import { Card, CardContent, CardHeader, CardTitle, CardDescription } from "@/components/ui/card";
import { Badge } from "@/components/ui/badge";
import { Button } from "@/components/ui/button";
import { Separator } from "@/components/ui/separator";
import {
  CalendarDays, ChevronLeft, ChevronRight, Diamond
} from "lucide-react";
import Sidebar from "@/components/Sidebar";
import Header from "@/components/Header";

const months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug"];

const timelineProjects = [
  {
    name: "Website Redesign",
    startMonth: 0,
    duration: 3,
    color: "bg-violet-500",
    lightColor: "bg-violet-100",
    phase: "Complete",
    milestones: [{ month: 2, label: "v1.0 Launch" }],
  },
  {
    name: "Mobile App",
    startMonth: 1,
    duration: 5,
    color: "bg-indigo-500",
    lightColor: "bg-indigo-100",
    phase: "In Progress",
    milestones: [{ month: 3, label: "Beta Release" }, { month: 5, label: "GA Launch" }],
  },
  {
    name: "Security Audit",
    startMonth: 3,
    duration: 3,
    color: "bg-amber-500",
    lightColor: "bg-amber-100",
    phase: "In Progress",
    milestones: [{ month: 5, label: "Audit Complete" }],
  },
  {
    name: "Design System",
    startMonth: 4,
    duration: 4,
    color: "bg-emerald-500",
    lightColor: "bg-emerald-100",
    phase: "Planning",
    milestones: [{ month: 6, label: "Alpha Build" }],
  },
];

const phaseColors: Record<string, string> = {
  "Planning": "bg-blue-100 text-blue-700",
  "In Progress": "bg-violet-100 text-violet-700",
  "Review": "bg-amber-100 text-amber-700",
  "Complete": "bg-emerald-100 text-emerald-700",
};

export default function TimelinePage() {
  const totalMonths = months.length;

  return (
    <div className="flex min-h-screen bg-slate-50">
      <Sidebar activePath="/timeline" />
      <div className="flex-1 lg:ml-64">
        <Header />
        <main className="p-6 space-y-6">
          {/* ── Header ── */}
          <div className="flex flex-col sm:flex-row items-start sm:items-center justify-between gap-4">
            <div>
              <h1 className="text-2xl font-bold text-slate-900 animate-fade-up">Timeline</h1>
              <p className="text-slate-500 mt-1">Project roadmap and milestone overview</p>
            </div>
            <div className="flex items-center gap-2">
              <Button variant="outline" size="sm"><ChevronLeft className="h-4 w-4" /></Button>
              <span className="text-sm font-medium text-slate-700 px-2">2026</span>
              <Button variant="outline" size="sm"><ChevronRight className="h-4 w-4" /></Button>
            </div>
          </div>

          {/* ── Legend ── */}
          <div className="flex flex-wrap items-center gap-4">
            {Object.entries(phaseColors).map(([phase, color]) => (
              <div key={phase} className="flex items-center gap-2">
                <div className={`h-3 w-8 rounded-full ${color.split(" ")[0]}`} />
                <span className="text-xs text-slate-600">{phase}</span>
              </div>
            ))}
            <div className="flex items-center gap-2">
              <Diamond className="h-3 w-3 text-slate-700 fill-slate-700" />
              <span className="text-xs text-slate-600">Milestone</span>
            </div>
          </div>

          {/* ── Gantt Chart ── */}
          <Card className="border-0 shadow-sm overflow-hidden">
            <CardContent className="p-0">
              <div className="overflow-x-auto">
                <div className="min-w-[700px]">
                  {/* Month Headers */}
                  <div className="flex border-b border-slate-100">
                    <div className="w-48 shrink-0 p-4 font-medium text-sm text-slate-500 border-r border-slate-100">Project</div>
                    <div className="flex-1 flex">
                      {months.map((month, i) => (
                        <div key={month} className={`flex-1 p-3 text-center text-xs font-medium border-r border-slate-50 ${i === 3 ? "bg-violet-50/50 text-violet-700" : "text-slate-400"}`}>
                          {month} 2026
                        </div>
                      ))}
                    </div>
                  </div>

                  {/* Project Rows */}
                  {timelineProjects.map((project, idx) => (
                    <div key={idx} className="flex border-b border-slate-50 hover:bg-slate-50/50 transition-colors">
                      <div className="w-48 shrink-0 p-4 border-r border-slate-100">
                        <p className="text-sm font-medium text-slate-900">{project.name}</p>
                        <Badge className={`${phaseColors[project.phase]} text-[10px] font-medium border-0 mt-1`}>{project.phase}</Badge>
                      </div>
                      <div className="flex-1 flex items-center relative py-4">
                        {/* Background grid */}
                        {months.map((_, i) => (
                          <div key={i} className={`flex-1 border-r border-slate-50 h-full absolute top-0 ${i === 3 ? "bg-violet-50/30" : ""}`} style={{ left: `${(i / totalMonths) * 100}%`, width: `${100 / totalMonths}%` }} />
                        ))}
                        {/* Bar */}
                        <div
                          className={`absolute h-8 rounded-full ${project.color} opacity-90 shadow-sm flex items-center justify-center animate-fade-up`}
                          style={{
                            left: `${(project.startMonth / totalMonths) * 100}%`,
                            width: `${(project.duration / totalMonths) * 100}%`,
                          }}
                        >
                          <span className="text-[10px] font-medium text-white truncate px-3">{project.name}</span>
                        </div>
                        {/* Milestones */}
                        {project.milestones.map((ms, mi) => (
                          <div key={mi} className="absolute top-1/2 -translate-y-1/2 z-10" style={{ left: `${((ms.month + 0.5) / totalMonths) * 100}%` }}>
                            <div className="relative group">
                              <Diamond className="h-4 w-4 text-slate-700 fill-slate-700" />
                              <div className="absolute bottom-full left-1/2 -translate-x-1/2 mb-1 hidden group-hover:block">
                                <div className="bg-slate-900 text-white text-[10px] px-2 py-1 rounded whitespace-nowrap">{ms.label}</div>
                              </div>
                            </div>
                          </div>
                        ))}
                      </div>
                    </div>
                  ))}
                </div>
              </div>
            </CardContent>
          </Card>

          {/* ── Upcoming Milestones ── */}
          <Card className="border-0 shadow-sm">
            <CardHeader>
              <CardTitle className="text-lg font-semibold text-slate-900">Upcoming Milestones</CardTitle>
              <CardDescription>Key dates and deliverables across all projects</CardDescription>
            </CardHeader>
            <CardContent className="space-y-3">
              {timelineProjects.flatMap(p => p.milestones.map(ms => ({ project: p.name, ...ms, color: p.color }))).sort((a, b) => a.month - b.month).map((ms, i) => (
                <div key={i} className="flex items-center gap-3 p-3 rounded-lg hover:bg-slate-50 transition-colors">
                  <div className={`h-8 w-8 rounded-lg ${ms.color} flex items-center justify-center`}>
                    <Diamond className="h-4 w-4 text-white fill-white" />
                  </div>
                  <div className="flex-1">
                    <p className="text-sm font-medium text-slate-900">{ms.label}</p>
                    <p className="text-xs text-slate-500">{ms.project}</p>
                  </div>
                  <Badge variant="outline" className="text-xs">
                    <CalendarDays className="mr-1 h-3 w-3" />
                    {months[ms.month]} 2026
                  </Badge>
                </div>
              ))}
            </CardContent>
          </Card>
        </main>
      </div>
    </div>
  );
}