"use client";

import { useState, useEffect, useCallback } from "react";
import { Plus, FolderKanban, ExternalLink, MoreHorizontal, Pencil, Trash2 } from "lucide-react";
import { Button } from "@/components/ui/button";
import { Badge } from "@/components/ui/badge";
import { Progress } from "@/components/ui/progress";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
import { Input } from "@/components/ui/input";
import { Textarea } from "@/components/ui/textarea";
import { Label } from "@/components/ui/label";
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
import { Dialog, DialogContent, DialogDescription, DialogFooter, DialogHeader, DialogTitle } from "@/components/ui/dialog";
import { DropdownMenu, DropdownMenuContent, DropdownMenuItem, DropdownMenuTrigger } from "@/components/ui/dropdown-menu";
import { AlertDialog, AlertDialogAction, AlertDialogCancel, AlertDialogContent, AlertDialogDescription, AlertDialogFooter, AlertDialogHeader, AlertDialogTitle } from "@/components/ui/alert-dialog";
import { ProjectCreateDialog } from "@/components/projects/project-create-dialog";
import Link from "next/link";
import { toast } from "sonner";

interface Project {
  id: string;
  name: string;
  description: string | null;
  status: "active" | "paused" | "completed" | "archived";
  domainId: string;
  color: string | null;
  icon: string | null;
  targetDate: string | null;
  taskCount: number;
  completedCount: number;
  progress: number;
  tags: { id: string; name: string; color: string | null }[];
}

const statusColors: Record<string, string> = {
  active: "bg-green-100 text-green-800 dark:bg-green-900 dark:text-green-200",
  paused: "bg-yellow-100 text-yellow-800 dark:bg-yellow-900 dark:text-yellow-200",
  completed: "bg-blue-100 text-blue-800 dark:bg-blue-900 dark:text-blue-200",
  archived: "bg-gray-100 text-gray-800 dark:bg-gray-800 dark:text-gray-200",
};

export default function ProjectsPage() {
  const [projects, setProjects] = useState<Project[]>([]);
  const [domainId, setDomainId] = useState<string | null>(null);
  const [domains, setDomains] = useState<{ id: string; name: string }[]>([]);
  const [createOpen, setCreateOpen] = useState(false);
  const [loading, setLoading] = useState(true);
  const [editingProject, setEditingProject] = useState<Project | null>(null);
  const [editName, setEditName] = useState("");
  const [editDescription, setEditDescription] = useState("");
  const [editStatus, setEditStatus] = useState<Project["status"]>("active");
  const [saveSaving, setSaveSaving] = useState(false);
  const [deleteProjectId, setDeleteProjectId] = useState<string | null>(null);
  const [deleting, setDeleting] = useState(false);

  // Fetch domains
  useEffect(() => {
    fetch("/api/domains?sort=sort_order")
      .then((res) => res.json())
      .then((data) => {
        const items = data.items || [];
        setDomains(items);
        if (items.length > 0 && !domainId) {
          setDomainId(items[0].id);
        }
      })
      .catch(() => {});
  }, []); // eslint-disable-line react-hooks/exhaustive-deps

  // Fetch projects
  const fetchProjects = useCallback(async () => {
    if (!domainId) return;
    setLoading(true);
    try {
      const res = await fetch(`/api/domains/${domainId}/projects`);
      const data = await res.json();
      setProjects(data.items || []);
    } catch {
      toast.error("Failed to load projects");
    } finally {
      setLoading(false);
    }
  }, [domainId]);

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

  // Edit a project
  const handleEdit = async () => {
    if (!editingProject || !editName.trim()) return;
    setSaveSaving(true);
    try {
      const res = await fetch(`/api/domains/${domainId}/projects/${editingProject.id}`, {
        method: "PATCH",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          name: editName.trim(),
          description: editDescription || null,
          status: editStatus,
        }),
      });
      if (!res.ok) throw new Error("Failed to update");
      toast.success("Project updated");
      setEditingProject(null);
      fetchProjects();
    } catch {
      toast.error("Failed to update project");
    } finally {
      setSaveSaving(false);
    }
  };

