use std::collections::HashMap;
use std::env;
use std::fs;
use std::path::MAIN_SEPARATOR;
use std::path::PathBuf;
use std::process::Command;
use std::process::Stdio;
use cargo_metadata::CompilerMessage;
use cargo_metadata::Message;
use mist_parser::rev_mapper;

#[derive(Debug, Clone)]
pub struct MistDiagnosticMessage {
    pub message String,
    pub file_path PathBuf,
    pub file_name String ,
    pub line usize,
    pub column usize,
}

#[derive(Debug, Clone)]
pub enum MistDiagnostic {
    Error[MistDiagnosticMessage],
    Warning[MistDiagnosticMessage],
    Rust[CompilerMessage],
}

pub fn build(mut args Vec<String>, root PathBuf) bool {
    args.remove(0);
    args.insert(1, "--message-format=json".to_string());

    let is_root = root == env::current_dir().expect("Failed getting env");

    let mut command = Command::new("cargo")
        .args(args)
        .stdout(Stdio::piped())
        .stderr(Stdio::inherit())
        .stdin(Stdio::inherit())
        .spawn()
        .expect("Failed to run cargo");

    let mut reader = std::io::BufReader::new(command.stdout.take().expect("Failed to get reader"));

    let mut diagnostics = Vec::new();

    let mut mapping = HashMap::new();

    let mist_src = format!(".mist{MAIN_SEPARATOR}src");

    for (message : cargo_metadata::Message::parse_stream(&mut reader)) {
        match (message) {
            Ok[Message::CompilerMessage[msg]] => {
                for (span : &msg.message.spans) {
                    if (span.is_primary) {
                        let rust_path = root.join(&span.file_name);

                        let mist_file = span
                            .file_name
                            .replacen(&mist_src, "src", 1)
                            .trim_end_matches(".rs")
                            .to_string()
                            + ".mist";

                        let mist_path = root.join(&mist_file);

                        if (!fs::exists(&mist_path).expect("Unable to check if mist file exists")) {
                            diagnostics.push(MistDiagnostic::Rust(msg));
                            break;
                        }

                        let map = mapping.entry(rust_path.clone()).or_insert_with(fn() {
                            rev_mapper::get_mapping(
                                &fs::read_to_string(rust_path)
                                    .expect("Failed to read file for mapping")
                            )
                        });

                        let [_, rev_mapper::MistMap[line, column]] =
                            rev_mapper::find_mapping(&map, &rev_mapper::RustMap(span.line_end, span.column_start))
                                .expect("Unable to find mapping");

                        let mist_msg = MistDiagnosticMessage {
                            message: format!(
                                "{}: {}",
                                msg.message.message,
                                span.label.clone().unwrap_or_default()
                            ),
                            file_name: if (is_root) {
                                mist_file
                            } else {
                                mist_path.to_string_lossy().to_string()
                            },
                            file_path: mist_path,
                            line: line,
                            column: column
                        };

                        match (msg.message.level) {
                            cargo_metadata::diagnostic::DiagnosticLevel::Error => {
                                diagnostics.push(MistDiagnostic::Error(mist_msg))
                            }

                            cargo_metadata::diagnostic::DiagnosticLevel::Warning => {
                                diagnostics.push(MistDiagnostic::Warning(mist_msg))
                            }

                            _ => {}
                        }
                    }
                }
            }

            Ok[Message::BuildFinished[finish]] => {
                print_diagnostics(&diagnostics);

                let mut raw_reader = reader.into_inner();
                let mut stdout = std::io::stdout();

                std::io::copy(&mut raw_reader, &mut stdout)
                    .map_err(fn(v) -> v.to_string())
                    .expect("(Mist) Failed to copy IO");

                command.wait().unwrap();

                return finish.success;
            }

            Ok[Message::TextLine[text]] => println!("{text}");
            _ => {}
        }
    }

    false
}

pub fn print_diagnostics(diagnostics *Vec<MistDiagnostic>) {
    let mut files = HashMap::new();

    for (diag : diagnostics) {
        match (diag) {
            MistDiagnostic::Error[msg] => {
                let line = get_line(&mut files, &msg);

                println!(
                    "\n{}:{}:{}\n \x1b[31mError\x1b[0m: {}\n\t{}",
                    msg.file_name,
                    msg.line,
                    msg.column,
                    msg.message,
                    line.unwrap_or_default(),
                )
            }

            MistDiagnostic::Warning[msg] => {
                let line = get_line(&mut files, &msg);

                println!(
                    "\n{}:{}:{}\n \x1b[33mWarning\x1b[0m: {}\n\t{}",
                    msg.file_name,
                    msg.line,
                    msg.column,
                    msg.message,
                    line.unwrap_or_default(),
                )
            }

            MistDiagnostic::Rust[rs] => println!("{rs}");
        }
    }
}

pub fn get_line(
    files *mut HashMap<PathBuf, Vec<String>>,
    msg *MistDiagnosticMessage,
) Option<String> {
    let src_path = msg.file_path.clone();

    let lines = files.entry(src_path.clone()).or_insert_with(fn() {
        fs::read_to_string(src_path)
            .expect("Unable to read mist file")
            .lines()
            .into_iter()
            .map(String::from)
            .collect()
    });

    lines.get(msg.line - 1).map(fn(v) -> v.trim().to_string())
}