import axios from "axios";
import type {
  InitRequest, InitResponse, DocumentRequest, AddDocResponse, BuildIndexResponse,
  QueryRequest, QueryResponse, CompareRequest, CompareResponse,
  KeywordAnalysisRequest, KeywordAnalysisResponse,
  KeywordMatchRequest, MatchResponse, BatchAnalysisRequest,
  CorpusStats, SimilarityDistribution, DisambiguationMetric, RetrievalMetric,
  TrainResponse, TrainEvalResponse,
  W2VInitResponse, W2VQueryResult, W2VSimilarWord,
  DatasetInfo, DatasetLoadRequest, DatasetLoadResponse, DatasetPreviewResponse,
  ContextAnalysisResponse,
} from "./types";

// HuggingFace Spaces proxy requires the __sign token on every request.
// Extract it from the page URL and attach to all API calls.
const _params = new URLSearchParams(window.location.search);
const _sign = _params.get("__sign");

const client = axios.create({
  baseURL: "/api",
  ...(_sign && { params: { __sign: _sign } }),
});
const long = { timeout: 600000 };

/** Extract a human-readable error message from an Axios error. */
export function getErrorMessage(err: unknown): string {
  if (axios.isAxiosError(err)) {
    if (err.code === "ECONNABORTED") return "Request timed out. The server may be busy.";
    if (!err.response) return "Cannot connect to server. Is it running? (uv run python server.py)";
    const detail = err.response.data?.detail;
    if (typeof detail === "string") return detail;
    if (typeof err.response.data === "string") return err.response.data;
    return `Server error (${err.response.status})`;
  }
  if (err instanceof Error) return err.message;
  return "An unexpected error occurred.";
}

/** Check if the backend is reachable. Returns null on success or an error message. */
export async function checkConnection(): Promise<string | null> {
  try {
    await client.get("/stats", { timeout: 5000 });
    return null;
  } catch (err) {
    if (axios.isAxiosError(err) && err.response?.status === 400) {
      // 400 = "Engine not initialized" — server is up, just no engine yet
      return null;
    }
    return getErrorMessage(err);
  }
}

/** Shared shape for all training requests (matches server TrainRequest). */
interface TrainRequestData {
  corpus_texts: string[];
  base_model: string;
  output_path: string;
  epochs: number;
  batch_size: number;
}

export const api = {
  // ---- Training ----
  trainUnsupervised: (data: TrainRequestData) =>
    client.post<TrainResponse>("/train/unsupervised", data, long).then(r => r.data),

  trainContrastive: (data: TrainRequestData) =>
    client.post<TrainResponse>("/train/contrastive", data, long).then(r => r.data),

  trainKeywords: (data: TrainRequestData & { keyword_meanings: Record<string, string> }) =>
    client.post<TrainResponse>("/train/keywords", data, long).then(r => r.data),

  trainEvaluate: (data: { test_pairs: { text_a: string; text_b: string; expected: number }[]; trained_model_path: string; base_model: string; corpus_texts: string[] }) =>
    client.post<TrainEvalResponse>("/train/evaluate", data).then(r => r.data),

  // ---- Engine ----
  init: (data: InitRequest) =>
    client.post<InitResponse>("/init", data).then(r => r.data),

  addDocument: (data: DocumentRequest) =>
    client.post<AddDocResponse>("/documents", data).then(r => r.data),

  buildIndex: () =>
    client.post<BuildIndexResponse>("/index/build").then(r => r.data),

  query: (data: QueryRequest) =>
    client.post<QueryResponse>("/query", data).then(r => r.data),

  compare: (data: CompareRequest) =>
    client.post<CompareResponse>("/compare", data).then(r => r.data),

  analyzeKeyword: (data: KeywordAnalysisRequest) =>
    client.post<KeywordAnalysisResponse>("/analyze/keyword", data).then(r => r.data),

  batchAnalyze: (data: BatchAnalysisRequest) =>
    client.post<Record<string, KeywordAnalysisResponse>>("/analyze/batch", data).then(r => r.data),

