use affine_doc_loader::{BlockInfo, CrawlResult, ParseError, parse_doc_from_binary};
use memory_indexer::{SearchHit, SnapshotData};
use napi_derive::napi;
use serde::Serialize;
use sqlx::Row;
use y_octo::DocOptions;

// Increment this whenever there is a breaking change in the index format or how
// updates are applied
const NBSTORE_INDEXER_VERSION: u32 = 1;

use super::{
  error::{Error, Result},
  storage::SqliteDocStorage,
};

#[napi(object)]
#[derive(Debug, Serialize)]
pub struct NativeBlockInfo {
  pub block_id: String,
  pub flavour: String,
  pub content: Option<Vec<String>>,
  pub blob: Option<Vec<String>>,
  pub ref_doc_id: Option<Vec<String>>,
  pub ref_info: Option<Vec<String>>,
  pub parent_flavour: Option<String>,
  pub parent_block_id: Option<String>,
  pub additional: Option<String>,
}

impl From<BlockInfo> for NativeBlockInfo {
  fn from(value: BlockInfo) -> Self {
    Self {
      block_id: value.block_id,
      flavour: value.flavour,
      content: value.content,
      blob: value.blob,
      ref_doc_id: value.ref_doc_id,
      ref_info: value.ref_info,
      parent_flavour: value.parent_flavour,
      parent_block_id: value.parent_block_id,
      additional: value.additional,
    }
  }
}

#[napi(object)]
#[derive(Debug, Serialize)]
pub struct NativeCrawlResult {
  pub blocks: Vec<NativeBlockInfo>,
  pub title: String,
  pub summary: String,
}

impl From<CrawlResult> for NativeCrawlResult {
  fn from(value: CrawlResult) -> Self {
    Self {
      blocks: value.blocks.into_iter().map(Into::into).collect(),
      title: value.title,
      summary: value.summary,
    }
  }
}

#[napi(object)]
#[derive(Debug, Serialize)]
pub struct NativeSearchHit {
  pub id: String,
  pub score: f64,
  pub terms: Vec<String>,
}

impl From<SearchHit> for NativeSearchHit {
  fn from(value: SearchHit) -> Self {
    Self {
      id: value.doc_id,
      score: value.score,
      terms: value.matched_terms.into_iter().map(|t| t.term).collect(),
    }
  }
}

#[napi(object)]
#[derive(Debug, Serialize)]
pub struct NativeMatch {
  pub start: u32,
  pub end: u32,
}

impl From<(u32, u32)> for NativeMatch {
  fn from(value: (u32, u32)) -> Self {
    Self {
      start: value.0,
      end: value.1,
    }
  }
}

impl SqliteDocStorage {
  pub async fn crawl_doc_data(&self, doc_id: &str) -> Result<NativeCrawlResult> {
    let doc_bin = self.load_doc_binary(doc_id).await?.ok_or(ParseError::DocNotFound)?;

    let result = parse_doc_from_binary(doc_bin, doc_id.to_string())?;
    Ok(result.into())
  }

  async fn load_doc_binary(&self, doc_id: &str) -> Result<Option<Vec<u8>>> {
    let snapshot = self.get_doc_snapshot(doc_id.to_string()).await?;
    let mut updates = self.get_doc_updates(doc_id.to_string()).await?;

    if snapshot.is_none() && updates.is_empty() {
      return Ok(None);
    }

    updates.sort_by_key(|a| a.timestamp);

    let mut segments = Vec::with_capacity(snapshot.as_ref().map(|_| 1).unwrap_or(0) + updates.len());
    if let Some(record) = snapshot {
      segments.push(record.bin.to_vec());
    }
    segments.extend(updates.into_iter().map(|update| update.bin.to_vec()));

    merge_updates(segments, doc_id).map(Some)
  }

  pub async fn init_index(&self) -> Result<()> {
    let snapshots = sqlx::query("SELECT index_name, data FROM idx_snapshots")
      .fetch_all(&self.pool)
      .await?;

    {
      let mut index = self.index.write().await;
      let config = bincode::config::standard();
      for row in snapshots {
        let index_name: String = row.get("index_name");
        let data: Vec<u8> = row.get("data");
        if let Ok(decompressed) = zstd::stream::decode_all(std::io::Cursor::new(&data))
          && let Ok((snapshot, _)) = bincode::serde::decode_from_slice::<SnapshotData, _>(&decompressed, config)
        {
          index.load_snapshot(&index_name, snapshot);
        }
      }
    }

    Ok(())
  }

  async fn compact_index(&self, index_name: &str) -> Result<()> {
    let snapshot_data = {
      let index = self.index.read().await;
      index.get_snapshot_data(index_name)
    };

    if let Some(data) = snapshot_data {
      let blob = bincode::serde::encode_to_vec(&data, bincode::config::standard())
        .map_err(|e| Error::Serialization(e.to_string()))?;
      let compressed =
        zstd::stream::encode_all(std::io::Cursor::new(&blob), 4).map_err(|e| Error::Serialization(e.to_string()))?;

      let mut tx = self.pool.begin().await?;

      sqlx::query("INSERT OR REPLACE INTO idx_snapshots (index_name, data) VALUES (?, ?)")
        .bind(index_name)
        .bind(compressed)
        .execute(&mut *tx)
        .await?;

      tx.commit().await?;
    }
    Ok(())
  }

  pub async fn flush_index(&self) -> Result<()> {
    let (dirty_docs, deleted_docs) = {
      let mut index = self.index.write().await;
      index.take_dirty_and_deleted()
    };

    if dirty_docs.is_empty() && deleted_docs.is_empty() {
      return Ok(());
    }

    let mut modified_indices = std::collections::HashSet::new();
    for index_name in deleted_docs.keys() {
      modified_indices.insert(index_name.clone());
    }
    for (index_name, _, _, _) in &dirty_docs {
      modified_indices.insert(index_name.clone());
    }

    for index_name in modified_indices {
      self.compact_index(&index_name).await?;
    }

