"use client";

import { useRef, useEffect, KeyboardEvent, useState } from "react";
import {
  Plus,
  Mic,
  ArrowUp,
  Box,
  Search,
  Database,
  FileText,
  Code2,
  X,
  Loader2,
  Paperclip,
  RotateCcw,
} from "lucide-react";
import { cn } from "@/lib/utils";
import { uploadAttachment, type AttachmentData } from "@/lib/api";
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from "@/components/ui/select";

interface Tool {
  id: string;
  icon: React.ElementType;
  label: string;
}

interface UploadingFile {
  id: string;
  file: File;
  status: "uploading" | "done" | "error";
  attachment?: AttachmentData;
  error?: string;
}

interface GeminiInputProps {
  value: string;
  onChange: (val: string) => void;
  onSubmit: (attachments?: AttachmentData[]) => void;
  isLoading?: boolean;
  activeTools: Set<string>;
  onActiveToolsChange: (tools: Set<string>) => void;
  selectedModel: "flash" | "auto" | "pro";
  onSelectedModelChange: (model: "flash" | "auto" | "pro") => void;
}

const TOOLS: Tool[] = [
  { id: "search", icon: Search, label: "搜索" },
  { id: "knowledge", icon: Database, label: "内部知识库" },
  { id: "sandbox", icon: Box, label: "沙盒" },
  { id: "document", icon: FileText, label: "文档生成" },
];

export function GeminiInput({
  value,
  onChange,
  onSubmit,
  isLoading,
  activeTools,
  onActiveToolsChange,
  selectedModel,
  onSelectedModelChange,
}: GeminiInputProps) {
  const textareaRef = useRef<HTMLTextAreaElement>(null);
  const fileInputRef = useRef<HTMLInputElement>(null);
  const [showTools, setShowTools] = useState(false);
  const [uploadingFiles, setUploadingFiles] = useState<UploadingFile[]>([]);

  // Auto-resize textarea
  useEffect(() => {
    const ta = textareaRef.current;
    if (!ta) return;
    ta.style.height = "auto";
    ta.style.height = Math.min(ta.scrollHeight, 200) + "px";
  }, [value]);

  const handleKeyDown = (e: KeyboardEvent<HTMLTextAreaElement>) => {
    if (e.key === "Enter" && !e.shiftKey) {
      e.preventDefault();
      if (canSend) handleSubmit();
    }
  };

  const toggleTool = (id: string) => {
    const next = new Set(activeTools);
    if (next.has(id)) {
      next.delete(id);
    } else {
      next.add(id);
    }
    onActiveToolsChange(next);
  };

  const hasUploading = uploadingFiles.some((f) => f.status === "uploading");
  const canSend = value.trim().length > 0 && !isLoading && !hasUploading;

  const handleSubmit = () => {
    const attachments = uploadingFiles
      .filter((f) => f.status === "done" && f.attachment)
      .map((f) => f.attachment!);
    onSubmit(attachments.length > 0 ? attachments : undefined);
    setUploadingFiles([]);
  };

  const doUpload = async (entry: UploadingFile) => {
    try {
      const attachment = await uploadAttachment(entry.file);
      setUploadingFiles((prev) =>
        prev.map((f) =>
          f.id === entry.id ? { ...f, status: "done", attachment } : f
        )
      );
    } catch (err) {
      setUploadingFiles((prev) =>
        prev.map((f) =>
          f.id === entry.id
            ? { ...f, status: "error", error: err instanceof Error ? err.message : "Upload failed" }
            : f
        )
      );
    }
  };

  const handleFileUpload = (e: React.ChangeEvent<HTMLInputElement>) => {
    const files = e.target.files;
    if (!files || files.length === 0) return;

    const newEntries: UploadingFile[] = Array.from(files).map((file) => ({
      id: `upload-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`,
      file,
      status: "uploading" as const,
    }));

    setUploadingFiles((prev) => [...prev, ...newEntries]);

    // Start uploads
    newEntries.forEach((entry) => doUpload(entry));

