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

use std::collections::HashMap;
use std::path::Path;
use std::path::PathBuf;
use std::rc::Rc;

use deno_ast::MediaType;
use deno_core::anyhow::Context;
use deno_core::error::AnyError;
use deno_core::futures;
use deno_core::futures::future::LocalBoxFuture;
use deno_runtime::deno_node::NodeResolver;
use deno_semver::package::PackageNv;
use deno_task_shell::ExecutableCommand;
use deno_task_shell::ExecuteResult;
use deno_task_shell::ShellCommand;
use deno_task_shell::ShellCommandContext;
use deno_task_shell::ShellPipeReader;
use deno_task_shell::ShellPipeWriter;
use lazy_regex::Lazy;
use regex::Regex;
use tokio::task::JoinHandle;
use tokio::task::LocalSet;

use crate::npm::CliNpmResolver;
use crate::npm::InnerCliNpmResolverRef;
use crate::npm::ManagedCliNpmResolver;

pub fn get_script_with_args(script: &str, argv: &[String]) -> String {
  let additional_args = argv
    .iter()
    // surround all the additional arguments in double quotes
    // and sanitize any command substitution
    .map(|a| format!("\"{}\"", a.replace('"', "\\\"").replace('$', "\\$")))
    .collect::<Vec<_>>()
    .join(" ");
  let script = format!("{script} {additional_args}");
  script.trim().to_owned()
}

pub struct TaskStdio(Option<ShellPipeReader>, ShellPipeWriter);

impl TaskStdio {
  pub fn stdout() -> Self {
    Self(None, ShellPipeWriter::stdout())
  }
  pub fn stderr() -> Self {
    Self(None, ShellPipeWriter::stderr())
  }
  pub fn piped() -> Self {
    let (r, w) = deno_task_shell::pipe();
    Self(Some(r), w)
  }
}

pub struct TaskIo {
  pub stdout: TaskStdio,
  pub stderr: TaskStdio,
}

impl Default for TaskIo {
  fn default() -> Self {
    Self {
      stderr: TaskStdio::stderr(),
      stdout: TaskStdio::stdout(),
    }
  }
}

pub struct RunTaskOptions<'a> {
  pub task_name: &'a str,
  pub script: &'a str,
  pub cwd: &'a Path,
  pub init_cwd: &'a Path,
  pub env_vars: HashMap<String, String>,
  pub argv: &'a [String],
  pub custom_commands: HashMap<String, Rc<dyn ShellCommand>>,
  pub root_node_modules_dir: Option<&'a Path>,
  pub stdio: Option<TaskIo>,
}

pub type TaskCustomCommands = HashMap<String, Rc<dyn ShellCommand>>;

pub struct TaskResult {
  pub exit_code: i32,
  pub stdout: Option<Vec<u8>>,
  pub stderr: Option<Vec<u8>>,
}

pub async fn run_task(
  opts: RunTaskOptions<'_>,
) -> Result<TaskResult, AnyError> {
  let script = get_script_with_args(opts.script, opts.argv);
  let seq_list = deno_task_shell::parser::parse(&script)
    .with_context(|| format!("Error parsing script '{}'.", opts.task_name))?;
  let env_vars =
    prepare_env_vars(opts.env_vars, opts.init_cwd, opts.root_node_modules_dir);
  let state =
    deno_task_shell::ShellState::new(env_vars, opts.cwd, opts.custom_commands);
  let stdio = opts.stdio.unwrap_or_default();
  let (
    TaskStdio(stdout_read, stdout_write),
    TaskStdio(stderr_read, stderr_write),
  ) = (stdio.stdout, stdio.stderr);

  fn read(reader: ShellPipeReader) -> JoinHandle<Result<Vec<u8>, AnyError>> {
    tokio::task::spawn_blocking(move || {
      let mut buf = Vec::new();
      reader.pipe_to(&mut buf)?;
      Ok(buf)
    })
  }

  let stdout = stdout_read.map(read);
  let stderr = stderr_read.map(read);

