"use client";

import { useState } from "react";
import { searchTrials, getTrialIntelligence } from "@/lib/api";
import { Search, MapPin, Calendar, Users, ChevronDown, ChevronUp, FlaskConical, Brain, ExternalLink, Clock, CheckCircle } from "lucide-react";
import { clsx } from "clsx";

const PHASES = ["", "1", "2", "3", "4"];
const PHASE_LABELS: Record<string, string> = { "": "All Phases", "1": "Phase I", "2": "Phase II", "3": "Phase III", "4": "Phase IV" };

const PHASE_COLORS: Record<string, string> = {
  PHASE1: "bg-blue-100 text-blue-700",
  PHASE2: "bg-violet-100 text-violet-700",
  PHASE3: "bg-emerald-100 text-emerald-700",
  PHASE4: "bg-amber-100 text-amber-700",
  "N/A": "bg-slate-100 text-slate-600",
};

function daysAgo(dateStr: string): string {
  if (!dateStr) return "";
  const d = new Date(dateStr);
  if (isNaN(d.getTime())) return "";
  const days = Math.floor((Date.now() - d.getTime()) / 86400000);
  if (days === 0) return "Updated today";
  if (days === 1) return "Updated yesterday";
  if (days < 30) return `Updated ${days}d ago`;
  if (days < 365) return `Updated ${Math.floor(days / 30)}mo ago`;
  return `Updated ${Math.floor(days / 365)}y ago`;
}

export default function TrialFinder() {
  const [condition, setCondition] = useState("");
  const [phase, setPhase] = useState("");
  const [trials, setTrials] = useState<any[]>([]);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState("");
  const [expanded, setExpanded] = useState<string | null>(null);
  const [searched, setSearched] = useState(false);
  const [intelligence, setIntelligence] = useState<Record<string, any>>({});
  const [loadingIntel, setLoadingIntel] = useState<string | null>(null);

  const handleSearch = async () => {
    if (!condition.trim()) return;
    setLoading(true);
    setError("");
    setSearched(true);
    setExpanded(null);
    setIntelligence({});
    try {
      const data = await searchTrials(condition, phase || undefined, 20);
      setTrials(data.trials);
    } catch (e: any) {
      setError(e.message);
      setTrials([]);
    }
    setLoading(false);
  };

  const handleExpand = async (nctId: string) => {
    const next = expanded === nctId ? null : nctId;
    setExpanded(next);
    if (next && !intelligence[next]) {
      setLoadingIntel(next);
      try {
        const intel = await getTrialIntelligence(next);
        setIntelligence((prev) => ({ ...prev, [next]: intel }));
      } catch {}
      setLoadingIntel(null);
    }
  };

  const handleKey = (e: React.KeyboardEvent) => {
    if (e.key === "Enter") handleSearch();
  };

  return (
    <div className="p-6 max-w-5xl mx-auto">
      <div className="mb-8">
        <h1 className="text-2xl font-bold text-slate-900 mb-1">Clinical Trial Finder</h1>
        <p className="text-slate-500 text-sm">Search ClinicalTrials.gov for recruiting studies — powered by real-time data</p>
      </div>

      {/* Search bar */}
      <div className="flex gap-3 mb-6">
        <div className="flex-1 relative">
          <Search className="absolute left-3 top-3 w-4 h-4 text-slate-400" />
          <input
            type="text"
            value={condition}
            onChange={(e) => setCondition(e.target.value)}
            onKeyDown={handleKey}
            placeholder="e.g. breast cancer, NSCLC, Alzheimer's disease..."
            className="w-full pl-9 pr-4 py-2.5 border border-slate-200 rounded-lg text-sm focus:outline-none focus:ring-2 focus:ring-indigo-500 bg-white"
          />
        </div>
        <select
          value={phase}
          onChange={(e) => setPhase(e.target.value)}
          className="border border-slate-200 rounded-lg px-3 py-2.5 text-sm bg-white focus:outline-none focus:ring-2 focus:ring-indigo-500"
        >
          {PHASES.map((p) => <option key={p} value={p}>{PHASE_LABELS[p]}</option>)}
        </select>
        <button
          onClick={handleSearch}
          disabled={loading || !condition.trim()}
          className="bg-indigo-600 text-white px-5 py-2.5 rounded-lg text-sm font-medium hover:bg-indigo-700 disabled:opacity-50 transition-colors"
        >
          {loading ? "Searching..." : "Search"}
        </button>
      </div>