  // Delete a project
  const handleDelete = async () => {
    if (!deleteProjectId) return;
    setDeleting(true);
    try {
      const res = await fetch(`/api/domains/${domainId}/projects/${deleteProjectId}`, { method: "DELETE" });
      if (!res.ok) throw new Error("Failed to delete");
      toast.success("Project deleted");
      setDeleteProjectId(null);
      fetchProjects();
    } catch {
      toast.error("Failed to delete project");
    } finally {
      setDeleting(false);
    }
  };

  // Open edit dialog
  const openEdit = (project: Project, e: React.MouseEvent) => {
    e.preventDefault();
    e.stopPropagation();
    setEditName(project.name);
    setEditDescription(project.description || "");
    setEditStatus(project.status);
    setEditingProject(project);
  };

  // Open delete confirmation
  const confirmDelete = (id: string, e: React.MouseEvent) => {
    e.preventDefault();
    e.stopPropagation();
    setDeleteProjectId(id);
  };

  // Listen for custom event to open create dialog
  useEffect(() => {
    const handler = () => setCreateOpen(true);
    document.addEventListener("open-create-project", handler);
    return () => document.removeEventListener("open-create-project", handler);
  }, []);

  return (
    <div>
      <div className="mb-6 flex items-center justify-between">
        <div>
          <h1 className="text-2xl font-bold">Projects</h1>
          <p className="mt-1 text-muted-foreground">Organize work into milestones and track progress.</p>
        </div>
        <div className="flex items-center gap-2">
          {domains.length > 1 && (
            <select
              value={domainId || ""}
              onChange={(e) => setDomainId(e.target.value)}
              className="rounded-md border bg-background px-3 py-1.5 text-sm"
              aria-label="Select domain"
            >
              {domains.map((d) => (
                <option key={d.id} value={d.id}>{d.name}</option>
              ))}
            </select>
          )}
          <Button onClick={() => setCreateOpen(true)}>
            <Plus className="mr-2 h-4 w-4" aria-hidden="true" />
            New project
          </Button>
        </div>
      </div>

      {loading ? (
        <div className="py-12 text-center text-muted-foreground">Loading projects...</div>
      ) : projects.length === 0 ? (
        <div className="py-12 text-center">
          <FolderKanban className="mx-auto h-12 w-12 text-muted-foreground/50" aria-hidden="true" />
          <p className="mt-4 text-muted-foreground">No projects yet. Create your first one!</p>
        </div>
      ) : (
        <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-3">
          {projects.map((project) => (
            <div key={project.id} className="group relative">
              <Link href={`/projects/${project.id}`}>
                <Card className="h-full cursor-pointer transition-colors hover:bg-accent/50">
                  <CardHeader className="pb-2">
                    <div className="flex items-start justify-between">
                      <div className="flex items-center gap-2">
                        {project.color && (
                          <div
                            className="h-3 w-3 rounded-full shrink-0"
                            style={{ backgroundColor: project.color }}
                          />
                        )}
                        <CardTitle className="text-base">{project.name}</CardTitle>
                      </div>
                      <ExternalLink className="h-4 w-4 text-muted-foreground shrink-0" aria-hidden="true" />
                    </div>
                  </CardHeader>
                  <CardContent>
                    {project.description && (
                      <p className="mb-3 text-sm text-muted-foreground line-clamp-2">{project.description}</p>
                    )}
                    <div className="mb-3 flex items-center gap-2">
                      <Badge variant="secondary" className={`text-xs ${statusColors[project.status] || ""}`}>
                        {project.status}
                      </Badge>
                      {project.targetDate && (
                        <span className="text-xs text-muted-foreground">
                          Due {new Date(project.targetDate).toLocaleDateString()}
                        </span>
                      )}
                    </div>
                    <div className="space-y-1">
                      <div className="flex items-center justify-between text-xs text-muted-foreground">
                        <span>{project.completedCount}/{project.taskCount} tasks</span>
                        <span>{project.progress}%</span>
                      </div>
                      <Progress value={project.progress} className="h-2" />
                    </div>
                    {project.tags.length > 0 && (
                      <div className="mt-3 flex flex-wrap gap-1">
                        {project.tags.map((tag) => (
                          <span
                            key={tag.id}
                            className="inline-flex items-center rounded-full px-2 py-0.5 text-xs"
                            style={{ backgroundColor: tag.color || "#e2e8f0", color: "#1e293b" }}
                          >
                            {tag.name}
                          </span>
                        ))}
                      </div>
                    )}
                  </CardContent>
                </Card>
              </Link>
              {/* Actions overlay */}
              <div className="absolute right-2 top-2 z-10 opacity-0 group-hover:opacity-100 transition-opacity">
                <DropdownMenu>
                  <DropdownMenuTrigger asChild>
                    <Button variant="secondary" size="icon" className="h-8 w-8">
                      <MoreHorizontal className="h-4 w-4" />
                    </Button>
                  </DropdownMenuTrigger>
                  <DropdownMenuContent align="end">
                    <DropdownMenuItem onClick={(e) => openEdit(project, e)}>
                      <Pencil className="mr-2 h-4 w-4" /> Edit
                    </DropdownMenuItem>
                    <DropdownMenuItem className="text-destructive" onClick={(e) => confirmDelete(project.id, e)}>
                      <Trash2 className="mr-2 h-4 w-4" /> Delete
                    </DropdownMenuItem>
                  </DropdownMenuContent>
                </DropdownMenu>
              </div>
            </div>
          ))}
        </div>
      )}

