//! Loading the published documentation tree (`site-docs/public`).
//!
//! Lives in the library rather than in `main.rs` so the test harness builds the
//! loader the same way production does. It used to be a private binary
//! function, and the harness could only construct a `DocLoader` with
//! `sections: vec![]`, so under test the site had no doc pages at all: nothing
//! could cover `/docs`, and the two integration tests that would have proven
//! the docs half of the sitemap and the search index had to be dropped.
//!
//! One definition means the harness cannot drift from the server the way an
//! imitation of this config would.

use docengine::{DocLoader, DocLoaderConfig};
use mnw_assumptions::Assumptions;
use std::sync::Arc;

/// Where the published docs live. `DOCS_PATH` overrides for a deployment whose
/// working directory is not the crate root.
pub fn docs_path() -> String {
    std::env::var("DOCS_PATH").unwrap_or_else(|_| "site-docs/public".to_string())
}

/// Where the business assumptions live, substituted into doc bodies.
pub fn assumptions_path() -> String {
    std::env::var("ASSUMPTIONS_PATH")
        .unwrap_or_else(|_| "docs/business/assumptions.toml".to_string())
}

/// Load and validate business assumptions. `Err` carries a human-readable
/// message; normal startup turns it into a panic, the check modes into a
/// sentinel line. Shared so the two paths validate identically.
pub fn load_assumptions() -> Result<Arc<Assumptions>, String> {
    let path = assumptions_path();
    let a = Assumptions::load(&path)
        .map_err(|e| format!("failed to load assumptions from {path}: {e}"))?;
    a.validate()
        .map_err(|e| format!("assumptions validation failed:\n{e}"))?;
    tracing::info!(path = %path, "assumptions loaded and validated");
    Ok(Arc::new(a))
}

/// Build the documentation loader from disk with the production config.
///
/// Shared by normal startup, the `MNW_CHECK_DOCS` integrity check, and the test
/// harness, so all three see the exact same sections, link prefix, examples
/// path, and assumption substitution. The broken-link report cannot drift from
/// what is served, and a test asserting over `/docs` is asserting over the real
/// tree.
pub fn build_doc_loader(assumptions: Arc<Assumptions>) -> DocLoader {
    let docs_path = docs_path();
    DocLoader::load(
        std::path::Path::new(&docs_path),
        &DocLoaderConfig {
            sections: vec![
                ("about".to_string(), "About".to_string()),
                ("guide".to_string(), "Guide".to_string()),
                ("developer".to_string(), "Developer".to_string()),
                ("legal".to_string(), "Legal".to_string()),
                ("support".to_string(), "Support".to_string()),
                ("tech".to_string(), "Tech".to_string()),
            ],
            link_prefix: "/docs".to_string(),
            unpublished_pattern: Some("unpublished/".to_string()),
            examples_path: Some(std::path::Path::new(&docs_path).join("../examples")),
            pre_process: Some(Box::new(move |md: &str| {
                assumptions.substitute(md).map_err(|e| e.to_string())
            })),
        },
    )
}