"use client";

import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
import type { TransactionRow, StatementRow, TagRow } from "./queries";
import type { CurrentUser } from "./auth";

interface TransactionsResponse {
  data: TransactionRow[];
  total: number;
  limit: number;
  offset: number;
}

interface TransactionFilters {
  from?: string;
  to?: string;
  category?: string;
  bank_name?: string;
  search?: string;
  statement_id?: string;
  tag_id?: string;
  sort_by?: string;
  sort_dir?: string;
  limit?: number;
  offset?: number;
}

function buildParams(filters: TransactionFilters): string {
  const params = new URLSearchParams();
  Object.entries(filters).forEach(([key, val]) => {
    if (val !== undefined && val !== "") params.set(key, String(val));
  });
  return params.toString();
}

export function useTransactions(filters: TransactionFilters) {
  return useQuery<TransactionsResponse>({
    queryKey: ["transactions", filters],
    queryFn: async () => {
      const res = await fetch(`/api/transactions?${buildParams(filters)}`);
      return res.json();
    },
  });
}

export function useTransaction(id: number) {
  return useQuery<TransactionRow>({
    queryKey: ["transaction", id],
    queryFn: async () => {
      const res = await fetch(`/api/transactions/${id}`);
      return res.json();
    },
  });
}

export function useStatements() {
  return useQuery<StatementRow[]>({
    queryKey: ["statements"],
    queryFn: async () => {
      const res = await fetch("/api/statements");
      return res.json();
    },
  });
}

export function useStatement(id: number) {
  return useQuery<StatementRow>({
    queryKey: ["statement", id],
    queryFn: async () => {
      const res = await fetch(`/api/statements/${id}`);
      return res.json();
    },
  });
}

export function useBanks() {
  return useQuery<string[]>({
    queryKey: ["banks"],
    queryFn: async () => {
      const res = await fetch("/api/merchants?type=banks");
      return res.json();
    },
  });
}

export function useUpdateTransaction() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async ({
      id,
      ...data
    }: {
      id: number;
      category?: string;
      merchant_normalized?: string;
      notes?: string;
    }) => {
      const res = await fetch(`/api/transactions/${id}`, {
        method: "PATCH",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(data),
      });
      return res.json();
    },
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ["transactions"] });
      qc.invalidateQueries({ queryKey: ["transaction"] });
    },
  });
}

export function useBulkAction() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async (body: {
      action: string;
      ids: number[];
      category?: string;
      merchant_normalized?: string;
      splits?: { participant_id: number; share_percent: number }[];
      tag_id?: number;
    }) => {
      const res = await fetch("/api/transactions/bulk", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(body),
      });
      if (!res.ok) {
        const err = await res.json();
        throw new Error(err.error || "Bulk action failed");
      }
      return res.json();
    },
    onSuccess: (_data, variables) => {
      qc.invalidateQueries({ queryKey: ["transactions"] });
      if (variables.action === "split") {
        qc.invalidateQueries({ queryKey: ["splits"] });
        qc.invalidateQueries({ queryKey: ["shared-transactions"] });
        qc.invalidateQueries({ queryKey: ["participant-balances"] });
      }
      if (variables.action === "tag" || variables.action === "untag") {
        qc.invalidateQueries({ queryKey: ["tags"] });
      }
    },
  });
}

export function useParticipants() {
  return useQuery<{ id: number; name: string; created_at: string }[]>({
    queryKey: ["participants"],
    queryFn: async () => {
      const res = await fetch("/api/participants");
      return res.json();
    },
  });
}

export function useParticipantBalances() {
  return useQuery<{ id: number; name: string; total_owed: number; unsettled_count: number }[]>({
    queryKey: ["participant-balances"],
    queryFn: async () => {
      const res = await fetch("/api/participants/balances");
      return res.json();
    },
  });
}

export function useSharedTransactions() {
  return useQuery({
    queryKey: ["shared-transactions"],
    queryFn: async () => {
      const res = await fetch("/api/shared-transactions");
      return res.json();
    },
  });
}

export function useTransactionSplits(transactionId: number) {
  return useQuery({
    queryKey: ["splits", transactionId],
    queryFn: async () => {
      const res = await fetch(`/api/transactions/${transactionId}/splits`);
      return res.json();
    },
  });
}

export function useSetSplits() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async ({
      transactionId,
      splits,
    }: {
      transactionId: number;
      splits: { participant_id: number; share_percent: number }[];
    }) => {
      const res = await fetch(`/api/transactions/${transactionId}/splits`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ splits }),
      });
      if (!res.ok) {
        const err = await res.json();
        throw new Error(err.error || "Failed to set splits");
      }
      return res.json();
    },
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ["splits"] });
      qc.invalidateQueries({ queryKey: ["shared-transactions"] });
      qc.invalidateQueries({ queryKey: ["participant-balances"] });
    },
  });
}

