"use client";

import { use, useState } from "react";
import Link from "next/link";
import {
  BarChart,
  Bar,
  XAxis,
  YAxis,
  Tooltip,
  ResponsiveContainer,
  Cell,
} from "recharts";
import { useTripAnalytics, useTrip, useTransactions } from "@/lib/hooks";
import { CreateTripModal } from "@/components/create-trip-modal";
import { formatCategory } from "@/lib/categories";
import { CATEGORY_COLORS, TOOLTIP_STYLE } from "@/lib/category-colors";

function fmtDate(d: string | null) {
  if (!d) return null;
  return new Date(d).toLocaleDateString("en-AU", { day: "2-digit", month: "short", year: "numeric" });
}

function StatCard({
  label,
  value,
  sub,
  color,
}: {
  label: string;
  value: string;
  sub?: string;
  color: string;
}) {
  return (
    <div className="bg-zinc-900 border border-zinc-800 rounded-xl p-5 relative overflow-hidden">
      <div className="absolute top-0 left-0 right-0 h-0.5" style={{ backgroundColor: color }} />
      <p className="text-xs text-zinc-500 mb-1">{label}</p>
      <p className="text-2xl font-semibold tabular-nums">{value}</p>
      {sub && <p className="text-xs text-zinc-600 mt-1 truncate">{sub}</p>}
    </div>
  );
}

function DailyTooltip({ active, payload, label }: { active?: boolean; payload?: { value: number }[]; label?: string }) {
  if (!active || !payload?.length) return null;
  return (
    <div style={TOOLTIP_STYLE} className="p-2.5 text-xs">
      <p className="text-zinc-400 mb-1">
        {label ? new Date(label).toLocaleDateString("en-AU", { day: "2-digit", month: "short", year: "numeric" }) : ""}
      </p>
      <p className="text-zinc-100 font-medium">${Number(payload[0].value).toFixed(2)}</p>
    </div>
  );
}

function CategoryTooltip({ active, payload }: { active?: boolean; payload?: { payload: { category: string }; value: number }[] }) {
  if (!active || !payload?.length) return null;
  return (
    <div style={TOOLTIP_STYLE} className="p-2.5 text-xs">
      <p className="text-zinc-400 mb-1">{formatCategory(payload[0].payload.category)}</p>
      <p className="text-zinc-100 font-medium">${Number(payload[0].value).toFixed(2)}</p>
    </div>
  );
}

export default function TripDetailPage({ params }: { params: Promise<{ id: string }> }) {
  const { id } = use(params);
  const tripId = Number(id);

  const { data: analytics, isLoading } = useTripAnalytics(tripId);
  const { data: trip } = useTrip(tripId);
  const [tab, setTab] = useState<"overview" | "transactions">("overview");
  const [editModal, setEditModal] = useState(false);

  const { data: txData } = useTransactions({ trip_id: id, limit: 500 });

  if (isLoading || !analytics) {
    return (
      <div className="space-y-6">
        <div className="h-32 bg-zinc-900 rounded-2xl animate-pulse" />
        <div className="grid grid-cols-2 sm:grid-cols-4 gap-4">
          {[...Array(4)].map((_, i) => <div key={i} className="h-24 bg-zinc-900 rounded-xl animate-pulse" />)}
        </div>
      </div>
    );
  }

  const { total_spend, transaction_count, num_days, daily_average, category_breakdown, daily_spend, top_merchants, tag_breakdown, participant_splits } = analytics;
  const t = analytics.trip;
  const maxMerchant = top_merchants[0]?.amount ?? 1;

  const dateRange = t.start_date && t.end_date
    ? `${fmtDate(t.start_date)} – ${fmtDate(t.end_date)}`
    : t.start_date
    ? `From ${fmtDate(t.start_date)}`
    : null;

