import axios, { AxiosError, InternalAxiosRequestConfig } from 'axios';
import type {
  AuthResponse,
  Category,
  PaginatedResponse,
  Tenant,
  User,
  Workflow,
  WorkflowStep,
} from '../types';

const api = axios.create({
  baseURL: '/api',
  headers: { 'Content-Type': 'application/json' },
});

let isRefreshing = false;
let failedQueue: Array<{
  resolve: (token: string) => void;
  reject: (err: unknown) => void;
}> = [];

function processQueue(error: unknown, token: string | null = null) {
  failedQueue.forEach((p) => {
    if (error) {
      p.reject(error);
    } else {
      p.resolve(token!);
    }
  });
  failedQueue = [];
}

api.interceptors.request.use((config: InternalAxiosRequestConfig) => {
  const token = localStorage.getItem('accessToken');
  if (token && config.headers) {
    config.headers.Authorization = `Bearer ${token}`;
  }
  return config;
});

api.interceptors.response.use(
  (response) => response,
  async (error: AxiosError) => {
    const originalRequest = error.config as InternalAxiosRequestConfig & {
      _retry?: boolean;
    };

    if (error.response?.status === 401 && !originalRequest._retry) {
      if (isRefreshing) {
        return new Promise((resolve, reject) => {
          failedQueue.push({
            resolve: (token: string) => {
              if (originalRequest.headers) {
                originalRequest.headers.Authorization = `Bearer ${token}`;
              }
              resolve(api(originalRequest));
            },
            reject,
          });
        });
      }

      originalRequest._retry = true;
      isRefreshing = true;

      const refreshToken = localStorage.getItem('refreshToken');
      if (!refreshToken) {
        localStorage.removeItem('accessToken');
        localStorage.removeItem('refreshToken');
        window.location.href = '/login';
        return Promise.reject(error);
      }

      try {
        const { data } = await axios.post<{ accessToken: string; refreshToken: string }>(
          '/api/auth/refresh',
          { refreshToken },
        );
        localStorage.setItem('accessToken', data.accessToken);
        localStorage.setItem('refreshToken', data.refreshToken);
        processQueue(null, data.accessToken);
        if (originalRequest.headers) {
          originalRequest.headers.Authorization = `Bearer ${data.accessToken}`;
        }
        return api(originalRequest);
      } catch (refreshError) {
        processQueue(refreshError, null);
        localStorage.removeItem('accessToken');
        localStorage.removeItem('refreshToken');
        window.location.href = '/login';
        return Promise.reject(refreshError);
      } finally {
        isRefreshing = false;
      }
    }

    return Promise.reject(error);
  }
);

// --- Auth ---
// Login returns { accessToken, refreshToken, user } directly
// /me returns user object directly
// /refresh returns { accessToken, refreshToken } (no user)
export const authApi = {
  login: (email: string, password: string) =>
    api.post<AuthResponse>('/auth/login', { email, password }).then((r) => r.data),

  refresh: (refreshToken: string) =>
    api
      .post<{ accessToken: string; refreshToken: string }>('/auth/refresh', { refreshToken })
      .then((r) => r.data),

  me: () => api.get<User>('/auth/me').then((r) => r.data),

  logout: (refreshToken?: string | null) =>
    api.post('/auth/logout', { refreshToken }).then((r) => r.data),
};

// --- Tenants ---
// Backend returns { data: Tenant[] } (no pagination)
export const tenantsApi = {
  list: (params?: { page?: number; pageSize?: number; search?: string }) =>
    api
      .get<{ data: Tenant[] }>('/tenants', { params })
      .then((r) => {
        const tenants = r.data.data;
        // Client-side search if the backend doesn't support it
        let filtered = tenants;
        if (params?.search) {
          const s = params.search.toLowerCase();
          filtered = tenants.filter(
            (t) =>
              t.name.toLowerCase().includes(s) ||
              t.slug.toLowerCase().includes(s)
          );
        }
        // Client-side pagination
        const page = params?.page || 1;
        const pageSize = params?.pageSize || 20;
        const total = filtered.length;
        const totalPages = Math.ceil(total / pageSize) || 1;
        const start = (page - 1) * pageSize;
        const data = filtered.slice(start, start + pageSize);
        return { data, total, page, pageSize, totalPages } as PaginatedResponse<Tenant>;
      }),

  get: (id: string) =>
    api.get<{ data: Tenant }>(`/tenants/${id}`).then((r) => r.data.data),

  create: (data: Partial<Tenant>) =>
    api.post<{ data: Tenant }>('/tenants', data).then((r) => r.data.data),

  update: (id: string, data: Partial<Tenant>) =>
    api.put<{ data: Tenant }>(`/tenants/${id}`, data).then((r) => r.data.data),

  delete: (id: string) => api.delete(`/tenants/${id}`).then((r) => r.data),
};

