"use client";

import { useEffect, useMemo, useState } from "react";
import { CheckSquare, FileJson, GitBranch, Moon, Plus, Square, Sun, Trash2, X } from "lucide-react";
import { Button } from "@/components/ui/Button";
import { Badge } from "@/components/ui/Badge";
import type { TreeSummary } from "@/lib/tree/types";
import { cn } from "@/lib/utils";

interface TreeLibraryRailProps {
  trees: TreeSummary[];
  selectedTreeId: string | null;
  isLoading: boolean;
  isDeleting: boolean;
  darkMode: boolean;
  width: number;
  onResizeStart: (event: React.PointerEvent<HTMLButtonElement>) => void;
  onToggleDarkMode: () => void;
  onCreate: () => void;
  onSelect: (treeId: string) => void;
  onDelete: (treeId: string) => void;
  onBulkDelete: (treeIds: string[]) => void;
  onDeleteAll: () => void;
}

export function TreeLibraryRail({
  trees,
  selectedTreeId,
  isLoading,
  isDeleting,
  darkMode,
  width,
  onResizeStart,
  onToggleDarkMode,
  onCreate,
  onSelect,
  onDelete,
  onBulkDelete,
  onDeleteAll
}: TreeLibraryRailProps) {
  const [bulkDeleteMode, setBulkDeleteMode] = useState(false);
  const [selectedDeleteIds, setSelectedDeleteIds] = useState<Set<string>>(() => new Set());

  useEffect(() => {
    const availableIds = new Set(trees.map((tree) => tree.id));
    setSelectedDeleteIds((current) => {
      const next = new Set([...current].filter((treeId) => availableIds.has(treeId)));
      return next.size === current.size ? current : next;
    });
    if (trees.length === 0) setBulkDeleteMode(false);
  }, [trees]);

  const selectedCount = selectedDeleteIds.size;
  const allSelected = useMemo(
    () => trees.length > 0 && trees.every((tree) => selectedDeleteIds.has(tree.id)),
    [selectedDeleteIds, trees]
  );

  const toggleBulkDeleteMode = () => {
    setBulkDeleteMode((current) => {
      if (current) setSelectedDeleteIds(new Set());
      return !current;
    });
  };

  const toggleDeleteSelection = (treeId: string) => {
    setSelectedDeleteIds((current) => {
      const next = new Set(current);
      if (next.has(treeId)) next.delete(treeId);
      else next.add(treeId);
      return next;
    });
  };

  const toggleSelectAll = () => {
    setSelectedDeleteIds(allSelected ? new Set() : new Set(trees.map((tree) => tree.id)));
  };

  const deleteSelectedTrees = () => {
    const treeIds = [...selectedDeleteIds];
    if (treeIds.length === 0) return;
    if (!window.confirm(`Delete ${treeIds.length} selected saved tree${treeIds.length === 1 ? "" : "s"}?`)) return;
    onBulkDelete(treeIds);
    setSelectedDeleteIds(new Set());
  };

  const deleteEveryTree = () => {
    if (trees.length === 0) return;
    if (!window.confirm(`Delete all ${trees.length} saved trees? This cannot be undone.`)) return;
    onDeleteAll();
    setSelectedDeleteIds(new Set());
    setBulkDeleteMode(false);
  };

  return (
    <aside
      style={{ width, maxWidth: "min(460px, calc(100vw - 56px))" }}
      className="relative z-30 flex h-screen min-w-[240px] shrink-0 flex-col border-r border-paper-300 bg-white/82 shadow-panel backdrop-blur-xl"
    >
      <button
        type="button"
        aria-label="Resize tree library rail"
        onPointerDown={onResizeStart}
        className="absolute -right-1 top-0 z-20 h-full w-2 cursor-col-resize rounded-full transition hover:bg-claude-300/40 focus-visible:bg-claude-300/50 focus-visible:outline-none"
      />
      <div className="flex h-16 items-center justify-between border-b border-paper-300 px-4">
        <div className="flex min-w-0 items-center gap-3">
          <Button
            size="icon"
            variant="ghost"
            onClick={onToggleDarkMode}
            title={darkMode ? "Switch to light mode" : "Switch to dark mode"}
            className="shrink-0"
          >
            {darkMode ? <Sun className="h-4 w-4" /> : <Moon className="h-4 w-4" />}
          </Button>
          <div className="flex h-9 w-9 items-center justify-center rounded-lg bg-claude-500 text-white shadow-panel">
            <GitBranch className="h-4 w-4" />
          </div>
          <div className="min-w-0">
            <p className="text-sm font-semibold text-ink-900">Tree Visualizer</p>
            <p className="text-xs text-ink-500">trajectory saves</p>
          </div>
        </div>
        <Button size="icon" variant="ghost" onClick={onCreate} title="Create tree" className="shrink-0">
          <Plus className="h-4 w-4" />
        </Button>
      </div>

      <div className="border-b border-paper-200 px-4 py-3">
        <div className="flex items-center justify-between gap-2">
          <div className="flex min-w-0 items-center gap-2 text-xs font-semibold uppercase text-ink-500">
            <FileJson className="h-3.5 w-3.5 shrink-0" />
            <span className="truncate">/saves</span>
          </div>
          <Badge status={trees.length ? "valid" : "pending"}>{trees.length} trees</Badge>
        </div>

