"use client";

import { useState } from "react";
import {
  DndContext,
  DragEndEvent,
  DragOverlay,
  DragStartEvent,
  PointerSensor,
  useSensor,
  useSensors,
  closestCenter,
  useDroppable,
} from "@dnd-kit/core";
import { PageLayout, LoadingState, PageHeader } from "@/components/layout";
import {
  AccountCard,
  AccountEditDialog,
  AccountBulkActions,
} from "@/components/accounts";
import {
  FolderEditDialog,
} from "@/components/folders";
import { useBankingData } from "@/lib/hooks";
import { updateAccount, deleteAccount, addFolder, updateFolder, deleteFolder } from "@/lib/store-db";
import { Card, CardContent } from "@/components/ui/card";
import { Button } from "@/components/ui/button";
import { Building2, Folder, Plus, List, LayoutGrid } from "lucide-react";
import type { Account, Folder as FolderType } from "@/lib/types";
import { cn } from "@/lib/utils";
import { getAccountBalance } from "@/lib/account-utils";

// Composant wrapper pour les zones de drop des dossiers
function FolderDropZone({
  folderId,
  children,
}: {
  folderId: string;
  children: React.ReactNode;
}) {
  const { setNodeRef, isOver } = useDroppable({
    id: `folder-${folderId}`,
  });

  return (
    <div
      ref={setNodeRef}
      className={cn(
        isOver && "ring-2 ring-primary ring-offset-2 rounded-lg p-2"
      )}
    >
      {children}
    </div>
  );
}

export default function AccountsPage() {
  const { data, isLoading, refresh, refreshSilent, update } = useBankingData();
  const [editingAccount, setEditingAccount] = useState<Account | null>(null);
  const [isDialogOpen, setIsDialogOpen] = useState(false);
  const [selectedAccounts, setSelectedAccounts] = useState<Set<string>>(
    new Set(),
  );
  const [formData, setFormData] = useState({
    name: "",
    type: "CHECKING" as Account["type"],
    folderId: "folder-root",
    externalUrl: "",
    initialBalance: 0,
  });

  // Folder management state
  const [isFolderDialogOpen, setIsFolderDialogOpen] = useState(false);
  const [editingFolder, setEditingFolder] = useState<FolderType | null>(null);
  const [folderFormData, setFolderFormData] = useState({
    name: "",
    parentId: "folder-root" as string | null,
    color: "#6366f1",
  });
  const [activeId, setActiveId] = useState<string | null>(null);
  const [isCompactView, setIsCompactView] = useState(false);

  const sensors = useSensors(
    useSensor(PointerSensor, {
      activationConstraint: {
        distance: 8,
      },
    })
  );

  if (isLoading || !data) {
    return <LoadingState />;
  }

  const formatCurrency = (amount: number) => {
    return new Intl.NumberFormat("fr-FR", {
      style: "currency",
      currency: "EUR",
    }).format(amount);
  };

  const handleEdit = (account: Account) => {
    setEditingAccount(account);
    setFormData({
      name: account.name,
      type: account.type,
      folderId: account.folderId || "folder-root",
      externalUrl: account.externalUrl || "",
      initialBalance: account.initialBalance || 0,
    });
    setIsDialogOpen(true);
  };

  const handleSave = async () => {
    if (!editingAccount) return;

    try {
      const updatedAccount = {
        ...editingAccount,
        name: formData.name,
        type: formData.type,
        folderId: formData.folderId,
        externalUrl: formData.externalUrl || null,
        initialBalance: formData.initialBalance,
      };
      await updateAccount(updatedAccount);
      refresh();
      setIsDialogOpen(false);
      setEditingAccount(null);
    } catch (error) {
      console.error("Error updating account:", error);
      alert("Erreur lors de la mise à jour du compte");
    }
  };

  const handleDelete = async (accountId: string) => {
    if (!confirm("Supprimer ce compte et toutes ses transactions ?")) return;

    try {
      await deleteAccount(accountId);
      refresh();
    } catch (error) {
      console.error("Error deleting account:", error);
      alert("Erreur lors de la suppression du compte");
    }
  };