    // Reset file input so the same file can be selected again
    e.target.value = "";
  };

  const handleRetryUpload = (entry: UploadingFile) => {
    setUploadingFiles((prev) =>
      prev.map((f) =>
        f.id === entry.id ? { ...f, status: "uploading", error: undefined } : f
      )
    );
    doUpload({ ...entry, status: "uploading" });
  };

  const handleRemoveFile = (id: string) => {
    setUploadingFiles((prev) => prev.filter((f) => f.id !== id));
  };

  const formatSize = (bytes: number): string => {
    if (bytes < 1024) return `${bytes} B`;
    if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
    return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
  };

  return (
    <div className="sticky bottom-0 left-0 right-0 pb-6 pt-4 bg-gradient-to-t from-[var(--gem-bg)] via-[var(--gem-bg)]/90 to-transparent pointer-events-none">
      <div className="max-w-3xl mx-auto px-4 pointer-events-auto">
        {/* Input container */}
        <div className="bg-[var(--gem-surface)] border border-[var(--gem-border)] rounded-3xl shadow-lg focus-within:border-[var(--gem-border-hover)] transition-colors duration-150">
          {/* Uploaded files preview */}
          {uploadingFiles.length > 0 && (
            <div className="flex flex-wrap gap-2 px-4 pt-3 pb-1">
              {uploadingFiles.map((entry) => (
                <div
                  key={entry.id}
                  className={cn(
                    "flex items-center gap-2 px-2.5 py-1.5 rounded-lg text-xs border max-w-[220px]",
                    entry.status === "error"
                      ? "bg-red-500/10 border-red-500/30 text-red-400"
                      : "bg-[var(--gem-surface-2)] border-[var(--gem-border)] text-[var(--gem-text-secondary)]"
                  )}
                >
                  {entry.status === "uploading" && (
                    <Loader2 size={14} className="animate-spin flex-shrink-0 text-[var(--gem-blue)]" />
                  )}
                  {entry.status === "done" && (
                    <Paperclip size={14} className="flex-shrink-0 text-[var(--gem-text-muted)]" />
                  )}
                  {entry.status === "error" && (
                    <Paperclip size={14} className="flex-shrink-0" />
                  )}
                  <span className="truncate">
                    {entry.file.name}
                    {entry.status === "done" && entry.attachment && (
                      <span className="text-[var(--gem-text-muted)] ml-1">
                        {formatSize(entry.attachment.size_bytes)}
                      </span>
                    )}
                  </span>
                  {entry.status === "error" && (
                    <button
                      onClick={(e) => { e.stopPropagation(); handleRetryUpload(entry); }}
                      className="flex-shrink-0 hover:opacity-80 cursor-pointer"
                      aria-label="重试上传"
                      title="重试"
                    >
                      <RotateCcw size={12} />
                    </button>
                  )}
                  <button
                    onClick={(e) => { e.stopPropagation(); handleRemoveFile(entry.id); }}
                    className="flex-shrink-0 hover:opacity-80 cursor-pointer text-[var(--gem-text-muted)]"
                    aria-label="移除文件"
                  >
                    <X size={12} />
                  </button>
                </div>
              ))}
            </div>
          )}

          {/* Main input row */}
          <div className="flex items-end gap-2 px-4 py-3">
            {/* Left: File upload button */}
            <button
              onClick={() => fileInputRef.current?.click()}
              className="p-1.5 rounded-full text-[var(--gem-text-muted)] hover:text-[var(--gem-text)] hover:bg-[var(--gem-surface-2)] transition-colors duration-150 flex-shrink-0 cursor-pointer mb-0.5"
              aria-label="文件上传"
              title="上传文件"
            >
              <Plus size={20} />
            </button>
            <input
              ref={fileInputRef}
              type="file"
              multiple
              onChange={handleFileUpload}
              className="hidden"
              aria-label="文件选择"
            />

            {/* Tools toggle */}
            <button
              onClick={() => setShowTools(!showTools)}
              className={cn(
                "p-1.5 rounded-full transition-colors duration-150 flex-shrink-0 cursor-pointer mb-0.5",
                showTools
                  ? "bg-[var(--gem-blue)]/20 text-[var(--gem-blue)]"
                  : "text-[var(--gem-text-muted)] hover:text-[var(--gem-text)] hover:bg-[var(--gem-surface-2)]"
              )}
              aria-label="工具菜单"
              title="工具"
              aria-expanded={showTools}
            >
              <Box size={20} />
            </button>