      <ProjectCreateDialog
        open={createOpen}
        onOpenChange={setCreateOpen}
        domainId={domainId || ""}
        onCreated={fetchProjects}
      />

      {/* Edit Project Dialog */}
      <Dialog open={!!editingProject} onOpenChange={(open) => { if (!open) setEditingProject(null); }}>
        <DialogContent>
          <DialogHeader>
            <DialogTitle>Edit project</DialogTitle>
            <DialogDescription>Update project details.</DialogDescription>
          </DialogHeader>
          <div className="space-y-4">
            <div className="space-y-2">
              <Label htmlFor="edit-project-name">Name</Label>
              <Input id="edit-project-name" value={editName} onChange={(e) => setEditName(e.target.value)} autoFocus required />
            </div>
            <div className="space-y-2">
              <Label htmlFor="edit-project-description">Description</Label>
              <Textarea id="edit-project-description" value={editDescription} onChange={(e) => setEditDescription(e.target.value)} />
            </div>
            <div className="space-y-2">
              <Label htmlFor="edit-project-status">Status</Label>
              <Select value={editStatus} onValueChange={(v: any) => setEditStatus(v)}>
                <SelectTrigger id="edit-project-status">
                  <SelectValue />
                </SelectTrigger>
                <SelectContent>
                  <SelectItem value="active">Active</SelectItem>
                  <SelectItem value="paused">Paused</SelectItem>
                  <SelectItem value="completed">Completed</SelectItem>
                  <SelectItem value="archived">Archived</SelectItem>
                </SelectContent>
              </Select>
            </div>
          </div>
          <DialogFooter>
            <Button variant="outline" onClick={() => setEditingProject(null)}>Cancel</Button>
            <Button onClick={handleEdit} disabled={saveSaving || !editName.trim()}>
              {saveSaving ? "Saving..." : "Save"}
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>

      {/* Delete Project Confirmation */}
      <AlertDialog open={!!deleteProjectId} onOpenChange={(open) => { if (!open) setDeleteProjectId(null); }}>
        <AlertDialogContent>
          <AlertDialogHeader>
            <AlertDialogTitle>Delete project?</AlertDialogTitle>
            <AlertDialogDescription>This cannot be undone. All sections and tasks will also be deleted.</AlertDialogDescription>
          </AlertDialogHeader>
          <AlertDialogFooter>
            <AlertDialogCancel disabled={deleting}>Cancel</AlertDialogCancel>
            <AlertDialogAction onClick={handleDelete} disabled={deleting}>
              {deleting ? "Deleting..." : "Delete"}
            </AlertDialogAction>
          </AlertDialogFooter>
        </AlertDialogContent>
      </AlertDialog>
    </div>
  );
}