  const handleBulkDelete = async () => {
    const count = selectedAccounts.size;
    if (
      !confirm(
        `Supprimer ${count} compte${count > 1 ? "s" : ""} et toutes leurs transactions ?`,
      )
    )
      return;

    try {
      const ids = Array.from(selectedAccounts);
      const response = await fetch(
        `/api/banking/accounts?ids=${ids.join(",")}`,
        {
          method: "DELETE",
        },
      );
      if (!response.ok) {
        throw new Error("Failed to delete accounts");
      }
      setSelectedAccounts(new Set());
      refresh();
    } catch (error) {
      console.error("Error deleting accounts:", error);
      alert("Erreur lors de la suppression des comptes");
    }
  };

  const toggleSelectAccount = (accountId: string, selected: boolean) => {
    const newSelected = new Set(selectedAccounts);
    if (selected) {
      newSelected.add(accountId);
    } else {
      newSelected.delete(accountId);
    }
    setSelectedAccounts(newSelected);
  };

  // Folder management handlers
  const handleNewFolder = () => {
    setEditingFolder(null);
    setFolderFormData({ name: "", parentId: "folder-root", color: "#6366f1" });
    setIsFolderDialogOpen(true);
  };

  const handleEditFolder = (folder: FolderType) => {
    setEditingFolder(folder);
    setFolderFormData({
      name: folder.name,
      parentId: folder.parentId || "folder-root",
      color: folder.color,
    });
    setIsFolderDialogOpen(true);
  };

  const handleSaveFolder = async () => {
    const parentId =
      folderFormData.parentId === "folder-root" ? null : folderFormData.parentId;

    try {
      if (editingFolder) {
        await updateFolder({
          ...editingFolder,
          name: folderFormData.name,
          parentId,
          color: folderFormData.color,
        });
      } else {
        await addFolder({
          name: folderFormData.name,
          parentId,
          color: folderFormData.color,
          icon: "folder",
        });
      }
      refresh();
      setIsFolderDialogOpen(false);
    } catch (error) {
      console.error("Error saving folder:", error);
      alert("Erreur lors de la sauvegarde du dossier");
    }
  };

  const handleDeleteFolder = async (folderId: string) => {
    if (
      !confirm(
        "Supprimer ce dossier ? Les comptes seront déplacés à la racine."
      )
    )
      return;

    try {
      await deleteFolder(folderId);
      refresh();
    } catch (error) {
      console.error("Error deleting folder:", error);
      alert("Erreur lors de la suppression du dossier");
    }
  };

  // Drag and drop handlers
  const handleDragStart = (event: DragStartEvent) => {
    setActiveId(event.active.id as string);
  };

  const handleDragEnd = async (event: DragEndEvent) => {
    const { active, over } = event;
    setActiveId(null);

    if (!over || active.id === over.id || !data) return;

    const activeId = active.id as string;
    const overId = over.id as string;

    // Déplacer un compte vers un dossier
    if (activeId.startsWith("account-")) {
      const accountId = activeId.replace("account-", "");
      let targetFolderId: string | null = null;

      if (overId.startsWith("folder-")) {
        const folderId = overId.replace("folder-", "");
        targetFolderId = folderId === "root" ? null : folderId;
      } else if (overId.startsWith("account-")) {
        // Déplacer vers le dossier du compte cible
        const targetAccountId = overId.replace("account-", "");
        const targetAccount = data.accounts.find((a) => a.id === targetAccountId);
        if (targetAccount) {
          targetFolderId = targetAccount.folderId;
        }
      }

      if (targetFolderId !== undefined) {
        const account = data.accounts.find((a) => a.id === accountId);
        if (!account) return;

        // Sauvegarder l'état précédent pour rollback en cas d'erreur
        const previousData = data;

        // Optimistic update : mettre à jour immédiatement l'interface
        const updatedAccount = {
          ...account,
          folderId: targetFolderId,
        };
        const updatedAccounts = data.accounts.map((a) =>
          a.id === accountId ? updatedAccount : a
        );
        update({
          ...data,
          accounts: updatedAccounts,
        });

