import { Form, redirect, useLoaderData, useActionData, useNavigation } from 'react-router';
import type { Route } from './+types/admin.sports-seasons.$id.futures-odds';

import { findSportsSeasonById, updateSportsSeason } from '~/models/sports-season';
import { findParticipantsBySportsSeasonId } from '~/models/participant';
import { getAllParticipantEVsForSeason, batchSaveSourceOdds, batchUpsertParticipantEVs } from '~/models/participant-expected-value';
import { batchUpsertParticipantEvSnapshots } from '~/models/ev-snapshot';
import { getSimulator, type SimulatorType } from '~/services/simulations/registry';
import { calculateEV } from '~/services/ev-calculator';
import { Button } from '~/components/ui/button';
import { Input } from '~/components/ui/input';
import { Label } from '~/components/ui/label';
import { Textarea } from '~/components/ui/textarea';
import {
  Card,
  CardContent,
  CardDescription,
  CardHeader,
  CardTitle,
} from '~/components/ui/card';
import { useState } from 'react';
import { Loader2, Info, CheckCircle2, AlertCircle } from 'lucide-react';

export function meta({ data }: Route.MetaArgs): Route.MetaDescriptors {
  return [{ title: `Futures Odds — ${data?.sportsSeason?.name ?? "Sports Season"} - Brackt Admin` }];
}

export async function loader({ params }: Route.LoaderArgs) {
  const sportsSeasonId = params.id;

  const sportsSeason = await findSportsSeasonById(sportsSeasonId);

  if (!sportsSeason) {
    throw new Response('Sports season not found', { status: 404 });
  }

  const participants = await findParticipantsBySportsSeasonId(sportsSeasonId);
  const existingEVs = await getAllParticipantEVsForSeason(sportsSeasonId);

  // Show any saved odds regardless of what simulation ran afterwards
  const existingOdds = new Map(
    existingEVs
      .filter(ev => ev.sourceOdds !== null)
      .map(ev => [ev.participantId, ev.sourceOdds])
  );

  return {
    sportsSeason,
    participants,
    existingOdds,
  };
}

interface ActionData {
  success?: boolean;
  message?: string;
}

export async function action({ request, params }: Route.ActionArgs) {
  const sportsSeasonId = params.id;
  const formData = await request.formData();

  const sportsSeason = await findSportsSeasonById(sportsSeasonId);

  if (!sportsSeason) {
    return { success: false, message: 'Sports season not found' };
  }

  const participants = await findParticipantsBySportsSeasonId(sportsSeasonId);

  // Parse odds from form
  const futuresOdds: Array<{ participantId: string; odds: number; name: string }> = [];

  for (const participant of participants) {
    const oddsValue = formData.get(`odds_${participant.id}`) as string;
    if (oddsValue && oddsValue.trim() !== '') {
      const odds = Number(oddsValue);
      if (!isNaN(odds)) {
        futuresOdds.push({
          participantId: participant.id,
          odds,
          name: participant.name,
        });
      }
    }
  }

  if (futuresOdds.length === 0) {
    return { success: false, message: 'Please enter odds for at least one participant' };
  }

  if (!sportsSeason.sport?.simulatorType) {
    return { success: false, message: 'This sport has no simulator type configured. Set one on the sport in the admin panel.' };
  }

  if (sportsSeason.simulationStatus === 'running') {
    return { success: false, message: 'A simulation is already running. Please wait.' };
  }

  const scoringRules = {
    pointsFor1st: 100,
    pointsFor2nd: 70,
    pointsFor3rd: 50,
    pointsFor4th: 40,
    pointsFor5th: 25,
    pointsFor6th: 25,
    pointsFor7th: 15,
    pointsFor8th: 15,
  };

  // Persist the odds first so the simulator can read them
  await batchSaveSourceOdds(
    futuresOdds.map(({ participantId, odds }) => ({ participantId, sportsSeasonId, sourceOdds: odds }))
  );

  await updateSportsSeason(sportsSeasonId, { simulationStatus: 'running' });

  try {
    const simulator = getSimulator(sportsSeason.sport.simulatorType as SimulatorType);
    const results = await simulator.simulate(sportsSeasonId);

    if (results.length === 0) {
      throw new Error('Simulation returned no results.');
    }

    await batchUpsertParticipantEVs(
      results.map((r) => ({
        participantId: r.participantId,
        sportsSeasonId,
        probabilities: r.probabilities,
        scoringRules,
        source: 'elo_simulation' as const,
      }))
    );

    const today = new Date().toISOString().slice(0, 10);
    await batchUpsertParticipantEvSnapshots(
      results.map((r) => ({
        participantId: r.participantId,
        sportsSeasonId,
        snapshotDate: today,
        probFirst: r.probabilities.probFirst,
        probSecond: r.probabilities.probSecond,
        probThird: r.probabilities.probThird,
        probFourth: r.probabilities.probFourth,
        probFifth: r.probabilities.probFifth,
        probSixth: r.probabilities.probSixth,
        probSeventh: r.probabilities.probSeventh,
        probEighth: r.probabilities.probEighth,
        calculatedEV: calculateEV(r.probabilities, scoringRules),
        source: r.source,
      }))
    );

