import { useState } from "react";
import { Badge } from "~/components/ui/badge";
import { Card, CardContent, CardHeader, CardTitle } from "~/components/ui/card";
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from "~/components/ui/table";
import { cn } from "~/lib/utils";
import { PlayoffBracket, type Match } from "~/components/scoring/PlayoffBracket";
import { CheckCircle2, XCircle, Clock } from "lucide-react";
import type { Cs2StageResultWithName } from "~/models/cs2-major-stage";
import type { SeasonMatch } from "~/models/season-match";

type StageTab = 1 | 2 | 3 | "champions";

interface Ownership {
  participantId: string;
  teamName: string;
  teamId: string;
  ownerName?: string;
}

interface Cs2MatchRow extends Omit<SeasonMatch, "scheduledAt" | "startedAt" | "completedAt"> {
  scheduledAt: string | null;
  startedAt: string | null;
  completedAt: string | null;
}

interface PlayoffMatchWithRelations extends Match {
  participant1: { id: string; name: string } | null;
  participant2: { id: string; name: string } | null;
  winner: { id: string; name: string } | null;
  loser: { id: string; name: string } | null;
}

interface Props {
  cs2StageResults: Cs2StageResultWithName[];
  seasonMatches: Cs2MatchRow[];
  playoffMatches: PlayoffMatchWithRelations[];
  playoffRounds: string[];
  bracketTemplateId: string | null;
  teamOwnerships: Ownership[];
  userParticipantIds: string[];
}

const STAGE_LABELS: Record<StageTab, string> = {
  1: "Stage 1",
  2: "Stage 2",
  3: "Stage 3",
  champions: "Champions",
};

function SwissStageTab({
  stage,
  stageResults,
  matches,
  teamOwnerships,
  userParticipantIds,
}: {
  stage: 1 | 2 | 3;
  stageResults: Cs2StageResultWithName[];
  matches: Cs2MatchRow[];
  teamOwnerships: Ownership[];
  userParticipantIds: string[];
}) {
  const ownershipMap = new Map(teamOwnerships.map((o) => [o.participantId, o]));
  const userIds = new Set(userParticipantIds);

  const matchesInStage = matches.filter((m) => m.matchStage === stage);

  // Group teams by W-L record (approximated from stageEliminatedWins if eliminated, else unknown)
  const eliminated = stageResults.filter((r) => r.stageEliminated === stage);
  const advanced = stageResults.filter((r) => r.stageEliminated === null && r.stageEntry <= stage);

  if (stageResults.length === 0) {
    return (
      <p className="text-sm text-muted-foreground py-4">No teams assigned to this stage yet.</p>
    );
  }

  return (
    <div className="space-y-4">
      <Table>
        <TableHeader>
          <TableRow>
            <TableHead>Team</TableHead>
            <TableHead>Manager</TableHead>
            <TableHead className="text-right">W</TableHead>
            <TableHead className="text-right">L</TableHead>
            <TableHead>Status</TableHead>
          </TableRow>
        </TableHeader>
        <TableBody>
          {stageResults.map((r) => {
            const ownership = ownershipMap.get(r.participantId);
            const isUser = userIds.has(r.participantId);
            const wins = r.stageEliminated === stage ? (r.stageEliminatedWins ?? "—") : "—";
            const losses = r.stageEliminated === stage ? (3 - (r.stageEliminatedWins ?? 0)) : "—";
            const isElim = r.stageEliminated === stage;
            const isAdvanced = r.stageEliminated === null || (r.stageEliminated !== null && r.stageEliminated > stage);
            return (
              <TableRow
                key={r.participantId}
                className={cn(
                  isUser && "bg-electric/5",
                  isElim && "opacity-50"
                )}
              >
                <TableCell className="font-medium">
                  {r.participantName}
                  {isUser && <span className="ml-1.5 text-xs text-electric">★</span>}
                </TableCell>
                <TableCell className="text-muted-foreground text-sm">
                  {ownership ? ownership.teamName : "—"}
                </TableCell>
                <TableCell className="text-right">{wins}</TableCell>
                <TableCell className="text-right">{losses}</TableCell>
                <TableCell>
                  {isElim ? (
                    <span className="flex items-center gap-1 text-xs text-red-400">
                      <XCircle className="h-3 w-3" /> Eliminated
                    </span>
                  ) : isAdvanced ? (
                    <span className="flex items-center gap-1 text-xs text-emerald-400">
                      <CheckCircle2 className="h-3 w-3" /> Advanced
                    </span>
                  ) : (
                    <span className="flex items-center gap-1 text-xs text-muted-foreground">
                      <Clock className="h-3 w-3" /> In Progress
                    </span>
                  )}
                </TableCell>
              </TableRow>
            );
          })}
        </TableBody>
      </Table>