        <div className="mt-3 flex flex-wrap items-center gap-2">
          <Button
            size="sm"
            variant={bulkDeleteMode ? "primary" : "secondary"}
            onClick={toggleBulkDeleteMode}
            disabled={trees.length === 0 || isDeleting}
            className="min-w-0 flex-1"
          >
            {bulkDeleteMode ? <X className="h-3.5 w-3.5" /> : <CheckSquare className="h-3.5 w-3.5" />}
            {bulkDeleteMode ? "Cancel" : "Bulk Delete"}
          </Button>
          <Button
            size="sm"
            variant="ghost"
            onClick={deleteEveryTree}
            disabled={trees.length === 0 || isDeleting}
            className="min-w-0 flex-1 text-red-600 hover:text-red-700"
          >
            <Trash2 className="h-3.5 w-3.5" />
            Delete All
          </Button>
        </div>

        {bulkDeleteMode && (
          <div className="tree-delete-panel mt-3 rounded-lg p-2">
            <div className="flex items-center justify-between gap-2">
              <button
                type="button"
                onClick={toggleSelectAll}
                className="tree-delete-inline-action inline-flex items-center gap-2 rounded-md px-2 py-1 text-xs font-medium transition"
              >
                {allSelected ? <CheckSquare className="h-3.5 w-3.5" /> : <Square className="h-3.5 w-3.5" />}
                {allSelected ? "Clear all" : "Select all"}
              </button>
              <Button
                size="sm"
                variant="danger"
                onClick={deleteSelectedTrees}
                disabled={selectedCount === 0 || isDeleting}
              >
                <Trash2 className="h-3.5 w-3.5" />
                Delete {selectedCount}
              </Button>
            </div>
          </div>
        )}
      </div>

      <div className="scrollbar-thin flex-1 space-y-2 overflow-auto p-3">
        {isLoading ? (
          <div className="space-y-2">
            {[1, 2, 3].map((item) => (
              <div key={item} className="h-20 animate-pulse rounded-lg border border-paper-200 bg-paper-50" />
            ))}
          </div>
        ) : trees.length === 0 ? (
          <button
            onClick={onCreate}
            className="flex w-full flex-col items-start rounded-lg border border-dashed border-claude-300 bg-claude-50/70 p-4 text-left transition hover:bg-claude-50"
          >
            <span className="text-sm font-semibold text-ink-900">No saved trees</span>
            <span className="mt-1 text-xs leading-5 text-ink-500">Create or import a trajectory trace to populate this rail.</span>
          </button>
        ) : (
          trees.map((tree) => {
            const isMarkedForDelete = selectedDeleteIds.has(tree.id);
            return (
            <div
              key={tree.id}
              className={cn(
                "group rounded-lg border bg-white/76 p-3 transition",
                bulkDeleteMode && "tree-delete-card cursor-pointer",
                !bulkDeleteMode && selectedTreeId === tree.id
                  ? "border-claude-300 shadow-panel"
                  : "border-paper-200 hover:border-claude-200 hover:bg-claude-50/60",
                bulkDeleteMode && isMarkedForDelete && "tree-delete-card-selected shadow-sm"
              )}
            >
              <button
                type="button"
                className="w-full text-left"
                onClick={() => (bulkDeleteMode ? toggleDeleteSelection(tree.id) : onSelect(tree.id))}
              >
                <div className="flex items-start justify-between gap-2">
                  {bulkDeleteMode && (
                    <span className="tree-delete-check mt-0.5 shrink-0">
                      {isMarkedForDelete ? <CheckSquare className="h-4 w-4" /> : <Square className="h-4 w-4" />}
                    </span>
                  )}
                  <div className="min-w-0 flex-1">
                    <p className="truncate text-sm font-semibold text-ink-900">{tree.title}</p>
                    <p className="mt-1 break-all whitespace-normal font-mono text-[11px] leading-4 text-ink-400">{tree.id}</p>
                  </div>
                  <div className="shrink-0">
                    <Badge
                      status={
                        tree.validationStatus === "error"
                          ? "error"
                          : tree.validationStatus === "warning"
                            ? "warning"
                            : "valid"
                      }
                    >
                      {tree.validationStatus}
                    </Badge>
                  </div>
                </div>
                <div className="mt-3 flex items-center justify-between text-xs text-ink-500">
                  <span>{tree.nodeCount} nodes</span>
                  <span>{new Date(tree.updatedAt).toLocaleDateString()}</span>
                </div>
              </button>
              <div className={cn("mt-2 flex justify-end opacity-0 transition group-hover:opacity-100", bulkDeleteMode && "hidden")}>
                <Button
                  size="sm"
                  variant="ghost"
                  onClick={() => onDelete(tree.id)}
                  title="Delete tree"
                  className="text-red-600 hover:text-red-700"
                >
                  <Trash2 className="h-3.5 w-3.5" />
                  Delete
                </Button>
              </div>
            </div>
            );
          })
        )}
      </div>
    </aside>
  );
}