import { createFileRoute } from "@tanstack/react-router";
import { useEffect, useState } from "react";
import { supabase } from "@/integrations/supabase/client";
import { useAuth } from "@/lib/auth";
import { Button } from "@/components/ui/button";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";
import { Textarea } from "@/components/ui/textarea";
import { Switch } from "@/components/ui/switch";
import { Loader2, Inbox, KeyRound, RefreshCcw } from "lucide-react";
import { toast } from "sonner";

export const Route = createFileRoute("/settings/imap")({
  component: ImapSettingsPage,
});

const EMPTY = {
  host: "",
  port: "993",
  secure: true,
  username: "",
  folder: "INBOX",
  enabled: true,
  notes: "",
};

function ImapSettingsPage() {
  const { user, isAdmin } = useAuth();
  const [loading, setLoading] = useState(true);
  const [saving, setSaving] = useState(false);
  const [polling, setPolling] = useState(false);
  const [recordId, setRecordId] = useState<string | null>(null);
  const [form, setForm] = useState({ ...EMPTY });
  const [meta, setMeta] = useState<{
    last_polled_at: string | null;
    last_uid: number | null;
    last_error: string | null;
  }>({ last_polled_at: null, last_uid: null, last_error: null });

  const load = async () => {
    setLoading(true);
    const { data } = await supabase
      .from("imap_settings")
      .select("*")
      .order("updated_at", { ascending: false })
      .limit(1)
      .maybeSingle();
    if (data) {
      setRecordId(data.id);
      setForm({
        host: data.host ?? "",
        port: String(data.port ?? 993),
        secure: !!data.secure,
        username: data.username ?? "",
        folder: data.folder ?? "INBOX",
        enabled: data.enabled ?? true,
        notes: data.notes ?? "",
      });
      setMeta({
        last_polled_at: data.last_polled_at,
        last_uid: data.last_uid,
        last_error: data.last_error,
      });
    }
    setLoading(false);
  };

  useEffect(() => {
    if (isAdmin) load();
    else setLoading(false);
  }, [isAdmin]);

  const update = (k: keyof typeof EMPTY, v: string | boolean) =>
    setForm((f) => ({ ...f, [k]: v }));

  const save = async () => {
    if (!form.host || !form.username) {
      toast.error("Host and username are required");
      return;
    }
    setSaving(true);
    const payload = {
      host: form.host.trim(),
      port: parseInt(form.port, 10) || 993,
      secure: form.secure,
      username: form.username.trim(),
      folder: form.folder.trim() || "INBOX",
      enabled: form.enabled,
      notes: form.notes || null,
      updated_by: user?.id,
    };
    const { error } = recordId
      ? await supabase.from("imap_settings").update(payload).eq("id", recordId)
      : await supabase.from("imap_settings").insert(payload);
    setSaving(false);
    if (error) {
      toast.error("Could not save", { description: error.message });
      return;
    }
    toast.success("IMAP settings saved");
    load();
  };

  const pollNow = async () => {
    setPolling(true);
    try {
      const res = await fetch("/hooks/poll-imap", { method: "POST" });
      const body = await res.json();
      if (!res.ok || body.error) {
        toast.error("Poll failed", { description: body.error });
      } else {
        toast.success(`Imported ${body.imported ?? 0} new email(s)`);
      }
    } catch (e) {
      toast.error("Poll failed", {
        description: e instanceof Error ? e.message : String(e),
      });
    } finally {
      setPolling(false);
      load();
    }
  };

  if (!isAdmin) {
    return (
      <div className="text-sm text-muted-foreground py-8">
        Only administrators can manage IMAP settings.
      </div>
    );
  }
  if (loading) {
    return (
      <div className="flex justify-center py-16">
        <Loader2 className="h-5 w-5 animate-spin text-muted-foreground" />
      </div>
    );
  }

