"use client";

import { useState } from "react";
import { ChevronRight, ChevronDown, Circle, CheckCircle2, Clock } from "lucide-react";
import { cn } from "@/lib/utils";

export interface TreeNode {
  id: string;
  label: string;
  status?: "built" | "in_progress" | "missing";
  children?: TreeNode[];
  metadata?: {
    sessionsCount?: number;
    commitsCount?: number;
    cost?: number;
  };
}

interface TreeViewProps {
  data: TreeNode[];
  selectedId?: string | null;
  onSelect?: (node: TreeNode) => void;
  className?: string;
}

interface TreeNodeItemProps {
  node: TreeNode;
  level: number;
  selectedId?: string | null;
  onSelect?: (node: TreeNode) => void;
}

function TreeNodeItem({ node, level, selectedId, onSelect }: TreeNodeItemProps) {
  const [isExpanded, setIsExpanded] = useState(level === 0); // Auto-expand top level
  const hasChildren = node.children && node.children.length > 0;
  const isSelected = selectedId === node.id;

  const getStatusIcon = () => {
    if (!node.status) return null;
    
    switch (node.status) {
      case "built":
        return <CheckCircle2 className="h-3 w-3 text-primary" />;
      case "in_progress":
        return <Clock className="h-3 w-3 text-muted-foreground" />;
      case "missing":
        return <Circle className="h-3 w-3 text-muted-foreground/50" />;
    }
  };

  const getStatusColor = () => {
    if (!node.status) return "";
    
    switch (node.status) {
      case "built":
        return "bg-secondary hover:bg-muted border-l-2 border-l-primary";
      case "in_progress":
        return "bg-muted/40 hover:bg-muted border-l-2 border-l-border";
      case "missing":
        return "hover:bg-muted/30 border-l-2 border-l-transparent";
    }
  };

  return (
    <div>
      <div
        className={cn(
          "flex items-center gap-1.5 py-1.5 px-2 rounded-md cursor-pointer transition-all group",
          isSelected
            ? "bg-primary/10 text-primary font-medium"
            : getStatusColor(),
          level > 0 && "text-sm"
        )}
        style={{ paddingLeft: `${level * 12 + 8}px` }}
        onClick={() => {
          if (hasChildren) {
            setIsExpanded(!isExpanded);
          }
          if (onSelect) {
            onSelect(node);
          }
        }}
      >
        {hasChildren ? (
          <button
            className="hover:bg-muted/50 rounded p-0.5 transition-transform"
            onClick={(e) => {
              e.stopPropagation();
              setIsExpanded(!isExpanded);
            }}
          >
            {isExpanded ? (
              <ChevronDown className="h-3.5 w-3.5 text-muted-foreground" />
            ) : (
              <ChevronRight className="h-3.5 w-3.5 text-muted-foreground" />
            )}
          </button>
        ) : (
          <div className="w-4 flex items-center justify-center">
            {getStatusIcon()}
          </div>
        )}
        
        <span className={cn(
          "flex-1 truncate",
          level === 0 && "font-semibold text-xs uppercase tracking-wide text-muted-foreground",
          level === 1 && "font-medium",
          level > 1 && "text-muted-foreground"
        )}>
          {node.label}
        </span>

        {node.metadata && (
          <div className="flex items-center gap-1.5 opacity-0 group-hover:opacity-100 transition-opacity">
            {node.metadata.sessionsCount && node.metadata.sessionsCount > 0 && (
              <span className="text-[10px] font-medium text-primary bg-primary/10 px-1.5 py-0.5 rounded">
                {node.metadata.sessionsCount}s
              </span>
            )}
            {node.metadata.commitsCount && node.metadata.commitsCount > 0 && (
              <span className="text-[10px] font-medium text-muted-foreground bg-muted px-1.5 py-0.5 rounded">
                {node.metadata.commitsCount}c
              </span>
            )}
          </div>
        )}
      </div>

      {hasChildren && isExpanded && (
        <div className="space-y-0.5">
          {node.children!.map((child) => (
            <TreeNodeItem
              key={child.id}
              node={child}
              level={level + 1}
              selectedId={selectedId}
              onSelect={onSelect}
            />
          ))}
        </div>
      )}
    </div>
  );
}

export function TreeView({ data, selectedId, onSelect, className }: TreeViewProps) {
  return (
    <div className={cn("space-y-0.5", className)}>
      {data.map((node) => (
        <TreeNodeItem
          key={node.id}
          node={node}
          level={0}
          selectedId={selectedId}
          onSelect={onSelect}
        />
      ))}
    </div>
  );
}