import { type ClassValue, clsx } from "clsx";
import { twMerge } from "tailwind-merge";
import { deriveAgentUrlKey, deriveProjectUrlKey } from "@paperclipai/shared";

export function cn(...inputs: ClassValue[]) {
  return twMerge(clsx(inputs));
}

export function formatCents(cents: number): string {
  return `$${(cents / 100).toFixed(2)}`;
}

export function formatDate(date: Date | string): string {
  return new Date(date).toLocaleDateString("en-US", {
    month: "short",
    day: "numeric",
    year: "numeric",
  });
}

export function formatDateTime(date: Date | string): string {
  return new Date(date).toLocaleString("en-US", {
    month: "short",
    day: "numeric",
    year: "numeric",
    hour: "numeric",
    minute: "2-digit",
  });
}

export function relativeTime(date: Date | string): string {
  const now = Date.now();
  const then = new Date(date).getTime();
  const diffSec = Math.round((now - then) / 1000);
  if (diffSec < 60) return "just now";
  const diffMin = Math.round(diffSec / 60);
  if (diffMin < 60) return `${diffMin}m ago`;
  const diffHr = Math.round(diffMin / 60);
  if (diffHr < 24) return `${diffHr}h ago`;
  const diffDay = Math.round(diffHr / 24);
  if (diffDay < 30) return `${diffDay}d ago`;
  return formatDate(date);
}

export function formatTokens(n: number): string {
  if (n >= 1_000_000) return `${(n / 1_000_000).toFixed(1)}M`;
  if (n >= 1_000) return `${(n / 1_000).toFixed(1)}k`;
  return String(n);
}

/** Build an issue URL using the human-readable identifier when available. */
export function issueUrl(issue: { id: string; identifier?: string | null }): string {
  return `/issues/${issue.identifier ?? issue.id}`;
}

/** Build an agent route URL using the short URL key when available. */
export function agentRouteRef(agent: { id: string; urlKey?: string | null; name?: string | null }): string {
  return agent.urlKey ?? deriveAgentUrlKey(agent.name, agent.id);
}

/** Build an agent URL using the short URL key when available. */
export function agentUrl(agent: { id: string; urlKey?: string | null; name?: string | null }): string {
  return `/agents/${agentRouteRef(agent)}`;
}

/** Build a project route reference using the short URL key when available. */
export function projectRouteRef(project: { id: string; urlKey?: string | null; name?: string | null }): string {
  return project.urlKey ?? deriveProjectUrlKey(project.name, project.id);
}

/** Build a project URL using the short URL key when available. */
export function projectUrl(project: { id: string; urlKey?: string | null; name?: string | null }): string {
  return `/projects/${projectRouteRef(project)}`;
}