// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.

use std::collections::HashMap;
use std::sync::Arc;

use deno_ast::MediaType;
use deno_ast::ModuleSpecifier;
use deno_ast::ParsedSource;
use deno_core::error::AnyError;
use deno_core::parking_lot::Mutex;
use deno_core::serde_json;
use deno_graph::CapturingModuleParser;
use deno_graph::DefaultModuleAnalyzer;
use deno_graph::ModuleInfo;
use deno_graph::ModuleParser;
use deno_runtime::deno_webstorage::rusqlite::params;

use super::cache_db::CacheDB;
use super::cache_db::CacheDBConfiguration;
use super::cache_db::CacheFailure;
use super::FastInsecureHasher;

const SELECT_MODULE_INFO: &str = "
SELECT
  module_info
FROM
  moduleinfocache
WHERE
  specifier=?1
  AND media_type=?2
  AND source_hash=?3
LIMIT 1";

pub static PARSED_SOURCE_CACHE_DB: CacheDBConfiguration =
  CacheDBConfiguration {
    table_initializer: "CREATE TABLE IF NOT EXISTS moduleinfocache (
      specifier TEXT PRIMARY KEY,
      media_type TEXT NOT NULL,
      source_hash TEXT NOT NULL,
      module_info TEXT NOT NULL
    );",
    on_version_change: "DELETE FROM moduleinfocache;",
    preheat_queries: &[SELECT_MODULE_INFO],
    on_failure: CacheFailure::InMemory,
  };

#[derive(Clone, Default)]
struct ParsedSourceCacheSources(
  Arc<Mutex<HashMap<ModuleSpecifier, ParsedSource>>>,
);

/// It's ok that this is racy since in non-LSP situations
/// this will only ever store one form of a parsed source
/// and in LSP settings the concurrency will be enforced
/// at a higher level to ensure this will have the latest
/// parsed source.
impl deno_graph::ParsedSourceStore for ParsedSourceCacheSources {
  fn set_parsed_source(
    &self,
    specifier: deno_graph::ModuleSpecifier,
    parsed_source: ParsedSource,
  ) -> Option<ParsedSource> {
    self.0.lock().insert(specifier, parsed_source)
  }

  fn get_parsed_source(
    &self,
    specifier: &deno_graph::ModuleSpecifier,
  ) -> Option<ParsedSource> {
    self.0.lock().get(specifier).cloned()
  }
}

/// A cache of `ParsedSource`s, which may be used with `deno_graph`
/// for cached dependency analysis.
pub struct ParsedSourceCache {
  db: CacheDB,
  sources: ParsedSourceCacheSources,
}

impl ParsedSourceCache {
  #[cfg(test)]
  pub fn new_in_memory() -> Self {
    Self {
      db: CacheDB::in_memory(&PARSED_SOURCE_CACHE_DB, crate::version::deno()),
      sources: Default::default(),
    }
  }

  pub fn new(db: CacheDB) -> Self {
    Self {
      db,
      sources: Default::default(),
    }
  }

  pub fn get_parsed_source_from_esm_module(
    &self,
    module: &deno_graph::EsmModule,
  ) -> Result<ParsedSource, deno_ast::Diagnostic> {
    self.get_or_parse_module(
      &module.specifier,
      module.source.clone(),
      module.media_type,
    )
  }

  /// Gets the matching `ParsedSource` from the cache
  /// or parses a new one and stores that in the cache.
  pub fn get_or_parse_module(
    &self,
    specifier: &deno_graph::ModuleSpecifier,
    source: Arc<str>,
    media_type: MediaType,
  ) -> deno_core::anyhow::Result<ParsedSource, deno_ast::Diagnostic> {
    let parser = self.as_capturing_parser();
    // this will conditionally parse because it's using a CapturingModuleParser
    parser.parse_module(specifier, source, media_type)
  }

  /// Frees the parsed source from memory.
  pub fn free(&self, specifier: &ModuleSpecifier) {
    self.sources.0.lock().remove(specifier);
  }

  pub fn as_analyzer(&self) -> Box<dyn deno_graph::ModuleAnalyzer> {
    Box::new(ParsedSourceCacheModuleAnalyzer::new(
      self.db.clone(),
      self.sources.clone(),
    ))
  }

  /// Creates a parser that will reuse a ParsedSource from the store
  /// if it exists, or else parse.
  pub fn as_capturing_parser(&self) -> CapturingModuleParser {
    CapturingModuleParser::new(None, &self.sources)
  }
}

struct ParsedSourceCacheModuleAnalyzer {
  conn: CacheDB,
  sources: ParsedSourceCacheSources,
}

impl ParsedSourceCacheModuleAnalyzer {
  pub fn new(conn: CacheDB, sources: ParsedSourceCacheSources) -> Self {
    Self { conn, sources }
  }

  pub fn get_module_info(
    &self,
    specifier: &ModuleSpecifier,
    media_type: MediaType,
    expected_source_hash: &str,
  ) -> Result<Option<ModuleInfo>, AnyError> {
    let query = SELECT_MODULE_INFO;
    let res = self.conn.query_row(
      query,
      params![
        &specifier.as_str(),
        serialize_media_type(media_type),
        &expected_source_hash,
      ],
      |row| {
        let module_info: String = row.get(0)?;
        let module_info = serde_json::from_str(&module_info)?;
        Ok(module_info)
      },
    )?;
    Ok(res)
  }

  pub fn set_module_info(
    &self,
    specifier: &ModuleSpecifier,
    media_type: MediaType,
    source_hash: &str,
    module_info: &ModuleInfo,
  ) -> Result<(), AnyError> {
    let sql = "
      INSERT OR REPLACE INTO
        moduleinfocache (specifier, media_type, source_hash, module_info)
      VALUES
        (?1, ?2, ?3, ?4)";
    self.conn.execute(
      sql,
      params![
        specifier.as_str(),
        serialize_media_type(media_type),
        &source_hash,
        &serde_json::to_string(&module_info)?,
      ],
    )?;
    Ok(())
  }
}

