import type { ReactElement } from "react";
import { Card, SectionHeader, Badge } from "@mosaic/ui";
import type { RecentActivity } from "@/lib/api/dashboard";

type BadgeVariantType =
  | "badge-amber"
  | "badge-red"
  | "badge-teal"
  | "badge-blue"
  | "badge-muted"
  | "badge-purple"
  | "badge-pulse";

interface ActivityDisplayItem {
  id: string;
  icon: string;
  iconBg: string;
  title: string;
  highlight: string;
  rest: string;
  timestamp: string;
  badge?:
    | {
        text: string;
        variant: BadgeVariantType;
      }
    | undefined;
}

export interface ActivityFeedProps {
  items?: RecentActivity[] | undefined;
}

/* ------------------------------------------------------------------ */
/*  Mapping helpers                                                    */
/* ------------------------------------------------------------------ */

function getIconForAction(action: string): { icon: string; iconBg: string } {
  const lower = action.toLowerCase();
  if (lower.includes("complet") || lower.includes("finish") || lower.includes("success")) {
    return { icon: "\u2713", iconBg: "rgba(20,184,166,0.15)" };
  }
  if (lower.includes("fail") || lower.includes("error")) {
    return { icon: "\u2717", iconBg: "rgba(229,72,77,0.15)" };
  }
  if (lower.includes("warn") || lower.includes("limit")) {
    return { icon: "\u26A0", iconBg: "rgba(245,158,11,0.15)" };
  }
  if (lower.includes("start") || lower.includes("creat")) {
    return { icon: "\u2191", iconBg: "rgba(47,128,255,0.15)" };
  }
  if (lower.includes("update") || lower.includes("modif")) {
    return { icon: "\u21BB", iconBg: "rgba(139,92,246,0.15)" };
  }
  return { icon: "\u2022", iconBg: "rgba(100,116,139,0.15)" };
}

function getBadgeForAction(action: string): ActivityDisplayItem["badge"] {
  const lower = action.toLowerCase();
  if (lower.includes("fail") || lower.includes("error")) {
    return { text: "error", variant: "badge-red" };
  }
  if (lower.includes("warn") || lower.includes("limit")) {
    return { text: "warn", variant: "badge-amber" };
  }
  return undefined;
}

function formatRelativeTime(isoDate: string): string {
  const now = Date.now();
  const then = new Date(isoDate).getTime();
  const diffMs = now - then;

  if (Number.isNaN(diffMs) || diffMs < 0) return "just now";

  const minutes = Math.floor(diffMs / 60_000);
  if (minutes < 1) return "just now";
  if (minutes < 60) return `${String(minutes)}m ago`;

  const hours = Math.floor(minutes / 60);
  if (hours < 24) return `${String(hours)}h ago`;

  const days = Math.floor(hours / 24);
  return `${String(days)}d ago`;
}

function mapActivityToDisplay(activity: RecentActivity): ActivityDisplayItem {
  const { icon, iconBg } = getIconForAction(activity.action);
  return {
    id: activity.id,
    icon,
    iconBg,
    title: "",
    highlight: activity.entityType,
    rest: ` ${activity.action} (${activity.entityId})`,
    timestamp: formatRelativeTime(activity.createdAt),
    badge: getBadgeForAction(activity.action),
  };
}

/* ------------------------------------------------------------------ */
/*  Components                                                         */
/* ------------------------------------------------------------------ */

interface ActivityItemRowProps {
  item: ActivityDisplayItem;
}

function ActivityItemRow({ item }: ActivityItemRowProps): ReactElement {
  return (
    <div
      style={{
        display: "flex",
        alignItems: "flex-start",
        gap: 12,
        padding: "10px 0",
        borderBottom: "1px solid var(--border)",
      }}
    >
      <div
        style={{
          width: 28,
          height: 28,
          borderRadius: 6,
          flexShrink: 0,
          background: item.iconBg,
          display: "flex",
          alignItems: "center",
          justifyContent: "center",
          fontSize: "0.8rem",
          color: "var(--text)",
        }}
      >
        {item.icon}
      </div>
      <div style={{ flex: 1, minWidth: 0 }}>
        <div
          style={{
            fontSize: "0.8rem",
            color: "var(--text-2)",
            lineHeight: 1.4,
          }}
        >
          {item.title}
          <strong style={{ color: "var(--text)" }}>{item.highlight}</strong>
          {item.rest}
          {item.badge !== undefined && (
            <Badge variant={item.badge.variant} style={{ marginLeft: 6 }}>
              {item.badge.text}
            </Badge>
          )}
        </div>
        <div
          style={{
            fontSize: "0.7rem",
            fontFamily: "var(--mono)",
            color: "var(--muted)",
            marginTop: 2,
          }}
        >
          {item.timestamp}
        </div>
      </div>
    </div>
  );
}

export function ActivityFeed({ items }: ActivityFeedProps): ReactElement {
  const displayItems = items ? items.map(mapActivityToDisplay) : [];

  return (
    <Card>
      <SectionHeader title="Activity Feed" subtitle="Recent agent events" />
      <div>
        {displayItems.length > 0 ? (
          displayItems.map((item) => <ActivityItemRow key={item.id} item={item} />)
        ) : (
          <div
            style={{
              padding: "24px 0",
              textAlign: "center",
              fontSize: "0.8rem",
              color: "var(--muted)",
            }}
          >
            No recent activity
          </div>
        )}
      </div>
    </Card>
  );
}