# -*- coding: utf-8 -*-
"""Shared helpers for standalone RAG example tests."""
import math
import os
import re
import sys
import time
import types

ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
if ROOT_DIR not in sys.path:
    sys.path.insert(0, ROOT_DIR)

from bdirag.document_processor import Document
from examples.sample_data import SAMPLE_BIDDING_DOCS


TEST_QUERIES = [
    "project budget amount",
    "bid bond amount",
    "qualification requirements",
    "evaluation method",
    "warranty period",
    "payment terms",
    "project code XX-ZB",
    "delivery time",
]


def install_rank_bm25_fallback():
    """Expose the repo BM25 fallback as rank_bm25 for methods that import it."""
    if "rank_bm25" in sys.modules:
        return
    from bdirag.rag_methods.bm25_backend import SimpleBM25Okapi

    module = types.ModuleType("rank_bm25")
    module.BM25Okapi = SimpleBM25Okapi
    sys.modules["rank_bm25"] = module


class _ScoreList(list):
    def flatten(self):
        return self


class _SimpleTfidfVectorizer(object):
    def __init__(self):
        self.vocabulary_ = {}

    def fit_transform(self, texts):
        for text in texts:
            for token in _tokens(text):
                if token not in self.vocabulary_:
                    self.vocabulary_[token] = len(self.vocabulary_)
        return self.transform(texts)

    def transform(self, texts):
        vectors = []
        for text in texts:
            vector = [0.0] * len(self.vocabulary_)
            for token in _tokens(text):
                index = self.vocabulary_.get(token)
                if index is not None:
                    vector[index] += 1.0
            norm = math.sqrt(sum(v * v for v in vector)) or 1.0
            vectors.append([v / norm for v in vector])
        return vectors


def _simple_cosine_similarity(query_vecs, matrix):
    query = query_vecs[0] if query_vecs else []
    scores = _ScoreList()
    for vector in matrix:
        scores.append(sum(a * b for a, b in zip(query, vector)))
    return scores


class _SimpleKMeans(object):
    def __init__(self, n_clusters=2, random_state=None):
        self.n_clusters = max(1, int(n_clusters))
        self.random_state = random_state

    def fit_predict(self, embeddings):
        return [i % self.n_clusters for i in range(len(embeddings))]


def install_sklearn_fallback():
    """Install tiny sklearn-compatible modules used by the example tests."""
    sklearn = types.ModuleType("sklearn")
    feature_extraction = types.ModuleType("sklearn.feature_extraction")
    text = types.ModuleType("sklearn.feature_extraction.text")
    metrics = types.ModuleType("sklearn.metrics")
    pairwise = types.ModuleType("sklearn.metrics.pairwise")
    cluster = types.ModuleType("sklearn.cluster")

    text.TfidfVectorizer = _SimpleTfidfVectorizer
    pairwise.cosine_similarity = _simple_cosine_similarity
    cluster.KMeans = _SimpleKMeans

    sklearn.feature_extraction = feature_extraction
    sklearn.metrics = metrics
    sklearn.cluster = cluster
    feature_extraction.text = text
    metrics.pairwise = pairwise

    sys.modules["sklearn"] = sklearn
    sys.modules["sklearn.feature_extraction"] = feature_extraction
    sys.modules["sklearn.feature_extraction.text"] = text
    sys.modules["sklearn.metrics"] = metrics
    sys.modules["sklearn.metrics.pairwise"] = pairwise
    sys.modules["sklearn.cluster"] = cluster


def make_documents():
    return [
        Document(
            page_content=doc["content"],
            metadata={"title": doc["title"], "source": doc["title"]},
        )
        for doc in SAMPLE_BIDDING_DOCS
    ]


def _tokens(text):
    return re.findall(r"[A-Za-z0-9]+", (text or "").lower())


class FakeEmbedding(object):
    def __init__(self, dimension=64):
        self.dimension = dimension

    def _embed(self, text):
        vector = [0.0] * self.dimension
        for token in _tokens(text):
            index = sum(ord(ch) for ch in token) % self.dimension
            vector[index] += 1.0
        norm = math.sqrt(sum(v * v for v in vector)) or 1.0
        return [v / norm for v in vector]

    def embed_documents(self, texts):
        return [self._embed(text) for text in texts]

    def embed_query(self, text):
        return self._embed(text)


class SimpleVectorStore(object):
    def __init__(self):
        self.documents = []
        self.embeddings = []

    def add_documents(self, documents, embeddings):
        self.documents.extend(documents)
        self.embeddings.extend(embeddings)

    def similarity_search(self, query_embedding, k=10):
        scored = []
        for doc, embedding in zip(self.documents, self.embeddings):
            score = sum(a * b for a, b in zip(query_embedding, embedding))
            if score > 0:
                scored.append((doc, float(score)))
        scored.sort(key=lambda item: item[1], reverse=True)
        return scored[:k]

