decl-lang 0.3.0

//! `decl check` / `decl evaluate` / `decl validate` / `decl fmt` (cli.ts). Output is byte-identical to
//! the reference implementation's CLI so the three implementations can
//! be diffed (tests/parity/differential.py).
use crate::ast::DeclBody;
use crate::checker::check_module;
use crate::conformance::judge_corpus;
use crate::fmt::format;
use crate::module::{load_modules, run_universe, Bind, LoadResult, Module};
use crate::package::{open_package_universe, verify_lock};
use crate::semantics::{json_str, read_json, Diag};
use std::collections::HashMap;
use std::path::{Path, PathBuf};
use std::rc::Rc;

fn usage() -> i32 {
    eprintln!("usage:\n  decl --version\n  decl check <file>... [--json]\n  decl evaluate <file> [--input name=doc.json]... [--output name[=file]]... [--json]\n  decl validate <dir>\n  decl validate <file> [--input name=doc.json]... [--expect-errors E1,E2] [--json]\n  decl fmt <file>... [--check]\n  decl repl [file.decl] [--input name=doc.json]... [--script session.txt | --script -] [--compact]");
    2
}

/// the module graph of an entry file inside its package universe
/// (manifest and lock diagnostics first), as the reference CLI opens it
pub fn open_universe(file: &str) -> LoadResult {
    let abs = std::path::absolute(file).unwrap_or_else(|_| PathBuf::from(file));
    let pkg = open_package_universe(&abs);
    let mut diags: Vec<Diag> = vec![];
    if let Some(u) = &pkg {
        diags.extend(u.diags.clone());
        diags.extend(verify_lock(u));
    }
    let r = load_modules(&abs, pkg.as_ref().map(|u| &u.resolver), None);
    diags.extend(r.diags);
    LoadResult {
        modules: r.modules,
        entry: r.entry,
        diags,
    }
}

fn print_diag(file: &str, d: &Diag, json: bool, collected: &mut Vec<String>) {
    if json {
        collected.push(d.to_json(Some(file)));
        return;
    }
    eprintln!(
        "{file}: {}{}{}{}: {}",
        d.severity,
        d.code
            .as_ref()
            .map(|c| format!(" [{c}]"))
            .unwrap_or_default(),
        d.id.as_ref().map(|i| format!(" {i}")).unwrap_or_default(),
        if d.path.is_empty() {
            String::new()
        } else {
            format!(" at {}", d.path)
        },
        d.message
    );
}

/// the documents named by `--input`, each bound to the module that
/// declares its input (§10): `name=doc.json`; Err carries the exit code
/// of a usage error (already printed)
/// the documents named by --input, each bound to the module that declares
/// its input (§10): `name=doc.json`. A usage error (bad spec, unknown input)
/// is printed and returned as exit 2; a document that cannot be read or is
/// not well-formed JSON is returned as one E6004 diagnostic (exit 1)
pub fn input_binds(
    modules: &[Rc<Module>],
    specs: &[String],
) -> Result<Vec<Bind>, (i32, Option<Diag>)> {
    let doc_error = |name: &str, message: String| -> (i32, Option<Diag>) {
        (
            1,
            Some(Diag {
                severity: "error".into(),
                id: None,
                message,
                path: name.to_string(),
                code: Some("E6004".into()),
                loc: None,
                by: None,
            }),
        )
    };
    let mut binds = vec![];
    for spec in specs {
        let Some((name, file)) = spec.split_once('=') else {
            eprintln!("--input expects name=doc.json, got {spec}");
            return Err((2, None));
        };
        let Some(module) = modules
            .iter()
            .find(|m| m.env.inputs.borrow().contains_key(name))
        else {
            eprintln!("no input named {name}");
            return Err((2, None));
        };
        let text = match std::fs::read_to_string(file) {
            Ok(t) => t,
            Err(_) => {
                return Err(doc_error(
                    name,
                    format!("bound document cannot be read: {file}"),
                ))
            }
        };
        let raw = match read_json(&text) {
            Ok(v) => v,
            Err(_) => {
                return Err(doc_error(
                    name,
                    format!("bound document is not well-formed JSON: {file}"),
                ));
            }
        };
        binds.push(Bind {
            module: Some(module.clone()),
            input: name.to_string(),
            raw,
        });
    }
    Ok(binds)
}

