export const STORAGE_KEY = "image-prompt-studio:simple-prompt:v1";

export const GENERATION_DEFAULTS = {
  size: "1024x1024",
  quality: "high",
  outputFormat: "png",
  background: "auto",
  count: 1,
  moderation: "auto",
  outputCompression: 90,
};

export const EXAMPLE_PROMPTS = [
  "一只白色陶瓷杯放在浅灰色窗边桌面上，晨光柔和，极简产品摄影，干净背景，苹果官网质感。",
  "未来感电动车停在雾气很轻的海边公路，银色车身，阴天柔光，电影级写实海报。",
  "一间现代风格客厅，浅木地板，奶油白沙发，大面积自然光，室内设计杂志封面感。",
  "一款无线耳机悬浮在纯白背景中，蓝色柔和反射光，商业广告风，细节锐利。",
];

export const PROCESSING_STAGES = [
  {
    title: "整理 Prompt",
    detail: "检查内容并准备发送到服务端。",
    thresholdMs: 1400,
  },
  {
    title: "连接 gpt-image-2",
    detail: "向 OpenAI Images API 发起图片生成请求。",
    thresholdMs: 5200,
  },
  {
    title: "等待渲染",
    detail: "模型正在生成高质量图片，这一步通常最耗时。",
    thresholdMs: 15000,
  },
  {
    title: "准备下载",
    detail: "接收 base64 图片并整理成浏览器可下载文件。",
    thresholdMs: 24000,
  },
];

export function sanitizePrompt(input) {
  return String(input ?? "")
    .replace(/\r/g, "")
    .replace(/[ \t]+\n/g, "\n")
    .replace(/\n{3,}/g, "\n\n")
    .split("\n")
    .map((line) => line.trim())
    .join("\n")
    .trim();
}

export function buildPromptStats(prompt) {
  const cleanPrompt = sanitizePrompt(prompt);

  if (!cleanPrompt) {
    return "输入一句清晰的画面描述即可开始。";
  }

  const lineCount = cleanPrompt.split("\n").length;
  const charCount = cleanPrompt.length;

  return `${charCount} 个字符 · ${lineCount} 行`;
}

export function buildDownloadStem(prompt) {
  const normalized = sanitizePrompt(prompt)
    .toLowerCase()
    .replace(/[^a-z0-9\u4e00-\u9fa5\s-]/g, "")
    .trim()
    .replace(/\s+/g, "-")
    .slice(0, 48);

  return normalized || "generated-image";
}

export function createProcessingSnapshot(elapsedMs, isComplete = false) {
  if (isComplete) {
    return {
      progress: 1,
      activeStageIndex: PROCESSING_STAGES.length - 1,
      lead: "图片已生成完成，可以预览和下载。",
    };
  }

  const safeElapsed = Math.max(0, elapsedMs);
  const finalThreshold =
    PROCESSING_STAGES[PROCESSING_STAGES.length - 1]?.thresholdMs ?? 24000;
  const progress = Math.min(0.92, safeElapsed / finalThreshold);
  const activeStageIndex = resolveActiveStageIndex(safeElapsed);
  const activeStage = PROCESSING_STAGES[activeStageIndex];

  return {
    progress,
    activeStageIndex,
    lead: activeStage
      ? `${activeStage.title}中... ${activeStage.detail}`
      : "正在处理，请稍候。",
  };
}

function resolveActiveStageIndex(elapsedMs) {
  for (let index = PROCESSING_STAGES.length - 1; index >= 0; index -= 1) {
    if (elapsedMs >= PROCESSING_STAGES[index].thresholdMs) {
      return index;
    }
  }

  return 0;
}