      {error && (
        <div className="bg-red-50 border border-red-200 text-red-700 rounded-lg px-4 py-3 text-sm mb-4">{error}</div>
      )}

      {searched && !loading && trials.length === 0 && !error && (
        <div className="text-center py-12 text-slate-400">
          <FlaskConical className="w-10 h-10 mx-auto mb-3 opacity-40" />
          <p>No trials found. Try a different condition or phase.</p>
        </div>
      )}

      {trials.length > 0 && (
        <div className="space-y-3">
          <div className="flex items-center justify-between">
            <p className="text-sm text-slate-500">{trials.length} trials found for <strong>{condition}</strong></p>
            <div className="flex items-center gap-1.5 text-xs text-slate-400">
              <Clock className="w-3 h-3" />
              Sorted by most recently updated
            </div>
          </div>
          {trials.map((trial) => {
            const isExpanded = expanded === trial.nct_id;
            const phaseKey = trial.phase?.replace("PHASE", "Phase ") || "N/A";
            const recency = daysAgo(trial.last_updated);
            const intel = intelligence[trial.nct_id];
            const isLoadingIntel = loadingIntel === trial.nct_id;
            return (
              <div key={trial.nct_id} className="bg-white rounded-xl border border-slate-200 overflow-hidden">
                <button
                  className="w-full text-left p-5 hover:bg-slate-50 transition-colors"
                  onClick={() => handleExpand(trial.nct_id)}
                >
                  <div className="flex items-start justify-between gap-4">
                    <div className="flex-1 min-w-0">
                      <div className="flex items-center gap-2 flex-wrap mb-1">
                        <span className={clsx("text-xs font-semibold px-2 py-0.5 rounded-full", PHASE_COLORS[trial.phase] || PHASE_COLORS["N/A"])}>
                          {phaseKey}
                        </span>
                        <span className="text-xs text-emerald-600 bg-emerald-50 px-2 py-0.5 rounded-full font-medium">
                          {trial.status}
                        </span>
                        {trial.eligible_patients_in_graph > 0 && (
                          <span className="text-xs text-indigo-600 bg-indigo-50 px-2 py-0.5 rounded-full font-medium flex items-center gap-1">
                            <Brain className="w-3 h-3" />{trial.eligible_patients_in_graph} matched
                          </span>
                        )}
                        {recency && (
                          <span className="text-xs text-slate-400 flex items-center gap-1">
                            <Clock className="w-3 h-3" />{recency}
                          </span>
                        )}
                      </div>
                      <h3 className="font-semibold text-slate-900 text-sm leading-snug">{trial.title}</h3>
                      <p className="text-xs text-slate-500 mt-1">{trial.nct_id} · {trial.sponsor}</p>
                    </div>
                    <div className="flex items-center gap-4 shrink-0 text-xs text-slate-500">
                      <span className="flex items-center gap-1"><MapPin className="w-3 h-3" />{trial.location_count} sites</span>
                      <span className="flex items-center gap-1"><Users className="w-3 h-3" />{trial.enrollment}</span>
                      {isExpanded ? <ChevronUp className="w-4 h-4" /> : <ChevronDown className="w-4 h-4" />}
                    </div>
                  </div>
                </button>

                {isExpanded && (
                  <div className="border-t border-slate-100 px-5 py-4 bg-slate-50 space-y-4">
                    {trial.brief_summary && (
                      <p className="text-sm text-slate-600 leading-relaxed">{trial.brief_summary.slice(0, 500)}{trial.brief_summary.length > 500 ? "…" : ""}</p>
                    )}

                    <div className="grid grid-cols-2 gap-4 text-xs">
                      <div><div className="font-semibold text-slate-700 mb-1">Age Range</div><div className="text-slate-600">{trial.min_age || "18 years"} – {trial.max_age || "No max"}</div></div>
                      <div><div className="font-semibold text-slate-700 mb-1">Sex</div><div className="text-slate-600 capitalize">{trial.sex?.toLowerCase() || "All"}</div></div>
                      <div><div className="font-semibold text-slate-700 mb-1">Start Date</div><div className="text-slate-600">{trial.start_date || "N/A"}</div></div>
                      <div><div className="font-semibold text-slate-700 mb-1">Completion</div><div className="text-slate-600">{trial.completion_date || "N/A"}</div></div>
                    </div>