  let local = LocalSet::new();
  let future = async move {
    let exit_code = deno_task_shell::execute_with_pipes(
      seq_list,
      state,
      ShellPipeReader::stdin(),
      stdout_write,
      stderr_write,
    )
    .await;
    Ok::<_, AnyError>(TaskResult {
      exit_code,
      stdout: if let Some(stdout) = stdout {
        Some(stdout.await??)
      } else {
        None
      },
      stderr: if let Some(stderr) = stderr {
        Some(stderr.await??)
      } else {
        None
      },
    })
  };
  local.run_until(future).await
}

fn prepare_env_vars(
  mut env_vars: HashMap<String, String>,
  initial_cwd: &Path,
  node_modules_dir: Option<&Path>,
) -> HashMap<String, String> {
  const INIT_CWD_NAME: &str = "INIT_CWD";
  if !env_vars.contains_key(INIT_CWD_NAME) {
    // if not set, set an INIT_CWD env var that has the cwd
    env_vars.insert(
      INIT_CWD_NAME.to_string(),
      initial_cwd.to_string_lossy().to_string(),
    );
  }
  if !env_vars.contains_key(crate::npm::NPM_CONFIG_USER_AGENT_ENV_VAR) {
    env_vars.insert(
      crate::npm::NPM_CONFIG_USER_AGENT_ENV_VAR.into(),
      crate::npm::get_npm_config_user_agent(),
    );
  }
  if let Some(node_modules_dir) = node_modules_dir {
    prepend_to_path(
      &mut env_vars,
      node_modules_dir.join(".bin").to_string_lossy().to_string(),
    );
  }
  env_vars
}

fn prepend_to_path(env_vars: &mut HashMap<String, String>, value: String) {
  match env_vars.get_mut("PATH") {
    Some(path) => {
      if path.is_empty() {
        *path = value;
      } else {
        *path =
          format!("{}{}{}", value, if cfg!(windows) { ";" } else { ":" }, path);
      }
    }
    None => {
      env_vars.insert("PATH".to_string(), value);
    }
  }
}

pub fn real_env_vars() -> HashMap<String, String> {
  std::env::vars()
    .map(|(k, v)| {
      if cfg!(windows) {
        (k.to_uppercase(), v)
      } else {
        (k, v)
      }
    })
    .collect::<HashMap<String, String>>()
}

// WARNING: Do not depend on this env var in user code. It's not stable API.
pub(crate) const USE_PKG_JSON_HIDDEN_ENV_VAR_NAME: &str =
  "DENO_INTERNAL_TASK_USE_PKG_JSON";

pub struct NpmCommand;

impl ShellCommand for NpmCommand {
  fn execute(
    &self,
    mut context: ShellCommandContext,
  ) -> LocalBoxFuture<'static, ExecuteResult> {
    if context.args.first().map(|s| s.as_str()) == Some("run")
      && context.args.len() >= 2
      // for now, don't run any npm scripts that have a flag because
      // we don't handle stuff like `--workspaces` properly
      && !context.args.iter().any(|s| s.starts_with('-'))
    {
      // run with deno task instead
      let mut args = Vec::with_capacity(context.args.len());
      args.push("task".to_string());
      args.extend(context.args.iter().skip(1).cloned());

      let mut state = context.state;
      state.apply_env_var(USE_PKG_JSON_HIDDEN_ENV_VAR_NAME, "1");
      return ExecutableCommand::new(
        "deno".to_string(),
        std::env::current_exe().unwrap(),
      )
      .execute(ShellCommandContext {
        args,
        state,
        ..context
      });
    }