      {matchesInStage.length > 0 && (
        <div>
          <h3 className="text-sm font-medium text-muted-foreground mb-2">Matches</h3>
          <div className="space-y-1">
            {matchesInStage.map((m) => {
              const p1Name = m.participant1Id
                ? stageResults.find((r) => r.participantId === m.participant1Id)?.participantName ?? m.participant1Id.slice(0, 8)
                : "TBD";
              const p2Name = m.participant2Id
                ? stageResults.find((r) => r.participantId === m.participant2Id)?.participantName ?? m.participant2Id.slice(0, 8)
                : "TBD";
              const dateStr = m.scheduledAt
                ? new Date(m.scheduledAt).toLocaleDateString(undefined, { month: "short", day: "numeric" })
                : null;
              return (
                <div
                  key={m.id}
                  className={cn(
                    "flex items-center justify-between text-sm px-3 py-1.5 rounded-md",
                    m.status === "complete" ? "bg-muted/30" : "bg-muted/10"
                  )}
                >
                  <span className={cn(m.winnerId === m.participant1Id && "font-semibold text-emerald-400")}>{p1Name}</span>
                  <span className="text-xs text-muted-foreground px-2">
                    {m.status === "complete"
                      ? `${m.participant1Score ?? 0}–${m.participant2Score ?? 0}`
                      : dateStr ?? "vs"}
                  </span>
                  <span className={cn("text-right", m.winnerId === m.participant2Id && "font-semibold text-emerald-400")}>{p2Name}</span>
                </div>
              );
            })}
          </div>
        </div>
      )}
    </div>
  );
}

export function Cs2MajorEventView({
  cs2StageResults,
  seasonMatches,
  playoffMatches,
  playoffRounds,
  bracketTemplateId,
  teamOwnerships,
  userParticipantIds,
}: Props) {
  const hasChampionsActivity = playoffMatches.some((m) => m.winnerId !== null);
  const highestActiveStage: 1 | 2 | 3 =
    cs2StageResults.some((r) => r.stageEntry >= 3 || r.stageEliminated === 3) ? 3 :
    cs2StageResults.some((r) => r.stageEntry >= 2 || r.stageEliminated === 2) ? 2 : 1;
  const [activeTab, setActiveTab] = useState<StageTab>(
    hasChampionsActivity ? "champions" : highestActiveStage
  );

  const tabs: StageTab[] = [1, 2, 3, "champions"];
  const ownershipMap = new Map(teamOwnerships.map((o) => [o.participantId, o]));

  return (
    <div className="space-y-4">
      {/* Tab bar */}
      <div className="flex gap-1 rounded-lg bg-muted p-1 w-fit">
        {tabs.map((tab) => (
          <button
            key={tab}
            type="button"
            onClick={() => setActiveTab(tab)}
            className={cn(
              "px-3 py-1.5 text-sm font-medium rounded-md transition-colors",
              activeTab === tab
                ? "bg-background text-foreground shadow-sm"
                : "text-muted-foreground hover:text-foreground"
            )}
          >
            {STAGE_LABELS[tab]}
          </button>
        ))}
      </div>

      {/* Swiss stage tabs */}
      {activeTab !== "champions" && (
        <SwissStageTab
          stage={activeTab as 1 | 2 | 3}
          stageResults={cs2StageResults.filter(
            (r) =>
              r.stageEntry <= (activeTab as number) &&
              (r.stageEliminated === null || r.stageEliminated >= (activeTab as number))
          )}
          matches={seasonMatches}
          teamOwnerships={teamOwnerships}
          userParticipantIds={userParticipantIds}
        />
      )}

      {/* Champions Stage bracket */}
      {activeTab === "champions" && (
        playoffMatches.length > 0 ? (
          <PlayoffBracket
            matches={playoffMatches}
            rounds={playoffRounds}
            bracketTemplateId={bracketTemplateId}
            teamOwnerships={teamOwnerships}
            userParticipantIds={userParticipantIds}
            showOwnership={true}
            title="Champions Stage"
            mode="bracket"
          />
        ) : (
          <Card>
            <CardContent className="py-8 text-center">
              <p className="text-muted-foreground text-sm">
                Champions Stage bracket will be available once Stage 3 is complete.
              </p>
            </CardContent>
          </Card>
        )
      )}
    </div>
  );
}