"use client";

import { useCallback, useMemo, useRef } from "react";
import { Handle, Position, type NodeProps, type Node } from "@xyflow/react";
import { useCanvasStore, type WorkspaceNodeData } from "@/store/canvas";
import { showToast } from "@/components/Toaster";
import { Tooltip } from "@/components/Tooltip";
import { STATUS_CONFIG, TIER_CONFIG } from "@/lib/design-tokens";
import { useShallow } from "zustand/react/shallow";

/** Stable selector: returns children, grandchild flag, and descendant count for a node */
function useHierarchyInfo(parentId: string) {
  const childIds = useCanvasStore(
    useCallback((s) => s.nodes.filter((n) => n.data.parentId === parentId).map((n) => n.id).join(","), [parentId])
  );
  const children = useCanvasStore(
    useShallow((s) => s.nodes.filter((n) => n.data.parentId === parentId))
  );
  const hasGrandchildren = useCanvasStore(
    useCallback((s) => {
      const ids = childIds.split(",").filter(Boolean);
      return ids.length > 0 && ids.some((cid) => s.nodes.some((n) => n.data.parentId === cid));
    }, [childIds])
  );
  const descendantCount = useCanvasStore(
    useCallback((s) => countDescendants(parentId, s.nodes), [parentId])
  );
  return { children, hasGrandchildren, descendantCount };
}

/** Eject/extract arrow icon — visually distinct from delete ✕ */
function EjectIcon() {
  return (
    <svg width="10" height="10" viewBox="0 0 10 10" fill="none" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round" strokeLinejoin="round">
      <path d="M3 7L7 3" />
      <path d="M4 3H7V6" />
    </svg>
  );
}

export function WorkspaceNode({ id, data }: NodeProps<Node<WorkspaceNodeData>>) {
  const statusCfg = STATUS_CONFIG[data.status] || STATUS_CONFIG.offline;
  const tierCfg = TIER_CONFIG[data.tier] || { label: `T${data.tier}`, color: "text-zinc-500 bg-zinc-800" };
  const selectedNodeId = useCanvasStore((s) => s.selectedNodeId);
  const selectNode = useCanvasStore((s) => s.selectNode);
  const openContextMenu = useCanvasStore((s) => s.openContextMenu);
  const nestNode = useCanvasStore((s) => s.nestNode);
  const isDragTarget = useCanvasStore((s) => s.dragOverNodeId === id);
  const isSelected = selectedNodeId === id;
  const isOnline = data.status === "online";

  // Get children + hierarchy info (single stable selector avoids redundant re-renders)
  const { children, hasGrandchildren, descendantCount } = useHierarchyInfo(id);
  const hasChildren = children.length > 0;

  const skills = getSkillNames(data.agentCard);

  const handleExtract = useCallback(
    (childId: string) => nestNode(childId, null),
    [nestNode]
  );

