// Copyright 2018 the Deno authors. All rights reserved. MIT license.
use libc::c_int;
use libdeno;
use log;
use std::ffi::CStr;
use std::ffi::CString;
use std::mem;
use std::process::exit;
use std::vec::Vec;
use version;

// Creates vector of strings, Vec<String>
#[cfg(test)]
macro_rules! svec {
    ($($x:expr),*) => (vec![$($x.to_string()),*]);
}

#[derive(Debug, PartialEq, Default)]
pub struct DenoFlags {
  pub help: bool,
  pub log_debug: bool,
  pub version: bool,
  pub reload: bool,
  pub recompile: bool,
  pub allow_write: bool,
  pub allow_net: bool,
  pub allow_env: bool,
  pub deps_flag: bool,
  pub types_flag: bool,
}

pub fn process(flags: &DenoFlags) {
  if flags.help {
    print_usage();
    exit(0);
  }

  if flags.version {
    version::print_version();
    exit(0);
  }

  let mut log_level = log::LevelFilter::Info;
  if flags.log_debug {
    log_level = log::LevelFilter::Debug;
  }
  log::set_max_level(log_level);
}

pub fn print_usage() {
  println!(
    "Usage: deno script.ts
--allow-write      Allow file system write access.
--allow-net        Allow network access.
--allow-env        Allow environment access.
--recompile        Force recompilation of TypeScript code.
-v or --version    Print the version.
-r or --reload     Reload cached remote resources.
-D or --log-debug  Log debug output.
-h or --help       Print this message.
--v8-options       Print V8 command line options.
--deps             Print module dependencies.
--types            Print runtime TypeScript declarations.

Environment variables:
DENO_DIR           Set deno's base directory."
  );
}

// Parses flags for deno. This does not do v8_set_flags() - call that separately.
pub fn set_flags(args: Vec<String>) -> (DenoFlags, Vec<String>) {
  let args = v8_set_flags(args);

  let mut flags = DenoFlags::default();
  let mut rest = Vec::new();
  let mut arg_iter = args.iter();

  while let Some(a) = arg_iter.next() {
    if a.len() > 1 && &a[0..2] == "--" {
      match a.as_str() {
        "--help" => flags.help = true,
        "--log-debug" => flags.log_debug = true,
        "--version" => flags.version = true,
        "--reload" => flags.reload = true,
        "--recompile" => flags.recompile = true,
        "--allow-write" => flags.allow_write = true,
        "--allow-net" => flags.allow_net = true,
        "--allow-env" => flags.allow_env = true,
        "--deps" => flags.deps_flag = true,
        "--types" => flags.types_flag = true,
        "--" => break,
        _ => unimplemented!(),
      }
    } else if a.len() > 1 && &a[0..1] == "-" {
      let mut iter = a.chars().skip(1); // skip the "-"
      while let Some(f) = iter.next() {
        match f {
          'h' => flags.help = true,
          'D' => flags.log_debug = true,
          'v' => flags.version = true,
          'r' => flags.reload = true,
          _ => unimplemented!(),
        }
      }
    } else {
      rest.push(a.clone());
    }
  }

  // add any remaining arguments to `rest`
  rest.extend(arg_iter.map(|s| s.clone()));
  return (flags, rest);
}

#[test]
fn test_set_flags_1() {
  let (flags, rest) = set_flags(svec!["deno", "--version"]);
  assert_eq!(rest, svec!["deno"]);
  assert_eq!(
    flags,
    DenoFlags {
      version: true,
      ..DenoFlags::default()
    }
  );
}

#[test]
fn test_set_flags_2() {
  let (flags, rest) = set_flags(svec!["deno", "-r", "-D", "script.ts"]);
  assert_eq!(rest, svec!["deno", "script.ts"]);
  assert_eq!(
    flags,
    DenoFlags {
      log_debug: true,
      reload: true,
      ..DenoFlags::default()
    }
  );
}

