import { memo, useCallback, useEffect, useMemo, useState } from "react";
import { Check, Copy, PanelRightClose, Square } from "lucide-react";
import { Button } from "@/components/ui/button";
import type { CodePreviewPayload } from "@/components/chat/CodePreviewContext";

interface CodePreviewPanelProps {
  code: CodePreviewPayload | null;
  onClose: () => void;
}

export const CodePreviewPanel = memo(function CodePreviewPanel({ code, onClose }: CodePreviewPanelProps) {
  const [copied, setCopied] = useState(false);
  const [viewMode, setViewMode] = useState<"code" | "preview">("code");
  const lines = useMemo(() => code?.code.replace(/\n$/, "").split("\n") ?? [], [code?.code]);
  const canPreview = code?.language === "html";
  const isSubAgent = code?.kind === "subagent";

  const handleCopy = useCallback(() => {
    if (!code) return;
    navigator.clipboard.writeText(code.code).then(() => {
      setCopied(true);
      window.setTimeout(() => setCopied(false), 1600);
    });
  }, [code]);

  // Sync viewMode when code changes
  useEffect(() => {
    if (code?.previewMode) {
      setViewMode(code.previewMode);
    }
  }, [code?.previewMode]);

  return (
    <aside
      className="h-full shrink-0 overflow-hidden border-l transition-[width,opacity,transform] duration-300 ease-out"
      style={{
        width: code ? "min(48vw, 760px)" : 0,
        opacity: code ? 1 : 0,
        transform: code ? "translateX(0)" : "translateX(18px)",
        borderColor: "var(--border-subtle)",
        background: "var(--surface-ground)",
      }}
      aria-hidden={!code}
    >
      <div className="flex h-full w-[min(48vw,760px)] flex-col">
        <div
          className={isSubAgent ? "flex min-h-14 shrink-0 items-center justify-between gap-3 border-b px-4 py-3" : "flex h-12 shrink-0 items-center justify-between gap-3 border-b px-3"}
          style={{ borderColor: "var(--border-subtle)" }}
        >
          <div className="min-w-0">
            <div className={isSubAgent ? "truncate text-sm font-medium" : "truncate text-sm font-medium"} style={{ color: "var(--text-primary)" }}>
              {code?.title || code?.language || "text"}
            </div>
            <div className={isSubAgent ? "mt-0.5 line-clamp-1 text-xs" : "text-xs"} style={{ color: "var(--text-muted)" }}>
              {code?.subtitle || `${code?.lineCount ?? 0} lines`}
            </div>
          </div>
          <div className="flex items-center gap-1">
            {isSubAgent && code?.status && (
              <span
                className="mr-2 rounded-md border px-2 py-1 text-xs"
                style={{
                  borderColor: "var(--border-subtle)",
                  color: "var(--text-muted)",
                  backgroundColor: "var(--surface-elevated)",
                }}
              >
                {code.status === "ok" ? "completed" : code.status}
              </span>
            )}
            {isSubAgent && code?.status === "pending" && (
              <Button variant="ghost" size="sm" onClick={code.onStop}>
                <Square data-icon="inline-start" />
                Stop
              </Button>
            )}
            {canPreview && (
              <div className="flex items-center rounded-md border overflow-hidden mr-2" style={{ borderColor: "var(--border-default)" }}>
                <button
                  onClick={() => setViewMode("code")}
                  className="px-3 py-1 text-xs font-medium transition-colors"
                  style={{
                    backgroundColor: viewMode === "code" ? "var(--accent)" : "transparent",
                    color: viewMode === "code" ? "var(--accent-fg)" : "var(--text-secondary)",
                  }}
                >
                  Code
                </button>
                <button
                  onClick={() => setViewMode("preview")}
                  className="px-3 py-1 text-xs font-medium transition-colors"
                  style={{
                    backgroundColor: viewMode === "preview" ? "var(--accent)" : "transparent",
                    color: viewMode === "preview" ? "var(--accent-fg)" : "var(--text-secondary)",
                  }}
                >
                  Preview
                </button>
              </div>
            )}
            <Button variant="ghost" size="sm" onClick={handleCopy} disabled={!code}>
              {copied ? <Check data-icon="inline-start" /> : <Copy data-icon="inline-start" />}
              {copied ? "Copied" : "Copy"}
            </Button>
            <Button variant="ghost" size="icon-sm" onClick={onClose} aria-label="Close code preview">
              <PanelRightClose />
            </Button>
          </div>
        </div>

        <div className="min-h-0 flex-1 overflow-auto">
          {viewMode === "preview" && canPreview ? (
            <iframe
              title="HTML Preview"
              srcDoc={code?.code ?? ""}
              className="w-full h-full border-0"
              sandbox="allow-scripts"
            />
          ) : (
            <div
              className="grid min-w-max grid-cols-[auto_1fr] text-[13px] leading-[1.65]"
            >
              <div
                className="select-none border-r px-3 py-4 text-right font-mono tabular-nums"
                style={{
                  borderColor: "var(--border-subtle)",
                  color: "var(--text-muted)",
                  backgroundColor: "var(--surface-elevated)",
                }}
                aria-hidden="true"
              >
                {lines.map((_, index) => (
                  <div key={index}>{index + 1}</div>
                ))}
              </div>
              <pre
                className="m-0 min-h-full px-4 py-4 font-mono outline-none"
                style={{
                  color: "var(--text-primary)",
                  backgroundColor: "var(--surface-ground)",
                }}
              >
                <code>{code?.code ?? ""}</code>
              </pre>
            </div>
          )}
        </div>
      </div>
    </aside>
  );
});