  return (
    <div className="space-y-6">
      {/* Hero */}
      <div
        className="relative rounded-2xl overflow-hidden p-6"
        style={{
          background: `linear-gradient(135deg, ${t.color}28 0%, #18181b 60%)`,
          borderLeft: `3px solid ${t.color}`,
        }}
      >
        <div className="flex items-start justify-between gap-4 flex-wrap">
          <div>
            <div className="flex items-center gap-2 mb-1">
              <Link href="/trips" className="text-xs text-zinc-500 hover:text-zinc-300 transition-colors">
                ← Trips
              </Link>
            </div>
            <h1 className="text-2xl font-bold">{t.name}</h1>
            {dateRange && <p className="text-sm text-zinc-400 mt-1">{dateRange}</p>}
            {t.description && <p className="text-sm text-zinc-500 mt-1">{t.description}</p>}
          </div>
          <button
            onClick={() => setEditModal(true)}
            className="px-3 py-1.5 bg-zinc-800/80 hover:bg-zinc-700 text-zinc-300 rounded-lg text-sm transition-colors flex-shrink-0"
          >
            Edit Trip
          </button>
        </div>
      </div>

      {/* Stat cards */}
      <div className="grid grid-cols-2 sm:grid-cols-4 gap-4">
        <StatCard label="Total Spend" value={`$${Number(total_spend).toFixed(2)}`} sub="all transactions" color={t.color} />
        <StatCard label="Transactions" value={String(transaction_count)} sub="total" color={t.color} />
        <StatCard label="Daily Average" value={`$${Number(daily_average).toFixed(2)}`} sub="per day" color={t.color} />
        <StatCard label="Days" value={String(num_days)} sub={dateRange ?? "date range"} color={t.color} />
      </div>

      {/* Tab bar */}
      <div className="flex gap-0 border-b border-zinc-800">
        {(["overview", "transactions"] as const).map((tabName) => (
          <button
            key={tabName}
            onClick={() => setTab(tabName)}
            className={`px-5 py-2.5 text-sm capitalize transition-colors border-b-2 -mb-px ${
              tab === tabName
                ? "border-current text-white font-medium"
                : "border-transparent text-zinc-500 hover:text-zinc-300"
            }`}
            style={tab === tabName ? { borderColor: t.color } : {}}
          >
            {tabName}
          </button>
        ))}
      </div>

      {tab === "overview" && (
        <div className="space-y-5">
          {/* Daily spend */}
          {daily_spend.length > 0 && (
            <div className="bg-zinc-900 border border-zinc-800 rounded-xl p-5">
              <h3 className="text-sm font-medium mb-4">Daily Spend</h3>
              <ResponsiveContainer width="100%" height={200}>
                <BarChart data={daily_spend} margin={{ top: 4, right: 8, bottom: 0, left: 8 }}>
                  <XAxis
                    dataKey="date"
                    tick={{ fill: "#71717a", fontSize: 11 }}
                    axisLine={false}
                    tickLine={false}
                    tickFormatter={(v) => new Date(v).toLocaleDateString("en-AU", { day: "2-digit", month: "short" })}
                    interval="preserveStartEnd"
                  />
                  <YAxis
                    tick={{ fill: "#71717a", fontSize: 11 }}
                    axisLine={false}
                    tickLine={false}
                    tickFormatter={(v) => `$${v}`}
                    width={52}
                  />
                  <Tooltip content={<DailyTooltip />} cursor={{ fill: "#27272a" }} />
                  <Bar dataKey="amount" fill={t.color} radius={[3, 3, 0, 0]} maxBarSize={40} opacity={0.85} />
                </BarChart>
              </ResponsiveContainer>
            </div>
          )}