    Ok(())
  }

  pub fn index_version() -> u32 {
    memory_indexer::InMemoryIndex::snapshot_version() + NBSTORE_INDEXER_VERSION
  }

  pub async fn fts_add(&self, index_name: &str, doc_id: &str, text: &str, index: bool) -> Result<()> {
    let mut idx = self.index.write().await;
    idx.add_doc(index_name, doc_id, text, index);
    Ok(())
  }

  pub async fn fts_delete(&self, index_name: &str, doc_id: &str) -> Result<()> {
    let mut idx = self.index.write().await;
    idx.remove_doc(index_name, doc_id);
    Ok(())
  }

  pub async fn fts_get(&self, index_name: &str, doc_id: &str) -> Result<Option<String>> {
    let idx = self.index.read().await;
    Ok(idx.get_doc(index_name, doc_id))
  }

  pub async fn fts_search(&self, index_name: &str, query: &str) -> Result<Vec<NativeSearchHit>> {
    let idx = self.index.read().await;
    Ok(idx.search_hits(index_name, query).into_iter().map(Into::into).collect())
  }

  pub async fn fts_get_matches(&self, index_name: &str, doc_id: &str, query: &str) -> Result<Vec<NativeMatch>> {
    let idx = self.index.read().await;
    Ok(
      idx
        .get_matches(index_name, doc_id, query)
        .into_iter()
        .map(Into::into)
        .collect(),
    )
  }

  pub async fn fts_get_matches_for_terms(
    &self,
    index_name: &str,
    doc_id: &str,
    terms: Vec<String>,
  ) -> Result<Vec<NativeMatch>> {
    let idx = self.index.read().await;
    Ok(
      idx
        .get_matches_for_terms(index_name, doc_id, &terms)
        .into_iter()
        .map(Into::into)
        .collect(),
    )
  }
}

fn merge_updates(mut segments: Vec<Vec<u8>>, guid: &str) -> Result<Vec<u8>> {
  if segments.is_empty() {
    return Err(ParseError::DocNotFound.into());
  }

  if segments.len() == 1 {
    return segments.pop().ok_or(ParseError::DocNotFound.into());
  }

  let mut doc = DocOptions::new().with_guid(guid.to_string()).build();
  for update in segments.iter() {
    doc
      .apply_update_from_binary_v1(update)
      .map_err(|_| ParseError::InvalidBinary)?;
  }

  let buffer = doc
    .encode_update_v1()
    .map_err(|err| ParseError::ParserError(err.to_string()))?;

  Ok(buffer)
}

#[cfg(test)]
mod tests {
  use std::path::{Path, PathBuf};

  use affine_doc_loader::ParseError;
  use assert_json_diff::assert_json_eq;
  use chrono::Utc;
  use serde_json::Value;
  use tokio::fs;
  use uuid::Uuid;

  use super::{super::error::Error, *};

  const DEMO_BIN: &[u8] = include_bytes!("../../../../common/native/fixtures/demo.ydoc");
  const DEMO_JSON: &[u8] = include_bytes!("../../../../common/native/fixtures/demo.ydoc.json");

  fn temp_workspace_dir() -> PathBuf {
    std::env::temp_dir().join(format!("affine-native-{}", Uuid::new_v4()))
  }

  async fn init_db(path: &Path) -> SqliteDocStorage {
    fs::create_dir_all(path.parent().unwrap()).await.unwrap();
    let storage = SqliteDocStorage::new(path.to_string_lossy().into_owned());
    storage.connect().await.unwrap();
    storage
  }

  async fn cleanup(path: &Path) {
    let _ = fs::remove_dir_all(path.parent().unwrap()).await;
  }

  #[tokio::test]
  async fn parse_demo_snapshot_matches_fixture() {
    let base = temp_workspace_dir();
    fs::create_dir_all(&base).await.unwrap();
    let db_path = base.join("storage.db");

    let storage = init_db(&db_path).await;
    sqlx::query(r#"INSERT INTO snapshots (doc_id, data, updated_at) VALUES (?, ?, ?)"#)
      .bind("demo-doc")
      .bind(DEMO_BIN)
      .bind(Utc::now().naive_utc())
      .execute(&storage.pool)
      .await
      .unwrap();

    let result = storage.crawl_doc_data("demo-doc").await.unwrap();

    let mut expected: Value = serde_json::from_slice(DEMO_JSON).unwrap();
    let mut actual = serde_json::to_value(&result).unwrap();
    for document in [&mut expected, &mut actual] {
      for block in document["blocks"].as_array_mut().unwrap() {
        if let Some(additional) = block["additional"].as_str() {
          block["additional"] = serde_json::from_str(additional).unwrap();
        }
      }
    }
    assert_json_eq!(expected, actual);

    storage.close().await;
    cleanup(&db_path).await;
  }

  #[tokio::test]
  async fn missing_doc_returns_error() {
    let base = temp_workspace_dir();
    fs::create_dir_all(&base).await.unwrap();
    let db_path = base.join("storage.db");

    let storage = init_db(&db_path).await;

    let err = storage.crawl_doc_data("absent-doc").await.unwrap_err();
    assert!(matches!(err, Error::Parse(ParseError::DocNotFound)));

    storage.close().await;
    cleanup(&db_path).await;
  }
}