    // fallback to running the real npm command
    let npm_path = match context.state.resolve_command_path("npm") {
      Ok(path) => path,
      Err(err) => {
        let _ = context.stderr.write_line(&format!("{}", err));
        return Box::pin(futures::future::ready(
          ExecuteResult::from_exit_code(err.exit_code()),
        ));
      }
    };
    ExecutableCommand::new("npm".to_string(), npm_path).execute(context)
  }
}

pub struct NodeCommand;

impl ShellCommand for NodeCommand {
  fn execute(
    &self,
    context: ShellCommandContext,
  ) -> LocalBoxFuture<'static, ExecuteResult> {
    // run with deno if it's a simple invocation, fall back to node
    // if there are extra flags
    let mut args = Vec::with_capacity(context.args.len());
    if context.args.len() > 1
      && (
        context.args[0].starts_with('-') // has a flag
        || !matches!(
          MediaType::from_str(&context.args[0]),
          MediaType::Cjs | MediaType::Mjs | MediaType::JavaScript
        )
        // not a script file
      )
    {
      return ExecutableCommand::new(
        "node".to_string(),
        "node".to_string().into(),
      )
      .execute(context);
    }

    args.extend(["run", "-A"].into_iter().map(|s| s.to_string()));
    args.extend(context.args.iter().cloned());

    let mut state = context.state;

    state.apply_env_var(USE_PKG_JSON_HIDDEN_ENV_VAR_NAME, "1");
    ExecutableCommand::new("deno".to_string(), std::env::current_exe().unwrap())
      .execute(ShellCommandContext {
        args,
        state,
        ..context
      })
  }
}

pub struct NodeGypCommand;

impl ShellCommand for NodeGypCommand {
  fn execute(
    &self,
    context: ShellCommandContext,
  ) -> LocalBoxFuture<'static, ExecuteResult> {
    // at the moment this shell command is just to give a warning if node-gyp is not found
    // in the future, we could try to run/install node-gyp for the user with deno
    if context.state.resolve_command_path("node-gyp").is_err() {
      log::warn!("{} node-gyp was used in a script, but was not listed as a dependency. Either add it as a dependency or install it globally (e.g. `npm install -g node-gyp`)", crate::colors::yellow("Warning"));
    }
    ExecutableCommand::new(
      "node-gyp".to_string(),
      "node-gyp".to_string().into(),
    )
    .execute(context)
  }
}

pub struct NpxCommand;

impl ShellCommand for NpxCommand {
  fn execute(
    &self,
    mut context: ShellCommandContext,
  ) -> LocalBoxFuture<'static, ExecuteResult> {
    if let Some(first_arg) = context.args.first().cloned() {
      if let Some(command) = context.state.resolve_custom_command(&first_arg) {
        let context = ShellCommandContext {
          args: context.args.iter().skip(1).cloned().collect::<Vec<_>>(),
          ..context
        };
        command.execute(context)
      } else {
        // can't find the command, so fallback to running the real npx command
        let npx_path = match context.state.resolve_command_path("npx") {
          Ok(npx) => npx,
          Err(err) => {
            let _ = context.stderr.write_line(&format!("{}", err));
            return Box::pin(futures::future::ready(
              ExecuteResult::from_exit_code(err.exit_code()),
            ));
          }
        };
        ExecutableCommand::new("npx".to_string(), npx_path).execute(context)
      }
    } else {
      let _ = context.stderr.write_line("npx: missing command");
      Box::pin(futures::future::ready(ExecuteResult::from_exit_code(1)))
    }
  }
}

#[derive(Clone)]
struct NpmPackageBinCommand {
  name: String,
  npm_package: PackageNv,
}

impl ShellCommand for NpmPackageBinCommand {
  fn execute(
    &self,
    context: ShellCommandContext,
  ) -> LocalBoxFuture<'static, ExecuteResult> {
    let mut args = vec![
      "run".to_string(),
      "-A".to_string(),
      if self.npm_package.name == self.name {
        format!("npm:{}", self.npm_package)
      } else {
        format!("npm:{}/{}", self.npm_package, self.name)
      },
    ];

    args.extend(context.args);
    let executable_command = deno_task_shell::ExecutableCommand::new(
      "deno".to_string(),
      std::env::current_exe().unwrap(),
    );
    executable_command.execute(ShellCommandContext { args, ..context })
  }
}

