// Hugging Face Dataset Server API Service
import type {
  DatasetRowsResponse,
  DatasetFirstRowsResponse,
  DatasetSplitsResponse,
  DatasetError,
} from "./types";
import yaml from "js-yaml";
const BASE_URL = "https://datasets-server.huggingface.co";

/**
 * Fetch the first 100 rows of a dataset
 */
export async function fetchFirstRows(
  dataset: string,
  config: string = "default",
  split: string = "train",
  token?: string
): Promise<DatasetFirstRowsResponse> {
  const url = `${BASE_URL}/first-rows?dataset=${encodeURIComponent(
    dataset
  )}&config=${encodeURIComponent(config)}&split=${encodeURIComponent(split)}`;

  const headers: HeadersInit = {};
  if (token) {
    headers["Authorization"] = `Bearer ${token}`;
  }

  const response = await fetch(url, { headers });

  if (!response.ok) {
    const error: DatasetError = await response.json();
    throw new Error(
      error.error || `Failed to fetch dataset: ${response.statusText}`
    );
  }

  return response.json();
}

/**
 * Fetch paginated rows from a dataset
 * @param offset Starting row index (0-based)
 * @param length Number of rows to fetch (max 100)
 */
export async function fetchRows(
  dataset: string,
  config: string = "default",
  split: string = "train",
  offset: number = 0,
  length: number = 100,
  token?: string
): Promise<DatasetRowsResponse> {
  const url = `${BASE_URL}/rows?dataset=${encodeURIComponent(
    dataset
  )}&config=${encodeURIComponent(config)}&split=${encodeURIComponent(
    split
  )}&offset=${offset}&length=${length}`;

  const headers: HeadersInit = {};
  if (token) {
    headers["Authorization"] = `Bearer ${token}`;
  }

  const response = await fetch(url, { headers });

  if (!response.ok) {
    const error: DatasetError = await response.json();
    throw new Error(
      error.error || `Failed to fetch dataset: ${response.statusText}`
    );
  }

  return response.json();
}

/**
 * List available splits for a dataset
 */
export async function fetchSplits(
  dataset: string,
  token?: string
): Promise<DatasetSplitsResponse> {
  const url = `${BASE_URL}/splits?dataset=${encodeURIComponent(dataset)}`;

  const headers: HeadersInit = {};
  if (token) {
    headers["Authorization"] = `Bearer ${token}`;
  }

  const response = await fetch(url, { headers });

  if (!response.ok) {
    const error: DatasetError = await response.json();
    throw new Error(
      error.error || `Failed to fetch splits: ${response.statusText}`
    );
  }

  return response.json();
}

/**
 * Check if a dataset is valid and accessible
 */
export async function checkDatasetValid(
  dataset: string,
  token?: string
): Promise<boolean> {
  const url = `${BASE_URL}/is-valid?dataset=${encodeURIComponent(dataset)}`;

  const headers: HeadersInit = {};
  if (token) {
    headers["Authorization"] = `Bearer ${token}`;
  }

  const response = await fetch(url, { headers });

  if (!response.ok) {
    return false;
  }

  const data = await response.json();
  return data.valid === true;
}

/**
 * Fetch all rows from a jurisdiction config (for term/definition data)
 */
export async function fetchAllRows(
  dataset: string,
  config: string,
  split: string = "train",
  token?: string
): Promise<any[]> {
  const allRows: any[] = [];
  let offset = 0;
  const batchSize = 100;
  let hasMore = true;

  while (hasMore) {
    const response = await fetchRows(
      dataset,
      config,
      split,
      offset,
      batchSize,
      token
    );
    const rows = response.rows.map((r) => r.row);
    allRows.push(...rows);

    offset += rows.length;
    hasMore = offset < response.num_rows_total;
  }

  return allRows;
}

export async function fetchDatasetFileRaw(
  dataset: string, // "owner/dataset-name"
  filePath: string, // "config.yaml"
  branch = "main",
  token?: string
): Promise<string> {
  const url = `https://huggingface.co/datasets/${dataset}/raw/${encodeURIComponent(
    branch
  )}/${filePath}`;
  const headers: HeadersInit = {};
  if (token) {
    headers["Authorization"] = `Bearer ${token}`;
  }
  const res = await fetch(url, { headers });
  if (!res.ok)
    throw new Error(`Failed to fetch file: ${res.status} ${res.statusText}`);
  return res.text();
}

export interface DatasetConfigYaml {
  scoring_model: string;
  scoring_provider: string;
  synthesis_model: string;
  synthesis_provider: string;
  jurisdiction1: string;
  jurisdiction2: string;
  description: string;
  grading_templates_1_uid: string;
  grading_templates_2_uid: string;
  generation_date?: string;
}

export async function fetchDatasetConfigYaml(
  dataset: string,
  filePath = "config.yaml",
  branch = "main",
  token?: string
): Promise<DatasetConfigYaml | null> {
  const text = await fetchDatasetFileRaw(dataset, filePath, branch, token);
  return yaml.load(text) as DatasetConfigYaml;
}