import { useState } from "react";
import { useQuery } from "@tanstack/react-query";
import { useNavigate } from "react-router-dom";
import {
  Loader2,
  AlertCircle,
  Search,
  Users,
  Shield,
  ChevronLeft,
  ChevronRight,
  Globe,
  Target,
  Crosshair,
} from "lucide-react";
import {
  getThreatActors,
  type ThreatActorSummary,
  type ListThreatActorsParams,
} from "../api/threat-actors";

/** Coverage colour based on percentage. */
function coverageColor(pct: number) {
  if (pct >= 80) return "text-green-400";
  if (pct >= 50) return "text-yellow-400";
  if (pct >= 20) return "text-orange-400";
  return "text-red-400";
}

function coverageBg(pct: number) {
  if (pct >= 80) return "bg-green-500";
  if (pct >= 50) return "bg-yellow-500";
  if (pct >= 20) return "bg-orange-500";
  return "bg-red-500";
}

/** Motivation badge colour. */
function motivationColor(m: string | null) {
  switch (m?.toLowerCase()) {
    case "espionage":
      return "border-purple-500/30 bg-purple-900/50 text-purple-400";
    case "financial":
      return "border-yellow-500/30 bg-yellow-900/50 text-yellow-400";
    case "destruction":
      return "border-red-500/30 bg-red-900/50 text-red-400";
    case "hacktivism":
      return "border-cyan-500/30 bg-cyan-900/50 text-cyan-400";
    default:
      return "border-gray-600/30 bg-gray-800/50 text-gray-400";
  }
}

export default function ThreatActorsPage() {
  const navigate = useNavigate();
  const [search, setSearch] = useState("");
  const [motivation, setMotivation] = useState("");
  const [page, setPage] = useState(0);
  const limit = 24;

  const params: ListThreatActorsParams = {
    offset: page * limit,
    limit,
    ...(search ? { search } : {}),
    ...(motivation ? { motivation } : {}),
  };

  const { data, isLoading, error } = useQuery({
    queryKey: ["threat-actors", params],
    queryFn: () => getThreatActors(params),
  });

  const totalPages = data ? Math.ceil(data.total / limit) : 0;

  return (
    <div className="space-y-6">
      {/* Header */}
      <div>
        <h1 className="text-2xl font-bold text-white flex items-center gap-2">
          <Users className="h-7 w-7 text-purple-400" />
          Threat Actors
        </h1>
        <p className="mt-1 text-sm text-gray-400">
          APT groups and threat actor profiles from MITRE ATT&CK with coverage analysis
        </p>
      </div>

      {/* Filters */}
      <div className="flex flex-wrap items-center gap-3">
        {/* Search */}
        <div className="relative flex-1 min-w-[200px] max-w-md">
          <Search className="absolute left-3 top-1/2 h-4 w-4 -translate-y-1/2 text-gray-500" />
          <input
            type="text"
            placeholder="Search actors, aliases..."
            value={search}
            onChange={(e) => { setSearch(e.target.value); setPage(0); }}
            className="w-full rounded-lg border border-gray-700 bg-gray-800 py-2 pl-10 pr-4 text-sm text-gray-300 placeholder-gray-500 focus:border-cyan-500 focus:outline-none"
          />
        </div>

        {/* Motivation filter */}
        <select
          value={motivation}
          onChange={(e) => { setMotivation(e.target.value); setPage(0); }}
          className="rounded-lg border border-gray-700 bg-gray-800 px-3 py-2 text-sm text-gray-300 focus:border-cyan-500 focus:outline-none"
        >
          <option value="">All Motivations</option>
          <option value="espionage">Espionage</option>
          <option value="financial">Financial</option>
          <option value="destruction">Destruction</option>
          <option value="hacktivism">Hacktivism</option>
        </select>
      </div>

      {/* Loading */}
      {isLoading && (
        <div className="flex items-center justify-center py-16">
          <Loader2 className="h-8 w-8 animate-spin text-cyan-400" />
        </div>
      )}

      {/* Error */}
      {error && (
        <div className="rounded-xl border border-red-500/30 bg-red-900/20 p-6 text-center">
          <AlertCircle className="mx-auto h-8 w-8 text-red-400" />
          <p className="mt-2 text-sm text-red-400">
            Failed to load threat actors: {(error as Error)?.message}
          </p>
        </div>
      )}

