jsonata-core 2.2.4

use clap::Parser;
use jsonata_core::evaluator::{Context, Evaluator};
use jsonata_core::parser;
use jsonata_core::value::JValue;
use std::io::Read;
use std::process::ExitCode;

mod bindings;
mod error_format;
mod resolve;

/// Evaluate JSONata expressions against JSON data.
#[derive(Parser, Debug)]
#[command(
    name = "jsonata",
    version,
    about = "Evaluate JSONata expressions against JSON data"
)]
pub(crate) struct Cli {
    /// Compact JSON output (default: pretty-printed)
    #[arg(short = 'c', long)]
    pub(crate) compact: bool,

    /// Print string results without surrounding quotes
    #[arg(short = 'r', long = "raw-output")]
    pub(crate) raw_output: bool,

    /// Don't read input; $ is undefined
    #[arg(short = 'n', long = "null-input")]
    pub(crate) null_input: bool,

    /// Read the expression from a file instead of the first positional argument
    #[arg(short = 'f', long = "from-file", value_name = "FILE")]
    pub(crate) from_file: Option<String>,

    /// Bind $NAME to a string value: --arg NAME=VALUE
    #[arg(long = "arg", value_name = "NAME=VALUE", action = clap::ArgAction::Append)]
    pub(crate) arg: Vec<String>,

    /// Bind $NAME to a parsed JSON value: --argjson NAME=JSON
    #[arg(long = "argjson", value_name = "NAME=JSON", action = clap::ArgAction::Append)]
    pub(crate) argjson: Vec<String>,

    /// The JSONata expression (or, with --from-file, the input data file)
    #[arg(value_name = "EXPRESSION_OR_FILE")]
    pub(crate) positional1: Option<String>,

    /// The input data file (used only when --from-file supplies the expression)
    #[arg(value_name = "FILE")]
    pub(crate) positional2: Option<String>,
}

fn main() -> ExitCode {
    let cli = Cli::parse();
    run(cli)
}

fn run(cli: Cli) -> ExitCode {
    let (expr_source, input_source) = match resolve::resolve(&cli) {
        Ok(v) => v,
        Err(msg) => {
            eprintln!("error: {}", msg);
            return ExitCode::from(2);
        }
    };

    // Validate --arg/--argjson bindings before touching the filesystem or
    // parsing the expression, so malformed usage (exit 2) always takes
    // precedence over input-read errors (exit 3) and parse errors (exit 1).
    let var_bindings = match bindings::parse_bindings(&cli.arg, &cli.argjson) {
        Ok(b) => b,
        Err(msg) => {
            eprintln!("error: {}", msg);
            return ExitCode::from(2);
        }
    };

    let expression = match expr_source {
        resolve::ExpressionSource::Inline(s) => s,
        resolve::ExpressionSource::File(path) => match std::fs::read_to_string(&path) {
            Ok(s) => s,
            Err(e) => {
                eprintln!("error: could not read expression file {}: {}", path, e);
                return ExitCode::from(2);
            }
        },
    };

    let data = match input_source {
        resolve::InputSource::Null => JValue::Undefined,
        resolve::InputSource::Stdin => match read_input(None) {
            Ok(data) => data,
            Err((msg, code)) => {
                eprintln!("{}", msg);
                return ExitCode::from(code);
            }
        },
        resolve::InputSource::File(path) => match read_input(Some(&path)) {
            Ok(data) => data,
            Err((msg, code)) => {
                eprintln!("{}", msg);
                return ExitCode::from(code);
            }
        },
    };

    let ast = match parser::parse(&expression) {
        Ok(ast) => ast,
        Err(e) => {
            eprintln!("{}", e.display_message());
            return ExitCode::from(1);
        }
    };

    let mut context = Context::new();
    for (name, value) in var_bindings {
        context.bind(name, value);
    }
    let mut evaluator = Evaluator::with_context(context);
    let result = match evaluator.evaluate(&ast, &data) {
        Ok(v) => v,
        Err(e) => {
            eprintln!("{}", error_format::format_evaluator_error(&e));
            return ExitCode::from(1);
        }
    };

    if result.is_undefined() {
        return ExitCode::SUCCESS;
    }

    print_result(&result, cli.compact, cli.raw_output)
}

fn print_result(result: &JValue, compact: bool, raw_output: bool) -> ExitCode {
    if raw_output {
        if let JValue::String(s) = result {
            println!("{}", s);
            return ExitCode::SUCCESS;
        }
    }

    let text = if compact {
        result.to_json_string()
    } else {
        result.to_json_string_pretty()
    };

    match text {
        Ok(s) => {
            println!("{}", s);
            ExitCode::SUCCESS
        }
        Err(e) => {
            eprintln!("error: could not serialize result: {}", e);
            ExitCode::from(1)
        }
    }
}

// NOTE: multi-document stdin (e.g. `{"a":1}\n{"a":2}\n`) is NOT supported —
// JValue::from_json_str rejects trailing non-whitespace content after the
// first JSON value with a serde_json "trailing characters" error, surfaced
// here as exit code 3. jq's --slurp/streaming semantics are explicitly out
// of scope for this CLI (see Phase 1 of the design spec).

/// Reads and JSON-parses the input document from a file path, or stdin if
/// `path` is `None`. Returns `(stderr message, exit code)` on failure.
fn read_input(path: Option<&str>) -> Result<JValue, (String, u8)> {
    let raw = match path {
        Some(p) => std::fs::read_to_string(p)
            .map_err(|e| (format!("error: could not read input file {}: {}", p, e), 2))?,
        None => {
            let mut buf = String::new();
            std::io::stdin()
                .read_to_string(&mut buf)
                .map_err(|e| (format!("error: could not read stdin: {}", e), 2))?;
            buf
        }
    };
    JValue::from_json_str(&raw).map_err(|e| (format!("error: invalid JSON input: {}", e), 3))
}