use std::collections::HashMap;
use colored::*;
use std::fmt::Write;
use std::time;

#[derive(Debug, Default, Serialize, Deserialize)]
pub struct EvalOptions {
  pub execution_method: ExecutionMethod,
  pub debug_passes: HashMap<String, PassDebugOptionsDescriptor>,
  pub debug_timing: bool,
}

#[derive(Debug, Hash, PartialEq)]
pub struct PassDescriptor {
  pub name: String,
  pub debug_options: Vec<String>
}

#[derive(Debug, Serialize, Deserialize)]
pub struct PassDebugOptionsDescriptor {
  pub opts: Vec<String>,
}

#[derive(Debug, Serialize, Deserialize)]
pub enum ExecutionMethod {
  Compile,
  Interpret,
}
impl Default for ExecutionMethod {
  fn default() -> ExecutionMethod {
    ExecutionMethod::Interpret
  }
}

#[derive(Debug, Default)]
pub struct UnfinishedComputation {
  artifacts: Vec<(String, TraceArtifact)>,
  pub durations: Vec<time::Duration>,
  pub cur_debug_options: Vec<String>,
}

#[derive(Debug)]
pub struct FinishedComputation {
  artifacts: Vec<(String, TraceArtifact)>,
  durations: Vec<time::Duration>,
  text_output: Result<String, String>,
}

impl UnfinishedComputation {
  pub fn add_artifact(&mut self, artifact: TraceArtifact) {
    self.artifacts.push((artifact.stage_name.clone(), artifact));
  }
  pub fn finish(self, text_output: Result<String, String>) -> FinishedComputation {
    FinishedComputation {
      artifacts: self.artifacts,
      text_output,
      durations: self.durations,
    }
  }
  pub fn output(self, output: Result<String, String>) -> FinishedComputation {
    FinishedComputation {
      artifacts: self.artifacts,
      text_output: output,
      durations: self.durations,
    }
  }
}

impl FinishedComputation {

  fn get_timing(&self) -> Option<String> {
    if self.durations.len() != 0 {
      let mut buf = String::new();
      write!(&mut buf, "Timing: ").unwrap();
      for duration in self.durations.iter() {
        let timing = (duration.as_secs() as f64) + (duration.subsec_nanos() as f64 * 1e-9);
        write!(&mut buf, "{}s, ", timing).unwrap()
      }
      write!(&mut buf, "\n").unwrap();
      Some(buf)
    } else {
      None
    }
  }

  pub fn to_repl(&self) -> String {
    let mut buf = String::new();
    for (stage, artifact) in self.artifacts.iter() {
      let color = artifact.text_color;
      let stage = stage.color(color).bold();
      let output = artifact.debug_output.color(color);
      write!(&mut buf, "{}: {}\n", stage, output).unwrap();
    }

    match self.get_timing() {
      Some(timing) => write!(&mut buf, "{}", timing).unwrap(),
      None => ()
    }

    match self.text_output {
      Ok(ref output) => write!(&mut buf, "{}", output).unwrap(),
      Err(ref err) => write!(&mut buf, "{} {}", "Error: ".red().bold(), err).unwrap(),
    }
    buf
  }
  pub fn to_noninteractive(&self) -> Option<String> {
    match self.text_output {
      Ok(_) => {
        let mut buf = String::new();
        for (stage, artifact) in self.artifacts.iter() {
          let color = artifact.text_color;
          let stage = stage.color(color).bold();
          let output = artifact.debug_output.color(color);
          write!(&mut buf, "{}: {}\n", stage, output).unwrap();
        }
        if buf == "" { None } else { Some(buf) }
      },
      Err(ref s) => Some(format!("{} {}", "Error: ".red().bold(), s))
    }
  }
}

#[derive(Debug)]
pub struct TraceArtifact {
  stage_name: String,
  debug_output: String,
  text_color: &'static str,
}

impl TraceArtifact {
  pub fn new(stage: &str, debug: String) -> TraceArtifact {
    let color = match stage {
      "parse_trace"  | "ast" => "red",
      "ast_reducing" => "red",
      "tokens" => "green",
      "type_check" => "magenta",
      _ => "blue",
    };
    TraceArtifact { stage_name: stage.to_string(), debug_output: debug, text_color: color}
  }

  pub fn new_parse_trace(trace: Vec<String>) -> TraceArtifact {
    let mut output = String::new();

    for t in trace {
      output.push_str(&t);
      output.push_str("\n");
    }

    TraceArtifact { stage_name: "parse_trace".to_string(), debug_output: output, text_color: "red"}
  }
}

pub trait ProgrammingLanguageInterface {
  fn execute_pipeline(&mut self, _input: &str, _eval_options: &EvalOptions) -> FinishedComputation {
    FinishedComputation { artifacts: vec![], text_output: Err(format!("Execution pipeline not done")), durations: vec![] }
  }

  fn get_language_name(&self) -> String;
  fn get_source_file_suffix(&self) -> String;
  fn get_passes(&self) -> Vec<PassDescriptor> {
    vec![]
  }
  fn handle_custom_interpreter_directives(&mut self, _commands: &Vec<&str>) -> Option<String> {
    None
  }
  fn custom_interpreter_directives_help(&self) -> String {
    format!(">> No custom interpreter directives specified <<")
  }
  fn get_doc(&self, _commands: &Vec<&str>) -> Option<String> {
    None
  }
}