//! CLI for checking documentation coverage on files changed since a base branch.
//!
//! Usage: `source-map-check [--worktree <path>] [--base <branch>]`
//!
//! Exits with code 1 and prints LLM-friendly directions when public items are
//! missing doc comments. Exits 0 (silently) when all changed files are fully
//! documented or when there are no relevant changes to check.

use source_map_gen::{CheckResult, check_files_ratcheted};
use std::path::{Path, PathBuf};
use std::process::Command;

fn main() {
    let args: Vec<String> = std::env::args().collect();
    let worktree = parse_arg(&args, "--worktree").unwrap_or_else(|| ".".to_string());
    let base = parse_arg(&args, "--base").unwrap_or_else(|| "master".to_string());

    let worktree_path = Path::new(&worktree);

    let output = match Command::new("git")
        .args(["diff", "--name-only", &format!("{base}...HEAD")])
        .current_dir(worktree_path)
        .output()
    {
        Ok(o) => o,
        Err(e) => {
            eprintln!("source-map-check: git diff failed: {e}");
            std::process::exit(1);
        }
    };

    if !output.status.success() {
        // Base branch not found or other git error — skip the check gracefully.
        return;
    }

    let changed: Vec<PathBuf> = String::from_utf8_lossy(&output.stdout)
        .lines()
        .filter(|l| !l.is_empty())
        .map(|l| worktree_path.join(l))
        .filter(|p| p.exists())
        .collect();

    if changed.is_empty() {
        return;
    }

    let file_refs: Vec<&Path> = changed.iter().map(PathBuf::as_path).collect();

    match check_files_ratcheted(&file_refs, worktree_path, &base) {
        CheckResult::Ok => {}
        CheckResult::Failures(failures) => {
            eprintln!(
                "Doc coverage check failed. Add doc comments to the following items before committing:\n"
            );
            for f in &failures {
                eprintln!("  {}", f.to_direction());
            }
            eprintln!(
                "\nRe-run: cargo run -p source-map-gen --bin source-map-check -- --worktree . --base master"
            );
            std::process::exit(1);
        }
    }
}

/// Parse a flag value from an argument list (e.g. `--flag value`).
fn parse_arg(args: &[String], flag: &str) -> Option<String> {
    args.windows(2).find(|w| w[0] == flag).map(|w| w[1].clone())
}