          <div className="grid grid-cols-1 lg:grid-cols-2 gap-5">
            {/* Category breakdown */}
            {category_breakdown.length > 0 && (
              <div className="bg-zinc-900 border border-zinc-800 rounded-xl p-5">
                <h3 className="text-sm font-medium mb-4">By Category</h3>
                <ResponsiveContainer width="100%" height={Math.max(120, category_breakdown.length * 32)}>
                  <BarChart
                    data={category_breakdown}
                    layout="vertical"
                    margin={{ top: 0, right: 60, bottom: 0, left: 100 }}
                  >
                    <XAxis type="number" tick={{ fill: "#71717a", fontSize: 11 }} axisLine={false} tickLine={false} tickFormatter={(v) => `$${v}`} />
                    <YAxis
                      type="category"
                      dataKey="category"
                      tick={{ fill: "#a1a1aa", fontSize: 12 }}
                      axisLine={false}
                      tickLine={false}
                      tickFormatter={formatCategory}
                      width={98}
                    />
                    <Tooltip content={<CategoryTooltip />} cursor={{ fill: "#27272a" }} />
                    <Bar dataKey="amount" radius={[0, 3, 3, 0]} maxBarSize={22}>
                      {category_breakdown.map((entry) => (
                        <Cell key={entry.category} fill={CATEGORY_COLORS[entry.category] || "#6366f1"} opacity={0.85} />
                      ))}
                    </Bar>
                  </BarChart>
                </ResponsiveContainer>
              </div>
            )}

            {/* Top merchants */}
            {top_merchants.length > 0 && (
              <div className="bg-zinc-900 border border-zinc-800 rounded-xl p-5">
                <h3 className="text-sm font-medium mb-4">Top Merchants</h3>
                <div className="space-y-3">
                  {top_merchants.map((m, i) => (
                    <div key={m.merchant} className="flex items-center gap-3">
                      <span className="text-xs text-zinc-600 w-4 tabular-nums text-right">{i + 1}</span>
                      <div className="flex-1 min-w-0">
                        <div className="flex items-center justify-between mb-1">
                          <span className="text-sm truncate">{m.merchant || "Unknown"}</span>
                          <span className="text-sm font-mono tabular-nums ml-2 flex-shrink-0">${Number(m.amount).toFixed(2)}</span>
                        </div>
                        <div className="h-1.5 bg-zinc-800 rounded-full overflow-hidden">
                          <div
                            className="h-full rounded-full"
                            style={{
                              width: `${(m.amount / maxMerchant) * 100}%`,
                              backgroundColor: t.color,
                              opacity: 0.7,
                            }}
                          />
                        </div>
                      </div>
                    </div>
                  ))}
                </div>
              </div>
            )}
          </div>

          {/* Tag breakdown */}
          {tag_breakdown.length > 0 && (
            <div className="bg-zinc-900 border border-zinc-800 rounded-xl p-5">
              <h3 className="text-sm font-medium mb-3">By Tag</h3>
              <div className="flex flex-wrap gap-2">
                {tag_breakdown.map((tag) => (
                  <div
                    key={tag.tag_id}
                    className="flex items-center gap-2 px-3 py-2 rounded-lg border border-zinc-800 bg-zinc-800/50"
                  >
                    <span className="w-2.5 h-2.5 rounded-full flex-shrink-0" style={{ backgroundColor: tag.color }} />
                    <span className="text-sm font-medium">{tag.name}</span>
                    <span className="text-xs text-zinc-500">{tag.count} txns</span>
                    <span className="text-sm font-mono tabular-nums text-zinc-300">${Number(tag.amount).toFixed(2)}</span>
                  </div>
                ))}
              </div>
            </div>
          )}

