import type { LightingBeamAngle, LightingDirection, LightingPosition, LightingPreset, LightingSettings } from "@/types";

export const DEFAULT_LIGHTING_SETTINGS: LightingSettings = {
  enabled: false,
  viewMode: "perspective",
  smartMode: false,
  brightness: 50,
  color: "#ffffff",
  mainLightDirection: "front",
  lightPosition: { x: 0, y: 0, z: 1 },
  beamAngle: 45,
  rimLight: false,
  smartPrompt: "",
  referenceImage: null,
  selectedPresetId: null,
};

export const LIGHTING_PRESETS: LightingPreset[] = [
  {
    id: "overexposed-film",
    label: "过曝胶片",
    thumbnail: "linear-gradient(135deg, #f7ead1 0%, #ffffff 55%, #d8b47f 100%)",
    prompt: "overexposed film lighting, soft bloom, warm highlights",
    settings: {
      brightness: 100,
      color: "#ffffff",
      mainLightDirection: "front",
      lightPosition: { x: 0, y: 0, z: 1 },
      beamAngle: 45,
      smartPrompt: "柯达胶片感的曝光和柔和高光，只调整打光",
    },
  },
  {
    id: "blue-backlight",
    label: "蓝色逆光",
    thumbnail: "linear-gradient(135deg, #080b18 0%, #1646ff 60%, #dbe8ff 100%)",
    prompt: "blue backlight, cool rim glow, dramatic contrast",
    settings: {
      brightness: 50,
      color: "#3438ff",
      mainLightDirection: "bottom",
      lightPosition: { x: 0, y: 1, z: 0 },
      beamAngle: 45,
      rimLight: false,
      smartPrompt: "",
    },
  },
  {
    id: "rembrandt",
    label: "伦勃朗光",
    thumbnail: "linear-gradient(135deg, #1b120d 0%, #b9824c 55%, #f3d3a0 100%)",
    prompt: "Rembrandt lighting, painterly side key light, soft shadow triangle",
    settings: {
      brightness: 50,
      color: "#ffffff",
      mainLightDirection: "left",
      lightPosition: { x: -0.58, y: -0.58, z: 0.58 },
      beamAngle: 45,
      smartPrompt: "",
    },
  },
  {
    id: "cyberpunk",
    label: "赛博朋克",
    thumbnail: "linear-gradient(135deg, #06121c 0%, #00d1ff 45%, #ff2bd6 100%)",
    prompt: "cyberpunk neon lighting, teal and magenta glow, high contrast",
    settings: {
      brightness: 50,
      color: "#ffffff",
      mainLightDirection: "front",
      lightPosition: { x: 0, y: 0, z: 1 },
      beamAngle: 45,
      rimLight: false,
      smartPrompt: "《银翼杀手2045》同款青紫高反差打光，只调整光影",
    },
  },
  {
    id: "sunset-dream",
    label: "落日迷幻",
    thumbnail: "linear-gradient(135deg, #2a0f2d 0%, #ff7b3a 58%, #ffd36a 100%)",
    prompt: "dreamy sunset lighting, warm low-angle glow, hazy atmosphere",
    settings: {
      brightness: 50,
      color: "#ffffff",
      mainLightDirection: "front",
      lightPosition: { x: 0, y: 0, z: 1 },
      beamAngle: 45,
      smartPrompt: "",
    },
  },
  {
    id: "mystic-low-key",
    label: "神秘暗调",
    thumbnail: "linear-gradient(135deg, #030303 0%, #18201d 55%, #5d806f 100%)",
    prompt: "mysterious low-key lighting, deep shadows, subtle green highlights",
    settings: {
      brightness: 10,
      color: "#ffffff",
      mainLightDirection: "front",
      lightPosition: { x: 0, y: 0, z: 1 },
      beamAngle: 45,
      smartPrompt: "百叶窗打光，神秘优雅",
    },
  },
  {
    id: "golden-hour",
    label: "黄金时刻",
    thumbnail: "linear-gradient(135deg, #3b1e09 0%, #ffb33c 50%, #fff1b9 100%)",
    prompt: "golden hour lighting, soft warm sunlight, natural glow",
    settings: {
      brightness: 50,
      color: "#ffffff",
      mainLightDirection: "front",
      lightPosition: { x: 0, y: 0, z: 1 },
      beamAngle: 45,
      smartPrompt: "黄金时刻暖色光影，只调整光照和阴影",
    },
  },
  {
    id: "cool-morning",
    label: "清晨冷灰",
    thumbnail: "linear-gradient(135deg, #20242b 0%, #8796a8 55%, #dbe5ee 100%)",
    prompt: "cool morning light, desaturated grey-blue ambience, gentle shadows",
    settings: {
      brightness: 50,
      color: "#ffffff",
      mainLightDirection: "front",
      lightPosition: { x: 0, y: 0, z: 1 },
      beamAngle: 45,
      smartPrompt: "清晨冷灰色温和柔和阴影，只调整光照和色温",
    },
  },
];

