//! Generate the ordinal → export-name table that import resolution needs.
//!
//! 🔴 **THE SOURCE CHANGED, AND THE OLD ONE COULD FAIL SILENTLY.** In `xenia-rs`
//! this parsed Canary's `xboxkrnl_table.inc` / `xam_table.inc` through a
//! **relative path to a sibling checkout** — `../xenia-canary/src/…`. When that
//! path was not there (a container, another machine, a fresh clone) it printed a
//! `cargo:warning` and returned an empty table, and every import in the database
//! came out unresolved. A build that quietly produces a worse artifact is the
//! failure mode this project keeps meeting.
//!
//! The source is now `docs/reference/xbox360-exports.json`, which is **in this
//! repository** — 2,913 exports across `xboxkrnl.exe`, `xam.xex` and `xbdm.xex`,
//! adopted in Phase 2 of `docs/agents/CONSOLIDATION.md`. There is no sibling
//! checkout to be missing, and if the file is unreadable this **fails the
//! build** rather than degrading.

use std::path::Path;
use std::{env, fs, io::Write};

fn main() {
    let manifest = env::var("CARGO_MANIFEST_DIR").unwrap();
    let json_path = Path::new(&manifest)
        .parent()
        .and_then(Path::parent)
        .unwrap()
        .join("docs/reference/xbox360-exports.json");
    println!("cargo:rerun-if-changed={}", json_path.display());

    let raw = fs::read_to_string(&json_path).unwrap_or_else(|e| {
        panic!(
            "sylpheed-xexdb: cannot read the export table at {} ({e}).\n\
             Import names would all resolve to None and the database would be \
             silently poorer, so this is a hard error rather than a warning.",
            json_path.display()
        )
    });
    let doc: serde_json::Value =
        serde_json::from_str(&raw).expect("export table is not valid JSON");

    let out = Path::new(&env::var("OUT_DIR").unwrap()).join("ordinals.rs");
    let mut f = fs::File::create(&out).unwrap();
    writeln!(
        f,
        "/// Auto-generated from `docs/reference/xbox360-exports.json`."
    )
    .unwrap();
    writeln!(
        f,
        "pub fn resolve_ordinal(lib: &str, ordinal: u16) -> Option<&'static str> {{"
    )
    .unwrap();
    writeln!(f, "    match lib {{").unwrap();

    let mut total = 0usize;
    for (module, file) in [
        ("xboxkrnl", "xboxkrnl.exe"),
        ("xam", "xam.xex"),
        ("xbdm", "xbdm.xex"),
    ] {
        writeln!(f, "        \"{file}\" => match ordinal {{").unwrap();
        let exports = doc["modules"][module]["exports"]
            .as_array()
            .unwrap_or_else(|| panic!("no exports array for module {module}"));
        for e in exports {
            let (Some(ord), Some(name)) = (e["ordinal"].as_u64(), e["name"].as_str()) else {
                continue;
            };
            if ord > u16::MAX as u64 {
                continue;
            }
            writeln!(f, "            0x{ord:04X} => Some(\"{name}\"),").unwrap();
            total += 1;
        }
        writeln!(f, "            _ => None,\n        }},").unwrap();
    }
    writeln!(f, "        _ => None,\n    }}\n}}").unwrap();

    // A count in the build log, so "the table is there" is observable rather
    // than assumed. 2,913 is what Phase 2 adopted.
    println!("cargo:warning=sylpheed-xexdb: {total} ordinals from xbox360-exports.json");
}