        // Faire la requête en arrière-plan
        try {
          await updateAccount(updatedAccount);
          // Refresh silencieux pour synchroniser avec le serveur sans loader
          refreshSilent();
        } catch (error) {
          console.error("Error moving account:", error);
          // Rollback en cas d'erreur
          update(previousData);
          alert("Erreur lors du déplacement du compte");
        }
      }
    }
  };


  const getTransactionCount = (accountId: string) => {
    return data.transactions.filter((t) => t.accountId === accountId).length;
  };

  const totalBalance = data.accounts.reduce(
    (sum, a) => sum + getAccountBalance(a),
    0,
  );

  // Grouper les comptes par folder
  const accountsByFolder = data.accounts.reduce(
    (acc, account) => {
      const folderId = account.folderId || "no-folder";
      if (!acc[folderId]) {
        acc[folderId] = [];
      }
      acc[folderId].push(account);
      return acc;
    },
    {} as Record<string, Account[]>,
  );

  // Obtenir les folders racine (sans parent) et les trier par nom
  const rootFolders = data.folders
    .filter((f) => !f.parentId)
    .sort((a, b) => a.name.localeCompare(b.name));

  return (
    <PageLayout>
      <PageHeader
        title="Comptes"
        description="Gérez vos comptes bancaires et leur organisation"
        actions={
          <div className="flex items-center gap-2">
            <Button
              variant="outline"
              size="icon"
              onClick={() => setIsCompactView(!isCompactView)}
              title={isCompactView ? "Vue détaillée" : "Vue compacte"}
            >
              {isCompactView ? (
                <LayoutGrid className="w-4 h-4" />
              ) : (
                <List className="w-4 h-4" />
              )}
            </Button>
            <Button onClick={handleNewFolder}>
              <Plus className="w-4 h-4 mr-2" />
              Nouveau dossier
            </Button>
          </div>
        }
        rightContent={
          <div className="text-right">
            <p className="text-sm text-muted-foreground">Solde total</p>
            <p
              className={cn(
                "text-2xl font-bold",
                totalBalance >= 0 ? "text-emerald-600" : "text-red-600"
              )}
            >
              {formatCurrency(totalBalance)}
            </p>
          </div>
        }
      />

      {data.accounts.length === 0 ? (
        <Card>
          <CardContent className="flex flex-col items-center justify-center py-12">
            <Building2 className="w-16 h-16 text-muted-foreground mb-4" />
            <h3 className="text-lg font-semibold mb-2">Aucun compte</h3>
            <p className="text-muted-foreground text-center mb-4">
              Importez un fichier OFX depuis le tableau de bord pour ajouter
              votre premier compte.
            </p>
          </CardContent>
        </Card>
      ) : (
        <>
          <AccountBulkActions
            selectedCount={selectedAccounts.size}
            onDelete={handleBulkDelete}
          />
          <DndContext
            sensors={sensors}
            collisionDetection={closestCenter}
            onDragStart={handleDragStart}
            onDragEnd={handleDragEnd}
          >
            <div className="space-y-6">
              {/* Afficher d'abord les comptes sans dossier */}
              {accountsByFolder["no-folder"] &&
                accountsByFolder["no-folder"].length > 0 && (
                  <FolderDropZone folderId="root">
                    <div className="flex items-center gap-2 mb-4">
                      <Folder className="w-5 h-5 text-muted-foreground" />
                      <h2 className="text-lg font-semibold">Sans dossier</h2>
                      <span className="text-sm text-muted-foreground">
                        ({accountsByFolder["no-folder"].length})
                      </span>
                      <span
                        className={cn(
                          "text-sm font-semibold tabular-nums ml-auto",
                          accountsByFolder["no-folder"].reduce(
                            (sum, a) => sum + getAccountBalance(a),
                            0,
                          ) >= 0
                            ? "text-emerald-600"
                            : "text-red-600",
                        )}
                      >
                        {formatCurrency(
                          accountsByFolder["no-folder"].reduce(
                            (sum, a) => sum + getAccountBalance(a),
                            0,
                          ),
                        )}
                      </span>
                    </div>
                    <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
                      {accountsByFolder["no-folder"].map((account) => {
                        const folder = data.folders.find(
                          (f) => f.id === account.folderId,
                        );

