import hashlib
import math
import sys
from dataclasses import dataclass
from pathlib import Path

import pytest

# The modules under test live in the sibling scripts/ directory.
sys.path.insert(0, str(Path(__file__).parent.parent / "scripts"))

import wiki_config
import wiki_search
import wiki_sync
from wiki_db import EMBEDDING_DIMS

CONFIG_TEMPLATE = """
embedding:
  endpoint: http://embed.invalid:11434
  model: qwen3-embedding:0.6b
  dims: 1024
  batch: 4
  keep_alive: -1
  query_prefix: "Instruct: task\\nQuery: "

sources:
{sources}
"""

WORKSPACE_SOURCE = """  workspace:
    kind: workspace
    paths:
      - "notes/**"
      - "develop/**"
    include: ["*.md"]
    exclude:
      - "**/inbox/**"
      - "develop/history.md"
"""


@dataclass
class WikiEnv:
    workspace: Path
    wiki_dir: Path
    config_path: Path
    db_path: Path
    log_path: Path

    def write_config(self, sources: str = WORKSPACE_SOURCE) -> None:
        self.config_path.write_text(CONFIG_TEMPLATE.format(sources=sources), encoding="utf-8")

    def write_file(self, rel_path: str, text: str) -> Path:
        path = self.workspace / rel_path
        path.parent.mkdir(parents=True, exist_ok=True)
        path.write_text(text, encoding="utf-8")
        return path

    def log_text(self) -> str:
        return self.log_path.read_text(encoding="utf-8") if self.log_path.exists() else ""


@pytest.fixture
def wiki_env(tmp_path, monkeypatch) -> WikiEnv:
    """Redirect every wiki path at a throwaway workspace."""
    workspace = tmp_path / "workspace"
    wiki_dir = workspace / "wiki"
    wiki_dir.mkdir(parents=True)

    env = WikiEnv(
        workspace=workspace,
        wiki_dir=wiki_dir,
        config_path=wiki_dir / "config.yaml",
        db_path=wiki_dir / "index.sqlite",
        log_path=workspace / "log" / "wiki_sync.log",
    )

    monkeypatch.setenv("WIKI_DB", str(env.db_path))
    monkeypatch.setenv("WIKI_CONFIG", str(env.config_path))
    monkeypatch.setattr(wiki_config, "WORKSPACE", workspace)
    monkeypatch.setattr(wiki_config, "WIKI_DIR", wiki_dir)
    monkeypatch.setattr(wiki_config, "REMOTE_DIR", wiki_dir / "remote")
    monkeypatch.setattr(wiki_config, "LOCK_PATH", wiki_dir / ".sync.lock")
    monkeypatch.setattr(wiki_sync, "WIKI_DIR", wiki_dir)
    monkeypatch.setattr(wiki_sync, "LOCK_PATH", wiki_dir / ".sync.lock")
    monkeypatch.setattr(wiki_sync, "SYNC_LOG_PATH", env.log_path)

    env.write_config()
    return env


class FakeEmbedder:
    """Bag-of-words vectors: cosine tracks lexical overlap, so ranks are predictable.

    Enough to exercise the KNN and RRF plumbing without a live model. Semantic quality
    is measured against the real endpoint, not here.
    """

    def __init__(self, config):
        self.config = config
        self.calls: list[list[str]] = []

    def embed_documents(self, texts):
        self.calls.append(list(texts))
        return [self._vector(text) for text in texts]

    def embed_query(self, text):
        return self._vector(self.config.query_prefix + text)

    def probe(self):
        return None

    def _vector(self, text: str) -> list[float]:
        vector = [0.0] * EMBEDDING_DIMS
        for word in _words(text):
            digest = hashlib.sha256(word.encode("utf-8")).digest()
            vector[int.from_bytes(digest[:4], "big") % EMBEDDING_DIMS] += 1.0
        norm = math.sqrt(sum(value * value for value in vector))
        if norm == 0.0:
            vector[0] = 1.0
            return vector
        return [value / norm for value in vector]


def _words(text: str) -> list[str]:
    return [word for word in "".join(c.lower() if c.isalnum() else " " for c in text).split() if len(word) > 2]


@pytest.fixture
def fake_embedder(monkeypatch):
    """Swap the Ollama client for the deterministic fake in both entry points."""
    created: list[FakeEmbedder] = []

    def factory(config):
        embedder = FakeEmbedder(config)
        created.append(embedder)
        return embedder

    monkeypatch.setattr(wiki_sync, "OllamaEmbedder", factory)
    monkeypatch.setattr(wiki_search, "OllamaEmbedder", factory)
    return created