          {/* Participant splits */}
          {participant_splits.length > 0 && (
            <div className="bg-zinc-900 border border-zinc-800 rounded-xl overflow-hidden">
              <div className="px-5 py-3 border-b border-zinc-800 flex items-center justify-between">
                <h3 className="text-sm font-medium">Participant Splits</h3>
                <Link href="/shared" className="text-xs text-zinc-500 hover:text-zinc-300">
                  View in Shared →
                </Link>
              </div>
              <table className="w-full text-sm">
                <thead>
                  <tr className="border-b border-zinc-800">
                    {["Person", "Share of this trip"].map((h) => (
                      <th
                        key={h}
                        className={`px-5 py-2.5 text-xs text-zinc-500 font-medium ${h === "Person" ? "text-left" : "text-right"}`}
                      >
                        {h}
                      </th>
                    ))}
                  </tr>
                </thead>
                <tbody>
                  {participant_splits.map((p) => (
                    <tr key={p.participant_id} className="border-b border-zinc-800/50 last:border-0">
                      <td className="px-5 py-3 font-medium">{p.name}</td>
                      <td className="px-5 py-3 text-right tabular-nums font-mono">${Number(p.owed).toFixed(2)}</td>
                    </tr>
                  ))}
                </tbody>
              </table>
              {/* Settled/unsettled was reported from transaction_splits.settled,
                  which nothing sets — so every trip showed 100% unsettled forever,
                  including ones already paid in full. Settlement is tracked across
                  the whole relationship, not per trip: payments carry no trip
                  attribution, so a per-trip figure cannot be computed. */}
              <p className="px-5 py-2.5 text-xs text-zinc-500 border-t border-zinc-800">
                Settlement is tracked across all shared expenses, not per trip —
                see <Link href="/shared" className="text-zinc-400 hover:text-zinc-200 underline">Shared</Link> for
                what is actually owed.
              </p>
            </div>
          )}

          {category_breakdown.length === 0 && daily_spend.length === 0 && (
            <div className="text-center py-12 text-zinc-600">
              <p className="text-sm">No transactions assigned to this trip yet.</p>
              <Link href="/transactions" className="text-indigo-400 hover:text-indigo-300 text-sm mt-1 inline-block">
                Go to Transactions to assign some →
              </Link>
            </div>
          )}
        </div>
      )}

      {tab === "transactions" && (
        <div>
          {!txData?.data.length ? (
            <div className="text-center py-12 text-zinc-600">
              <p className="text-sm">No transactions assigned to this trip yet.</p>
              <Link href="/transactions" className="text-indigo-400 hover:text-indigo-300 text-sm mt-1 inline-block">
                Go to Transactions to assign some →
              </Link>
            </div>
          ) : (
            <div className="border border-zinc-800 rounded-xl overflow-hidden">
              <table className="w-full text-sm">
                <thead>
                  <tr className="border-b border-zinc-800 bg-zinc-900/60">
                    {["Date", "Description", "Merchant", "Category", "Amount"].map((h) => (
                      <th
                        key={h}
                        className={`px-4 py-2.5 text-xs text-zinc-500 font-medium ${h === "Amount" ? "text-right" : "text-left"}`}
                      >
                        {h}
                      </th>
                    ))}
                  </tr>
                </thead>
                <tbody>
                  {txData.data.map((tx) => (
                    <tr key={tx.id} className="border-b border-zinc-800/40 last:border-0 hover:bg-zinc-900/40 transition-colors">
                      <td className="px-4 py-2.5 text-xs text-zinc-400 whitespace-nowrap">
                        {new Date(tx.transaction_date).toLocaleDateString("en-AU", { day: "2-digit", month: "short" })}
                      </td>
                      <td className="px-4 py-2.5 max-w-xs truncate text-zinc-300">{tx.description}</td>
                      <td className="px-4 py-2.5 text-zinc-400 truncate">{tx.effective_merchant || "—"}</td>
                      <td className="px-4 py-2.5 text-zinc-500 text-xs">{formatCategory(tx.effective_category)}</td>
                      <td className="px-4 py-2.5 text-right tabular-nums font-mono text-red-400">
                        ${Number(tx.amount).toFixed(2)}
                      </td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
          )}
        </div>
      )}

      {editModal && trip && (
        <CreateTripModal trip={trip} onClose={() => setEditModal(false)} />
      )}
    </div>
  );
}