// todo(dsherret): change this to be stored as an integer next time
// the cache version is bumped
fn serialize_media_type(media_type: MediaType) -> &'static str {
  use MediaType::*;
  match media_type {
    JavaScript => "1",
    Jsx => "2",
    Mjs => "3",
    Cjs => "4",
    TypeScript => "5",
    Mts => "6",
    Cts => "7",
    Dts => "8",
    Dmts => "9",
    Dcts => "10",
    Tsx => "11",
    Json => "12",
    Wasm => "13",
    TsBuildInfo => "14",
    SourceMap => "15",
    Unknown => "16",
  }
}

impl deno_graph::ModuleAnalyzer for ParsedSourceCacheModuleAnalyzer {
  fn analyze(
    &self,
    specifier: &ModuleSpecifier,
    source: Arc<str>,
    media_type: MediaType,
  ) -> Result<ModuleInfo, deno_ast::Diagnostic> {
    // attempt to load from the cache
    let source_hash = compute_source_hash(source.as_bytes());
    match self.get_module_info(specifier, media_type, &source_hash) {
      Ok(Some(info)) => return Ok(info),
      Ok(None) => {}
      Err(err) => {
        log::debug!(
          "Error loading module cache info for {}. {:#}",
          specifier,
          err
        );
      }
    }

    // otherwise, get the module info from the parsed source cache
    let parser = CapturingModuleParser::new(None, &self.sources);
    let analyzer = DefaultModuleAnalyzer::new(&parser);

    let module_info = analyzer.analyze(specifier, source, media_type)?;

    // then attempt to cache it
    if let Err(err) =
      self.set_module_info(specifier, media_type, &source_hash, &module_info)
    {
      log::debug!(
        "Error saving module cache info for {}. {:#}",
        specifier,
        err
      );
    }

    Ok(module_info)
  }
}

fn compute_source_hash(bytes: &[u8]) -> String {
  FastInsecureHasher::hash(bytes).to_string()
}

#[cfg(test)]
mod test {
  use deno_graph::PositionRange;
  use deno_graph::SpecifierWithRange;

  use super::*;

  #[test]
  pub fn parsed_source_cache_module_analyzer_general_use() {
    let conn = CacheDB::in_memory(&PARSED_SOURCE_CACHE_DB, "1.0.0");
    let cache = ParsedSourceCacheModuleAnalyzer::new(conn, Default::default());
    let specifier1 =
      ModuleSpecifier::parse("https://localhost/mod.ts").unwrap();
    let specifier2 =
      ModuleSpecifier::parse("https://localhost/mod2.ts").unwrap();
    assert_eq!(
      cache
        .get_module_info(&specifier1, MediaType::JavaScript, "1")
        .unwrap(),
      None
    );

    let mut module_info = ModuleInfo::default();
    module_info.jsdoc_imports.push(SpecifierWithRange {
      range: PositionRange {
        start: deno_graph::Position {
          line: 0,
          character: 3,
        },
        end: deno_graph::Position {
          line: 1,
          character: 2,
        },
      },
      text: "test".to_string(),
    });
    cache
      .set_module_info(&specifier1, MediaType::JavaScript, "1", &module_info)
      .unwrap();
    assert_eq!(
      cache
        .get_module_info(&specifier1, MediaType::JavaScript, "1")
        .unwrap(),
      Some(module_info.clone())
    );
    assert_eq!(
      cache
        .get_module_info(&specifier2, MediaType::JavaScript, "1")
        .unwrap(),
      None,
    );
    // different media type
    assert_eq!(
      cache
        .get_module_info(&specifier1, MediaType::TypeScript, "1")
        .unwrap(),
      None,
    );
    // different source hash
    assert_eq!(
      cache
        .get_module_info(&specifier1, MediaType::JavaScript, "2")
        .unwrap(),
      None,
    );

    // try recreating with the same version
    let conn = cache.conn.recreate_with_version("1.0.0");
    let cache = ParsedSourceCacheModuleAnalyzer::new(conn, Default::default());

    // should get it
    assert_eq!(
      cache
        .get_module_info(&specifier1, MediaType::JavaScript, "1")
        .unwrap(),
      Some(module_info)
    );

    // try recreating with a different version
    let conn = cache.conn.recreate_with_version("1.0.1");
    let cache = ParsedSourceCacheModuleAnalyzer::new(conn, Default::default());

    // should no longer exist
    assert_eq!(
      cache
        .get_module_info(&specifier1, MediaType::JavaScript, "1")
        .unwrap(),
      None,
    );
  }
}