"use client";

import { useState, useMemo, Suspense } from "react";
import { useRouter, useSearchParams } from "next/navigation";
import Link from "next/link";
import { TopNav } from "@/components/layout/top-nav";
import { AmbientParticles } from "@/components/ui/ambient-particles";
import { useApp } from "@/lib/app-context";
import { generateId } from "@/lib/store";
import type { TrainingTask, TrainingTaskType } from "@/lib/types";

type WizardStep = 1 | 2 | 3 | 4;

const TEMPLATES = [
  { id: "sdxl_lora", name: "SDXL LoRA", desc: "基于 SDXL 底模，兼顾速度与效果（占位）" },
  { id: "flux_lora", name: "Flux LoRA", desc: "基于 Flux 底模，细节更精细（占位）" },
  { id: "sd15_lora", name: "SD 1.5 LoRA", desc: "轻量训练，适合像素/卡通（占位）" },
];

function TrainingWizardInner() {
  const router = useRouter();
  const search = useSearchParams();
  const { stylePacks, characters, upsertTrainingTask } = useApp();

  const initType = (search.get("type") as TrainingTaskType) || "style_lora";
  const initSourceId = search.get("sourceId") ?? "";

  const [step, setStep] = useState<WizardStep>(1);
  const [type, setType] = useState<TrainingTaskType>(initType);
  const [sourceId, setSourceId] = useState(initSourceId);
  const [template, setTemplate] = useState("sdxl_lora");
  const [name, setName] = useState("");
  const [trainingSetSize, setTrainingSetSize] = useState(12);

  const sources = type === "style_lora" ? stylePacks : characters;

  const selectedSource = useMemo(
    () => sources.find((s) => s.id === sourceId),
    [sources, sourceId]
  );

  const canNext = useMemo(() => {
    if (step === 1) return !!sourceId;
    if (step === 2) return !!template && trainingSetSize > 0;
    if (step === 3) return true;
    return true;
  }, [step, sourceId, template, trainingSetSize]);

  const defaultName = useMemo(() => {
    if (!selectedSource) return "";
    return `${selectedSource.name} ${type === "style_lora" ? "风格" : "角色"} LoRA v1`;
  }, [selectedSource, type]);

  const finalName = name.trim() || defaultName;

  const handleSubmit = () => {
    const now = Date.now();
    const t: TrainingTask = {
      id: generateId("train-"),
      name: finalName || "未命名训练任务",
      type,
      status: "queued",
      progress: 0,
      sourceId,
      template,
      trainingSet: Array.from({ length: trainingSetSize }).map((_, i) => `asset-pick-${i + 1}`),
      logs: ["[占位] 训练任务已提交，排队中..."],
      estCost: "≈ ¥18（占位）",
      createdAt: now,
      updatedAt: now,
    };
    upsertTrainingTask(t);
    alert("（占位）训练任务已提交。真实训练能力尚未接入。");
    router.push(`/training/${t.id}`);
  };

  const stepLabels = ["选择来源", "训练配置", "数据集校验", "提交确认"];

  return (
    <div className="h-screen flex flex-col">
      <AmbientParticles count={10} />
      <TopNav />

      <main className="flex-1 overflow-y-auto">
        <div className="max-w-3xl mx-auto px-4 md:px-8 py-6 md:py-8">
          {/* 面包屑 */}
          <div className="flex items-center gap-1.5 text-xs text-[var(--text-secondary)] mb-4">
            <Link href="/training" className="hover:text-[var(--accent)] cursor-pointer">
              训练中心
            </Link>
            <span>/</span>
            <span className="text-[var(--text-primary)]">新建训练任务</span>
          </div>

          <div className="flex items-center gap-2 mb-5">
            <h1 className="typo-h1">新建训练任务</h1>
            <span className="phase-chip">Phase 2</span>
          </div>

          {/* Step indicator */}
          <div className="flex items-center justify-between mb-6">
            {stepLabels.map((label, i) => {
              const n = (i + 1) as WizardStep;
              const active = step === n;
              const done = step > n;
              return (
                <div key={label} className="flex-1 flex items-center">
                  <div className="flex items-center gap-2">
                    <div
                      className={`w-6 h-6 rounded-full flex items-center justify-center text-[11px] font-medium
                                  transition-all ${
                                    active
                                      ? "bg-[var(--accent)] text-[var(--bg-primary)]"
                                      : done
                                      ? "bg-[var(--accent)]/20 text-[var(--accent)]"
                                      : "bg-[var(--bg-tertiary)] text-[var(--text-secondary)] border border-[var(--border)]"
                                  }`}
                    >
                      {done ? "✓" : n}
                    </div>
                    <span className={`text-xs hidden md:inline ${active ? "text-[var(--text-primary)] font-medium" : "text-[var(--text-secondary)]"}`}>
                      {label}
                    </span>
                  </div>
                  {i < stepLabels.length - 1 && (
                    <div className={`flex-1 h-[1px] mx-2 ${done ? "bg-[var(--accent)]/40" : "bg-[var(--border)]"}`} />
                  )}
                </div>
              );
            })}
          </div>