/// `decl evaluate`: (exit code, the document for stdout, diagnostics tagged
/// with the file each is reported against, bare stderr lines to print
/// after them). What to emit, and where (§5.5): each `--output name[=file]`
/// names a root — an output, or an input bound by --input or demanded
/// through its fallback — and the file its document goes to (stdout
/// without one); with no --output, the entry module's exported outputs, as
/// one object keyed by name, on stdout
pub fn evaluate(
    file: &str,
    outputs: &[String],
    inputs: &[String],
) -> (i32, Option<String>, Vec<(String, Diag)>, Vec<String>) {
    let tag = |ds: Vec<Diag>| -> Vec<(String, Diag)> {
        ds.into_iter().map(|d| (file.to_string(), d)).collect()
    };
    let mut targets: Vec<(String, Option<String>)> = vec![];
    for spec in outputs {
        let (name, dest) = match spec.split_once('=') {
            Some((n, f)) => (n.to_string(), Some(f.to_string())),
            None => (spec.clone(), None),
        };
        if name.is_empty() || dest.as_deref() == Some("") {
            eprintln!("--output expects name or name=file, got {spec}");
            return (2, None, vec![], vec![]);
        }
        targets.push((name, dest));
    }
    if targets.iter().filter(|(_, f)| f.is_none()).count() > 1 {
        eprintln!("--output: at most one document can go to stdout");
        return (2, None, vec![], vec![]);
    }
    let r = open_universe(file);
    let Some(entry) = r.entry else {
        return (1, None, tag(r.diags), vec![]);
    };
    if !r.diags.is_empty() {
        return (1, None, tag(r.diags), vec![]);
    }
    let checks: Vec<(String, Diag)> = r
        .modules
        .iter()
        .flat_map(|m| {
            let path = file_tag(file, Some(entry.path.as_path()), &m.path);
            check_module(&m.decls, Some(m.env.clone()), None)
                .into_iter()
                .map(move |d| (path.clone(), d))
                .collect::<Vec<_>>()
        })
        .collect();
    if !checks.is_empty() {
        return (1, None, checks, vec![]);
    }
    let binds = match input_binds(&r.modules, inputs) {
        Ok(b) => b,
        Err((code, diag)) => {
            return (
                code,
                None,
                diag.into_iter().map(|d| (file.to_string(), d)).collect(),
                vec![],
            )
        }
    };
    let (eng, diags) = run_universe(&r.modules, &entry, binds);
    if diags.iter().any(|d| d.severity == "error") {
        return (1, None, tag(diags), vec![]);
    }
    let names: Vec<String> = if targets.is_empty() {
        entry
            .decls
            .iter()
            .filter(|d| d.exported)
            .filter_map(|d| match &d.body {
                DeclBody::Output { name, .. } => Some(name.clone()),
                _ => None,
            })
            .collect()
    } else {
        targets.iter().map(|(n, _)| n.clone()).collect()
    };
    let mut notes = vec![];
    for n in &names {
        if entry.env.root(n).is_none() {
            notes.push(format!("no root named {n}"));
        }
    }
    if !notes.is_empty() {
        return (1, None, tag(diags), notes);
    }
    let doc = |n: &str| eng.serialize(&entry.env.root(n).unwrap(), n, false);
    let mut text = None;
    if targets.is_empty() {
        if names.is_empty() {
            notes.push(format!(
                "{file}: exports no output; --output <name> selects a root"
            ));
        }
        text = Some(format!(
            "{{{}}}",
            names
                .iter()
                .map(|n| format!("{}:{}", json_str(n), doc(n)))
                .collect::<Vec<_>>()
                .join(",")
        ));
    } else {
        for (n, dest) in &targets {
            match dest {
                None => text = Some(doc(n)),
                Some(path) => {
                    if std::fs::write(path, doc(n) + "\n").is_err() {
                        notes.push(format!("cannot write {path}"));
                        return (1, None, tag(diags), notes);
                    }
                }
            }
        }
    }
    (0, text, tag(diags), notes)
}