export function useSettleSplits() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async (body: { participant_id?: number; split_ids?: number[] }) => {
      const res = await fetch("/api/splits/settle", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(body),
      });
      return res.json();
    },
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ["shared-transactions"] });
      qc.invalidateQueries({ queryKey: ["participant-balances"] });
    },
  });
}

export function useCurrentUser() {
  return useQuery<CurrentUser>({
    queryKey: ["me"],
    queryFn: async () => {
      const res = await fetch("/api/me");
      if (!res.ok) throw new Error("Not authenticated");
      return res.json();
    },
  });
}

export function useUpdateStatement() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async ({ id, owner_id }: { id: number; owner_id: number }) => {
      const res = await fetch(`/api/statements/${id}`, {
        method: "PATCH",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ owner_id }),
      });
      return res.json();
    },
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ["statements"] });
      qc.invalidateQueries({ queryKey: ["transactions"] });
    },
  });
}

export function useTags() {
  return useQuery<(TagRow & { transaction_count: number })[]>({
    queryKey: ["tags"],
    queryFn: async () => {
      const res = await fetch("/api/tags");
      return res.json();
    },
  });
}

export function useCreateTag() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async ({ name, color }: { name: string; color?: string }) => {
      const res = await fetch("/api/tags", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ name, color }),
      });
      if (!res.ok) {
        const err = await res.json();
        throw new Error(err.error || "Failed to create tag");
      }
      return res.json();
    },
    onSuccess: () => qc.invalidateQueries({ queryKey: ["tags"] }),
  });
}

export function useDeleteTag() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async (id: number) => {
      await fetch(`/api/tags/${id}`, { method: "DELETE" });
    },
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ["tags"] });
      qc.invalidateQueries({ queryKey: ["transactions"] });
    },
  });
}

export function useAddTransactionTag() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async ({ transactionId, tagId }: { transactionId: number; tagId: number }) => {
      await fetch(`/api/transactions/${transactionId}/tags`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ tag_id: tagId }),
      });
    },
    onSuccess: () => qc.invalidateQueries({ queryKey: ["transactions"] }),
  });
}

export function useRemoveTransactionTag() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async ({ transactionId, tagId }: { transactionId: number; tagId: number }) => {
      await fetch(`/api/transactions/${transactionId}/tags`, {
        method: "DELETE",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ tag_id: tagId }),
      });
    },
    onSuccess: () => qc.invalidateQueries({ queryKey: ["transactions"] }),
  });
}

export function useCreateParticipant() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async ({ name, email }: { name: string; email?: string }) => {
      const res = await fetch("/api/participants", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ name, email }),
      });
      if (!res.ok) {
        const err = await res.json();
        throw new Error(err.error || "Failed to create participant");
      }
      return res.json();
    },
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ["participants"] });
      qc.invalidateQueries({ queryKey: ["participant-balances"] });
    },
  });
}

// --- Rules ---

export interface RuleRow {
  id: number;
  name: string;
  conditions: { field: string; operator: string; value: string }[];
  actions: { set_category?: string; add_tag_ids?: number[]; set_merchant?: string };
  enabled: boolean;
  priority: number;
  created_at: string;
}

export function useRules() {
  return useQuery<RuleRow[]>({
    queryKey: ["rules"],
    queryFn: async () => {
      const res = await fetch("/api/rules");
      return res.json();
    },
  });
}

export function useCreateRule() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async (data: Omit<RuleRow, "id" | "created_at">) => {
      const res = await fetch("/api/rules", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(data),
      });
      if (!res.ok) throw new Error("Failed to create rule");
      return res.json();
    },
    onSuccess: () => qc.invalidateQueries({ queryKey: ["rules"] }),
  });
}

export function useUpdateRule() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async ({ id, ...data }: Partial<RuleRow> & { id: number }) => {
      const res = await fetch(`/api/rules/${id}`, {
        method: "PATCH",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(data),
      });
      if (!res.ok) throw new Error("Failed to update rule");
      return res.json();
    },
    onSuccess: () => qc.invalidateQueries({ queryKey: ["rules"] }),
  });
}

export function useDeleteRule() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async (id: number) => {
      await fetch(`/api/rules/${id}`, { method: "DELETE" });
    },
    onSuccess: () => qc.invalidateQueries({ queryKey: ["rules"] }),
  });
}

export function useApplyRules() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: async () => {
      const res = await fetch("/api/rules/apply", { method: "POST" });
      if (!res.ok) throw new Error("Failed to apply rules");
      return res.json() as Promise<{ matched: number; transactions_affected: number }>;
    },
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ["transactions"] });
      qc.invalidateQueries({ queryKey: ["rules"] });
    },
  });
}