// --- Users ---
// Backend returns { data: User[] } (no pagination)
export const usersApi = {
  list: (params?: {
    page?: number;
    pageSize?: number;
    search?: string;
    tenantId?: string;
    role?: string;
  }) =>
    api
      .get<{ data: User[] }>('/users', {
        params: {
          tenantId: params?.tenantId,
        },
      })
      .then((r) => {
        let users = r.data.data;
        // Client-side search
        if (params?.search) {
          const s = params.search.toLowerCase();
          users = users.filter(
            (u) =>
              u.firstName.toLowerCase().includes(s) ||
              u.lastName.toLowerCase().includes(s) ||
              u.email.toLowerCase().includes(s)
          );
        }
        // Client-side role filter
        if (params?.role) {
          users = users.filter((u) => u.role === params.role);
        }
        // Client-side pagination
        const page = params?.page || 1;
        const pageSize = params?.pageSize || 20;
        const total = users.length;
        const totalPages = Math.ceil(total / pageSize) || 1;
        const start = (page - 1) * pageSize;
        const data = users.slice(start, start + pageSize);
        return { data, total, page, pageSize, totalPages } as PaginatedResponse<User>;
      }),

  get: (id: string) =>
    api.get<{ data: User }>(`/users/${id}`).then((r) => r.data.data),

  create: (data: Partial<User> & { password?: string }) =>
    api.post<{ data: User }>('/users', data).then((r) => r.data.data),

  update: (id: string, data: Partial<User>) =>
    api.put<{ data: User }>(`/users/${id}`, data).then((r) => r.data.data),

  delete: (id: string) => api.delete(`/users/${id}`).then((r) => r.data),
};

// --- Workflows ---
// Backend list returns { data: Workflow[], pagination: { page, limit, total, totalPages } }
// Backend uses "limit" query param (not "pageSize")
// Single-item endpoints return { data: Workflow }
export const workflowsApi = {
  list: (params?: {
    page?: number;
    pageSize?: number;
    search?: string;
    status?: string;
    categoryId?: string;
    tenantId?: string;
    isTemplate?: boolean;
    tags?: string;
  }) =>
    api
      .get<{
        data: Workflow[];
        pagination: { page: number; limit: number; total: number; totalPages: number };
      }>('/workflows', {
        params: {
          page: params?.page,
          limit: params?.pageSize,
          search: params?.search,
          status: params?.status,
          categoryId: params?.categoryId,
          tenantId: params?.tenantId,
          isTemplate: params?.isTemplate,
          tags: params?.tags,
        },
      })
      .then((r) => ({
        data: r.data.data,
        total: r.data.pagination.total,
        page: r.data.pagination.page,
        pageSize: r.data.pagination.limit,
        totalPages: r.data.pagination.totalPages,
      })),

  get: (id: string) =>
    api.get<{ data: Workflow }>(`/workflows/${id}`).then((r) => r.data.data),

  create: (data: Partial<Workflow>) =>
    api.post<{ data: Workflow }>('/workflows', data).then((r) => r.data.data),

  update: (id: string, data: Partial<Workflow>) =>
    api.put<{ data: Workflow }>(`/workflows/${id}`, data).then((r) => r.data.data),

  delete: (id: string) => api.delete(`/workflows/${id}`).then((r) => r.data),

  duplicate: (id: string) =>
    api.post<{ data: Workflow }>(`/workflows/${id}/duplicate`).then((r) => r.data.data),

  // Publish and archive use the PATCH /:id/status endpoint
  publish: (id: string) =>
    api
      .patch<{ data: Workflow }>(`/workflows/${id}/status`, { status: 'PUBLISHED' })
      .then((r) => r.data.data),

  archive: (id: string) =>
    api
      .patch<{ data: Workflow }>(`/workflows/${id}/status`, { status: 'ARCHIVED' })
      .then((r) => r.data.data),

  changeStatus: (id: string, status: Workflow['status']) =>
    api
      .patch<{ data: Workflow }>(`/workflows/${id}/status`, { status })
      .then((r) => r.data.data),
};

// --- Workflow Steps ---
export const stepsApi = {
  create: (workflowId: string, data: Partial<WorkflowStep>) =>
    api
      .post<{ data: WorkflowStep }>(`/workflows/${workflowId}/steps`, data)
      .then((r) => r.data.data),

  update: (workflowId: string, stepId: string, data: Partial<WorkflowStep>) =>
    api
      .put<{ data: WorkflowStep }>(`/workflows/${workflowId}/steps/${stepId}`, data)
      .then((r) => r.data.data),

  delete: (workflowId: string, stepId: string) =>
    api.delete(`/workflows/${workflowId}/steps/${stepId}`).then((r) => r.data),

  reorder: (workflowId: string, steps: { id: string; order: number }[]) =>
    api
      .patch(`/workflows/${workflowId}/steps/reorder`, { steps })
      .then((r) => r.data),
};

// --- Categories ---
export const categoriesApi = {
  list: () =>
    api.get<{ data: Category[] }>('/categories').then((r) => r.data.data),

  create: (data: Partial<Category>) =>
    api.post<{ data: Category }>('/categories', data).then((r) => r.data.data),

  update: (id: string, data: Partial<Category>) =>
    api.put<{ data: Category }>(`/categories/${id}`, data).then((r) => r.data.data),

  delete: (id: string) => api.delete(`/categories/${id}`).then((r) => r.data),
};

export default api;