"use client";

import { useEffect, useMemo, useState } from "react";
import { cn } from "@/lib/utils";

type GenerationPhase = "idle" | "queued" | "processing" | "finalizing" | "failed" | "completed";

interface GenerationDotPlaceholderProps {
  className?: string;
  title?: string;
  phase?: GenerationPhase;
  progress?: number | null;
  compact?: boolean;
  showProgress?: boolean;
}

const PHASE_TITLES: Record<GenerationPhase, string> = {
  idle: "正在创建图片",
  queued: "等待开始生成",
  processing: "生成初稿中",
  finalizing: "正在润饰细节",
  failed: "生成失败",
  completed: "生成完成",
};

const ROTATING_TITLES = ["正在创建图片", "生成初稿中", "正在润饰细节"];

function clampProgress(value: number) {
  if (!Number.isFinite(value)) return 0;
  return Math.max(0, Math.min(100, Math.round(value)));
}

function estimateProgress(phase: GenerationPhase, elapsedMs: number) {
  if (phase === "completed") return 100;
  if (phase === "failed") return 100;
  if (phase === "finalizing") return 96;
  if (phase === "queued") {
    return clampProgress(6 + Math.min(12, elapsedMs / 3500));
  }
  if (phase === "processing") {
    const eased = 1 - Math.exp(-elapsedMs / 85_000);
    return clampProgress(18 + eased * 78);
  }
  return clampProgress(Math.min(8, elapsedMs / 1000));
}

export function GenerationDotPlaceholder({
  className,
  title,
  phase = "processing",
  progress,
  compact = false,
  showProgress = true,
}: GenerationDotPlaceholderProps) {
  const [elapsedMs, setElapsedMs] = useState(0);

  useEffect(() => {
    const startedAt = Date.now();
    const timer = window.setInterval(() => {
      setElapsedMs(Date.now() - startedAt);
    }, 600);
    return () => window.clearInterval(timer);
  }, [phase]);

  const resolvedProgress = clampProgress(
    typeof progress === "number" ? progress : estimateProgress(phase, elapsedMs)
  );
  const rotatingTitle = ROTATING_TITLES[Math.floor(elapsedMs / 3200) % ROTATING_TITLES.length];
  const resolvedTitle = title || (phase === "processing" ? rotatingTitle : PHASE_TITLES[phase]);
  const dotOpacity = phase === "failed" ? 0.22 : 0.34;

  const progressStyle = useMemo(
    () => ({ width: `${resolvedProgress}%` }),
    [resolvedProgress]
  );

  return (
    <div
      className={cn(
        "relative isolate overflow-hidden rounded-[32px] bg-[#f4f4f4] text-[#565b63]",
        compact ? "min-h-[190px] p-5" : "min-h-[360px] p-8",
        className
      )}
    >
      <div className="relative z-10 flex h-full min-h-[inherit] flex-col">
        <div className={cn("font-semibold tracking-tight", compact ? "text-[15px]" : "text-[22px]")}>
          {resolvedTitle}
        </div>
        <div className="flex-1" />
        {showProgress ? (
          <div className="space-y-2">
            <div className="flex items-center justify-between text-[12px] font-medium text-[#7d838b]">
              <span>{phase === "failed" ? "已停止" : "生成进度"}</span>
              <span>{resolvedProgress}%</span>
            </div>
            <div className="h-1.5 overflow-hidden rounded-full bg-white/80 shadow-[inset_0_0_0_1px_rgba(0,0,0,0.035)]">
              <div
                className={cn(
                  "h-full rounded-full transition-[width] duration-700 ease-out",
                  phase === "failed" ? "bg-[#c7ccd3]" : "bg-[#9fa4aa]"
                )}
                style={progressStyle}
              />
            </div>
          </div>
        ) : null}
      </div>
      <div
        className="generation-dot-field generation-dot-field-a absolute inset-0"
        style={{ opacity: dotOpacity }}
      />
      <div
        className="generation-dot-field generation-dot-field-b absolute inset-0"
        style={{ opacity: dotOpacity * 0.9 }}
      />
      <style jsx>{`
        .generation-dot-field {
          background-image: radial-gradient(circle, rgba(40, 44, 50, 0.42) 1.35px, transparent 1.55px);
          background-size: ${compact ? "14px 14px" : "18px 18px"};
          animation: generation-dot-drift 7.5s ease-in-out infinite alternate;
          mask-image:
            radial-gradient(circle at 32% 69%, black 0 19%, rgba(0, 0, 0, 0.72) 27%, transparent 48%),
            radial-gradient(circle at 68% 36%, black 0 15%, rgba(0, 0, 0, 0.58) 25%, transparent 45%);
          -webkit-mask-image:
            radial-gradient(circle at 32% 69%, black 0 19%, rgba(0, 0, 0, 0.72) 27%, transparent 48%),
            radial-gradient(circle at 68% 36%, black 0 15%, rgba(0, 0, 0, 0.58) 25%, transparent 45%);
          mask-composite: add;
          -webkit-mask-composite: source-over;
        }

        .generation-dot-field-b {
          background-size: ${compact ? "18px 18px" : "23px 23px"};
          animation-duration: 9s;
          animation-direction: alternate-reverse;
          filter: blur(0.1px);
          transform: translate3d(6px, -4px, 0);
        }

        @keyframes generation-dot-drift {
          0% {
            background-position: 0 0;
            transform: translate3d(-3px, 2px, 0) scale(0.985);
          }
          100% {
            background-position: 26px 18px;
            transform: translate3d(5px, -4px, 0) scale(1.015);
          }
        }
      `}</style>
    </div>
  );
}