          <div className="rounded-xl surface-2 p-5 mb-5">
            {/* Step 1: 选择来源 */}
            {step === 1 && (
              <div className="space-y-4">
                <div>
                  <label className="block typo-micro mb-2" style={{ textTransform: "none" }}>训练类型</label>
                  <div className="flex gap-2">
                    {(["style_lora", "character_lora"] as const).map((t) => (
                      <button
                        key={t}
                        onClick={() => {
                          setType(t);
                          setSourceId("");
                        }}
                        className={`flex-1 px-3 py-2.5 text-sm rounded-lg border cursor-pointer transition-all ${
                          type === t
                            ? "border-[var(--accent)] bg-[var(--accent)]/10 text-[var(--accent)] font-medium"
                            : "border-[var(--border)] text-[var(--text-secondary)] hover:text-[var(--text-primary)]"
                        }`}
                      >
                        {t === "style_lora" ? "风格 LoRA" : "角色 LoRA"}
                      </button>
                    ))}
                  </div>
                </div>

                <div>
                  <label className="block typo-micro mb-2" style={{ textTransform: "none" }}>
                    选择{type === "style_lora" ? "风格集" : "角色卡"}来源
                  </label>
                  {sources.length === 0 ? (
                    <div className="placeholder-card rounded-lg p-6 text-center text-xs text-[var(--text-secondary)]">
                      暂无可用{type === "style_lora" ? "风格集" : "角色卡"}，请先创建
                    </div>
                  ) : (
                    <div className="grid grid-cols-1 md:grid-cols-2 gap-2 max-h-72 overflow-y-auto">
                      {sources.map((s) => (
                        <button
                          key={s.id}
                          onClick={() => setSourceId(s.id)}
                          className={`text-left px-3 py-2.5 rounded-lg border cursor-pointer transition-all ${
                            sourceId === s.id
                              ? "border-[var(--accent)] bg-[var(--accent)]/8"
                              : "border-[var(--border)] hover:border-[var(--accent)]/40"
                          }`}
                        >
                          <div className="text-sm text-[var(--text-primary)] font-medium truncate">{s.name}</div>
                          <div className="text-[10px] text-[var(--text-secondary)] truncate mt-0.5">
                            {s.description || "无描述"}
                          </div>
                        </button>
                      ))}
                    </div>
                  )}
                </div>
              </div>
            )}

            {/* Step 2: 训练配置 */}
            {step === 2 && (
              <div className="space-y-4">
                <div>
                  <label className="block typo-micro mb-2" style={{ textTransform: "none" }}>训练模板</label>
                  <div className="space-y-2">
                    {TEMPLATES.map((tpl) => (
                      <button
                        key={tpl.id}
                        onClick={() => setTemplate(tpl.id)}
                        className={`w-full text-left px-3 py-2.5 rounded-lg border cursor-pointer transition-all ${
                          template === tpl.id
                            ? "border-[var(--accent)] bg-[var(--accent)]/8"
                            : "border-[var(--border)] hover:border-[var(--accent)]/40"
                        }`}
                      >
                        <div className="flex items-center gap-2">
                          <span className="text-sm text-[var(--text-primary)] font-medium">{tpl.name}</span>
                          <span className="phase-chip">P2</span>
                        </div>
                        <div className="text-[10px] text-[var(--text-secondary)] mt-0.5">{tpl.desc}</div>
                      </button>
                    ))}
                  </div>
                </div>

                <div>
                  <label className="block typo-micro mb-2" style={{ textTransform: "none" }}>
                    训练轮次（占位） — 当前示例为模拟配置项
                  </label>
                  <div className="grid grid-cols-3 gap-2">
                    {["快速 (3 epoch)", "标准 (6 epoch)", "深度 (10 epoch)"].map((opt, i) => (
                      <button
                        key={opt}
                        onClick={() => {}}
                        className={`px-2.5 py-2 text-xs rounded-lg border cursor-pointer ${
                          i === 1
                            ? "border-[var(--accent)] bg-[var(--accent)]/8 text-[var(--accent)]"
                            : "border-[var(--border)] text-[var(--text-secondary)]"
                        }`}
                      >
                        {opt}
                      </button>
                    ))}
                  </div>
                </div>
              </div>
            )}

