import {
  ArrowRight,
  CheckCircle2,
  ChevronRight,
  CreditCard,
  Database,
  FileUp,
  Globe,
  RefreshCw,
  Shield,
  UserPlus,
  Users,
  UsersRound,
} from "lucide-react";
import { useCallback, useEffect, useMemo, useState } from "react";
import {
  listMailGroups,
  listMyDomains,
  listOrgMembers,
  verifyMyDomainDns,
} from "../api";
import { getOrgDetails } from "./CompanyOverviewSetup";
import { formatRelativeTime, parseApiDate } from "../utils/datetime";

const HEALTH_ITEMS = [
  { purpose: "ownership", label: "Domain verified" },
  { purpose: "mx", label: "MX records" },
  { purpose: "spf", label: "SPF" },
  { purpose: "dkim", label: "DKIM" },
  { purpose: "dmarc", label: "DMARC" },
];

function companyTitle(account, details, domainName) {
  if (details?.companyName?.trim()) return details.companyName.trim();
  if (domainName) {
    const base = domainName.split(".")[0];
    return base.charAt(0).toUpperCase() + base.slice(1);
  }
  return `${account.first_name} ${account.last_name}`.trim();
}

function StatCard({ icon: Icon, tone, label, value, detail }) {
  return (
    <article className={`company-overview-stat tone-${tone}`}>
      <span className="company-overview-stat-icon" aria-hidden="true">
        <Icon size={18} />
      </span>
      <div>
        <p>{label}</p>
        <strong>{value}</strong>
        <small>{detail}</small>
      </div>
    </article>
  );
}

export default function CompanyOverview({ account, companyDomain, onNavigate }) {
  const token = sessionStorage.getItem("agmail_access_token");
  const domainName = companyDomain?.domain_name || account.company_domain || "";
  const details = getOrgDetails(account.id);
  const [loading, setLoading] = useState(true);
  const [members, setMembers] = useState({ items: [], counts: {} });
  const [groups, setGroups] = useState({ items: [], counts: {} });
  const [domains, setDomains] = useState([]);
  const [dnsChecks, setDnsChecks] = useState([]);
  const [lastChecked, setLastChecked] = useState(null);
  const [dnsLoading, setDnsLoading] = useState(false);
  const [dnsError, setDnsError] = useState("");

  const loadOverview = useCallback(async () => {
    setLoading(true);
    try {
      const [memberData, groupData, domainData] = await Promise.all([
        listOrgMembers(token),
        listMailGroups(token),
        listMyDomains(token),
      ]);
      setMembers(memberData);
      setGroups(groupData);
      setDomains(domainData);
    } finally {
      setLoading(false);
    }
  }, [token]);

  const loadDnsHealth = useCallback(async () => {
    const primary = domains.find((domain) => domain.domain_name === domainName) || domains[0];
    if (!primary) {
      setDnsChecks([]);
      return;
    }
    setDnsLoading(true);
    setDnsError("");
    try {
      const result = await verifyMyDomainDns(primary.id, token);
      const checkMap = Object.fromEntries(result.checks.map((check) => [check.purpose, check]));
      setDnsChecks(HEALTH_ITEMS.map((item) => ({
        ...item,
        verified: checkMap[item.purpose]?.verified ?? false,
        recommended: item.purpose === "dmarc" && !checkMap[item.purpose]?.verified,
      })));
      setLastChecked(new Date());
      if (result.status !== primary.status) {
        setDomains((current) => current.map((domain) => (
          domain.id === primary.id ? { ...domain, status: result.status } : domain
        )));
      }
    } catch (error) {
      setDnsError(error.message || "Could not verify DNS records.");
    } finally {
      setDnsLoading(false);
    }
  }, [domainName, domains, token]);

  useEffect(() => {
    loadOverview();
  }, [loadOverview]);

  useEffect(() => {
    if (!loading) {
      loadDnsHealth();
    }
  }, [loadDnsHealth, loading]);

  const activity = useMemo(() => {
    const events = [
      ...members.items.map((member) => ({
        id: `member-${member.id}`,
        icon: Users,
        text: `${member.first_name} ${member.last_name} joined the organization`,
        time: member.created_at,
      })),
      ...groups.items.map((group) => ({
        id: `group-${group.id}`,
        icon: UsersRound,
        text: `${group.name} group created`,
        time: group.created_at,
      })),
    ];
    return events
      .sort((left, right) => (parseApiDate(right.time)?.getTime() || 0) - (parseApiDate(left.time)?.getTime() || 0))
      .slice(0, 5);
  }, [groups.items, members.items]);

  const primaryDomain = domains.find((domain) => domain.domain_name === domainName) || domains[0];
  const secondaryCount = Math.max(0, domains.length - 1);
  const distributionCount = groups.items.filter((group) => group.group_type === "distribution").length;
  const dynamicCount = groups.items.filter((group) => group.group_type === "dynamic").length;

  return (
    <section className="company-overview">
      <header className="company-overview-head">
        <div className="company-overview-title">
          <span className="company-overview-logo" aria-hidden="true">
            {companyTitle(account, details, domainName).charAt(0).toUpperCase()}
          </span>
          <div>
            <div className="company-overview-name-row">
              <h1>{companyTitle(account, details, domainName)}</h1>
              <span className="company-overview-badge">Business</span>
            </div>
            <p>Manage your organisation, people and email settings.</p>
          </div>
        </div>
        <button type="button" className="company-overview-subscription" onClick={() => onNavigate?.("Billing")}>
          Manage subscription <ArrowRight size={15} />
        </button>
      </header>