                    {trial.locations?.length > 0 && (
                      <div>
                        <div className="font-semibold text-xs text-slate-700 mb-1">Sites</div>
                        <div className="flex flex-wrap gap-2">
                          {trial.locations.slice(0, 4).map((loc: any, i: number) => (
                            <span key={i} className="text-xs bg-white border border-slate-200 rounded px-2 py-0.5 text-slate-600">
                              {loc.facility || `${loc.city}, ${loc.state}`}
                            </span>
                          ))}
                          {trial.location_count > 4 && <span className="text-xs text-slate-400">+{trial.location_count - 4} more</span>}
                        </div>
                      </div>
                    )}

                    {trial.primary_outcomes?.length > 0 && (
                      <div>
                        <div className="font-semibold text-xs text-slate-700 mb-1">Primary Outcomes</div>
                        <ul className="text-xs text-slate-600 space-y-0.5">
                          {trial.primary_outcomes.map((o: string, i: number) => <li key={i}>· {o}</li>)}
                        </ul>
                      </div>
                    )}

                    {/* Graph intelligence panel */}
                    <div className="border border-indigo-100 rounded-lg p-3 bg-white">
                      <div className="flex items-center gap-1.5 text-xs font-semibold text-indigo-700 mb-2">
                        <Brain className="w-3.5 h-3.5" />Graph Intelligence
                        {trial.eligible_patients_in_graph === 0 && !intel && (
                          <span className="ml-auto text-slate-400 font-normal">Enriching graph…</span>
                        )}
                      </div>
                      {isLoadingIntel ? (
                        <p className="text-xs text-slate-400">Loading graph data…</p>
                      ) : intel ? (
                        <div className="space-y-2 text-xs">
                          <div className="flex items-center gap-2">
                            <CheckCircle className="w-3.5 h-3.5 text-emerald-500" />
                            <span className="text-slate-700"><strong>{intel.eligible_patients}</strong> patients in graph eligible for this trial</span>
                          </div>
                          {intel.top_biomarkers?.length > 0 && (
                            <div>
                              <div className="text-slate-500 mb-1">Top biomarkers among eligible patients:</div>
                              <div className="flex flex-wrap gap-1.5">
                                {intel.top_biomarkers.map((b: any, i: number) => (
                                  <span key={i} className="bg-indigo-50 text-indigo-700 px-2 py-0.5 rounded text-xs">{b.biomarker} ({b.patient_count})</span>
                                ))}
                              </div>
                            </div>
                          )}
                          {intel.similar_trials?.length > 0 && (
                            <div>
                              <div className="text-slate-500 mb-1">Similar trials (by shared eligible patients):</div>
                              <div className="space-y-1">
                                {intel.similar_trials.map((t: any, i: number) => (
                                  <div key={i} className="flex items-center gap-2">
                                    <span className="font-mono text-slate-500">{t.nct_id}</span>
                                    <span className="text-slate-600 truncate">{t.title?.slice(0, 50)}…</span>
                                    <span className="ml-auto text-indigo-600 shrink-0">{t.shared_patients} shared</span>
                                  </div>
                                ))}
                              </div>
                            </div>
                          )}
                        </div>
                      ) : (
                        <p className="text-xs text-slate-400">Trial not yet in graph — being ingested now.</p>
                      )}
                    </div>

                    <div className="flex items-center justify-between pt-1">
                      <span className="text-xs text-slate-400 flex items-center gap-1">
                        <CheckCircle className="w-3 h-3 text-emerald-400" />
                        Ingested to graph
                      </span>
                      {trial.ctgov_url && (
                        <a href={trial.ctgov_url} target="_blank" rel="noopener noreferrer"
                          className="flex items-center gap-1 text-xs text-indigo-600 hover:text-indigo-800 font-medium">
                          View on ClinicalTrials.gov <ExternalLink className="w-3 h-3" />
                        </a>
                      )}
                    </div>
                  </div>
                )}
              </div>
            );
          })}
        </div>
      )}
    </div>
  );
}