            {/* Step 3: 数据集校验 */}
            {step === 3 && (
              <div className="space-y-4">
                <div>
                  <label className="block typo-micro mb-2" style={{ textTransform: "none" }}>训练集规模（占位）</label>
                  <input
                    type="number"
                    min={1}
                    max={200}
                    value={trainingSetSize}
                    onChange={(e) => setTrainingSetSize(parseInt(e.target.value) || 0)}
                    className="w-full px-3 py-2 text-sm rounded-lg bg-[var(--bg-primary)]
                               border border-[var(--border)] focus:border-[var(--accent)]/40 outline-none"
                  />
                  <p className="text-[10px] text-[var(--text-secondary)] mt-1.5">
                    建议 8–30 张（占位）。当前为模拟值，真实训练集选择待 Phase 2。
                  </p>
                </div>

                <div className="placeholder-card rounded-lg p-3">
                  <div className="flex items-center justify-between mb-2">
                    <span className="typo-strong text-xs">自动校验</span>
                    <span className="text-[10px] text-[var(--accent)]">✓ 通过（占位）</span>
                  </div>
                  <ul className="text-[11px] text-[var(--text-secondary)] space-y-1">
                    <li>· 图片数量：{trainingSetSize} 张（符合建议范围）</li>
                    <li>· 分辨率：多数 ≥ 768px（占位）</li>
                    <li>· 重复检测：未发现重复图（占位）</li>
                    <li>· NSFW 扫描：未检出（占位）</li>
                  </ul>
                </div>
              </div>
            )}

            {/* Step 4: 提交确认 */}
            {step === 4 && (
              <div className="space-y-4">
                <div>
                  <label className="block typo-micro mb-2" style={{ textTransform: "none" }}>任务名称</label>
                  <input
                    value={name}
                    onChange={(e) => setName(e.target.value)}
                    placeholder={defaultName || "请先选择来源"}
                    className="w-full px-3 py-2 text-sm rounded-lg bg-[var(--bg-primary)]
                               border border-[var(--border)] focus:border-[var(--accent)]/40 outline-none"
                  />
                </div>

                <div className="rounded-lg surface-2 p-3 text-xs text-[var(--text-secondary)] space-y-1">
                  <div>类型：<span className="text-[var(--text-primary)]">{type === "style_lora" ? "风格 LoRA" : "角色 LoRA"}</span></div>
                  <div>来源：<span className="text-[var(--text-primary)]">{selectedSource?.name ?? "—"}</span></div>
                  <div>模板：<span className="text-[var(--text-primary)]">{template}</span></div>
                  <div>训练集：<span className="text-[var(--text-primary)]">{trainingSetSize} 张（占位）</span></div>
                  <div>预估成本：<span className="text-[var(--text-primary)]">≈ ¥18（占位）</span></div>
                  <div>预估耗时：<span className="text-[var(--text-primary)]">≈ 20 分钟（占位）</span></div>
                </div>

                <div className="placeholder-card rounded-lg p-3 text-[11px] text-[var(--text-secondary)]">
                  提交后会进入排队队列。该页面所有交互为占位演示，提交不会产生真实训练调用。
                </div>
              </div>
            )}
          </div>

          {/* Nav buttons */}
          <div className="flex items-center justify-between">
            <button
              onClick={() => {
                if (step === 1) router.push("/training");
                else setStep((step - 1) as WizardStep);
              }}
              className="px-3.5 py-2 text-xs rounded-xl border border-[var(--border)]
                         bg-[var(--bg-tertiary)] text-[var(--text-secondary)]
                         hover:text-[var(--text-primary)] cursor-pointer btn-hover-lift transition-all"
            >
              {step === 1 ? "取消" : "上一步"}
            </button>

            {step < 4 ? (
              <button
                onClick={() => canNext && setStep((step + 1) as WizardStep)}
                disabled={!canNext}
                className="px-4 py-2 text-xs rounded-xl font-medium
                           bg-[var(--accent)] text-[var(--bg-primary)]
                           hover:bg-[var(--accent-hover)] disabled:opacity-40 disabled:cursor-not-allowed
                           cursor-pointer btn-hover-lift transition-all"
              >
                下一步
              </button>
            ) : (
              <button
                onClick={handleSubmit}
                className="px-4 py-2 text-xs rounded-xl font-medium
                           bg-[var(--accent)] text-[var(--bg-primary)]
                           hover:bg-[var(--accent-hover)]
                           cursor-pointer btn-hover-lift transition-all"
              >
                提交训练任务
              </button>
            )}
          </div>
        </div>
      </main>
    </div>
  );
}

export default function TrainingWizardPage() {
  return (
    <Suspense fallback={<div className="h-screen" />}>
      <TrainingWizardInner />
    </Suspense>
  );
}