  return (
    <div
      role="button"
      tabIndex={0}
      aria-label={`${data.name} workspace — ${data.status}`}
      aria-pressed={isSelected}
      onClick={(e) => {
        e.stopPropagation();
        selectNode(isSelected ? null : id);
      }}
      onDoubleClick={(e) => {
        e.stopPropagation();
        if (hasChildren) {
          window.dispatchEvent(new CustomEvent("molecule:zoom-to-team", { detail: { nodeId: id } }));
        }
      }}
      onContextMenu={(e) => {
        e.preventDefault();
        e.stopPropagation();
        openContextMenu({ x: e.clientX, y: e.clientY, nodeId: id, nodeData: data });
      }}
      onKeyDown={(e) => {
        if (e.key === "Enter" || e.key === " ") {
          e.preventDefault();
          selectNode(isSelected ? null : id);
        } else if (e.key === "ContextMenu") {
          e.preventDefault();
          const rect = (e.currentTarget as HTMLElement).getBoundingClientRect();
          openContextMenu({
            x: rect.left + rect.width / 2,
            y: rect.top + rect.height / 2,
            nodeId: id,
            nodeData: data,
          });
        }
      }}
      className={`
        group relative rounded-xl
        ${hasGrandchildren ? "min-w-[720px] max-w-[960px]" : hasChildren ? "min-w-[320px] max-w-[450px]" : "min-w-[210px] max-w-[280px]"}
        cursor-pointer overflow-hidden
        transition-all duration-200 ease-out
        ${isDragTarget
          ? "bg-emerald-950/40 border-2 border-emerald-400/60 ring-2 ring-emerald-400/20 scale-[1.03]"
          : isSelected
          ? "bg-zinc-900/95 border border-blue-500/70 ring-1 ring-blue-500/30 shadow-lg shadow-blue-500/10"
          : "bg-zinc-900/90 border border-zinc-700/80 hover:border-zinc-500/60 shadow-lg shadow-black/30 hover:shadow-xl hover:shadow-black/40"
        }
        backdrop-blur-sm
        focus:outline-none focus-visible:ring-2 focus-visible:ring-blue-500/70 focus-visible:ring-offset-1 focus-visible:ring-offset-zinc-950
      `}
    >
      {/* Status gradient bar at top */}
      <div className={`absolute inset-x-0 top-0 h-8 bg-gradient-to-b ${statusCfg.bar} pointer-events-none`} />

      <Handle
        type="target"
        position={Position.Top}
        className="!w-2.5 !h-1 !rounded-full !bg-zinc-600/80 !border-0 !-top-0.5 hover:!bg-blue-400 hover:!h-1.5 transition-all"
      />

      <div className="relative px-3.5 py-2.5">
        {/* Header row */}
        <div className="flex items-center justify-between gap-2 mb-1">
          <div className="flex items-center gap-2 min-w-0">
            <div className={`w-2 h-2 rounded-full shrink-0 ${statusCfg.dot} ${statusCfg.glow} shadow-sm`} />
            <span className="text-[13px] font-semibold text-zinc-100 truncate leading-tight">
              {data.name}
            </span>
          </div>
          <div className="flex items-center gap-1.5 shrink-0">
            {hasChildren && (
              <span className="text-[10px] font-mono text-violet-300 bg-violet-900/40 border border-violet-700/30 px-1.5 py-0.5 rounded-md">
                {descendantCount} sub
              </span>
            )}
            <span className={`text-[10px] font-mono px-1.5 py-0.5 rounded-md ${tierCfg.color}`}>
              {tierCfg.label}
            </span>
          </div>
        </div>

        {/* Runtime badge — prefers workspace.runtime (DB column) over
            agent_card.runtime (agent-reported). Phase 30 remote agents
            (runtime='external') get a distinct purple "REMOTE" pill.
            We treat empty-string DB values as "missing" so an unbackfilled
            row falls through to the agent-card value rather than rendering
            a blank pill. */}
        {(() => {
          const dbRuntime = typeof data.runtime === "string" && data.runtime !== ""
            ? data.runtime : null;
          const cardRuntime = data.agentCard && typeof (data.agentCard as Record<string, unknown>).runtime === "string"
            ? (data.agentCard as Record<string, string>).runtime
            : null;
          const runtime = dbRuntime ?? cardRuntime;
          if (!runtime) return null;
          return (
            <div className="mb-1 flex items-center gap-1">
              {runtime === "external" ? (
                <span
                  className="text-[7px] font-mono px-1.5 py-0.5 rounded-md text-violet-200 bg-violet-900/50 border border-violet-500/40"
                  title="Phase 30 remote agent — runs outside this platform's Docker network. Lifecycle managed via heartbeat-based polling, not Docker exec."
                >
                  ★ REMOTE
                </span>
              ) : (
                <span className="text-[7px] font-mono px-1.5 py-0.5 rounded-md text-zinc-400 bg-zinc-800/60 border border-zinc-700/30">
                  {runtime}
                </span>
              )}
            </div>
          );
        })()}

