// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.

use std::sync::Arc;

use deno_ast::MediaType;
use deno_ast::ModuleSpecifier;
use deno_core::error::AnyError;
use deno_runtime::deno_fs;
use deno_runtime::deno_node::DenoFsNodeResolverEnv;
use node_resolver::analyze::CjsAnalysis as ExtNodeCjsAnalysis;
use node_resolver::analyze::CjsAnalysisExports;
use node_resolver::analyze::CjsCodeAnalyzer;
use node_resolver::analyze::NodeCodeTranslator;
use serde::Deserialize;
use serde::Serialize;

use crate::cache::CacheDBHash;
use crate::cache::NodeAnalysisCache;
use crate::resolver::CliNodeResolver;
use crate::util::fs::canonicalize_path_maybe_not_exists;

pub type CliNodeCodeTranslator =
  NodeCodeTranslator<CliCjsCodeAnalyzer, DenoFsNodeResolverEnv>;

/// Resolves a specifier that is pointing into a node_modules folder.
///
/// Note: This should be called whenever getting the specifier from
/// a Module::External(module) reference because that module might
/// not be fully resolved at the time deno_graph is analyzing it
/// because the node_modules folder might not exist at that time.
pub fn resolve_specifier_into_node_modules(
  specifier: &ModuleSpecifier,
) -> ModuleSpecifier {
  specifier
    .to_file_path()
    .ok()
    // this path might not exist at the time the graph is being created
    // because the node_modules folder might not yet exist
    .and_then(|path| canonicalize_path_maybe_not_exists(&path).ok())
    .and_then(|path| ModuleSpecifier::from_file_path(path).ok())
    .unwrap_or_else(|| specifier.clone())
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum CliCjsAnalysis {
  /// The module was found to be an ES module.
  Esm,
  /// The module was CJS.
  Cjs {
    exports: Vec<String>,
    reexports: Vec<String>,
  },
}

pub struct CliCjsCodeAnalyzer {
  cache: NodeAnalysisCache,
  fs: deno_fs::FileSystemRc,
  node_resolver: Arc<CliNodeResolver>,
}

impl CliCjsCodeAnalyzer {
  pub fn new(
    cache: NodeAnalysisCache,
    fs: deno_fs::FileSystemRc,
    node_resolver: Arc<CliNodeResolver>,
  ) -> Self {
    Self {
      cache,
      fs,
      node_resolver,
    }
  }

  async fn inner_cjs_analysis(
    &self,
    specifier: &ModuleSpecifier,
    source: &str,
  ) -> Result<CliCjsAnalysis, AnyError> {
    let source_hash = CacheDBHash::from_source(source);
    if let Some(analysis) =
      self.cache.get_cjs_analysis(specifier.as_str(), source_hash)
    {
      return Ok(analysis);
    }

    let mut media_type = MediaType::from_specifier(specifier);
    if media_type == MediaType::Json {
      return Ok(CliCjsAnalysis::Cjs {
        exports: vec![],
        reexports: vec![],
      });
    }

    if media_type == MediaType::JavaScript {
      if let Some(package_json) =
        self.node_resolver.get_closest_package_json(specifier)?
      {
        match package_json.typ.as_str() {
          "commonjs" => {
            media_type = MediaType::Cjs;
          }
          "module" => {
            media_type = MediaType::Mjs;
          }
          _ => {}
        }
      }
    }

    let analysis = deno_core::unsync::spawn_blocking({
      let specifier = specifier.clone();
      let source: Arc<str> = source.into();
      move || -> Result<_, deno_ast::ParseDiagnostic> {
        let parsed_source = deno_ast::parse_program(deno_ast::ParseParams {
          specifier,
          text: source,
          media_type,
          capture_tokens: true,
          scope_analysis: false,
          maybe_syntax: None,
        })?;
        if parsed_source.is_script() {
          let analysis = parsed_source.analyze_cjs();
          Ok(CliCjsAnalysis::Cjs {
            exports: analysis.exports,
            reexports: analysis.reexports,
          })
        } else if media_type == MediaType::Cjs {
          // FIXME: `deno_ast` should internally handle MediaType::Cjs implying that
          // the result must never be Esm
          Ok(CliCjsAnalysis::Cjs {
            exports: vec![],
            reexports: vec![],
          })
        } else {
          Ok(CliCjsAnalysis::Esm)
        }
      }
    })
    .await
    .unwrap()?;

    self
      .cache
      .set_cjs_analysis(specifier.as_str(), source_hash, &analysis);

    Ok(analysis)
  }
}

#[async_trait::async_trait(?Send)]
impl CjsCodeAnalyzer for CliCjsCodeAnalyzer {
  async fn analyze_cjs(
    &self,
    specifier: &ModuleSpecifier,
    source: Option<String>,
  ) -> Result<ExtNodeCjsAnalysis, AnyError> {
    let source = match source {
      Some(source) => source,
      None => {
        if let Ok(path) = specifier.to_file_path() {
          if let Ok(source_from_file) =
            self.fs.read_text_file_lossy_async(path, None).await
          {
            source_from_file
          } else {
            return Ok(ExtNodeCjsAnalysis::Cjs(CjsAnalysisExports {
              exports: vec![],
              reexports: vec![],
            }));
          }
        } else {
          return Ok(ExtNodeCjsAnalysis::Cjs(CjsAnalysisExports {
            exports: vec![],
            reexports: vec![],
          }));
        }
      }
    };
    let analysis = self.inner_cjs_analysis(specifier, &source).await?;
    match analysis {
      CliCjsAnalysis::Esm => Ok(ExtNodeCjsAnalysis::Esm(source)),
      CliCjsAnalysis::Cjs { exports, reexports } => {
        Ok(ExtNodeCjsAnalysis::Cjs(CjsAnalysisExports {
          exports,
          reexports,
        }))
      }
    }
  }
}