"use client";

import { useState, useEffect } from "react";
import { Plus, Trash2, Eye, CheckCircle2, Circle } from "lucide-react";
import { Button } from "@/components/ui/button";
import {
  Card,
  CardContent,
  CardDescription,
  CardHeader,
  CardTitle,
} from "@/components/ui/card";
import { Input } from "@/components/ui/input";
import { Textarea } from "@/components/ui/textarea";
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
  DialogTrigger,
} from "@/components/ui/dialog";
import { getTasks, createTask, deleteTask, getTask, Task } from "@/lib/api";

export default function Home() {
  const [tasks, setTasks] = useState<Task[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  // Add task form state
  const [newTitle, setNewTitle] = useState("");
  const [newDescription, setNewDescription] = useState("");
  const [addDialogOpen, setAddDialogOpen] = useState(false);
  const [adding, setAdding] = useState(false);

  // View task state
  const [viewTask, setViewTask] = useState<Task | null>(null);
  const [viewDialogOpen, setViewDialogOpen] = useState(false);
  const [viewLoading, setViewLoading] = useState(false);

  // Delete state
  const [deletingId, setDeletingId] = useState<number | null>(null);

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

  async function loadTasks() {
    try {
      setLoading(true);
      const data = await getTasks();
      setTasks(data);
      setError(null);
    } catch (err) {
      setError(err instanceof Error ? err.message : "Failed to load tasks");
    } finally {
      setLoading(false);
    }
  }

  async function handleAddTask(e: React.FormEvent) {
    e.preventDefault();
    if (!newTitle.trim()) return;

    try {
      setAdding(true);
      const task = await createTask(newTitle.trim(), newDescription.trim());
      setTasks((prev) => [...prev, task]);
      setNewTitle("");
      setNewDescription("");
      setAddDialogOpen(false);
    } catch (err) {
      setError(err instanceof Error ? err.message : "Failed to add task");
    } finally {
      setAdding(false);
    }
  }

  async function handleDeleteTask(id: number) {
    try {
      setDeletingId(id);
      await deleteTask(id);
      setTasks((prev) => prev.filter((t) => t.id !== id));
    } catch (err) {
      setError(err instanceof Error ? err.message : "Failed to delete task");
    } finally {
      setDeletingId(null);
    }
  }

  async function handleViewTask(id: number) {
    try {
      setViewLoading(true);
      setViewDialogOpen(true);
      const task = await getTask(id);
      setViewTask(task);
    } catch (err) {
      setError(err instanceof Error ? err.message : "Failed to load task");
      setViewDialogOpen(false);
    } finally {
      setViewLoading(false);
    }
  }

  return (
    <main className="min-h-screen bg-gradient-to-b from-background to-background/95">
      <div className="container mx-auto py-10 px-4">
        {/* Header */}
        <div className="flex justify-between items-center mb-8">
          <div>
            <h1 className="text-4xl font-bold tracking-tight">Task Manager</h1>
            <p className="text-muted-foreground mt-1">
              Organize and track your tasks efficiently
            </p>
          </div>

          {/* Add Task Dialog */}
          <Dialog open={addDialogOpen} onOpenChange={setAddDialogOpen}>
            <DialogTrigger asChild>
              <Button size="lg" className="gap-2">
                <Plus className="h-5 w-5" />
                Add Task
              </Button>
            </DialogTrigger>
            <DialogContent className="sm:max-w-[425px]">
              <form onSubmit={handleAddTask}>
                <DialogHeader>
                  <DialogTitle>Add New Task</DialogTitle>
                  <DialogDescription>
                    Create a new task to track. Fill in the details below.
                  </DialogDescription>
                </DialogHeader>
                <div className="grid gap-4 py-4">
                  <div className="grid gap-2">
                    <label htmlFor="title" className="text-sm font-medium">
                      Title
                    </label>
                    <Input
                      id="title"
                      placeholder="Enter task title..."
                      value={newTitle}
                      onChange={(e) => setNewTitle(e.target.value)}
                      required
                    />
                  </div>
                  <div className="grid gap-2">
                    <label
                      htmlFor="description"
                      className="text-sm font-medium"
                    >
                      Description
                    </label>
                    <Textarea
                      id="description"
                      placeholder="Enter task description..."
                      value={newDescription}
                      onChange={(e) => setNewDescription(e.target.value)}
                      rows={3}
                    />
                  </div>
                </div>
                <DialogFooter>
                  <Button type="submit" disabled={adding || !newTitle.trim()}>
                    {adding ? "Adding..." : "Add Task"}
                  </Button>
                </DialogFooter>
              </form>
            </DialogContent>
          </Dialog>
        </div>