/// Runs a module in the node_modules folder.
#[derive(Clone)]
pub struct NodeModulesFileRunCommand {
  pub command_name: String,
  pub path: PathBuf,
}

impl ShellCommand for NodeModulesFileRunCommand {
  fn execute(
    &self,
    mut context: ShellCommandContext,
  ) -> LocalBoxFuture<'static, ExecuteResult> {
    let mut args = vec![
      "run".to_string(),
      "--ext=js".to_string(),
      "-A".to_string(),
      self.path.to_string_lossy().to_string(),
    ];
    args.extend(context.args);
    let executable_command = deno_task_shell::ExecutableCommand::new(
      "deno".to_string(),
      std::env::current_exe().unwrap(),
    );
    // set this environment variable so that the launched process knows the npm command name
    context
      .state
      .apply_env_var("DENO_INTERNAL_NPM_CMD_NAME", &self.command_name);
    executable_command.execute(ShellCommandContext { args, ..context })
  }
}

pub fn resolve_custom_commands(
  npm_resolver: &dyn CliNpmResolver,
  node_resolver: &NodeResolver,
) -> Result<HashMap<String, Rc<dyn ShellCommand>>, AnyError> {
  let mut commands = match npm_resolver.as_inner() {
    InnerCliNpmResolverRef::Byonm(npm_resolver) => {
      let node_modules_dir = npm_resolver.root_node_modules_path().unwrap();
      resolve_npm_commands_from_bin_dir(node_modules_dir)
    }
    InnerCliNpmResolverRef::Managed(npm_resolver) => {
      resolve_managed_npm_commands(npm_resolver, node_resolver)?
    }
  };
  commands.insert("npm".to_string(), Rc::new(NpmCommand));
  Ok(commands)
}

pub fn resolve_npm_commands_from_bin_dir(
  node_modules_dir: &Path,
) -> HashMap<String, Rc<dyn ShellCommand>> {
  let mut result = HashMap::<String, Rc<dyn ShellCommand>>::new();
  let bin_dir = node_modules_dir.join(".bin");
  log::debug!("Resolving commands in '{}'.", bin_dir.display());
  match std::fs::read_dir(&bin_dir) {
    Ok(entries) => {
      for entry in entries {
        let Ok(entry) = entry else {
          continue;
        };
        if let Some(command) = resolve_bin_dir_entry_command(entry) {
          result.insert(command.command_name.clone(), Rc::new(command));
        }
      }
    }
    Err(err) => {
      log::debug!("Failed read_dir for '{}': {:#}", bin_dir.display(), err);
    }
  }
  result
}

fn resolve_bin_dir_entry_command(
  entry: std::fs::DirEntry,
) -> Option<NodeModulesFileRunCommand> {
  if entry.path().extension().is_some() {
    return None; // only look at files without extensions (even on Windows)
  }
  let file_type = entry.file_type().ok()?;
  let path = if file_type.is_file() {
    entry.path()
  } else if file_type.is_symlink() {
    entry.path().canonicalize().ok()?
  } else {
    return None;
  };
  let text = std::fs::read_to_string(&path).ok()?;
  let command_name = entry.file_name().to_string_lossy().to_string();
  if let Some(path) = resolve_execution_path_from_npx_shim(path, &text) {
    log::debug!(
      "Resolved npx command '{}' to '{}'.",
      command_name,
      path.display()
    );
    Some(NodeModulesFileRunCommand { command_name, path })
  } else {
    log::debug!("Failed resolving npx command '{}'.", command_name);
    None
  }
}

/// This is not ideal, but it works ok because it allows us to bypass
/// the shebang and execute the script directly with Deno.
fn resolve_execution_path_from_npx_shim(
  file_path: PathBuf,
  text: &str,
) -> Option<PathBuf> {
  static SCRIPT_PATH_RE: Lazy<Regex> =
    lazy_regex::lazy_regex!(r#""\$basedir\/([^"]+)" "\$@""#);

  let maybe_first_line = {
    let index = text.find("\n")?;
    Some(&text[0..index])
  };

  if let Some(first_line) = maybe_first_line {
    // NOTE(bartlomieju): this is not perfect, but handle two most common scenarios
    // where Node is run without any args. If there are args then we use `NodeCommand`
    // struct.
    if first_line == "#!/usr/bin/env node"
      || first_line == "#!/usr/bin/env -S node"
    {
      // launch this file itself because it's a JS file
      return Some(file_path);
    }
  }