  return (
    <div className="space-y-6 max-w-3xl">
      <Card className="border-border/60">
        <CardHeader>
          <CardTitle className="font-serif text-base flex items-center gap-2">
            <Inbox className="h-4 w-4 text-muted-foreground" /> Incoming mail (IMAP)
          </CardTitle>
        </CardHeader>
        <CardContent className="grid gap-4 sm:grid-cols-2">
          <Field label="IMAP host *">
            <Input
              value={form.host}
              onChange={(e) => update("host", e.target.value)}
              placeholder="imap.gmail.com"
            />
          </Field>
          <Field label="Port *">
            <Input
              type="number"
              value={form.port}
              onChange={(e) => update("port", e.target.value)}
              placeholder="993"
            />
          </Field>
          <Field label="Username *">
            <Input
              value={form.username}
              onChange={(e) => update("username", e.target.value)}
              placeholder="inbox@yourfirm.com"
            />
          </Field>
          <Field label="Folder">
            <Input
              value={form.folder}
              onChange={(e) => update("folder", e.target.value)}
              placeholder="INBOX"
            />
          </Field>
          <div className="space-y-1.5 sm:col-span-2">
            <Label className="text-xs">Password</Label>
            <div className="flex items-center gap-2 h-9 px-3 rounded-md border bg-muted/30 text-xs text-muted-foreground">
              <KeyRound className="h-3.5 w-3.5" />
              Stored securely as the <code>IMAP_PASSWORD</code> secret. For Gmail/Workspace, use an App Password.
            </div>
          </div>
          <div className="sm:col-span-2 flex items-center justify-between rounded-md border p-3">
            <div>
              <div className="text-sm font-medium">Use TLS / SSL</div>
              <div className="text-xs text-muted-foreground">
                Required for port 993. Off for 143 (STARTTLS).
              </div>
            </div>
            <Switch
              checked={form.secure}
              onCheckedChange={(v) => update("secure", v)}
            />
          </div>
          <Field label="Notes" className="sm:col-span-2">
            <Textarea
              rows={2}
              value={form.notes}
              onChange={(e) => update("notes", e.target.value)}
            />
          </Field>
          <div className="sm:col-span-2 flex items-center justify-between rounded-md border p-3">
            <div>
              <div className="text-sm font-medium">Polling enabled</div>
              <div className="text-xs text-muted-foreground">
                When on, the system fetches new mail automatically every 5 minutes.
              </div>
            </div>
            <Switch
              checked={form.enabled}
              onCheckedChange={(v) => update("enabled", v)}
            />
          </div>
        </CardContent>
      </Card>

      <div className="flex justify-between items-center gap-3">
        <Button
          variant="outline"
          onClick={pollNow}
          disabled={polling || !recordId}
        >
          {polling ? (
            <Loader2 className="h-4 w-4 mr-2 animate-spin" />
          ) : (
            <RefreshCcw className="h-4 w-4 mr-2" />
          )}
          Poll now
        </Button>
        <Button onClick={save} disabled={saving}>
          {saving && <Loader2 className="h-4 w-4 mr-2 animate-spin" />}
          Save IMAP settings
        </Button>
      </div>

      {recordId && (
        <Card className="border-border/60">
          <CardHeader>
            <CardTitle className="font-serif text-base">Last poll</CardTitle>
          </CardHeader>
          <CardContent className="text-sm space-y-1">
            <div>
              <span className="text-muted-foreground">Last polled at:</span>{" "}
              {meta.last_polled_at
                ? new Date(meta.last_polled_at).toLocaleString()
                : "never"}
            </div>
            <div>
              <span className="text-muted-foreground">Last UID seen:</span>{" "}
              {meta.last_uid ?? "—"}
            </div>
            {meta.last_error && (
              <div className="text-destructive">
                <span className="font-medium">Last error:</span> {meta.last_error}
              </div>
            )}
          </CardContent>
        </Card>
      )}
    </div>
  );
}

function Field({
  label,
  className,
  children,
}: {
  label: string;
  className?: string;
  children: React.ReactNode;
}) {
  return (
    <div className={`space-y-1.5 ${className ?? ""}`}>
      <Label className="text-xs">{label}</Label>
      {children}
    </div>
  );
}