        {/* Role */}
        {data.role && (
          <div className="text-[10px] text-zinc-400 mb-1.5 leading-tight">{data.role}</div>
        )}

        {/* Skills */}
        {skills.length > 0 && (
          <div className="flex flex-wrap gap-1 mb-1.5">
            {skills.slice(0, 4).map((skill) => (
              <span
                key={skill}
                className={`text-[10px] px-1.5 py-0.5 rounded-md border ${
                  isOnline
                    ? "text-emerald-300/80 bg-emerald-950/30 border-emerald-800/30"
                    : "text-zinc-400 bg-zinc-800/60 border-zinc-700/40"
                }`}
              >
                {skill}
              </span>
            ))}
            {skills.length > 4 && (
              <span className="text-[10px] text-zinc-500 self-center">
                +{skills.length - 4}
              </span>
            )}
          </div>
        )}

        {/* Embedded children — rendered INSIDE the parent node */}
        {hasChildren && (
          <EmbeddedTeam members={children} depth={0} onSelect={selectNode} onExtract={handleExtract} />
        )}

        {/* Current task */}
        {data.currentTask && (
          <Tooltip text={String(data.currentTask)}>
            <div className="flex items-center gap-1.5 mt-1 bg-amber-950/20 px-2 py-1 rounded-md border border-amber-800/20 cursor-default">
              <div className="w-1.5 h-1.5 rounded-full bg-amber-400 motion-safe:animate-pulse shrink-0" />
              <span className="text-[10px] text-amber-300/80 truncate">{data.currentTask}</span>
            </div>
          </Tooltip>
        )}

        {/* Needs restart banner */}
        {data.needsRestart && !data.currentTask && (
          <button
            onClick={(e) => {
              e.stopPropagation();
              useCanvasStore.getState().restartWorkspace(id).catch(() => showToast("Restart failed", "error"));
            }}
            className="flex items-center gap-1.5 mt-1 w-full bg-sky-950/30 px-2 py-1 rounded-md border border-sky-800/30 hover:bg-sky-900/40 transition-colors text-left"
          >
            <span className="text-[10px]">↻</span>
            <span className="text-[10px] text-sky-300/80">Restart to apply changes</span>
          </button>
        )}

        {/* Bottom row: status / active tasks */}
        <div className="flex items-center justify-between mt-0.5">
          {data.status !== "online" ? (
            <div className={`text-[10px] uppercase tracking-widest font-medium ${
              data.status === "failed" ? "text-red-400" :
              data.status === "degraded" ? "text-amber-400" :
              data.status === "provisioning" ? "text-sky-400" :
              "text-zinc-500"
            }`}>
              {statusCfg.label}
            </div>
          ) : <div />}

          {data.activeTasks > 0 && (
            <div className="flex items-center gap-1">
              <div className="w-1 h-1 rounded-full bg-amber-400 motion-safe:animate-pulse" />
              <span className="text-[10px] text-amber-300/80 tabular-nums">
                {data.activeTasks} task{data.activeTasks > 1 ? "s" : ""}
              </span>
            </div>
          )}
        </div>

        {/* Degraded error preview */}
        {data.status === "degraded" && data.lastSampleError && (
          <div
            className="text-[10px] text-amber-300/60 truncate mt-1 bg-amber-950/20 px-1.5 py-0.5 rounded border border-amber-800/20"
            title={data.lastSampleError}
          >
            {data.lastSampleError}
          </div>
        )}
      </div>

      <Handle
        type="source"
        position={Position.Bottom}
        className="!w-2.5 !h-1 !rounded-full !bg-zinc-600/80 !border-0 !-bottom-0.5 hover:!bg-blue-400 hover:!h-1.5 transition-all"
      />
    </div>
  );
}

const MAX_NESTING_DEPTH = 3;