    await updateSportsSeason(sportsSeasonId, { simulationStatus: 'idle' });
  } catch (error) {
    await updateSportsSeason(sportsSeasonId, { simulationStatus: 'failed' });
    console.error('Error running simulation:', error);
    return {
      success: false,
      message: error instanceof Error ? error.message : 'Simulation failed',
    };
  }

  return redirect(`/admin/sports-seasons/${sportsSeasonId}/expected-values`);
}

function normalizeName(name: string): string {
  return name.toLowerCase().replace(/[^a-z0-9\s]/g, '').replace(/\s+/g, ' ').trim();
}

export default function AdminSportsSeasonFuturesOdds() {
  const { sportsSeason, participants, existingOdds } = useLoaderData<typeof loader>();
  const actionData = useActionData<ActionData>();
  const navigation = useNavigation();

  // Initialize odds values from existing data
  const [oddsValues, setOddsValues] = useState<Record<string, string>>(() => {
    const initial: Record<string, string> = {};
    participants.forEach(p => {
      const existingOdd = existingOdds.get(p.id);
      if (existingOdd !== undefined && existingOdd !== null) {
        initial[p.id] = existingOdd.toString();
      }
    });
    return initial;
  });

  // Bulk import state
  const [bulkText, setBulkText] = useState('');
  const [parseResults, setParseResults] = useState<{
    matched: Array<{ participantId: string; name: string; odds: number; inputName: string }>;
    unmatched: Array<{ inputName: string; odds: number }>;
  } | null>(null);

  function findParticipantMatch(inputName: string) {
    const normalizedInput = normalizeName(inputName);
    const normalized = participants.map(p => ({ p, n: normalizeName(p.name) }));

    const exact = normalized.find(({ n }) => n === normalizedInput);
    if (exact) return exact.p;

    const contains = normalized.find(({ n }) => n.includes(normalizedInput) || normalizedInput.includes(n));
    if (contains) return contains.p;

    const inputWords = normalizedInput.split(' ').filter(w => w.length > 2);
    const overlap = normalized.find(({ n }) => {
      const pWords = n.split(' ').filter(w => w.length > 2);
      const shared = inputWords.filter(w => pWords.includes(w));
      return shared.length > 0 && shared.length >= Math.min(inputWords.length, pWords.length) * 0.5;
    });

    return overlap?.p ?? null;
  }

  function parseBulkText() {
    const lines = bulkText.split('\n');
    const oddsPattern = /^(.+?)\s+([+-]\d{2,6})\s*$/;

    const matched: Array<{ participantId: string; name: string; odds: number; inputName: string }> = [];
    const unmatched: Array<{ inputName: string; odds: number }> = [];
    const seenParticipants = new Set<string>();

    for (const line of lines) {
      const trimmed = line.trim();
      if (!trimmed || trimmed.length < 3) continue;

      const match = oddsPattern.exec(trimmed);
      if (!match) continue;

      const inputName = match[1].trim();
      const odds = parseInt(match[2], 10);
      if (isNaN(odds)) continue;

      const participant = findParticipantMatch(inputName);
      if (participant && !seenParticipants.has(participant.id)) {
        seenParticipants.add(participant.id);
        matched.push({ participantId: participant.id, name: participant.name, odds, inputName });
      } else if (!participant) {
        unmatched.push({ inputName, odds });
      }
    }

    setParseResults({ matched, unmatched });
  }

  function applyMatches() {
    if (!parseResults) return;
    const newOdds = { ...oddsValues };
    for (const m of parseResults.matched) {
      newOdds[m.participantId] = m.odds.toString();
    }
    setOddsValues(newOdds);
    setParseResults(null);
    setBulkText('');
  }

  const isSubmitting = navigation.state === 'submitting';

  return (
    <div className="container mx-auto py-8">
      <div className="mb-8">
        <h1 className="text-3xl font-bold mb-2">Futures Odds Entry</h1>
        <p className="text-muted-foreground">
          {sportsSeason.sport.name} - {sportsSeason.name}
        </p>
      </div>

      {/* Bulk Import */}
      <Card className="mb-6">
        <CardHeader>
          <CardTitle>Bulk Import</CardTitle>
          <CardDescription>
            Paste odds from FanDuel, DraftKings, OddsChecker, or any site. Each line should end with
            American odds (e.g. <code>Kansas City Chiefs +450</code>). Team names are fuzzy-matched to
            participants.
          </CardDescription>
        </CardHeader>
        <CardContent className="space-y-4">
          <Textarea
            placeholder={`Paste odds here, one team per line:\nKansas City Chiefs +450\nSan Francisco 49ers +600\nBaltimore Ravens +700`}
            value={bulkText}
            onChange={e => { setBulkText(e.target.value); setParseResults(null); }}
            rows={8}
            className="font-mono text-sm"
          />
          <Button type="button" variant="outline" onClick={parseBulkText} disabled={!bulkText.trim()}>
            Parse Odds
          </Button>

