import { ListOrdered } from "lucide-react";
import { Link } from "react-router";
import { Button } from "~/components/ui/button";
import { Card, CardContent, CardHeader } from "~/components/ui/card";
import { GradientIcon } from "~/components/ui/GradientIcon";
import { TeamAvatar } from "~/components/TeamAvatar";
import type { AvatarData, RawFlagConfig } from "~/lib/flag-types";
import { StatColumn, StatDivider, DeltaBadge, RankingDisplay } from "./StatHelpers";

/** Mirrors PointsDisplay gating: only project while the team still has participants live. */
function hasProjection(entry: StandingsPreviewEntry): boolean {
  return (
    entry.projectedPoints !== null &&
    entry.projectedPoints !== undefined &&
    entry.participantsRemaining !== undefined &&
    entry.participantsRemaining > 0
  );
}

// ─── Row styles ───────────────────────────────────────────────────────────────

const ROW_RANK_CLASSES: Record<number, string> = {
  1: "bg-yellow-500/10 hover:bg-yellow-500/15",
  2: "bg-white/[0.14] hover:bg-white/[0.18]",
  3: "bg-orange-600/[0.08] hover:bg-orange-600/[0.12]",
};

function rowClasses(currentRank: number | undefined, hasHref: boolean): string {
  const podium = currentRank !== undefined ? ROW_RANK_CLASSES[currentRank] : undefined;
  const base = podium ?? `bg-white/[0.04] ${hasHref ? "hover:bg-white/[0.07]" : ""}`;
  return `flex flex-col sm:flex-row sm:items-center gap-0 rounded-lg px-3 py-3 sm:px-5 sm:py-4 transition-colors ${base}`;
}

// ─── Row content ──────────────────────────────────────────────────────────────

function RowContent({
  entry,
  showProjected,
}: {
  entry: StandingsPreviewEntry;
  showProjected: boolean;
}) {
  // Only reserve the delta line when this row actually changed. A row with no rank
  // or point movement drops the line entirely (no "—" placeholders); rows that moved
  // keep aligned columns by showing "—" for whichever stat didn't change.
  const rowHasChange =
    (entry.rankChange !== undefined && entry.rankChange !== 0) ||
    (entry.pointChange !== undefined && entry.pointChange !== 0);

  return (
    <>
      {/* Left: avatar + name */}
      <div className="flex items-center gap-3 flex-1 min-w-0">
        <TeamAvatar
          teamId={entry.teamId}
          teamName={entry.teamName}
          logoUrl={entry.logoUrl}
          flagConfig={entry.flagConfig}
          avatarType={entry.avatarType}
          ownerAvatarData={entry.ownerAvatarData}
        />
        <div className="min-w-0">
          <p className="font-medium text-sm leading-tight truncate">{entry.teamName}</p>
          {entry.ownerName && (
            <p className="text-xs text-muted-foreground truncate">{entry.ownerName}</p>
          )}
        </div>
      </div>

      {/* Right: stats — second row on mobile */}
      <div className="flex items-center gap-4 w-full border-t border-border/30 pt-2 mt-1 sm:w-auto sm:border-0 sm:pt-0 sm:mt-0 sm:shrink-0">
        <RankingDisplay
          displayRank={entry.displayRank}
          rankChange={entry.rankChange}
          reserveDelta={rowHasChange}
        />
        {showProjected && <StatDivider />}
        {showProjected && (
          <StatColumn
            label="Projected"
            reserveDelta={rowHasChange}
            value={
              hasProjection(entry) ? (
                <span className="text-2xl font-normal leading-none text-muted-foreground">
                  {Math.round(entry.projectedPoints as number).toLocaleString("en-US")}
                </span>
              ) : (
                <span className="text-2xl font-normal leading-none text-muted-foreground/40">
                  —
                </span>
              )
            }
          />
        )}
        <StatDivider />
        <StatColumn
          label="Points"
          reserveDelta={rowHasChange}
          value={
            <span className="text-2xl font-bold leading-none text-electric">
              {Math.round(entry.points).toLocaleString("en-US")}
            </span>
          }
          delta={
            entry.pointChange !== undefined && entry.pointChange !== 0 ? (
              <DeltaBadge delta={entry.pointChange} kind="points" />
            ) : undefined
          }
        />
      </div>
    </>
  );
}

// ─── Public API ───────────────────────────────────────────────────────────────

export interface StandingsPreviewEntry {
  teamId: string;
  teamName: string;
  ownerName?: string | null;
  logoUrl?: string | null;
  flagConfig?: RawFlagConfig | null;
  avatarType?: string | null;
  ownerAvatarData?: AvatarData | null;
  /** Pre-computed display rank. T prefix (if any) is stripped at render time. */
  displayRank: string | number;
  /** Numeric rank used to select the gold/silver/bronze row tint (1–3 only). */
  currentRank?: number;
  points: number;
  href?: string;
  /** Positive = moved up, negative = moved down. From TeamStanding.rankChange. */
  rankChange?: number;
  /** 7-day point delta. From TeamStanding.sevenDayPointChange. */
  pointChange?: number;
  /** Projected final points. From TeamStanding.projectedPoints. */
  projectedPoints?: number | null;
  /** Live participants left; projection only shown while > 0. */
  participantsRemaining?: number;
}

export interface StandingsPreviewProps {
  entries: StandingsPreviewEntry[];
  description?: string;
  fullStandingsHref?: string;
  /** When true, adds a "Projected" column (projected final points). Default false. */
  showProjected?: boolean;
}

export function StandingsPreview({
  entries,
  description,
  fullStandingsHref,
  showProjected = false,
}: StandingsPreviewProps) {
  return (
    <Card className="gap-2">
      <CardHeader className="px-3 sm:px-6 pb-2">
        <div className="flex items-center justify-between">
          <div className="flex items-center gap-2">
            <GradientIcon icon={ListOrdered} className="h-5 w-5 shrink-0" />
            <div>
              <h2 className="text-xl font-bold leading-none tracking-tight">Standings</h2>
              {description && (
                <p className="text-sm text-muted-foreground mt-0.5">{description}</p>
              )}
            </div>
          </div>
          {fullStandingsHref && (
            <Button variant="outline" size="sm" asChild>
              <Link to={fullStandingsHref}>Full Standings</Link>
            </Button>
          )}
        </div>
      </CardHeader>
      <CardContent className="px-3 sm:px-6">
        <div className="space-y-3">
          {entries.map((entry) =>
            entry.href ? (
              <Link
                key={entry.teamId}
                to={entry.href}
                className={rowClasses(entry.currentRank, true)}
              >
                <RowContent entry={entry} showProjected={showProjected} />
              </Link>
            ) : (
              <div key={entry.teamId} className={rowClasses(entry.currentRank, false)}>
                <RowContent entry={entry} showProjected={showProjected} />
              </div>
            )
          )}
        </div>
      </CardContent>
    </Card>
  );
}