//! `wai.delivery.rung_price` (extensions/rung-price.md): the committed corpus
//! `live-conformance/prices/` regenerates byte for byte from its fixed seeds, holds no other file,
//! every case in it gets the outcome it states, §8 lists exactly the reasons the reference reports
//! and §6.2 exactly its limits, in order.
#![cfg(feature = "rung_price")]

use std::collections::BTreeMap;
use std::path::PathBuf;
use wai::rung_price::{corpus, CODES, LIMITS};

fn wai_dir() -> PathBuf {
    PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("..")
}

fn committed() -> BTreeMap<String, String> {
    let dir = wai_dir().join("live-conformance/prices");
    std::fs::read_dir(&dir)
        .expect("the committed corpus")
        .flatten()
        .map(|e| (e.file_name().to_string_lossy().into_owned(), e.path()))
        .filter(|(n, _)| n != "README.md")
        .map(|(n, p)| (n, std::fs::read_to_string(p).expect("a text file")))
        .collect()
}

/// The text of the section of `text` that starts at the line `heading`, to the next heading of
/// the same level.
fn section<'a>(text: &'a str, heading: &str) -> &'a str {
    let at = text.find(&format!("\n{heading}")).unwrap_or_else(|| panic!("no {heading}"));
    let level = heading.split(' ').next().expect("a heading's hashes");
    let end = text[at + 1..].find(&format!("\n{level} ")).map_or(text.len(), |e| at + 1 + e);
    &text[at..end]
}

/// The first code of each table row of a section: `| \`code\` | …`.
fn listed(section: &str) -> Vec<String> {
    section.lines().filter(|l| l.starts_with("| `")).filter_map(|l| l.split('`').nth(1).map(String::from)).collect()
}

#[test]
fn the_committed_corpus_regenerates_from_its_seeds() {
    let files = committed();
    let generated: BTreeMap<String, String> = corpus::generate().into_iter().collect();
    let extra: Vec<&String> = files.keys().filter(|k| !generated.contains_key(*k)).collect();
    let missing: Vec<&String> = generated.keys().filter(|k| !files.contains_key(*k)).collect();
    let differ: Vec<&String> = generated.iter().filter(|(k, v)| files.get(*k).is_some_and(|f| f != *v)).map(|(k, _)| k).collect();
    assert!(extra.is_empty() && missing.is_empty() && differ.is_empty(), "extra {extra:?}, missing {missing:?}, differ {differ:?}: run `wai_rung_price_vectors gen`");
}

#[test]
fn every_case_gets_its_stated_outcome() {
    let fails = corpus::verify(&committed());
    assert!(fails.is_empty(), "{}", fails.join("\n"));
}

/// §8 of the extension lists exactly the codes `CODES` has, each once, in order.
#[test]
fn the_extension_lists_the_reasons() {
    let text = std::fs::read_to_string(wai_dir().join("extensions/rung-price.md")).expect("the extension");
    let want: Vec<String> = CODES.iter().map(|c| c.to_string()).collect();
    assert_eq!(listed(section(&text, "## 8. Reasons")), want, "§8's table and CODES differ");
}

/// §6.2's table lists exactly the limits `LIMITS` has, in order.
#[test]
fn the_extension_lists_the_limits() {
    let text = std::fs::read_to_string(wai_dir().join("extensions/rung-price.md")).expect("the extension");
    let want: Vec<String> = LIMITS.iter().map(|c| c.to_string()).collect();
    assert_eq!(listed(section(&text, "### 6.2 Candidates and removals")), want, "§6.2's table and LIMITS differ");
}