const DIRECTION_LABELS: Record<LightingDirection, string> = {
  left: "left side key light",
  top: "top key light",
  right: "right side key light",
  front: "front key light",
  bottom: "bottom uplight",
  back: "back light",
};

const DIRECTION_INSTRUCTIONS: Record<LightingDirection, string> = {
  left: "Place the main light on the left side of the subject and cast natural shadows to the right.",
  top: "Place the main light above the subject and create soft downward shadows.",
  right: "Place the main light on the right side of the subject and cast natural shadows to the left.",
  front: "Place the main light in front of the subject for clear facial illumination.",
  bottom: "Place the main light below the subject for controlled uplighting.",
  back: "Place the main light behind the subject and create a clean backlit silhouette.",
};

function brightnessInstruction(value: number): string {
  if (value >= 75) return "Use bright high-key illumination without washing out important details.";
  if (value >= 55) return "Use balanced medium-bright illumination with readable details.";
  if (value >= 35) return "Use restrained low-key illumination with visible form and controlled shadows.";
  return "Use dark cinematic illumination while keeping the subject recognizable.";
}

function positionInstruction(position: LightingPosition): string {
  const horizontal = position.x <= -0.25 ? "camera-left" : position.x >= 0.25 ? "camera-right" : "centered";
  const vertical = position.y <= -0.25 ? "above the subject" : position.y >= 0.25 ? "below the subject" : "near eye level";
  const depth = position.z <= -0.25 ? "behind the subject" : position.z >= 0.25 ? "in front of the subject" : "on the subject plane";

  return [
    `light source vector x=${position.x.toFixed(2)}`,
    `y=${position.y.toFixed(2)}`,
    `z=${position.z.toFixed(2)}`,
    `${horizontal}, ${vertical}, ${depth}`,
    "aim the light directly at the center of the source image",
  ].join(", ");
}

function beamAngleInstruction(angle: LightingBeamAngle): string {
  const width = Math.abs(angle) === 45 ? "focused flashlight-like beam" : "wide studio softbox spread";
  const tilt = angle < 0 ? "negative tilt angle" : "positive tilt angle";
  return `${angle} degree beam angle, ${width}, ${tilt}`;
}

export function normalizeLightingSettings(settings?: LightingSettings | null): LightingSettings {
  const current = settings ?? null;
  return {
    ...DEFAULT_LIGHTING_SETTINGS,
    ...(current ?? {}),
    lightPosition: {
      ...DEFAULT_LIGHTING_SETTINGS.lightPosition,
      ...(current?.lightPosition ?? {}),
    },
  };
}

export function buildLightingPrompt(settings?: LightingSettings | null): string {
  const lighting = normalizeLightingSettings(settings);
  if (!lighting.enabled) return "";

  const preset = LIGHTING_PRESETS.find((item) => item.id === lighting.selectedPresetId);
  const parts = [
    "Lighting plan:",
    DIRECTION_LABELS[lighting.mainLightDirection],
    DIRECTION_INSTRUCTIONS[lighting.mainLightDirection],
    `${lighting.brightness}% brightness`,
    brightnessInstruction(lighting.brightness),
    `light color ${lighting.color}`,
    positionInstruction(lighting.lightPosition),
    beamAngleInstruction(lighting.beamAngle),
  ];

  if (lighting.rimLight) {
    parts.push("visible rim light around the subject");
  }

  if (preset?.prompt) {
    parts.push(preset.prompt);
  }

  if (lighting.smartMode && lighting.smartPrompt.trim()) {
    parts.push(lighting.smartPrompt.trim());
  }

  return parts.join(", ");
}

export function buildOptimizedLightingPrompt(
  basePrompt: string | null | undefined,
  settings?: LightingSettings | null
): string {
  const lightingPrompt = buildLightingPrompt(settings);
  const userPrompt = (basePrompt ?? "").trim();

  if (!lightingPrompt) {
    return userPrompt;
  }

  const userIntent = userPrompt
    ? `User intent: ${userPrompt}`
    : "User intent: relight the uploaded image according to the lighting plan.";

  return [
    "STRICT image-to-image relighting task: use the uploaded image as the locked source image.",
    userIntent,
    lightingPrompt,
    "The output must show the same exact person from the source image: identical face identity, facial features, age, expression, hair, body shape, hands, pose, clothing, accessories, and camera/phone.",
    "Preserve the original composition, camera angle, crop, background, object layout, readable text overlays, and image style.",
    "Only change illumination: light direction, brightness, color temperature, shadows, highlights, reflections, and ambient lighting mood required by the lighting plan.",
    "Treat any preset or style wording as a lighting reference only, not permission to redesign the person, outfit, background, pose, scene, or photographic composition.",
    "Do not add or remove people or objects, do not beautify or re-age the person, do not replace the face, do not change hairstyle or clothing, do not crop the subject, and do not create a different scene.",
  ].join("\n");
}