//! Embedding-ABI M1 codegen (spec §4): `Target::StaticLib` lowering
//! emits NO `@main` trampoline, NO `MissingEntryMain`, and one
//! external `define i64 @backtest_step(...)` (the author-chosen C
//! symbol from `(export "backtest_step")`) forwarding to the
//! internal `@ail_embed_backtest_step_step` (module
//! `embed_backtest_step` == file stem, per Design-decision 6).
//! Executable-target lowering is byte-unchanged (the
//! `missing_entry_main_is_error` in-source pin still holds).

use ailang_core::Workspace;
use std::path::PathBuf;

fn load(file: &str) -> Workspace {
    let path = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
        .parent().unwrap().parent().unwrap()
        .join("examples").join(file);
    ailang_surface::load_workspace(&path).unwrap()
}

#[test]
fn staticlib_emits_forwarder_no_main() {
    let ws = load("embed_backtest_step.ail");
    let ir = ailang_codegen::lower_workspace_staticlib_with_alloc(
        &ws, ailang_codegen::AllocStrategy::Rc).unwrap();
    assert!(!ir.contains("define i32 @main()"),
        "staticlib IR must not emit the @main trampoline");
    assert!(ir.contains("@backtest_step("),
        "staticlib IR must emit the external @backtest_step entrypoint \
         (the author-chosen C symbol — invariant under module rename)");
    assert!(ir.contains("@ail_embed_backtest_step_step("),
        "the forwarder must call the internal \
         @ail_embed_backtest_step_step (module embed_backtest_step)");

    // M2: forwarder takes a leading ptr %ctx and routes it through TLS
    // around the UNCHANGED internal call.
    assert!(ir.contains("@__ail_tls_ctx = external thread_local global ptr"),
        "staticlib module must declare the external thread-local ctx slot;\nIR:\n{ir}");
    assert!(ir.contains("define i64 @backtest_step(ptr %ctx, i64 %a0, i64 %a1)"),
        "forwarder must take a leading ptr %ctx;\nIR:\n{ir}");
    assert!(ir.contains("store ptr %ctx, ptr @__ail_tls_ctx"),
        "forwarder must publish ctx into the TLS slot;\nIR:\n{ir}");
    assert!(ir.contains("call i64 @ail_embed_backtest_step_step(i64 %a0, i64 %a1)"),
        "internal call must stay byte-unchanged (no ctx arg);\nIR:\n{ir}");
}

/// M3: a single-ctor scalar record param/ret crosses the embedding
/// C boundary as a bare `ptr` (the frozen payload pointer —
/// design/contracts/0006-frozen-value-layout.md). The M2 forwarder body
/// is byte-unchanged: leading `ptr %ctx`, TLS save/store/restore, the
/// internal `@ail_<module>_<fn>` call carrying no ctx arg and no
/// aggregate calling convention (no `sret`/`byval` — a record is a
/// bare ptr, not an LLVM aggregate). Internal symbol is module-
/// qualified `@ail_embed_backtest_step_record_step` (module ==
/// file stem, Design-decision 6).
#[test]
fn staticlib_record_forwarder_is_ptr_passthrough() {
    let ws = load("embed_backtest_step_record.ail");
    let ir = ailang_codegen::lower_workspace_staticlib_with_alloc(
        &ws, ailang_codegen::AllocStrategy::Rc).unwrap();
    // record param + ret cross as bare ptr; ctx leading; M2 TLS shape.
    assert!(ir.contains("define ptr @backtest_step(ptr %ctx, ptr %a0, double %a1)"),
        "record fwd: ptr ret, leading ptr %ctx, ptr record param, double sample;\nIR:\n{ir}");
    assert!(ir.contains("store ptr %ctx, ptr @__ail_tls_ctx"),
        "M2 TLS store byte-unchanged;\nIR:\n{ir}");
    assert!(ir.contains("call ptr @ail_embed_backtest_step_record_step(ptr %a0, double %a1)"),
        "internal call byte-unchanged (no ctx arg, module-qualified);\nIR:\n{ir}");
    assert!(!ir.contains("sret") && !ir.contains("byval"),
        "no aggregate convention introduced — record is a bare ptr;\nIR:\n{ir}");
    assert!(!ir.contains("define i32 @main()"),
        "staticlib: no @main;\nIR:\n{ir}");
}

#[test]
fn executable_target_still_emits_main() {
    let ws = load("embed_backtest_step.ail");
    // Default executable lowering is unaffected by the new field;
    // backtest has no `main`, so exe-target lowering still rejects.
    let err = ailang_codegen::lower_workspace_with_alloc(
        &ws, ailang_codegen::AllocStrategy::Rc).unwrap_err();
    assert!(format!("{err}").contains("has no `main` def"),
        "exe target must still surface MissingEntryMain; got {err}");
}