"use client";

import { useState } from "react";
import { GanttChart, toGanttTasks } from "@/components/gantt";
import type { GanttTask } from "@/components/gantt";
import { TaskStatus, TaskPriority, type Task } from "@mosaic/shared";

/**
 * Demo page for Gantt Chart component
 * 
 * This page demonstrates the GanttChart component with sample data
 * showing various task states, durations, and interactions.
 */
export default function GanttDemoPage(): React.ReactElement {
  // Sample tasks for demonstration
  const baseTasks: Task[] = [
    {
      id: "task-1",
      workspaceId: "demo-workspace",
      title: "Project Planning",
      description: "Initial project planning and requirements gathering",
      status: TaskStatus.COMPLETED,
      priority: TaskPriority.HIGH,
      dueDate: new Date("2026-02-10"),
      assigneeId: null,
      creatorId: "demo-user",
      projectId: null,
      parentId: null,
      sortOrder: 0,
      metadata: {
        startDate: "2026-02-01",
      },
      completedAt: new Date("2026-02-09"),
      createdAt: new Date("2026-02-01"),
      updatedAt: new Date("2026-02-09"),
    },
    {
      id: "task-2",
      workspaceId: "demo-workspace",
      title: "Design Phase",
      description: "Create mockups and design system",
      status: TaskStatus.IN_PROGRESS,
      priority: TaskPriority.HIGH,
      dueDate: new Date("2026-02-25"),
      assigneeId: null,
      creatorId: "demo-user",
      projectId: null,
      parentId: null,
      sortOrder: 1,
      metadata: {
        startDate: "2026-02-11",
        dependencies: ["task-1"],
      },
      completedAt: null,
      createdAt: new Date("2026-02-11"),
      updatedAt: new Date("2026-02-15"),
    },
    {
      id: "task-3",
      workspaceId: "demo-workspace",
      title: "Backend Development",
      description: "Build API and database",
      status: TaskStatus.NOT_STARTED,
      priority: TaskPriority.MEDIUM,
      dueDate: new Date("2026-03-20"),
      assigneeId: null,
      creatorId: "demo-user",
      projectId: null,
      parentId: null,
      sortOrder: 2,
      metadata: {
        startDate: "2026-02-20",
        dependencies: ["task-1"],
      },
      completedAt: null,
      createdAt: new Date("2026-02-01"),
      updatedAt: new Date("2026-02-01"),
    },
    {
      id: "task-4",
      workspaceId: "demo-workspace",
      title: "Frontend Development",
      description: "Build user interface components",
      status: TaskStatus.NOT_STARTED,
      priority: TaskPriority.MEDIUM,
      dueDate: new Date("2026-03-25"),
      assigneeId: null,
      creatorId: "demo-user",
      projectId: null,
      parentId: null,
      sortOrder: 3,
      metadata: {
        startDate: "2026-02-26",
        dependencies: ["task-2"],
      },
      completedAt: null,
      createdAt: new Date("2026-02-01"),
      updatedAt: new Date("2026-02-01"),
    },
    {
      id: "task-5",
      workspaceId: "demo-workspace",
      title: "Integration Testing",
      description: "Test all components together",
      status: TaskStatus.PAUSED,
      priority: TaskPriority.HIGH,
      dueDate: new Date("2026-04-05"),
      assigneeId: null,
      creatorId: "demo-user",
      projectId: null,
      parentId: null,
      sortOrder: 4,
      metadata: {
        startDate: "2026-03-26",
        dependencies: ["task-3", "task-4"],
      },
      completedAt: null,
      createdAt: new Date("2026-02-01"),
      updatedAt: new Date("2026-03-15"),
    },
    {
      id: "task-6",
      workspaceId: "demo-workspace",
      title: "Deployment",
      description: "Deploy to production",
      status: TaskStatus.NOT_STARTED,
      priority: TaskPriority.HIGH,
      dueDate: new Date("2026-04-10"),
      assigneeId: null,
      creatorId: "demo-user",
      projectId: null,
      parentId: null,
      sortOrder: 5,
      metadata: {
        startDate: "2026-04-06",
        dependencies: ["task-5"],
      },
      completedAt: null,
      createdAt: new Date("2026-02-01"),
      updatedAt: new Date("2026-02-01"),
    },
    {
      id: "task-7",
      workspaceId: "demo-workspace",
      title: "Documentation",
      description: "Write user and developer documentation",
      status: TaskStatus.IN_PROGRESS,
      priority: TaskPriority.LOW,
      dueDate: new Date("2026-04-08"),
      assigneeId: null,
      creatorId: "demo-user",
      projectId: null,
      parentId: null,
      sortOrder: 6,
      metadata: {
        startDate: "2026-03-01",
      },
      completedAt: null,
      createdAt: new Date("2026-03-01"),
      updatedAt: new Date("2026-03-10"),
    },
  ];

  const ganttTasks = toGanttTasks(baseTasks);
  const [selectedTask, setSelectedTask] = useState<GanttTask | null>(null);
  const [showDependencies, setShowDependencies] = useState(false);

  const handleTaskClick = (task: GanttTask): void => {
    setSelectedTask(task);
  };

  const statusCounts = {
    total: ganttTasks.length,
    completed: ganttTasks.filter((t) => t.status === TaskStatus.COMPLETED).length,
    inProgress: ganttTasks.filter((t) => t.status === TaskStatus.IN_PROGRESS).length,
    notStarted: ganttTasks.filter((t) => t.status === TaskStatus.NOT_STARTED).length,
    paused: ganttTasks.filter((t) => t.status === TaskStatus.PAUSED).length,
  };

  return (
    <div className="min-h-screen bg-gray-50 p-8">
      <div className="max-w-7xl mx-auto">
        {/* Header */}
        <div className="mb-8">
          <h1 className="text-3xl font-bold text-gray-900 mb-2">
            Gantt Chart Component Demo
          </h1>
          <p className="text-gray-600">
            Interactive project timeline visualization with task dependencies
          </p>
        </div>