      <div className="company-overview-stats">
        <StatCard
          icon={Users}
          tone="coral"
          label="Total users"
          value={loading ? "—" : members.counts.all ?? members.items.length}
          detail={loading ? "Loading…" : `${members.counts.active ?? 0} active • ${members.counts.invited ?? 0} pending`}
        />
        <StatCard
          icon={UsersRound}
          tone="violet"
          label="Groups"
          value={loading ? "—" : groups.items.length}
          detail={loading ? "Loading…" : `${distributionCount} distribution • ${dynamicCount} dynamic`}
        />
        <StatCard
          icon={Globe}
          tone="green"
          label="Domains"
          value={loading ? "—" : domains.length}
          detail={loading ? "Loading…" : `1 primary • ${secondaryCount} secondary`}
        />
        <StatCard
          icon={Database}
          tone="amber"
          label="Total storage"
          value="—"
          detail="of 100 GB"
        />
      </div>

      <div className="company-overview-grid">
        <section className="company-overview-panel">
          <header className="company-overview-panel-head">
            <h2>Domain health</h2>
          </header>
          {primaryDomain ? (
            <>
              <button
                type="button"
                className="company-overview-domain-row"
                onClick={() => onNavigate?.("Domains")}
              >
                <span>
                  <strong>{primaryDomain.domain_name}</strong>
                  <em>Primary</em>
                </span>
                <ChevronRight size={16} />
              </button>
              <ul className="company-overview-health-list">
                {dnsChecks.map((item) => (
                  <li key={item.purpose}>
                    <span className={`company-overview-health-icon${item.verified ? " ok" : item.recommended ? " warn" : ""}`}>
                      <CheckCircle2 size={15} />
                    </span>
                    <span>{item.label}</span>
                    {item.recommended && !item.verified && (
                      <em className="company-overview-health-badge">Recommended</em>
                    )}
                  </li>
                ))}
              </ul>
              <footer className="company-overview-panel-footer">
                <span>
                  {dnsError
                    ? dnsError
                    : lastChecked
                      ? `Last checked ${formatRelativeTime(lastChecked, { compact: true })}`
                      : "Not checked yet"}
                </span>
                <button type="button" onClick={loadDnsHealth} disabled={dnsLoading || !primaryDomain}>
                  <RefreshCw size={14} className={dnsLoading ? "spinning" : ""} />
                  {dnsLoading ? "Checking…" : "Recheck"}
                </button>
              </footer>
            </>
          ) : (
            <p className="company-overview-empty">No domains configured yet.</p>
          )}
        </section>

        <section className="company-overview-panel">
          <header className="company-overview-panel-head">
            <h2>Recent activity</h2>
          </header>
          {activity.length === 0 ? (
            <p className="company-overview-empty">No recent activity yet.</p>
          ) : (
            <ul className="company-overview-activity">
              {activity.map((item) => {
                const Icon = item.icon;
                return (
                  <li key={item.id}>
                    <span className="company-overview-activity-icon" aria-hidden="true">
                      <Icon size={15} />
                    </span>
                    <div>
                      <p>{item.text}</p>
                      <time>{formatRelativeTime(item.time, { compact: true })}</time>
                    </div>
                  </li>
                );
              })}
            </ul>
          )}
        </section>

        <section className="company-overview-panel">
          <header className="company-overview-panel-head">
            <h2>Admin shortcuts</h2>
          </header>
          <ul className="company-overview-shortcuts">
            <li>
              <button type="button" onClick={() => onNavigate?.("People")}>
                <UserPlus size={16} /> Add user
              </button>
            </li>
            <li>
              <button
                type="button"
                onClick={() => {
                  sessionStorage.setItem("agmail_open_people_import", "1");
                  onNavigate?.("People");
                }}
              >
                <FileUp size={16} /> Invite users via CSV
              </button>
            </li>
            <li>
              <button type="button" onClick={() => onNavigate?.("Groups")}>
                <UsersRound size={16} /> Create group
              </button>
            </li>
            <li>
              <button type="button" onClick={() => onNavigate?.("Security")}>
                <Shield size={16} /> Security settings
              </button>
            </li>
            <li>
              <button type="button" onClick={() => onNavigate?.("Billing")}>
                <CreditCard size={16} /> Manage billing
              </button>
            </li>
          </ul>
        </section>
      </div>
    </section>
  );
}