  matchKeyword: (data: KeywordMatchRequest) =>
    client.post<MatchResponse>("/match", data).then(r => r.data),

  analyzeContext: (data: { keyword: string; cluster_threshold?: number; top_words?: number }) =>
    client.post<ContextAnalysisResponse>("/analyze/context", data).then(r => r.data),

  similarWords: (data: { word: string; top_k: number }) =>
    client.post<{ word: string; similar: { word: string; score: number }[] }>("/analyze/similar-words", data).then(r => r.data),

  getStats: () =>
    client.get<CorpusStats>("/stats").then(r => r.data),

  pollLogs: (cursor: number = 0) =>
    client.get<{ lines: string[]; cursor: number }>(`/logs/poll?cursor=${cursor}`).then(r => r.data),

  getCorpusTexts: (maxDocs: number = 500) =>
    client.get<{ documents: { doc_id: string; text: string }[]; count: number }>(`/corpus/texts?max_docs=${maxDocs}`).then(r => r.data),

  getDocument: (docId: string) =>
    client.get<{ doc_id: string; text: string; num_chunks: number }>(`/documents/${encodeURIComponent(docId)}`).then(r => r.data),

  // ---- Engine persistence ----
  saveEngine: () =>
    client.post<{ status: string; chunks: number; documents: number }>("/engine/save").then(r => r.data),

  hasSavedState: () =>
    client.get<{ exists: boolean }>("/engine/has-saved-state").then(r => r.data),

  // ---- Evaluation ----
  getSimilarityDistribution: () =>
    client.get<SimilarityDistribution>("/eval/similarity-distribution").then(r => r.data),

  evalDisambiguation: (data: { ground_truth: { keyword: string; text: string; true_meaning: string }[]; candidate_meanings: Record<string, string[]> }) =>
    client.post<{ metrics: DisambiguationMetric[] }>("/eval/disambiguation", data).then(r => r.data),

  evalRetrieval: (data: { queries: { query: string; relevant_doc_ids?: string[]; relevant_texts?: string[] }[]; k_values: number[] }) =>
    client.post<{ metrics: RetrievalMetric[] }>("/eval/retrieval", data).then(r => r.data),

  // ---- Word2Vec ----
  w2vInit: (data: { corpus_texts: string[]; vector_size: number; window: number; epochs: number }) =>
    client.post<W2VInitResponse>("/w2v/init", data, long).then(r => r.data),

  w2vInitFromEngine: (params?: { vector_size?: number; window?: number; epochs?: number }) =>
    client.post<W2VInitResponse & { documents_used: number }>(`/w2v/init-from-engine`, null, {
      ...long,
      params: { ...(_sign && { __sign: _sign }), ...params },
    }).then(r => r.data),

  w2vStatus: () =>
    client.get<{ ready: boolean; vocab_size?: number; sentences?: number; vector_size?: number; has_saved_state?: boolean }>("/w2v/status").then(r => r.data),

  w2vReset: () =>
    client.post<{ status: string; message: string }>("/w2v/reset").then(r => r.data),

  w2vCompare: (data: { text_a: string; text_b: string }) =>
    client.post<CompareResponse>("/w2v/compare", data).then(r => r.data),

  w2vQuery: (data: { text: string; top_k: number }) =>
    client.post<{ query: string; results: W2VQueryResult[] }>("/w2v/query", data).then(r => r.data),

  w2vSimilarWords: (data: { word: string; top_k: number }) =>
    client.post<{ word: string; similar: W2VSimilarWord[] }>("/w2v/similar-words", data).then(r => r.data),

  // ---- Dataset (HuggingFace) ----
  datasetInfo: () =>
    client.get<DatasetInfo>("/dataset/info").then(r => r.data),

  datasetLoad: (data: DatasetLoadRequest) =>
    client.post<DatasetLoadResponse>("/dataset/load", data, long).then(r => r.data),

  datasetPreview: (maxDocs: number = 10, sourceFilter?: string) =>
    client.post<DatasetPreviewResponse>(`/dataset/preview?max_docs=${maxDocs}${sourceFilter ? `&source_filter=${sourceFilter}` : ""}`).then(r => r.data),
};