"use client";

import { ArrowDown, ArrowUp, BookOpen, ChevronLeft, ChevronRight, Crosshair, Pause, Rows3 } from "lucide-react";
import { Button } from "@/components/ui/Button";
import { getTreeNavigationState } from "@/lib/tree/navigation";
import { visibleNodeIdsForStep } from "@/lib/tree/playback";
import type { TrajectoryTree } from "@/lib/tree/types";
import { cn } from "@/lib/utils";

export type CompactNavigatorFocusMode = "node" | "floor";

interface CompactTreeNavigatorProps {
  tree: TrajectoryTree | null;
  revealCount: number;
  selectedNodeId: string | null;
  autoReadEnabled: boolean;
  onNavigate: (nodeId: string, mode: CompactNavigatorFocusMode) => void;
  onToggleAutoRead: () => void;
}

function shortLabel(value: string) {
  const trimmed = value.trim();
  if (trimmed.length <= 46) return trimmed;
  return `${trimmed.slice(0, 43)}...`;
}

export function CompactTreeNavigator({
  tree,
  revealCount,
  selectedNodeId,
  autoReadEnabled,
  onNavigate,
  onToggleAutoRead
}: CompactTreeNavigatorProps) {
  if (!tree || tree.nodes.length === 0) return null;

  const visibleIds = visibleNodeIdsForStep(tree.nodes, revealCount);
  const navigation = getTreeNavigationState(tree.nodes, visibleIds, selectedNodeId);
  const current = navigation.currentNode;
  if (!current) return null;

  const currentFloorPosition = navigation.floors.indexOf(navigation.currentDepth) + 1;
  const totalFloors = navigation.floors.length;

  return (
    <div className="pointer-events-none absolute bottom-5 left-1/2 z-20 w-[min(calc(100%-2rem),900px)] -translate-x-1/2">
      <div className="pointer-events-auto rounded-xl border border-paper-300 bg-white/86 p-2.5 shadow-panel backdrop-blur-xl">
        <div className="flex flex-col gap-2 lg:flex-row lg:items-center">
          <div className="flex min-w-0 flex-1 items-center gap-2">
            <div className="flex items-center gap-1 rounded-lg border border-paper-300 bg-paper-50 p-1">
              <Button
                size="icon"
                variant="ghost"
                disabled={!navigation.previousNode}
                title="View previous node"
                onClick={() => navigation.previousNode && onNavigate(navigation.previousNode.id, "node")}
              >
                <ChevronLeft className="h-4 w-4" />
              </Button>
              <Button
                size="icon"
                variant="ghost"
                disabled={!navigation.nextNode}
                title="View next node"
                onClick={() => navigation.nextNode && onNavigate(navigation.nextNode.id, "node")}
              >
                <ChevronRight className="h-4 w-4" />
              </Button>
            </div>

            <div className="min-w-0 flex-1">
              <div className="flex items-center gap-2">
                <span className="rounded-md bg-claude-500 px-2 py-1 font-mono text-[11px] font-semibold text-white">
                  {current.id}
                </span>
                <span className="truncate text-xs font-semibold text-ink-700">{current.kind}</span>
                <span className="hidden text-xs text-ink-400 sm:inline">
                  {navigation.currentIndex + 1}/{navigation.orderedNodes.length}
                </span>
              </div>
              <div className="mt-1 truncate text-xs text-ink-500">{shortLabel(current.goal || "Untitled node")}</div>
            </div>
          </div>

          <div className="flex flex-wrap items-center gap-2 lg:justify-end">
            <div className="flex items-center gap-1 rounded-lg border border-paper-300 bg-paper-50 p-1">
              <Button
                size="icon"
                variant="ghost"
                disabled={!navigation.previousFloorNode}
                title="View previous floor"
                onClick={() => navigation.previousFloorNode && onNavigate(navigation.previousFloorNode.id, "floor")}
              >
                <ArrowUp className="h-4 w-4" />
              </Button>
              <div className="flex h-9 items-center gap-1 px-2 text-xs font-medium text-ink-600">
                <Rows3 className="h-4 w-4 text-claude-500" />
                {currentFloorPosition}/{totalFloors}
              </div>
              <Button
                size="icon"
                variant="ghost"
                disabled={!navigation.nextFloorNode}
                title="View next floor"
                onClick={() => navigation.nextFloorNode && onNavigate(navigation.nextFloorNode.id, "floor")}
              >
                <ArrowDown className="h-4 w-4" />
              </Button>
            </div>

            <div className="flex items-center gap-1 rounded-lg border border-paper-300 bg-white/82 p-1 shadow-sm">
              <Button
                size="sm"
                variant="ghost"
                title="Recenter current node"
                onClick={() => onNavigate(current.id, "node")}
              >
                <Crosshair className="h-4 w-4" />
                Focus
              </Button>
              <Button
                className="min-w-[104px]"
                size="sm"
                variant={autoReadEnabled ? "primary" : "secondary"}
                title={autoReadEnabled ? "Pause auto read" : "Auto read notes"}
                onClick={onToggleAutoRead}
              >
                {autoReadEnabled ? <Pause className="h-4 w-4" /> : <BookOpen className="h-4 w-4" />}
                {autoReadEnabled ? "Pause" : "Auto read"}
              </Button>
            </div>
          </div>
        </div>

        {navigation.sameFloorNodes.length > 1 && (
          <div className="mt-2 flex items-center gap-2 border-t border-paper-200 pt-2">
            <span className="shrink-0 text-[11px] font-semibold uppercase text-ink-400">Neighbors</span>
            <div className="flex min-w-0 flex-1 gap-1 overflow-x-auto scrollbar-thin">
              {navigation.sameFloorNodes.map((node) => (
                <button
                  key={node.id}
                  type="button"
                  className={cn(
                    "shrink-0 rounded-full border px-2.5 py-1 text-xs font-semibold transition",
                    node.id === current.id
                      ? "border-claude-300 bg-claude-50 text-claude-700"
                      : "border-paper-300 bg-white/70 text-ink-500 hover:border-claude-300 hover:text-claude-700"
                  )}
                  title={node.goal || node.id}
                  onClick={() => onNavigate(node.id, "floor")}
                >
                  {node.id}
                </button>
              ))}
            </div>
          </div>
        )}
      </div>
    </div>
  );
}