iowo/crates/app/src/main.rs

use crate::{config::Configs, error_reporting::report_serde_json_err};

mod cli {
    use clap::{Parser, Subcommand};

    #[derive(Parser)]
    struct Args {
        #[command(subcommand)]
        command: Command,
    }

    #[derive(Clone, Subcommand)]
    enum Command {}
}

mod config {
    use serde::{Deserialize, Serialize};

    #[derive(Debug, Serialize, Deserialize)]
    pub struct Configs<'a> {
        example_value: i32,
        example_string: &'a str,
    }

    impl Configs<'_> {
        pub fn read_json(config_text: &str) -> serde_json::Result<Configs<'_>> {
            serde_json::from_str(config_text)
        }
    }
}

mod error_reporting {
    use std::{ops::Range, process};

    use ariadne::{Report, Source};

    pub fn report_serde_json_err(src: &str, err: serde_json::Error) -> ! {
        use ariadne::{Color, ColorGenerator, Fmt, Label, Report, ReportKind, Source};
        let offset = try_reconstruct_loc(src, err.line(), err.column());

        Report::build(ariadne::ReportKind::Error, "test", offset)
            .with_label(Label::new(("test", offset..offset)))
            .with_message(err.to_string())
            .finish()
            .print(("test", Source::from(src)))
            .unwrap();
        process::exit(1);
    }
    fn try_reconstruct_loc(src: &str, line_nr: usize, col_nr: usize) -> usize {
        let (line_nr, col_nr) = (line_nr - 1, col_nr - 1);

        src.lines().enumerate().fold(0, |acc, (i, line)| {
            if i < line_nr {
                acc + line.len()
            } else if i == line_nr {
                acc + col_nr
            } else {
                acc
            }
        })
    }
}

fn main() {
    const TEST_JSON_CONFIG: &str = "{ \"example_value\": 42, \"example_string\": \"meow\" }";
    const TEST_JSON_CONFIG_BROKEN: &str = "{ 
    \"example_value\": \"42\", 
    \"example_string\": \"meow\" 
}";

    dbg!(Configs::read_json(TEST_JSON_CONFIG_BROKEN)
        .map_err(|e| report_serde_json_err(TEST_JSON_CONFIG_BROKEN, e)));
}