use std::{
    env, fs,
    path::{Path, PathBuf},
};

use anyhow::{Context, Result};
use ariadne::{
    CharSet, Color, Config as CliConfig, Label, Report as CliReport,
    ReportKind as CliReportKind, Source, LabelAttach
};
use lib::{Report, LINTS};
use rnix::{TextRange, WalkEvent};

fn analyze(source: &str) -> Result<Vec<Report>> {
    let parsed = rnix::parse(source).as_result()?;

    Ok(parsed
        .node()
        .preorder_with_tokens()
        .filter_map(|event| match event {
            WalkEvent::Enter(child) => LINTS.get(&child.kind()).map(|rules| {
                rules
                    .iter()
                    .filter_map(|rule| rule.validate(&child))
                    .collect::<Vec<_>>()
            }),
            _ => None,
        })
        .flatten()
        .collect())
}

fn print_report(report: Report, file_src: &str, file_path: &Path) -> Result<()> {
    let range = |at: TextRange| at.start().into()..at.end().into();
    let src_id = file_path.to_str().unwrap_or("<unknown>");
    let offset = report
        .diagnostics
        .iter()
        .map(|d| d.at.start().into())
        .min()
        .unwrap_or(0usize);
    report
        .diagnostics
        .iter()
        .fold(
            CliReport::build(CliReportKind::Warning, src_id, offset)
            .with_config(
                CliConfig::default()
                    .with_cross_gap(true)
                    .with_multiline_arrows(false)
                    .with_label_attach(LabelAttach::Middle)
                    .with_char_set(CharSet::Unicode),
            )
            .with_message(report.note)
            .with_code(report.code),
            |cli_report, diagnostic| {
                let cli_report = cli_report.with_label(
                    Label::new((src_id, range(diagnostic.at)))
                        .with_message(&diagnostic.message)
                        .with_color(Color::Magenta),
                );
                if let Some(s) = &diagnostic.suggestion {
                    let replacement_msg = format!("Try: `{}`", s.fix);
                    cli_report.with_label(
                        Label::new((src_id, range(s.at)))
                            .with_message(replacement_msg)
                            .with_color(Color::Yellow),
                    )
                } else {
                    cli_report
                }
            },
        )
        .finish()
        .eprint((src_id, Source::from(file_src)))
        .context("failed to print report to stdout")
}

fn _main() -> Result<()> {
    // TODO: accept cli args, construct a CLI config with a list of files to analyze
    let args = env::args();
    for (file_src, file_path, reports) in args
        .skip(1)
        .map(|s| PathBuf::from(&s))
        .filter(|p| p.is_file())
        .filter_map(|path| {
            let s = fs::read_to_string(&path).ok()?;
            analyze(&s)
                .map(|analysis_result| (s, path, analysis_result))
                .ok()
        })
    {
        for r in reports {
            print_report(r, &file_src, &file_path)?
        }
    }
    Ok(())
}
fn main() {
    match _main() {
        Err(e) => eprintln!("{}", e),
        _ => {}
    }
}