      {/* Grid */}
      {data && data.items.length > 0 && (
        <>
          <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4">
            {data.items.map((actor: ThreatActorSummary) => (
              <button
                key={actor.id}
                onClick={() => navigate(`/threat-actors/${actor.id}`)}
                className="group rounded-xl border border-gray-800 bg-gray-900 p-5 text-left transition-all hover:border-purple-500/40 hover:bg-gray-900/80"
              >
                {/* Name + ID */}
                <div className="flex items-start justify-between">
                  <div className="min-w-0">
                    <h3 className="truncate text-base font-semibold text-gray-200 group-hover:text-white">
                      {actor.name}
                    </h3>
                    {actor.mitre_id && (
                      <span className="text-xs font-mono text-purple-400">{actor.mitre_id}</span>
                    )}
                  </div>
                  <Crosshair className="h-5 w-5 shrink-0 text-gray-600 group-hover:text-purple-400 transition-colors" />
                </div>

                {/* Country + Motivation */}
                <div className="mt-3 flex flex-wrap items-center gap-2">
                  {actor.country && (
                    <span className="inline-flex items-center gap-1 rounded-full border border-gray-700 bg-gray-800 px-2 py-0.5 text-[11px] text-gray-400">
                      <Globe className="h-3 w-3" />
                      {actor.country}
                    </span>
                  )}
                  {actor.motivation && (
                    <span className={`inline-flex rounded-full border px-2 py-0.5 text-[11px] font-medium ${motivationColor(actor.motivation)}`}>
                      {actor.motivation}
                    </span>
                  )}
                </div>

                {/* Sectors */}
                {actor.target_sectors && actor.target_sectors.length > 0 && (
                  <div className="mt-2 flex items-center gap-1.5">
                    <Target className="h-3 w-3 text-gray-600 shrink-0" />
                    <span className="truncate text-[11px] text-gray-500">
                      {actor.target_sectors.slice(0, 3).join(", ")}
                      {actor.target_sectors.length > 3 && ` +${actor.target_sectors.length - 3}`}
                    </span>
                  </div>
                )}

                {/* Stats */}
                <div className="mt-4 flex items-center justify-between border-t border-gray-800 pt-3">
                  <div className="flex items-center gap-1.5 text-xs text-gray-400">
                    <Shield className="h-3.5 w-3.5" />
                    {actor.technique_count} techniques
                  </div>
                  <div className="flex items-center gap-2">
                    <div className="h-1.5 w-16 overflow-hidden rounded-full bg-gray-800">
                      <div
                        className={`h-full rounded-full ${coverageBg(actor.coverage_pct)}`}
                        style={{ width: `${Math.min(actor.coverage_pct, 100)}%` }}
                      />
                    </div>
                    <span className={`text-xs font-medium ${coverageColor(actor.coverage_pct)}`}>
                      {actor.coverage_pct}%
                    </span>
                  </div>
                </div>
              </button>
            ))}
          </div>

          {/* Pagination */}
          {totalPages > 1 && (
            <div className="flex items-center justify-between">
              <span className="text-sm text-gray-400">
                Showing {page * limit + 1}–{Math.min((page + 1) * limit, data.total)} of{" "}
                {data.total}
              </span>
              <div className="flex items-center gap-2">
                <button
                  onClick={() => setPage(Math.max(0, page - 1))}
                  disabled={page === 0}
                  className="rounded-lg border border-gray-700 bg-gray-800 p-2 text-gray-400 hover:text-white disabled:opacity-40"
                >
                  <ChevronLeft className="h-4 w-4" />
                </button>
                <span className="text-sm text-gray-400">
                  Page {page + 1} of {totalPages}
                </span>
                <button
                  onClick={() => setPage(Math.min(totalPages - 1, page + 1))}
                  disabled={page >= totalPages - 1}
                  className="rounded-lg border border-gray-700 bg-gray-800 p-2 text-gray-400 hover:text-white disabled:opacity-40"
                >
                  <ChevronRight className="h-4 w-4" />
                </button>
              </div>
            </div>
          )}
        </>
      )}

      {/* Empty */}
      {data && data.items.length === 0 && (
        <div className="rounded-xl border border-gray-800 bg-gray-900 p-12 text-center">
          <Users className="mx-auto h-12 w-12 text-gray-600" />
          <h3 className="mt-4 text-lg font-medium text-gray-300">No Threat Actors Found</h3>
          <p className="mt-1 text-sm text-gray-500">
            Import threat actors from MITRE CTI via the Data Sources panel.
          </p>
        </div>
      )}
    </div>
  );
}