import { db } from "@/lib/db";
import { isOverdue, isDueSoon, describeRecurrence } from "@/lib/tasks/schedule";
import { formatDate } from "@/lib/utils";
import { AddTaskButton } from "@/components/tasks/add-task-button";
import { CompleteTaskButton } from "@/components/tasks/complete-task-button";
import { Badge } from "@/components/ui/badge";
import { Card, CardContent } from "@/components/ui/card";
import { CalendarDays, Leaf, Home, Wrench, CheckCircle2, AlertCircle, Clock } from "lucide-react";
import Link from "next/link";

export const metadata = { title: "Reminders" };

const CATEGORY_ICONS = {
  GARDEN:    Leaf,
  HOME:      Home,
  EQUIPMENT: Wrench,
  OTHER:     Clock,
};

const CATEGORY_LABELS = {
  GARDEN:    "Garden",
  HOME:      "Home",
  EQUIPMENT: "Equipment",
  OTHER:     "Other",
};

export default async function TasksPage() {
  const tasks = await db.task.findMany({
    where: { active: true },
    orderBy: { nextDue: "asc" },
    include: { plant: { select: { id: true, commonName: true, variety: true } } },
  });

  const overdue  = tasks.filter((t) => isOverdue(t.nextDue));
  const upcoming = tasks.filter((t) => !isOverdue(t.nextDue) && isDueSoon(t.nextDue, 60));
  const later    = tasks.filter((t) => !isOverdue(t.nextDue) && !isDueSoon(t.nextDue, 60));

  return (
    <div className="space-y-6">
      <div className="flex items-center justify-between">
        <div>
          <h1 className="font-display text-2xl font-semibold">Reminders</h1>
          <p className="text-sm text-muted-foreground mt-0.5">
            {overdue.length > 0
              ? `${overdue.length} overdue · ${upcoming.length} coming up`
              : `${upcoming.length} coming up in the next 60 days`}
          </p>
        </div>
        <AddTaskButton />
      </div>

      {tasks.length === 0 && (
        <div className="text-center py-16 text-muted-foreground">
          <CalendarDays className="h-12 w-12 mx-auto mb-4 opacity-20" />
          <p className="font-medium">No reminders yet</p>
          <p className="text-sm mt-1">Add your first reminder to start tracking what needs doing.</p>
        </div>
      )}

      {overdue.length > 0 && (
        <Section title="Overdue" icon={AlertCircle} iconClass="text-destructive">
          {overdue.map((task) => (
            <TaskCard key={task.id} task={task} overdue />
          ))}
        </Section>
      )}

      {upcoming.length > 0 && (
        <Section title="Coming up" icon={CalendarDays} iconClass="text-[hsl(var(--leaf))]">
          {upcoming.map((task) => (
            <TaskCard key={task.id} task={task} />
          ))}
        </Section>
      )}

      {later.length > 0 && (
        <Section title="Later" icon={Clock} iconClass="text-muted-foreground">
          {later.map((task) => (
            <TaskCard key={task.id} task={task} />
          ))}
        </Section>
      )}
    </div>
  );
}

function Section({ title, icon: Icon, iconClass, children }: {
  title: string;
  icon: React.ElementType;
  iconClass: string;
  children: React.ReactNode;
}) {
  return (
    <div className="space-y-2">
      <div className="flex items-center gap-2 mb-3">
        <Icon className={`h-4 w-4 ${iconClass}`} />
        <h2 className="font-display text-lg font-semibold">{title}</h2>
      </div>
      {children}
    </div>
  );
}

function TaskCard({ task, overdue = false }: {
  task: Awaited<ReturnType<typeof db.task.findMany>>[0] & {
    plant: { id: string; commonName: string; variety: string | null } | null;
  };
  overdue?: boolean;
}) {
  const Icon = CATEGORY_ICONS[task.category];
  const daysUntil = Math.ceil((new Date(task.nextDue).getTime() - Date.now()) / 86400000);

  return (
    <Card className={overdue ? "border-destructive/40" : ""}>
      <CardContent className="py-3 px-4 flex items-start gap-3">
        <Icon className={`h-4 w-4 mt-0.5 shrink-0 ${overdue ? "text-destructive" : "text-muted-foreground"}`} />

        <div className="flex-1 min-w-0">
          <div className="flex items-start gap-2 flex-wrap">
            <p className="font-medium text-sm">{task.title}</p>
            <Badge variant="secondary" className="text-xs shrink-0">
              {CATEGORY_LABELS[task.category]}
            </Badge>
          </div>

          {task.plant && (
            <Link href={`/garden/${task.plant.id}`} className="text-xs text-[hsl(var(--leaf))] hover:underline">
              {task.plant.commonName}{task.plant.variety ? ` · ${task.plant.variety}` : ""}
            </Link>
          )}

          {task.notes && (
            <p className="text-xs text-muted-foreground mt-0.5">{task.notes}</p>
          )}

          <p className="text-xs text-muted-foreground mt-1">
            {describeRecurrence(task.recurrence, task.intervalDays, task.month)}
            {task.lastDone && ` · Last done ${formatDate(task.lastDone)}`}
          </p>
        </div>

        <div className="flex items-center gap-2 shrink-0">
          <div className="text-right">
            <p className={`text-xs font-medium ${overdue ? "text-destructive" : "text-muted-foreground"}`}>
              {overdue
                ? `${Math.abs(daysUntil)}d overdue`
                : daysUntil === 0 ? "Today"
                : daysUntil === 1 ? "Tomorrow"
                : `In ${daysUntil} days`}
            </p>
            <p className="text-xs text-muted-foreground">{formatDate(task.nextDue)}</p>
          </div>
          <CompleteTaskButton taskId={task.id} taskTitle={task.title} />
        </div>
      </CardContent>
    </Card>
  );
}