderSkyRenderState;
    const shaderEnvironmentTextureResolver = {
      resolveEnvironmentTexture: vi.fn().mockReturnValue(shaderTexture)
    };
    world.background = {
      mode: "shader"
    };

    const environment = resolveWorldEnvironmentState(
      world.background,
      null,
      null,
      null,
      shaderState,
      shaderEnvironmentTextureResolver
    );

    expect(
      shaderEnvironmentTextureResolver.resolveEnvironmentTexture
    ).toHaveBeenCalledWith(shaderState);
    expect(environment).toEqual({
      texture: shaderTexture,
      intensity: 1
    });
  });
});

describe("resolveWorldCelestialBodiesState", () => {
  it("returns aligned sun and moon overlay state when enabled", () => {
    const world = createDefaultWorldSettings();
    world.showCelestialBodies = true;

    const celestialBodies = resolveWorldCelestialBodiesState(
      world.showCelestialBodies,
      {
        colorHex: "#ffddaa",
        intensity: 1.8,
        direction: {
          x: 0.2,
          y: 0.9,
          z: -0.1
        }
      },
      {
        colorHex: "#c7d8ff",
        intensity: 0.28,
        direction: {
          x: -0.2,
          y: 0.45,
          z: 0.87
        }
      }
    );

    expect(celestialBodies.sun).toMatchObject({
      colorHex: "#ffddaa",
      intensity: 1.8,
      horizonVisibility: 1,
      size: 28
    });
    expect(celestialBodies.moon).toMatchObject({
      colorHex: "#c7d8ff",
      intensity: 0.28,
      horizonVisibility: 1,
      size: 20
    });
    expect(celestialBodies.sun?.direction.y ?? 0).toBeGreaterThan(0);
    expect(celestialBodies.moon?.direction.y ?? 0).toBeGreaterThan(0);
  });

  it("keeps celestial bodies visible through the lower horizon fade", () => {
    const celestialBodies = resolveWorldCelestialBodiesState(
      true,
      {
        colorHex: "#ffddaa",
        intensity: 1.8,
        direction: {
          x: 0.98,
          y: -0.16,
          z: -0.1
        }
      },
      null
    );

    expect(celestialBodies.sun).not.toBeNull();
    expect(celestialBodies.sun?.horizonVisibility ?? 0).toBeGreaterThan(0);
    expect(celestialBodies.sun?.horizonVisibility ?? 1).toBeLessThan(1);
  });

  it("hides celestial bodies when the feature is disabled or the light sits below the extended horizon fade", () => {
    const enabledButBelowHorizon = resolveWorldCelestialBodiesState(
      true,
      {
        colorHex: "#ffddaa",
        intensity: 1.8,
        direction: {
          x: 0.2,
          y: -0.35,
          z: -0.1
        }
      },
      {
        colorHex: "#c7d8ff",
        intensity: 0.28,
        direction: {
          x: -0.2,
          y: -0.45,
          z: 0.87
        }
      }
    );
    const disabled = resolveWorldCelestialBodiesState(
      false,
      {
        colorHex: "#ffddaa",
        intensity: 1.8,
        direction: {
          x: 0.2,
          y: 0.9,
          z: -0.1
        }
      },
      null
    );

    expect(enabledButBelowHorizon).toEqual({
      sun: null,
      moon: null
    });
    expect(disabled).toEqual({
      sun: null,
      moon: null
    });
  });

  it("resolves celestial horizon visibility with a longer below-horizon fade", () => {
    expect(resolveWorldCelestialHorizonVisibility(0)).toBe(1);
    expect(resolveWorldCelestialHorizonVisibility(-0.16)).toBeGreaterThan(0);
    expect(resolveWorldCelestialHorizonVisibility(-0.16)).toBeLessThan(1);
    expect(resolveWorldCelestialHorizonVisibility(-0.35)).toBe(0);
  });
});