          {parseResults && (
            <div className="space-y-3">
              {parseResults.matched.length > 0 && (
                <div>
                  <div className="flex items-center gap-2 text-sm font-medium text-emerald-400 mb-2">
                    <CheckCircle2 className="h-4 w-4" />
                    Matched ({parseResults.matched.length})
                  </div>
                  <div className="rounded-md border border-emerald-500/30 bg-emerald-500/10 divide-y divide-emerald-500/20 text-sm">
                    {parseResults.matched.map(m => (
                      <div key={m.participantId} className="flex justify-between px-3 py-1.5">
                        <span className="text-muted-foreground">{m.inputName}</span>
                        <span className="font-medium">
                          {m.name} &rarr; {m.odds > 0 ? '+' : ''}{m.odds}
                        </span>
                      </div>
                    ))}
                  </div>
                </div>
              )}

              {parseResults.unmatched.length > 0 && (
                <div>
                  <div className="flex items-center gap-2 text-sm font-medium text-amber-700 mb-2">
                    <AlertCircle className="h-4 w-4" />
                    Not matched ({parseResults.unmatched.length}) — enter manually below
                  </div>
                  <div className="rounded-md border border-amber-200 bg-amber-50 divide-y divide-amber-100 text-sm">
                    {parseResults.unmatched.map((u, i) => (
                      <div key={`${u.inputName}-${i}`} className="flex justify-between px-3 py-1.5">
                        <span>{u.inputName}</span>
                        <span className="font-medium">{u.odds > 0 ? '+' : ''}{u.odds}</span>
                      </div>
                    ))}
                  </div>
                </div>
              )}

              {parseResults.matched.length === 0 && parseResults.unmatched.length === 0 && (
                <p className="text-sm text-muted-foreground">No odds found. Make sure each line ends with a value like +450 or -200.</p>
              )}

              {parseResults.matched.length > 0 && (
                <Button type="button" onClick={applyMatches}>
                  Apply {parseResults.matched.length} matched odds to form
                </Button>
              )}
            </div>
          )}
        </CardContent>
      </Card>

      <div className="grid gap-6 lg:grid-cols-2">
        <div>
          <Card>
            <CardHeader>
              <CardTitle>Championship Futures Odds</CardTitle>
              <CardDescription>
                Enter American odds (e.g., +550, -200) for each participant's championship probability.
                Enter American odds, then run the ICM simulation to compute and save probability distributions.
              </CardDescription>
            </CardHeader>
            <CardContent>
              <Form method="post" className="space-y-4">
                <div className="space-y-3">
                  {participants.map((participant) => (
                    <div key={participant.id} className="grid grid-cols-2 gap-4 items-center">
                      <Label htmlFor={`odds_${participant.id}`}>{participant.name}</Label>
                      <Input
                        type="number"
                        id={`odds_${participant.id}`}
                        name={`odds_${participant.id}`}
                        placeholder="+550"
                        value={oddsValues[participant.id] ?? ''}
                        onChange={(e) =>
                          setOddsValues((prev) => ({
                            ...prev,
                            [participant.id]: e.target.value,
                          }))
                        }
                      />
                    </div>
                  ))}
                </div>

                <div className="bg-muted p-4 rounded-lg space-y-2">
                  <div className="flex items-center gap-2 font-medium">
                    <Info className="h-4 w-4" />
                    ICM Calculation
                  </div>
                  <div className="space-y-1 text-sm">
                    <div>Uses Independent Chip Model from poker tournaments</div>
                    <div>Works with any number of participants</div>
                    <div className="text-xs text-muted-foreground mt-2">
                      Every team gets probabilities for 1st-8th place, even longshots.
                    </div>
                  </div>
                </div>

                {actionData && !actionData.success && actionData.message && (
                  <div className="text-sm text-destructive">{actionData.message}</div>
                )}

                <Button type="submit" disabled={isSubmitting}>
                  {isSubmitting && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
                  {isSubmitting ? 'Running...' : 'Run Simulation'}
                </Button>
              </Form>
            </CardContent>
          </Card>

          <Card className="mt-4">
            <CardHeader>
              <CardTitle>How It Works</CardTitle>
            </CardHeader>
            <CardContent className="text-sm space-y-2">
              <ol className="list-decimal list-inside space-y-2">
                <li>Converts American odds to championship win probabilities</li>
                <li>Removes bookmaker vig (normalizes to 100%)</li>
                <li>Uses ICM algorithm to distribute probabilities across all placements</li>
                <li>Generates probability distribution (1st through 8th place) for ALL participants</li>
                <li>Even teams with +100000 odds get non-zero probabilities</li>
              </ol>
            </CardContent>
          </Card>
        </div>
      </div>
    </div>
  );
}