#![feature(slice_patterns, box_patterns, box_syntax)]
#![feature(proc_macro)]
extern crate itertools;
#[macro_use]
extern crate lazy_static;
#[macro_use]
extern crate maplit;

#[macro_use]
extern crate schala_repl;
#[macro_use]
extern crate schala_codegen;

use itertools::Itertools;
use schala_repl::{ProgrammingLanguageInterface, EvalOptions, TraceArtifact, UnfinishedComputation, FinishedComputation};

macro_rules! bx {
  ($e:expr) => { Box::new($e) }
}

mod builtin;

mod tokenizing;
mod parsing;
mod typechecking;
mod eval;

use self::typechecking::{TypeContext};

#[derive(ProgrammingLanguageInterface)]
#[LanguageName = "Schala"]
#[SourceFileExtension = "schala"]
#[PipelineSteps(tokenizing_stage, parsing_stage, symbol_table_stage, typechecking_stage, eval_stage)]
pub struct Schala {
  state: eval::State<'static>,
  type_context: TypeContext
}

impl Schala {
  pub fn new() -> Schala {
    Schala {
      state: eval::State::new(),
      type_context: TypeContext::new(),
    }
  }
}

fn tokenizing_stage(_handle: &mut Schala, input: &str, comp: Option<&mut UnfinishedComputation>) -> Result<Vec<tokenizing::Token>, String> {
  let tokens = tokenizing::tokenize(input);
  comp.map(|comp| {
    let token_string = tokens.iter().map(|t| format!("{:?}<L:{},C:{}>", t.token_type, t.offset.0, t.offset.1)).join(", ");
    comp.add_artifact(TraceArtifact::new("tokens", token_string));
  });

  let errors: Vec<String> = tokens.iter().filter_map(|t| t.get_error()).collect();
  if errors.len() == 0 {
    Ok(tokens)
  } else {
    Err(format!("{:?}", errors))
  }
}

fn parsing_stage(_handle: &mut Schala, input: Vec<tokenizing::Token>, comp: Option<&mut UnfinishedComputation>) -> Result<parsing::AST, parsing::ParseError> {

  let (ast, trace) = parsing::parse(input);
  comp.map(|comp| {
    //TODO need to control which of these debug stages get added
    comp.add_artifact(TraceArtifact::new_parse_trace(trace));
    comp.add_artifact(TraceArtifact::new("ast", format!("{:#?}", ast)));
  });
  ast
}

fn symbol_table_stage(handle: &mut Schala, input: parsing::AST, comp: Option<&mut UnfinishedComputation>) -> Result<parsing::AST, String> {
  match handle.type_context.add_top_level_types(&input) {
    Ok(()) => {
      let text = handle.type_context.debug_symbol_table();
      comp.map(|comp| comp.add_artifact(TraceArtifact::new("symbol_table", text)));
      Ok(input)
    },
    Err(msg) => Err(msg)
  }
}

fn typechecking_stage(handle: &mut Schala, input: parsing::AST, comp: Option<&mut UnfinishedComputation>) -> Result<parsing::AST, String> {
  match handle.type_context.type_check_ast(&input) {
    Ok(ty) => {
      comp.map(|comp| comp.add_artifact(TraceArtifact::new("type_check", format!("{:?}", ty))));
      Ok(input)
    },
    Err(msg) => Err(msg)
  }
}

fn eval_stage(handle: &mut Schala, input: parsing::AST, _comp: Option<&mut UnfinishedComputation>) -> Result<String, String> {
  let evaluation_outputs = handle.state.evaluate(input);
  let text_output: Result<Vec<String>, String> = evaluation_outputs
    .into_iter()
    .collect();

  let eval_output: Result<String, String> = text_output
    .map(|v| { v.into_iter().intersperse(format!("\n")).collect() });
  eval_output
}

/*
impl ProgrammingLanguageInterface for Schala {
  fn get_language_name(&self) -> String {
    "Schala".to_string()
  }

  fn get_source_file_suffix(&self) -> String {
    format!("schala")
  }

  fn execute_pipeline(&mut self, input: &str, options: &EvalOptions) -> FinishedComputation {
    let mut chain = pass_chain![self, options;
      tokenizing_stage,
      parsing_stage,
      symbol_table_stage,
      typechecking_stage,
      eval_stage
    ];
    chain(input)
  }

  fn get_stages(&self) -> Vec<String> {
    vec![
      format!("tokenizing_stage"),
      format!("parsing_stage"), //TODO handle both types of this
      format!("symbol_table_stage"),
      format!("typechecking_stage"),
      format!("eval_stage")
    ]
  }
}
*/