  // Search for...
  // > "$basedir/../next/dist/bin/next" "$@"
  // ...which is what it will look like on Windows
  SCRIPT_PATH_RE
    .captures(text)
    .and_then(|c| c.get(1))
    .map(|relative_path| {
      file_path.parent().unwrap().join(relative_path.as_str())
    })
}

fn resolve_managed_npm_commands(
  npm_resolver: &ManagedCliNpmResolver,
  node_resolver: &NodeResolver,
) -> Result<HashMap<String, Rc<dyn ShellCommand>>, AnyError> {
  let mut result = HashMap::new();
  let snapshot = npm_resolver.snapshot();
  for id in snapshot.top_level_packages() {
    let package_folder = npm_resolver.resolve_pkg_folder_from_pkg_id(id)?;
    let bin_commands =
      node_resolver.resolve_binary_commands(&package_folder)?;
    for bin_command in bin_commands {
      result.insert(
        bin_command.to_string(),
        Rc::new(NpmPackageBinCommand {
          name: bin_command,
          npm_package: id.nv.clone(),
        }) as Rc<dyn ShellCommand>,
      );
    }
  }
  if !result.contains_key("npx") {
    result.insert("npx".to_string(), Rc::new(NpxCommand));
  }
  Ok(result)
}

#[cfg(test)]
mod test {

  use super::*;

  #[test]
  fn test_prepend_to_path() {
    let mut env_vars = HashMap::new();

    prepend_to_path(&mut env_vars, "/example".to_string());
    assert_eq!(
      env_vars,
      HashMap::from([("PATH".to_string(), "/example".to_string())])
    );

    prepend_to_path(&mut env_vars, "/example2".to_string());
    let separator = if cfg!(windows) { ";" } else { ":" };
    assert_eq!(
      env_vars,
      HashMap::from([(
        "PATH".to_string(),
        format!("/example2{}/example", separator)
      )])
    );

    env_vars.get_mut("PATH").unwrap().clear();
    prepend_to_path(&mut env_vars, "/example".to_string());
    assert_eq!(
      env_vars,
      HashMap::from([("PATH".to_string(), "/example".to_string())])
    );
  }

  #[test]
  fn test_resolve_execution_path_from_npx_shim() {
    // example shim on unix
    let unix_shim = r#"#!/usr/bin/env node
"use strict";
console.log('Hi!');
"#;
    let path = PathBuf::from("/node_modules/.bin/example");
    assert_eq!(
      resolve_execution_path_from_npx_shim(path.clone(), unix_shim).unwrap(),
      path
    );
    // example shim on unix
    let unix_shim = r#"#!/usr/bin/env -S node
"use strict";
console.log('Hi!');
"#;
    let path = PathBuf::from("/node_modules/.bin/example");
    assert_eq!(
      resolve_execution_path_from_npx_shim(path.clone(), unix_shim).unwrap(),
      path
    );
    // example shim on windows
    let windows_shim = r#"#!/bin/sh
basedir=$(dirname "$(echo "$0" | sed -e 's,\\,/,g')")

case `uname` in
    *CYGWIN*|*MINGW*|*MSYS*) basedir=`cygpath -w "$basedir"`;;
esac

if [ -x "$basedir/node" ]; then
  exec "$basedir/node"  "$basedir/../example/bin/example" "$@"
else
  exec node  "$basedir/../example/bin/example" "$@"
fi"#;
    assert_eq!(
      resolve_execution_path_from_npx_shim(path.clone(), windows_shim).unwrap(),
      path.parent().unwrap().join("../example/bin/example")
    );
  }
}