        {/* Error Alert */}
        {error && (
          <div className="bg-destructive/15 border border-destructive text-destructive px-4 py-3 rounded-lg mb-6">
            {error}
            <button
              className="float-right font-bold"
              onClick={() => setError(null)}
            >
              &times;
            </button>
          </div>
        )}

        {/* Loading State */}
        {loading && (
          <div className="flex justify-center py-20">
            <div className="animate-pulse text-muted-foreground">
              Loading tasks...
            </div>
          </div>
        )}

        {/* Empty State */}
        {!loading && tasks.length === 0 && (
          <Card className="border-dashed">
            <CardContent className="flex flex-col items-center justify-center py-16">
              <Circle className="h-12 w-12 text-muted-foreground mb-4" />
              <h3 className="text-lg font-medium">No tasks yet</h3>
              <p className="text-muted-foreground text-center mt-1">
                Get started by adding your first task
              </p>
            </CardContent>
          </Card>
        )}

        {/* Task Grid */}
        {!loading && tasks.length > 0 && (
          <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
            {tasks.map((task) => (
              <Card
                key={task.id}
                className="group hover:shadow-lg transition-all duration-200 hover:border-primary/50"
              >
                <CardHeader className="pb-2">
                  <div className="flex items-start justify-between">
                    <div className="flex items-start gap-3 flex-1">
                      {task.completed ? (
                        <CheckCircle2 className="h-5 w-5 text-green-500 mt-0.5 flex-shrink-0" />
                      ) : (
                        <Circle className="h-5 w-5 text-muted-foreground mt-0.5 flex-shrink-0" />
                      )}
                      <CardTitle className="text-lg leading-tight">
                        {task.title}
                      </CardTitle>
                    </div>
                  </div>
                  <CardDescription className="pl-8 line-clamp-2">
                    {task.description || "No description"}
                  </CardDescription>
                </CardHeader>
                <CardContent className="pt-2">
                  <div className="flex items-center justify-between">
                    <span className="text-xs text-muted-foreground">
                      {new Date(task.createdAt).toLocaleDateString()}
                    </span>
                    <div className="flex gap-2">
                      <Button
                        variant="ghost"
                        size="icon"
                        onClick={() => handleViewTask(task.id)}
                      >
                        <Eye className="h-4 w-4" />
                      </Button>
                      <Button
                        variant="ghost"
                        size="icon"
                        className="text-destructive hover:text-destructive hover:bg-destructive/10"
                        onClick={() => handleDeleteTask(task.id)}
                        disabled={deletingId === task.id}
                      >
                        <Trash2 className="h-4 w-4" />
                      </Button>
                    </div>
                  </div>
                </CardContent>
              </Card>
            ))}
          </div>
        )}

        {/* View Task Dialog */}
        <Dialog open={viewDialogOpen} onOpenChange={setViewDialogOpen}>
          <DialogContent className="sm:max-w-[525px]">
            {viewLoading ? (
              <div className="py-8 text-center">
                <div className="animate-pulse text-muted-foreground">
                  Loading task...
                </div>
              </div>
            ) : viewTask ? (
              <>
                <DialogHeader>
                  <div className="flex items-center gap-3">
                    {viewTask.completed ? (
                      <CheckCircle2 className="h-6 w-6 text-green-500 flex-shrink-0" />
                    ) : (
                      <Circle className="h-6 w-6 text-muted-foreground flex-shrink-0" />
                    )}
                    <DialogTitle className="text-xl">
                      {viewTask.title}
                    </DialogTitle>
                  </div>
                </DialogHeader>
                <div className="mt-4 space-y-4">
                  <div>
                    <h4 className="text-sm font-medium text-muted-foreground mb-1">
                      Description
                    </h4>
                    <p className="text-sm">
                      {viewTask.description || "No description provided"}
                    </p>
                  </div>
                  <div className="flex gap-6 text-sm">
                    <div>
                      <span className="text-muted-foreground">Status: </span>
                      <span
                        className={
                          viewTask.completed
                            ? "text-green-500"
                            : "text-yellow-500"
                        }
                      >
                        {viewTask.completed ? "Completed" : "Pending"}
                      </span>
                    </div>
                    <div>
                      <span className="text-muted-foreground">Created: </span>
                      <span>
                        {new Date(viewTask.createdAt).toLocaleString()}
                      </span>
                    </div>
                  </div>
                </div>
                <DialogFooter className="mt-6">
                  <Button
                    variant="destructive"
                    onClick={() => {
                      handleDeleteTask(viewTask.id);
                      setViewDialogOpen(false);
                    }}
                  >
                    <Trash2 className="h-4 w-4 mr-2" />
                    Delete Task
                  </Button>
                </DialogFooter>
              </>
            ) : null}
          </DialogContent>
        </Dialog>
      </div>
    </main>
  );
}