use crate::path::GenericPath;
use crate::path::error::{FileNameError, DirectoryNameError};
use crate::terminal::error::TerminalError;


type ParseError<'a> =
  lalrpop_util::ParseError<usize, lalrpop_util::lexer::Token<'a>, &'a str>;

#[derive(Debug)]
pub enum Error {
  IO(std::io::Error),
  Parse(String),
  FileName(FileNameError),
  DirectoryName(DirectoryNameError),
  PathListHasEmptyComponents(String),
  PathLexicallyDirectory(GenericPath),
  PathLexicallyRelative(GenericPath),
  PathLexicallyInvalid(GenericPath),
  PathEmpiricallyFile(GenericPath),
  Terminal(TerminalError),
}

impl std::error::Error for Error { }

impl std::fmt::Display for Error {
  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
    match self {
      Error::IO(e) => e.fmt(f),
      Error::Parse(e) => e.fmt(f),
      Error::FileName(e) => e.fmt(f),
      Error::DirectoryName(e) => e.fmt(f),
      Error::PathListHasEmptyComponents(path_list) =>
        f.write_fmt(format_args!(
            "Path list has empty components: {}",
            path_list)),
      Error::PathLexicallyDirectory(path) =>
        f.write_fmt(format_args!(
            "The path {} ends in a slash, but is supposed to refer to a file, \
             not a directory.",
            path)),
      Error::PathLexicallyRelative(path) =>
        f.write_fmt(format_args!(
            "The path {} is relative, not absolute.",
            path)),
      Error::PathLexicallyInvalid(path) =>
        f.write_fmt(format_args!(
            "This isn't a valid path. {}",
            path)),
      Error::PathEmpiricallyFile(path) =>
        f.write_fmt(format_args!(
            "There's a file at {}, not a directory.",
            path)),
      Error::Terminal(e) => e.fmt(f),
    }
  }
}

impl From<()> for Error {
  fn from(_: ()) -> Error {
    unreachable!()
  }
}

impl From<std::io::Error> for Error {
  fn from(e: std::io::Error) -> Error {
    Error::IO(e)
  }
}

impl From<ParseError<'_>> for Error {
  fn from(e: ParseError<'_>) -> Error {
    Error::Parse(format!("{}", e))
  }
}

impl From<FileNameError> for Error {
  fn from(e: FileNameError) -> Error {
    Error::FileName(e)
  }
}

impl From<DirectoryNameError> for Error {
  fn from(e: DirectoryNameError) -> Error {
    Error::DirectoryName(e)
  }
}

impl From<TerminalError> for Error {
  fn from(e: TerminalError) -> Error {
    Error::Terminal(e)
  }
}