        {/* Stats */}
        <div className="grid grid-cols-5 gap-4 mb-6">
          <div className="bg-white p-4 rounded-lg border border-gray-200">
            <div className="text-2xl font-bold text-gray-900">{statusCounts.total}</div>
            <div className="text-sm text-gray-600">Total Tasks</div>
          </div>
          <div className="bg-green-50 p-4 rounded-lg border border-green-200">
            <div className="text-2xl font-bold text-green-700">{statusCounts.completed}</div>
            <div className="text-sm text-green-600">Completed</div>
          </div>
          <div className="bg-blue-50 p-4 rounded-lg border border-blue-200">
            <div className="text-2xl font-bold text-blue-700">{statusCounts.inProgress}</div>
            <div className="text-sm text-blue-600">In Progress</div>
          </div>
          <div className="bg-gray-100 p-4 rounded-lg border border-gray-300">
            <div className="text-2xl font-bold text-gray-700">{statusCounts.notStarted}</div>
            <div className="text-sm text-gray-600">Not Started</div>
          </div>
          <div className="bg-yellow-50 p-4 rounded-lg border border-yellow-200">
            <div className="text-2xl font-bold text-yellow-700">{statusCounts.paused}</div>
            <div className="text-sm text-yellow-600">Paused</div>
          </div>
        </div>

        {/* Controls */}
        <div className="bg-white p-4 rounded-lg border border-gray-200 mb-6">
          <div className="flex items-center gap-4">
            <label className="flex items-center gap-2 cursor-pointer">
              <input
                type="checkbox"
                checked={showDependencies}
                onChange={(e) => setShowDependencies(e.target.checked)}
                className="w-4 h-4 text-blue-600 border-gray-300 rounded focus:ring-blue-500"
              />
              <span className="text-sm text-gray-700">
                Show Dependencies (coming soon)
              </span>
            </label>
          </div>
        </div>

        {/* Gantt Chart */}
        <div className="bg-white rounded-lg border border-gray-200 shadow-sm overflow-hidden mb-6">
          <div className="p-4 border-b border-gray-200 bg-gray-50">
            <h2 className="text-lg font-semibold text-gray-900">
              Project Timeline
            </h2>
          </div>
          <div className="p-4">
            <GanttChart
              tasks={ganttTasks}
              onTaskClick={handleTaskClick}
              height={500}
              showDependencies={showDependencies}
            />
          </div>
        </div>

        {/* Selected Task Details */}
        {selectedTask && (
          <div className="bg-white p-6 rounded-lg border border-gray-200 shadow-sm">
            <h3 className="text-lg font-semibold text-gray-900 mb-4">
              Selected Task Details
            </h3>
            <div className="grid grid-cols-2 gap-4">
              <div>
                <div className="text-sm font-medium text-gray-500 mb-1">Title</div>
                <div className="text-gray-900">{selectedTask.title}</div>
              </div>
              <div>
                <div className="text-sm font-medium text-gray-500 mb-1">Status</div>
                <div className="text-gray-900">{selectedTask.status}</div>
              </div>
              <div>
                <div className="text-sm font-medium text-gray-500 mb-1">Priority</div>
                <div className="text-gray-900">{selectedTask.priority}</div>
              </div>
              <div>
                <div className="text-sm font-medium text-gray-500 mb-1">Duration</div>
                <div className="text-gray-900">
                  {Math.ceil(
                    (selectedTask.endDate.getTime() - selectedTask.startDate.getTime()) /
                      (1000 * 60 * 60 * 24)
                  )}{" "}
                  days
                </div>
              </div>
              <div>
                <div className="text-sm font-medium text-gray-500 mb-1">Start Date</div>
                <div className="text-gray-900">
                  {selectedTask.startDate.toLocaleDateString()}
                </div>
              </div>
              <div>
                <div className="text-sm font-medium text-gray-500 mb-1">End Date</div>
                <div className="text-gray-900">
                  {selectedTask.endDate.toLocaleDateString()}
                </div>
              </div>
              {selectedTask.description && (
                <div className="col-span-2">
                  <div className="text-sm font-medium text-gray-500 mb-1">Description</div>
                  <div className="text-gray-900">{selectedTask.description}</div>
                </div>
              )}
            </div>
          </div>
        )}

        {/* PDA-Friendly Language Notice */}
        <div className="mt-6 bg-blue-50 border border-blue-200 rounded-lg p-4">
          <h3 className="text-sm font-semibold text-blue-900 mb-2">
            🌟 PDA-Friendly Design
          </h3>
          <p className="text-sm text-blue-800">
            This component uses respectful, non-judgmental language. Tasks past their target
            date show "Target passed" instead of "OVERDUE", and approaching deadlines show
            "Approaching target" to maintain a positive, supportive tone.
          </p>
        </div>
      </div>
    </div>
  );
}