            {/* Textarea */}
            <textarea
              ref={textareaRef}
              value={value}
              onChange={(e) => onChange(e.target.value)}
              onKeyDown={handleKeyDown}
              placeholder="阐述你的图片"
              rows={1}
              className={cn(
                "flex-1 bg-transparent text-[var(--gem-text)] text-sm placeholder:text-[var(--gem-text-placeholder)] resize-none outline-none",
                "leading-relaxed py-0.5 min-h-[28px] max-h-[200px] overflow-y-auto scrollbar-thin"
              )}
              aria-label="消息输入"
              aria-multiline="true"
            />

            {/* Right controls */}
            <div className="flex items-center gap-1 flex-shrink-0 mb-0.5">
              <button
                className="p-1.5 rounded-full text-[var(--gem-text-muted)] hover:text-[var(--gem-text)] hover:bg-[var(--gem-surface-2)] transition-colors duration-150 cursor-pointer"
                aria-label="语音输入"
              >
                <Mic size={20} />
              </button>
              <button
                onClick={() => canSend && handleSubmit()}
                disabled={!canSend}
                aria-label="发送消息"
                className={cn(
                  "w-9 h-9 rounded-full flex items-center justify-center transition-all duration-150",
                  canSend
                    ? "bg-[var(--gem-blue)] text-white hover:bg-[var(--gem-blue-hover)] cursor-pointer shadow-md"
                    : "bg-[var(--gem-surface-2)] text-[var(--gem-text-placeholder)] cursor-not-allowed"
                )}
              >
                <ArrowUp
                  size={18}
                  className={cn(canSend ? "translate-y-px" : "")}
                />
              </button>
            </div>
          </div>

          {/* Bottom row: Model selector */}
          <div className="flex items-center justify-end px-4 pb-3 pt-0">
            <Select
              value={selectedModel}
              onValueChange={(val) =>
                onSelectedModelChange(val as "flash" | "auto" | "pro")
              }
            >
              <SelectTrigger className="h-7 w-24 rounded-full border border-[var(--gem-border)] bg-[var(--gem-surface-2)] text-[var(--gem-text-muted)] text-xs px-3 py-0 focus:ring-0 focus:ring-offset-0 hover:bg-[var(--gem-surface-3)] hover:text-[var(--gem-text)] transition-colors duration-150 cursor-pointer [&>svg]:opacity-60">
                <SelectValue />
              </SelectTrigger>
              <SelectContent className="bg-[var(--gem-surface)] border-[var(--gem-border)] text-[var(--gem-text)] text-xs rounded-xl min-w-[6rem]">
                <SelectItem value="auto" className="text-xs cursor-pointer focus:bg-[var(--gem-surface-2)]">Auto</SelectItem>
                <SelectItem value="flash" className="text-xs cursor-pointer focus:bg-[var(--gem-surface-2)]">Flash</SelectItem>
                <SelectItem value="pro" className="text-xs cursor-pointer focus:bg-[var(--gem-surface-2)]">Pro</SelectItem>
              </SelectContent>
            </Select>
          </div>

          {/* Tools panel (collapsible, below input) */}
          {showTools && (
            <div className="px-4 pb-3 pt-2 border-t border-[var(--gem-surface-2)]">
              <div className="flex items-center gap-2 flex-wrap">
                {TOOLS.map((tool) => {
                  const Icon = tool.icon;
                  const isActive = activeTools.has(tool.id);
                  return (
                    <button
                      key={tool.id}
                      onClick={() => toggleTool(tool.id)}
                      className={cn(
                        "flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-xs font-medium transition-all duration-150 cursor-pointer whitespace-nowrap",
                        isActive
                          ? "bg-[var(--gem-blue)] text-white border border-[var(--gem-blue)]"
                          : "bg-[var(--gem-surface-2)] text-[var(--gem-text-muted)] border border-transparent hover:bg-[var(--gem-surface-3)] hover:text-[var(--gem-text)]"
                      )}
                      aria-pressed={isActive}
                    >
                      <Icon size={14} />
                      <span>{tool.label}</span>
                    </button>
                  );
                })}
              </div>
            </div>
          )}
        </div>

        {/* Disclaimer */}
        <p className="text-center text-[11px] text-[var(--gem-text-placeholder)] mt-2.5">
          运营大脑可能会出错，请仔细检查其回复。{" "}
          <button className="underline hover:text-[var(--gem-text-muted)] transition-colors cursor-pointer">
            你的隐私与运营大脑应用
          </button>
        </p>
      </div>
    </div>
  );
}