//! The built-in grants of `recall`, `memory` and `ask_memory` (M5a spec, section 8; M5c spec,
//! section 9). Reading and writing memory is what an agent is, so no grant file can turn it off or
//! put questions in front of it; the prompt is protected by `memoryd`, which lets only clean
//! sessions edit identity.

use bxcore::{Grant, GrantProblem, sha256};

use crate::grants::LoadedGrant;

/// Ids starting with this are the built-ins'; an owner's grant file may not use one.
pub const RESERVED: &str = "builtin-";

/// The built-in grants' text, hashed for the audit log like a grant file's bytes.
pub const RECALL: &str = "tool = \"recall\"\nmode = \"auto\"\nmax_taint = \"secret\"\nresult_class = \"private\"\nuntrusted = false\n";
pub const MEMORY: &str = "tool = \"memory\"\nmode = \"auto\"\nmax_taint = \"secret\"\nresult_class = \"private\"\nuntrusted = false\n";
pub const ASK_MEMORY: &str = "tool = \"ask_memory\"\nmode = \"auto\"\nmax_taint = \"secret\"\nresult_class = \"private\"\nuntrusted = false\n";

/// The sentence for an owner's grant naming a memory tool.
pub const BUILT_IN: &str =
    "the policy of recall, memory and ask_memory is built in; remove this grant";

/// The three built-in grants, `builtin-memory`, `builtin-recall` and `builtin-ask-memory`.
pub fn grants() -> Result<Vec<LoadedGrant>, GrantProblem> {
    // For each (id, text) of `sources`:
    // `toml::from_str::<Grant>(text)` and `sha256(text.as_bytes())`, each error as a GrantProblem {
    // file: id, line: None, problem: e.to_string() }; build LoadedGrant { id, grant, sha256 }.
    // Collect into Result<Vec<LoadedGrant>, GrantProblem> (the first error wins).
    let sources: &[(&str, &str)] = &[
        ("builtin-memory", MEMORY),
        ("builtin-recall", RECALL),
        ("builtin-ask-memory", ASK_MEMORY),
    ];
    let mut out: Vec<LoadedGrant> = Vec::new();
    for (id, text) in sources {
        let problem = |error: String| GrantProblem {
            file: id.to_string(),
            line: None,
            problem: error,
        };
        let grant = toml::from_str::<Grant>(text).map_err(|e| problem(e.to_string()))?;
        let sha256 = sha256(text.as_bytes()).map_err(|e| problem(e.to_string()))?;
        out.push(LoadedGrant {
            id: id.to_string(),
            grant,
            sha256,
        });
    }
    Ok(out)
}