                          return (
                            <AccountCard
                              key={account.id}
                              account={account}
                              folder={folder}
                              transactionCount={getTransactionCount(account.id)}
                              onEdit={handleEdit}
                              onDelete={handleDelete}
                              formatCurrency={formatCurrency}
                              isSelected={selectedAccounts.has(account.id)}
                              onSelect={toggleSelectAccount}
                              draggableId={`account-${account.id}`}
                              compact={isCompactView}
                            />
                          );
                      })}
                    </div>
                  </FolderDropZone>
                )}

              {/* Afficher les comptes groupés par folder */}
              {rootFolders.map((folder) => {
                const folderAccounts = accountsByFolder[folder.id] || [];
                const folderBalance = folderAccounts.reduce(
                  (sum, a) => sum + getAccountBalance(a),
                  0,
                );

                return (
                  <FolderDropZone key={folder.id} folderId={folder.id}>
                    <div className="flex items-center gap-2 mb-4">
                      <div
                        className="w-5 h-5 rounded flex items-center justify-center"
                        style={{ backgroundColor: `${folder.color}20` }}
                      >
                        <Folder
                          className="w-4 h-4"
                          style={{ color: folder.color }}
                        />
                      </div>
                      <h2 className="text-lg font-semibold">{folder.name}</h2>
                      <span className="text-sm text-muted-foreground">
                        ({folderAccounts.length})
                      </span>
                      {folderAccounts.length > 0 && (
                        <span
                          className={cn(
                            "text-sm font-semibold tabular-nums",
                            folderBalance >= 0
                              ? "text-emerald-600"
                              : "text-red-600",
                          )}
                        >
                          {formatCurrency(folderBalance)}
                        </span>
                      )}
                      <Button
                        variant="ghost"
                        size="sm"
                        onClick={() => handleEditFolder(folder)}
                        className="ml-auto"
                      >
                        Modifier
                      </Button>
                      <Button
                        variant="ghost"
                        size="sm"
                        onClick={() => handleDeleteFolder(folder.id)}
                        className="text-destructive hover:text-destructive"
                      >
                        Supprimer
                      </Button>
                    </div>
                    {folderAccounts.length > 0 ? (
                      <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
                        {folderAccounts.map((account) => {
                          const accountFolder = data.folders.find(
                            (f) => f.id === account.folderId,
                          );

                          return (
                            <AccountCard
                              key={account.id}
                              account={account}
                              folder={accountFolder}
                              transactionCount={getTransactionCount(account.id)}
                              onEdit={handleEdit}
                              onDelete={handleDelete}
                              formatCurrency={formatCurrency}
                              isSelected={selectedAccounts.has(account.id)}
                              onSelect={toggleSelectAccount}
                              draggableId={`account-${account.id}`}
                              compact={isCompactView}
                            />
                          );
                        })}
                      </div>
                    ) : (
                      <Card>
                        <CardContent className="flex flex-col items-center justify-center py-8">
                          <Folder className="w-12 h-12 text-muted-foreground mb-2" />
                          <p className="text-sm text-muted-foreground">
                            Aucun compte dans ce dossier
                          </p>
                          <p className="text-xs text-muted-foreground mt-1">
                            Glissez-déposez un compte ici pour l'ajouter
                          </p>
                        </CardContent>
                      </Card>
                    )}
                  </FolderDropZone>
                );
              })}
            </div>
            <DragOverlay>
              {activeId ? (
                <div className="opacity-50">
                  {activeId.startsWith("account-") ? (
                    <Card>
                      <CardContent className="p-4">
                        {data.accounts.find(
                          (a) => a.id === activeId.replace("account-", "")
                        )?.name || ""}
                      </CardContent>
                    </Card>
                  ) : null}
                </div>
              ) : null}
            </DragOverlay>
          </DndContext>
        </>
      )}

      <AccountEditDialog
        open={isDialogOpen}
        onOpenChange={setIsDialogOpen}
        formData={formData}
        onFormDataChange={setFormData}
        folders={data.folders}
        onSave={handleSave}
      />

      <FolderEditDialog
        open={isFolderDialogOpen}
        onOpenChange={setIsFolderDialogOpen}
        editingFolder={editingFolder}
        formData={folderFormData}
        onFormDataChange={setFolderFormData}
        folders={data.folders}
        onSave={handleSaveFolder}
      />
    </PageLayout>
  );
}