/** Count all descendants (children + grandchildren + ...) */
function countDescendants(nodeId: string, allNodes: Node<WorkspaceNodeData>[], visited = new Set<string>()): number {
  if (visited.has(nodeId)) return 0;
  visited.add(nodeId);
  const directChildren = allNodes.filter((n) => n.data.parentId === nodeId);
  let count = directChildren.length;
  for (const child of directChildren) {
    count += countDescendants(child.id, allNodes, visited);
  }
  return count;
}

/** Subscribes to allNodes only when children exist — isolates re-renders from parent */
function EmbeddedTeam({ members, depth, onSelect, onExtract }: {
  members: Node<WorkspaceNodeData>[];
  depth: number;
  onSelect: (id: string) => void;
  onExtract: (id: string) => void;
}) {
  const allNodes = useCanvasStore((s) => s.nodes);
  // Use grid layout at depth 0 when there are multiple members (departments side-by-side)
  const useGrid = depth === 0 && members.length >= 2;
  return (
    <div className="mt-2 pt-2 border-t border-zinc-700/30">
      <div className="text-[10px] text-zinc-500 uppercase tracking-widest mb-1.5">Team Members</div>
      <div className={useGrid
        ? "grid grid-cols-2 gap-1.5 lg:grid-cols-3"
        : "space-y-1.5"
      }>
        {members.map((child) => (
          <TeamMemberChip key={child.id} node={child} allNodes={allNodes} depth={depth} onSelect={onSelect} onExtract={onExtract} />
        ))}
      </div>
    </div>
  );
}

/** Recursive mini-card — mirrors parent card layout at smaller scale */
function TeamMemberChip({
  node,
  allNodes,
  depth,
  onSelect,
  onExtract,
}: {
  node: Node<WorkspaceNodeData>;
  allNodes: Node<WorkspaceNodeData>[];
  depth: number;
  onSelect: (id: string) => void;
  onExtract: (id: string) => void;
}) {
  const { data } = node;
  const statusCfg = STATUS_CONFIG[data.status] || STATUS_CONFIG.offline;
  const tierCfg = TIER_CONFIG[data.tier] || { label: `T${data.tier}`, color: "text-zinc-500 bg-zinc-800" };
  const isOnline = data.status === "online";
  const skills = getSkillNames(data.agentCard);

  const subChildren = useMemo(
    () => allNodes.filter((n) => n.data.parentId === node.id),
    [allNodes, node.id]
  );
  const hasSubChildren = subChildren.length > 0;
  const descendantCount = useMemo(
    () => hasSubChildren ? countDescendants(node.id, allNodes) : 0,
    [allNodes, node.id, hasSubChildren]
  );

  return (
    <div
      className="group/child relative rounded-lg bg-zinc-800/60 hover:bg-zinc-700/70 border border-zinc-700/30 hover:border-zinc-600/40 overflow-hidden transition-colors cursor-pointer"
      onClick={(e) => {
        e.stopPropagation();
        onSelect(node.id);
      }}
      onContextMenu={(e) => {
        e.preventDefault();
        e.stopPropagation();
        useCanvasStore.getState().openContextMenu({ x: e.clientX, y: e.clientY, nodeId: node.id, nodeData: data });
      }}
    >
      {/* Status gradient bar */}
      <div className={`absolute inset-x-0 top-0 h-5 bg-gradient-to-b ${statusCfg.bar} pointer-events-none`} />