    def save(self, path):
        return None

    def load(self, path):
        return None


class _FakeMessage(object):
    def __init__(self, content):
        self.content = content


class _FakeChoice(object):
    def __init__(self, content):
        self.message = _FakeMessage(content)


class _FakeResponse(object):
    def __init__(self, content):
        self.choices = [_FakeChoice(content)]


class _FakeCompletions(object):
    def create(self, model=None, messages=None, temperature=None, max_tokens=None):
        prompt = messages[-1]["content"] if messages else ""
        return _FakeResponse(fake_llm_text(prompt))


class _FakeChat(object):
    def __init__(self):
        self.completions = _FakeCompletions()


class FakeLLMClient(object):
    def __init__(self):
        self.chat = _FakeChat()


def fake_llm_text(prompt):
    lower = (prompt or "").lower()
    if "json" in lower:
        return (
            '{"project_name": "sample bidding project", '
            '"budget_amount": "sample budget", '
            '"evaluation_method": "sample evaluation method"}'
        )
    if "0-1" in prompt or "0-1" in lower or "score" in lower:
        return "0.8"
    if "category" in lower or "classify" in lower:
        return "budget"
    if "simple" in lower and "complex" in lower:
        return "simple"
    if "sub" in lower or "variant" in lower:
        return "project budget\nqualification requirements\ndelivery time"
    if "step" in lower or "general" in lower:
        return "general bidding project information"
    return "Sample offline LLM answer for the standalone RAG test."


class FakeRerankModel(object):
    def compute_score(self, pairs):
        scores = []
        for query, text in pairs:
            query_words = set(_tokens(query))
            text_words = set(_tokens(text))
            scores.append(float(len(query_words & text_words)) + 0.1)
        return scores


def build_vector_rag(rag_cls, **kwargs):
    options = {
        "embedding_model": FakeEmbedding(),
        "vector_store": SimpleVectorStore(),
        "llm_client": FakeLLMClient(),
    }
    options.update(kwargs)
    return rag_cls(**options)


def print_results(method_name, query, results, elapsed):
    print("\nQuery: {}".format(query))
    print("-" * 60)
    print("  Retrieved {} documents in {:.4f}s".format(len(results), elapsed))
    for i, (doc, score) in enumerate(results, 1):
        title = doc.metadata.get("title", doc.metadata.get("source", "Unknown"))
        preview = doc.page_content[:100].replace("\n", " ")
        print("  [{}] {} (Score: {:.4f})".format(i, title, float(score)))
        print("      Preview: {}...".format(preview))


def jinrun_retrieval_test(method_name, rag, index_func=None, queries=None, k=3):
    print("=" * 60)
    print("{} - Standalone Retrieval Test".format(method_name))
    print("=" * 60)

    documents = make_documents()
    print("\n[1/2] Preparing documents...")
    print("  Prepared {} documents".format(len(documents)))

    print("\n[2/2] Building index...")
    if index_func is None:
        rag.index_documents(documents)
    else:
        index_func(rag, documents)
    print("  Index built successfully")

    print("\n" + "=" * 60)
    print("{} Retrieval Test Results".format(method_name))
    print("=" * 60)

    for query in queries or TEST_QUERIES:
        start = time.time()
        results = rag.retrieve(query, k=k)
        elapsed = time.time() - start
        print_results(method_name, query, results, elapsed)

    print("\n{} test complete!".format(method_name))


run_retrieval_test = jinrun_retrieval_test


def run_html_tree_test(rag_cls):
    sample_html = """
    <html><body>
      <h1>Sample Medical Equipment Procurement Bidding Announcement</h1>
      <h2>Project Overview</h2>
      <p>Project budget: 28,000,000 RMB</p>
      <p>Project code: XX-HOSP-2024-015</p>
      <h2>Qualification Requirements</h2>
      <p>Must have Medical Device Operation License and ISO 13485 certification.</p>
      <h2>Delivery and Warranty</h2>
      <p>Delivery time: within 90 calendar days. Warranty period: minimum 5 years.</p>
      <h2>Payment Terms</h2>
      <p>100% payment after installation, debugging and acceptance.</p>
    </body></html>
    """

    print("=" * 60)
    print("{} - Standalone HTML Tree Test".format(rag_cls.__name__))
    print("=" * 60)

    rag = rag_cls()
    rag.build_index(sample_html)
    print("  HTML tree index built successfully")

    for query in ["project budget", "qualification requirements", "delivery time", "payment terms"]:
        start = time.time()
        results = rag.query(query, k=3)
        elapsed = time.time() - start
        print_results(rag_cls.__name__, query, results, elapsed)

    print("\n{} test complete!".format(rag_cls.__name__))