use chumsky::{input::Stream, prelude::*};
use imbl::HashMap;
use std::env;
use std::fs;

const DEBUG_SCRIPT_COMPILE: bool = true;
const DEBUG_SCRIPT_RUN: bool = true;
const DEBUG_PRELUDE_COMPILE: bool = false;
const DEBUG_PRELUDE_RUN: bool = false;

mod base;

mod spans;
use crate::spans::Spanned;

mod lexer;
use crate::lexer::lexer;

mod parser;
use crate::parser::{parser, Ast};

mod validator;
use crate::validator::Validator;

mod errors;
use crate::errors::report_invalidation;

mod compiler;
use crate::compiler::Compiler;

mod value;
use value::Value;

mod vm;
use vm::Vm;

const PRELUDE: &str = include_str!("../assets/test_prelude.ld");

pub fn prelude() -> HashMap<&'static str, Value> {
    let tokens = lexer().parse(PRELUDE).into_output_errors().0.unwrap();
    let (parsed, parse_errors) = parser()
        .parse(Stream::from_iter(tokens).map((0..PRELUDE.len()).into(), |(t, s)| (t, s)))
        .into_output_errors();

    if !parse_errors.is_empty() {
        println!("ERROR PARSING PRELUDE:");
        println!("{:?}", parse_errors);
        panic!();
    }

    let parsed = parsed.unwrap();
    let (ast, span) = &parsed;

    let base = base::make_base();
    let mut base_env = imbl::HashMap::new();
    base_env.insert("base", base.clone());

    let mut validator = Validator::new(ast, span, "prelude", PRELUDE, base_env);

    validator.validate();

    if !validator.errors.is_empty() {
        println!("VALIDATION ERRORS IN PRLUDE:");
        report_invalidation(validator.errors);
        panic!();
    }

    let parsed: &'static Spanned<Ast> = Box::leak(Box::new(parsed));
    let mut compiler = Compiler::new(
        parsed,
        "prelude",
        PRELUDE,
        None,
        HashMap::new(),
        DEBUG_PRELUDE_COMPILE,
    );
    compiler.emit_constant(base);
    compiler.bind("base");
    compiler.compile();

    let chunk = compiler.chunk;
    let mut vm = Vm::new(chunk, DEBUG_PRELUDE_RUN);
    let prelude = vm.run().clone().unwrap();
    match prelude {
        Value::Dict(hashmap) => *hashmap,
        _ => unreachable!(),
    }
}

pub fn run(src: &'static str) {
    let (tokens, lex_errs) = lexer().parse(src).into_output_errors();
    if !lex_errs.is_empty() {
        println!("{:?}", lex_errs);
        return;
    }

    let tokens = tokens.unwrap();

    let (parse_result, parse_errors) = parser()
        .parse(Stream::from_iter(tokens).map((0..src.len()).into(), |(t, s)| (t, s)))
        .into_output_errors();
    if !parse_errors.is_empty() {
        println!("{:?}", parse_errors);
        return;
    }

    // ::sigh:: The AST should be 'static
    // This simplifies lifetimes, and
    // in any event, the AST should live forever
    let parsed: &'static Spanned<Ast> = Box::leak(Box::new(parse_result.unwrap()));

    let prelude = prelude();
    // let prelude = imbl::HashMap::new();

    let mut validator = Validator::new(&parsed.0, &parsed.1, "user input", src, prelude.clone());
    validator.validate();

    if !validator.errors.is_empty() {
        println!("Ludus found some validation errors:");
        report_invalidation(validator.errors);
        return;
    }

    let mut compiler = Compiler::new(parsed, "test", src, None, prelude, DEBUG_SCRIPT_COMPILE);
    // let base = base::make_base();
    // compiler.emit_constant(base);
    // compiler.bind("base");

    compiler.compile();
    if DEBUG_SCRIPT_COMPILE {
        println!("=== source code ===");
        println!("{src}");
        compiler.disassemble();
        println!("\n\n")
    }

    if DEBUG_SCRIPT_RUN {
        println!("=== vm run: test ===");
    }

    let vm_chunk = compiler.chunk;

    let mut vm = Vm::new(vm_chunk, DEBUG_SCRIPT_RUN);
    let result = vm.run();
    let output = match result {
        Ok(val) => val.show(),
        Err(panic) => format!("Ludus panicked! {panic}"),
    };
    vm.print_stack();
    println!("{output}");
}

pub fn ld_fmt(src: &'static str) -> Result<String, String> {
    let (tokens, lex_errs) = lexer().parse(src).into_output_errors();
    if !lex_errs.is_empty() {
        println!("{:?}", lex_errs);
        return Err(format!("{:?}", lex_errs));
    }

    let tokens = tokens.unwrap();

    let (parse_result, parse_errors) = parser()
        .parse(Stream::from_iter(tokens).map((0..src.len()).into(), |(t, s)| (t, s)))
        .into_output_errors();
    if !parse_errors.is_empty() {
        return Err(format!("{:?}", parse_errors));
    }

    // ::sigh:: The AST should be 'static
    // This simplifies lifetimes, and
    // in any event, the AST should live forever
    let parsed: &'static Spanned<Ast> = Box::leak(Box::new(parse_result.unwrap()));

    Ok(parsed.0.show())
}

pub fn main() {
    env::set_var("RUST_BACKTRACE", "1");
    let src: &'static str = fs::read_to_string("sandbox.ld").unwrap().leak();
    match ld_fmt(src) {
        Ok(src) => println!("{}", src),
        Err(msg) => println!("Could not format source with errors:\n{}", msg),
    }
    run(src);
}