      <div className="relative px-2 py-1.5">
        {/* Header: name + badges + extract */}
        <div className="flex items-center justify-between gap-1 mb-0.5">
          <div className="flex items-center gap-1.5 min-w-0">
            <div className={`w-1.5 h-1.5 rounded-full shrink-0 ${statusCfg.dot}`} />
            <span className="text-[10px] font-semibold text-zinc-200 truncate leading-tight">
              {data.name}
            </span>
          </div>
          <div className="flex items-center gap-1 shrink-0">
            {hasSubChildren && (
              <span className="text-[7px] font-mono text-violet-300 bg-violet-900/40 border border-violet-700/30 px-1 py-0.5 rounded">
                {descendantCount}
              </span>
            )}
            <span className={`text-[7px] font-mono px-1 py-0.5 rounded ${tierCfg.color}`}>
              {tierCfg.label}
            </span>
            <button
              onClick={(e) => {
                e.stopPropagation();
                onExtract(node.id);
              }}
              title="Extract from team"
              className="opacity-0 group-hover/child:opacity-100 text-zinc-500 hover:text-sky-400 transition-all"
            >
              <EjectIcon />
            </button>
          </div>
        </div>

        {/* Role */}
        {data.role && (
          <div className="text-[10px] text-zinc-500 mb-1 leading-tight truncate">{data.role}</div>
        )}

        {/* Skills */}
        {skills.length > 0 && (
          <div className="flex flex-wrap gap-0.5 mb-1">
            {skills.slice(0, 3).map((skill) => (
              <span
                key={skill}
                className={`text-[7px] px-1 py-0.5 rounded border ${
                  isOnline
                    ? "text-emerald-300/70 bg-emerald-950/20 border-emerald-800/20"
                    : "text-zinc-500 bg-zinc-800/40 border-zinc-700/30"
                }`}
              >
                {skill}
              </span>
            ))}
            {skills.length > 3 && (
              <span className="text-[7px] text-zinc-500 self-center">+{skills.length - 3}</span>
            )}
          </div>
        )}

        {/* Status + active tasks row */}
        <div className="flex items-center justify-between">
          {data.status !== "online" ? (
            <span className={`text-[9px] uppercase tracking-widest font-medium ${
              data.status === "failed" ? "text-red-400" :
              data.status === "degraded" ? "text-amber-400" :
              data.status === "provisioning" ? "text-sky-400" :
              "text-zinc-500"
            }`}>
              {statusCfg.label}
            </span>
          ) : <div />}
          {data.activeTasks > 0 && (
            <div className="flex items-center gap-0.5">
              <div className="w-1 h-1 rounded-full bg-amber-400 motion-safe:animate-pulse" />
              <span className="text-[9px] text-amber-300/80 tabular-nums">
                {data.activeTasks}
              </span>
            </div>
          )}
        </div>

        {/* Current task banner for sub-agents */}
        {data.currentTask && (
          <Tooltip text={String(data.currentTask)}>
            <div className="flex items-center gap-1 mt-0.5 px-1.5 py-0.5 bg-amber-950/20 rounded border border-amber-800/20 cursor-default">
              <div className="w-1 h-1 rounded-full bg-amber-400 motion-safe:animate-pulse shrink-0" />
              <span className="text-[9px] text-amber-300/70 truncate">{data.currentTask}</span>
            </div>
          </Tooltip>
        )}

        {/* Recursive sub-children rendered inside this card */}
        {hasSubChildren && depth < MAX_NESTING_DEPTH && (
          <div className="mt-1.5 pt-1.5 border-t border-zinc-700/20">
            <div className="text-[7px] text-zinc-600 uppercase tracking-widest mb-1">Team</div>
            <div className={subChildren.length >= 2 ? "grid grid-cols-2 gap-1" : "space-y-1"}>
              {subChildren.map((sub) => (
                <TeamMemberChip key={sub.id} node={sub} allNodes={allNodes} depth={depth + 1} onSelect={onSelect} onExtract={onExtract} />
              ))}
            </div>
          </div>
        )}
      </div>
    </div>
  );
}

function getSkillNames(agentCard: Record<string, unknown> | null): string[] {
  if (!agentCard) return [];
  const skills = agentCard.skills;
  if (!Array.isArray(skills)) return [];
  return skills.map((s: Record<string, unknown>) =>
    String(s.name || s.id || "")
  ).filter(Boolean);
}
