"use client";

import { useState } from "react";
import { useRouter } from "next/navigation";
import { History, RotateCcw, ChevronDown } from "lucide-react";
import { toast } from "sonner";
import { Button } from "@/components/ui/button";
import {
  Sheet,
  SheetContent,
  SheetHeader,
  SheetTitle,
  SheetTrigger,
} from "@/components/ui/sheet";

type VersionSummary = {
  id: string;
  version: number;
  title: string;
  createdAt: string;
};

type SnapshotData = {
  ingredients: unknown[];
  steps: unknown[];
};

type VersionDetail = {
  id: string;
  version: number;
  title: string;
  createdAt: string;
  snapshotData: SnapshotData;
};

function formatDate(dateStr: string): string {
  const date = new Date(dateStr);
  return date.toLocaleDateString("en-US", { month: "short", day: "numeric", year: "numeric" });
}

export function VersionHistoryButton({ recipeId }: { recipeId: string }) {
  const router = useRouter();
  const [open, setOpen] = useState(false);
  const [versions, setVersions] = useState<VersionSummary[]>([]);
  const [loading, setLoading] = useState(false);
  const [expandedId, setExpandedId] = useState<string | null>(null);
  const [expandedData, setExpandedData] = useState<Record<string, VersionDetail>>({});
  const [restoringId, setRestoringId] = useState<string | null>(null);

  async function handleOpen(isOpen: boolean) {
    setOpen(isOpen);
    if (isOpen) {
      setLoading(true);
      try {
        const res = await fetch(`/api/v1/recipes/${recipeId}/versions`);
        if (res.ok) {
          const data = await res.json() as VersionSummary[];
          setVersions(data);
        }
      } finally {
        setLoading(false);
      }
    }
  }

  async function handleExpand(version: VersionSummary) {
    if (expandedId === version.id) {
      setExpandedId(null);
      return;
    }
    setExpandedId(version.id);
    if (!expandedData[version.id]) {
      const res = await fetch(`/api/v1/recipes/${recipeId}/versions/${version.id}`);
      if (res.ok) {
        const data = await res.json() as VersionDetail;
        setExpandedData((prev) => ({ ...prev, [version.id]: data }));
      }
    }
  }

  async function handleRestore(version: VersionSummary) {
    setRestoringId(version.id);
    try {
      const res = await fetch(`/api/v1/recipes/${recipeId}/versions/${version.id}`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ action: "restore" }),
      });
      if (res.ok) {
        toast.success(`Recipe restored to version ${version.version}`);
        setOpen(false);
        router.refresh();
      } else {
        toast.error("Failed to restore version");
      }
    } finally {
      setRestoringId(null);
    }
  }

  return (
    <Sheet open={open} onOpenChange={handleOpen}>
      <SheetTrigger render={
        <Button variant="ghost" size="sm">
          <History className="h-4 w-4" />
          History
        </Button>
      } />
      <SheetContent>
        <SheetHeader>
          <SheetTitle>Version History</SheetTitle>
        </SheetHeader>

        <div className="mt-6 space-y-2">
          {loading && (
            <p className="text-sm text-muted-foreground">Loading versions...</p>
          )}

          {!loading && versions.length === 0 && (
            <p className="text-sm text-muted-foreground">No versions yet. Versions are saved automatically when you edit this recipe.</p>
          )}

          {versions.map((v) => {
            const isExpanded = expandedId === v.id;
            const detail = expandedData[v.id];

            return (
              <div key={v.id} className="border rounded-lg overflow-hidden">
                <div className="flex items-center gap-2 p-3">
                  <button
                    className="flex-1 text-left text-sm"
                    onClick={() => void handleExpand(v)}
                  >
                    <span className="font-medium">v{v.version}</span>
                    <span className="text-muted-foreground"> — {v.title} — {formatDate(v.createdAt)}</span>
                  </button>
                  <Button
                    variant="ghost"
                    size="icon"
                    className="h-7 w-7 shrink-0"
                    title="Expand"
                    onClick={() => void handleExpand(v)}
                  >
                    <ChevronDown className={`h-4 w-4 transition-transform ${isExpanded ? "rotate-180" : ""}`} />
                  </Button>
                  <Button
                    variant="outline"
                    size="sm"
                    className="shrink-0"
                    disabled={restoringId === v.id}
                    onClick={() => void handleRestore(v)}
                  >
                    <RotateCcw className="h-3 w-3" />
                    Restore
                  </Button>
                </div>

                {isExpanded && (
                  <div className="px-3 pb-3 text-sm text-muted-foreground border-t pt-2">
                    {!detail ? (
                      <p>Loading...</p>
                    ) : (
                      <p>
                        {(detail.snapshotData.ingredients as unknown[]).length} ingredient{(detail.snapshotData.ingredients as unknown[]).length !== 1 ? "s" : ""},{" "}
                        {(detail.snapshotData.steps as unknown[]).length} step{(detail.snapshotData.steps as unknown[]).length !== 1 ? "s" : ""}
                      </p>
                    )}
                  </div>
                )}
              </div>
            );
          })}
        </div>
      </SheetContent>
    </Sheet>
  );
}