"use client";

import { useState } from "react";
import { useTranslations } from "next-intl";
import { useRouter } from "next/navigation";
import { History, RotateCcw, ChevronDown, GitCompare } from "lucide-react";
import { toast } from "sonner";
import { Button } from "@/components/ui/button";
import {
  Sheet,
  SheetContent,
  SheetHeader,
  SheetTitle,
} from "@/components/ui/sheet";
import {
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog";
import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from "@/components/ui/tooltip";
import { VersionDiffView, type DiffSnapshot } from "@/components/recipe/version-diff-view";

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

type SnapshotData = DiffSnapshot & {
  description?: string | null;
  baseServings?: number;
  difficulty?: string | null;
  prepMins?: number | null;
  cookMins?: number | null;
  dietaryTags?: Record<string, boolean>;
};

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,
  currentSnapshot,
}: {
  recipeId: string;
  currentSnapshot: DiffSnapshot;
}) {
  const t = useTranslations("recipe");
  const tForm = useTranslations("recipeForm");
  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);
  const [comparingId, setComparingId] = 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 ensureDetail(versionId: string): Promise<VersionDetail | null> {
    if (expandedData[versionId]) return expandedData[versionId]!;
    const res = await fetch(`/api/v1/recipes/${recipeId}/versions/${versionId}`);
    if (!res.ok) return null;
    const data = await res.json() as VersionDetail;
    setExpandedData((prev) => ({ ...prev, [versionId]: data }));
    return data;
  }

  async function handleExpand(version: VersionSummary) {
    if (expandedId === version.id) {
      setExpandedId(null);
      return;
    }
    setExpandedId(version.id);
    await ensureDetail(version.id);
  }

  async function handleCompare(version: VersionSummary) {
    await ensureDetail(version.id);
    setComparingId(version.id);
  }

  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(t("historyRestoreFailed"));
      }
    } finally {
      setRestoringId(null);
    }
  }

  return (
    <>
      <TooltipProvider>
        <Tooltip>
          <TooltipTrigger render={
            <Button variant="ghost" size="icon" onClick={() => handleOpen(true)}>
              <History className="h-4 w-4" />
            </Button>
          } />
          <TooltipContent>History</TooltipContent>
        </Tooltip>
      </TooltipProvider>
      <Sheet open={open} onOpenChange={handleOpen}>
        <SheetContent>
        <SheetHeader>
          <SheetTitle>Version History</SheetTitle>
        </SheetHeader>

        <div className="p-2 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={tForm("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"
                    onClick={() => void handleCompare(v)}
                  >
                    <GitCompare className="h-3 w-3" />
                    Compare
                  </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.length} ingredient{detail.snapshotData.ingredients.length !== 1 ? "s" : ""},{" "}
                        {detail.snapshotData.steps.length} step{detail.snapshotData.steps.length !== 1 ? "s" : ""}
                      </p>
                    )}
                  </div>
                )}
              </div>
            );
          })}
        </div>
      </SheetContent>
    </Sheet>

    <Dialog open={comparingId !== null} onOpenChange={(isOpen) => !isOpen && setComparingId(null)}>
      <DialogContent className="max-w-2xl max-h-[85vh] overflow-y-auto">
        <DialogHeader>
          <DialogTitle>
            {comparingId ? `Compare v${expandedData[comparingId]?.version} with current` : "Compare"}
          </DialogTitle>
        </DialogHeader>
        {comparingId && expandedData[comparingId] && (
          <VersionDiffView before={expandedData[comparingId]!.snapshotData} after={currentSnapshot} />
        )}
      </DialogContent>
    </Dialog>
    </>
  );
}