#[test]
fn test_set_flags_3() {
  let (flags, rest) =
    set_flags(svec!["deno", "-r", "--deps", "script.ts", "--allow-write"]);
  assert_eq!(rest, svec!["deno", "script.ts"]);
  assert_eq!(
    flags,
    DenoFlags {
      reload: true,
      allow_write: true,
      deps_flag: true,
      ..DenoFlags::default()
    }
  );
}

#[test]
fn test_set_flags_4() {
  let (flags, rest) =
    set_flags(svec!["deno", "-Dr", "script.ts", "--allow-write"]);
  assert_eq!(rest, svec!["deno", "script.ts"]);
  assert_eq!(
    flags,
    DenoFlags {
      log_debug: true,
      reload: true,
      allow_write: true,
      ..DenoFlags::default()
    }
  );
}

#[test]
fn test_set_flags_5() {
  let (flags, rest) = set_flags(svec!["deno", "--types"]);
  assert_eq!(rest, svec!["deno"]);
  assert_eq!(
    flags,
    DenoFlags {
      types_flag: true,
      ..DenoFlags::default()
    }
  )
}

// Returns args passed to V8, followed by args passed to JS
fn v8_set_flags_preprocess(args: Vec<String>) -> (Vec<String>, Vec<String>) {
  let mut rest = vec![];

  // Filter out args that shouldn't be passed to V8
  let mut args: Vec<String> = args
    .into_iter()
    .filter(|arg| {
      if arg.as_str() == "--help" {
        rest.push(arg.clone());
        return false;
      }

      true
    })
    .collect();

  // Replace args being sent to V8
  for idx in 0..args.len() {
    if args[idx] == "--v8-options" {
      mem::swap(args.get_mut(idx).unwrap(), &mut String::from("--help"));
    }
  }

  (args, rest)
}

#[test]
fn test_v8_set_flags_preprocess_1() {
  let js_args = v8_set_flags_preprocess(vec![
    "deno".to_string(),
    "--v8-options".to_string(),
  ]);
  assert_eq!(
    js_args,
    (vec!["deno".to_string(), "--help".to_string()], vec![])
  );
}

#[test]
fn test_v8_set_flags_preprocess_2() {
  let js_args =
    v8_set_flags_preprocess(vec!["deno".to_string(), "--help".to_string()]);
  assert_eq!(
    js_args,
    (vec!["deno".to_string()], vec!["--help".to_string()])
  );
}

// Pass the command line arguments to v8.
// Returns a vector of command line arguments that v8 did not understand.
pub fn v8_set_flags(args: Vec<String>) -> Vec<String> {
  // deno_set_v8_flags(int* argc, char** argv) mutates argc and argv to remove
  // flags that v8 understands.
  // First parse core args, then converto to a vector of C strings.
  let (argv, rest) = v8_set_flags_preprocess(args);
  let mut argv = argv
    .iter()
    .map(|arg| CString::new(arg.as_str()).unwrap().into_bytes_with_nul())
    .collect::<Vec<_>>();

  // Make a new array, that can be modified by V8::SetFlagsFromCommandLine(),
  // containing mutable raw pointers to the individual command line args.
  let mut c_argv = argv
    .iter_mut()
    .map(|arg| arg.as_mut_ptr() as *mut i8)
    .collect::<Vec<_>>();
  // Store the length of the argv array in a local variable. We'll pass a
  // pointer to this local variable to deno_set_v8_flags(), which then
  // updates its value.
  let mut c_argc = c_argv.len() as c_int;
  // Let v8 parse the arguments it recognizes and remove them from c_argv.
  unsafe {
    libdeno::deno_set_v8_flags(&mut c_argc, c_argv.as_mut_ptr());
  };
  // If c_argc was updated we have to change the length of c_argv to match.
  c_argv.truncate(c_argc as usize);
  // Copy the modified arguments list into a proper rust vec and return it.
  c_argv
    .iter()
    .map(|ptr| unsafe {
      let cstr = CStr::from_ptr(*ptr as *const i8);
      let slice = cstr.to_str().unwrap();
      slice.to_string()
    })
    .chain(rest.into_iter())
    .collect()
}