/// single-file validation, module-aware like `check` and `evaluate`: load
/// the universe, check every module, then evaluate with the `--input`
/// documents bound (none bound is fine: fallbacks apply). Diagnostics come
/// tagged with the file each is reported against; Err carries a usage exit
/// code as a negative
pub fn validate_file(file: &str, inputs: &[String]) -> Result<Vec<(String, Diag)>, i64> {
    let r = open_universe(file);
    let mut diags: Vec<(String, Diag)> = r
        .diags
        .iter()
        .map(|d| (file.to_string(), d.clone()))
        .collect();
    let Some(entry) = r.entry else {
        return Ok(diags);
    };
    if !diags.is_empty() {
        return Ok(diags);
    }
    let checks: Vec<(String, Diag)> = r
        .modules
        .iter()
        .flat_map(|m| {
            let path = file_tag(file, Some(entry.path.as_path()), &m.path);
            check_module(&m.decls, Some(m.env.clone()), None)
                .into_iter()
                .map(move |d| (path.clone(), d))
                .collect::<Vec<_>>()
        })
        .collect();
    if !checks.is_empty() {
        return Ok(checks);
    }
    let binds = match input_binds(&r.modules, inputs) {
        Ok(b) => b,
        Err((_, Some(d))) => return Ok(vec![(file.to_string(), d)]),
        Err((code, None)) => return Err(-(code as i64)),
    };
    diags.extend(
        run_universe(&r.modules, &entry, binds)
            .1
            .into_iter()
            .map(|d| (file.to_string(), d)),
    );
    Ok(diags)
}

/// `decl check`: load each entry (following imports), report load
/// diagnostics and every module's static findings, tagged with their file
pub fn check_files(paths: &[String]) -> Vec<(String, Diag)> {
    let mut out = vec![];
    for f in paths {
        let r = open_universe(f);
        out.extend(r.diags.into_iter().map(|d| (f.clone(), d)));
        for m in &r.modules {
            let path = file_tag(f, r.entry.as_ref().map(|e| e.path.as_path()), &m.path);
            out.extend(
                check_module(&m.decls, Some(m.env.clone()), None)
                    .into_iter()
                    .map(|d| (path.clone(), d)),
            );
        }
    }
    out
}

/// the file a diagnostic is reported against: the entry module by the path
/// given on the command line, any other module by its absolute path
pub fn file_tag(given: &str, entry: Option<&Path>, module: &Path) -> String {
    if entry == Some(module) {
        given.to_string()
    } else {
        module.display().to_string()
    }
}

/// the command line: returns the process exit code
pub fn main(args: Vec<String>) -> i32 {
    let Some(cmd) = args.first().cloned() else {
        return usage();
    };
    // `decl --version`: the package's version, the same string on every registry
    if cmd == "--version" {
        println!("decl {}", env!("CARGO_PKG_VERSION"));
        return 0;
    }
    // `decl repl`: its own argument syntax (docs/tooling/02_repl.md)
    if cmd == "repl" {
        return crate::repl::run_repl(args[1..].to_vec());
    }
    let mut flags: HashMap<String, String> = HashMap::new();
    let mut input_flags: Vec<String> = vec![]; // --input name=doc.json, repeatable
    let mut output_flags: Vec<String> = vec![]; // --output name[=file], repeatable
    let mut pos: Vec<String> = vec![];
    let mut i = 1;
    while i < args.len() {
        let a = &args[i];
        if let Some(name) = a.strip_prefix("--") {
            if ["output", "input", "expect-errors"].contains(&name)
                && i + 1 < args.len()
                && !args[i + 1].starts_with("--")
            {
                if name == "input" {
                    input_flags.push(args[i + 1].clone());
                } else if name == "output" {
                    output_flags.push(args[i + 1].clone());
                } else {
                    flags.insert(name.to_string(), args[i + 1].clone());
                }
                i += 2;
                continue;
            }
            flags.insert(name.to_string(), "true".into());
        } else {
            pos.push(a.clone());
        }
        i += 1;
    }
    let json = flags.contains_key("json");
    let mut collected: Vec<String> = vec![];
    match cmd.as_str() {
        "check" => {
            if pos.is_empty() {
                return usage();
            }
            let diags = check_files(&pos);
            for (file, d) in &diags {
                print_diag(file, d, json, &mut collected);
            }
            if diags.is_empty() {
                eprintln!("ok: {} entry file(s) check clean", pos.len());
            }
            if json {
                println!("[{}]", collected.join(","));
            }
            if diags.is_empty() {
                0
            } else {
                1
            }
        }
        "evaluate" => {
            let Some(f) = pos.first() else { return usage() };
            let (code, text, diags, notes) = evaluate(f, &output_flags, &input_flags);
            if code == 2 {
                return 2; // a usage error: already printed, no report
            }
            for (file, d) in &diags {
                print_diag(file, d, json, &mut collected);
            }
            for n in &notes {
                eprintln!("{n}");
            }
            if json {
                println!(
                    "{{\"ok\":{},\"value\":{},\"diagnostics\":[{}]}}",
                    code == 0,
                    text.clone().unwrap_or_else(|| "null".into()),
                    collected.join(",")
                );
            } else if let Some(t) = text {
                println!("{t}");
            }
            code
        }
        "validate" => {
            let Some(target) = pos.first() else {
                return usage();
            };
            let tp = Path::new(target);
            if tp.is_dir() {
                let abs = std::path::absolute(tp).unwrap_or_else(|_| tp.to_path_buf());
                let (mut ok, mut fail) = (0, 0);
                for v in judge_corpus(&abs) {
                    if v.ok {
                        ok += 1;
                    } else {
                        fail += 1;
                        eprintln!("FAIL {} {}", v.file.display(), v.detail);
                    }
                }
                eprintln!("{ok} ok, {fail} failed");
                if fail > 0 {
                    1
                } else {
                    0
                }
            } else {
                let diags = match validate_file(target, &input_flags) {
                    Ok(d) => d,
                    Err(n) => return (-n) as i32,
                };
                for (file, d) in &diags {
                    print_diag(file, d, json, &mut collected);
                }
                if json {
                    println!("[{}]", collected.join(","));
                }
                let err_codes: Vec<String> = diags
                    .iter()
                    .filter(|(_, d)| d.severity == "error")
                    .map(|(_, d)| d.code.clone().unwrap_or_default())
                    .collect();
                if let Some(expect) = flags.get("expect-errors") {
                    let want: Vec<String> = expect
                        .split(',')
                        .map(|w| w.trim().to_string())
                        .filter(|w| !w.is_empty())
                        .collect();
                    let missing: Vec<&String> =
                        want.iter().filter(|w| !err_codes.contains(w)).collect();
                    let extra: Vec<&String> =
                        err_codes.iter().filter(|c| !want.contains(c)).collect();
                    if !missing.is_empty() || !extra.is_empty() {
                        if !missing.is_empty() {
                            eprintln!(
                                "expected error(s) not reported: {}",
                                missing
                                    .iter()
                                    .map(|s| s.as_str())
                                    .collect::<Vec<_>>()
                                    .join(", ")
                            );
                        }
                        if !extra.is_empty() {
                            eprintln!(
                                "unexpected error(s): {}",
                                extra
                                    .iter()
                                    .map(|s| s.as_str())
                                    .collect::<Vec<_>>()
                                    .join(", ")
                            );
                        }
                        return 1;
                    }
                    eprintln!(
                        "ok: expected errors reported ({})",
                        if want.is_empty() {
                            "none".to_string()
                        } else {
                            want.join(", ")
                        }
                    );
                    return 0;
                }
                if err_codes.is_empty() {
                    0
                } else {
                    1
                }
            }
        }
        "fmt" => {
            if pos.is_empty() {
                return usage();
            }
            let (mut changed, mut bad) = (0, 0);
            for f in &pos {
                let Ok(src) = std::fs::read_to_string(f) else {
                    eprintln!("{f}: cannot be read");
                    bad += 1;
                    continue;
                };
                let out = match format(&src) {
                    Ok(o) => o,
                    Err(e) => {
                        eprintln!("{f}: {e}");
                        bad += 1;
                        continue;
                    }
                };
                if out != src {
                    changed += 1;
                    if flags.contains_key("check") {
                        eprintln!("would reformat {f}");
                    } else {
                        let _ = std::fs::write(f, out);
                        eprintln!("reformatted {f}");
                    }
                }
            }
            if bad > 0 || (flags.contains_key("check") && changed > 0) {
                1
            } else {
                0
            }
        }
        _ => usage(),
    }
}