// Copyright (c) 2026 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
// vtest build: macos
//
// Bit-equality pin for s171: `register_consts_and_globals_from_flat`
// (flat-cursor port) must register the same globals + const_values as the
// legacy `register_consts_and_globals`. The flat port walks one file's
// top-level stmts via FileCursor and only rehydrates `.stmt_const_decl` /
// `.stmt_global_decl` nodes via `flat.decode_stmt`. ModuleStmt, FnDecl,
// StructDecl, EnumDecl, TypeDecl, ImportStmt etc. are never decoded.
module ssa

import v2.ast
import v2.types

fn make_consts_and_globals_fixture() []ast.File {
    return [
        ast.File{
            name:  'main.v'
            mod:   'main'
            stmts: [
                ast.Stmt(ast.ModuleStmt{
                    name: 'main'
                }),
                ast.Stmt(ast.ConstDecl{
                    fields: [
                        ast.FieldInit{
                            name:  'answer'
                            value: ast.Expr(ast.BasicLiteral{
                                kind:  .number
                                value: '42'
                            })
                        },
                    ]
                }),
                ast.Stmt(ast.GlobalDecl{
                    fields: [
                        ast.FieldDecl{
                            name:  'g_counter'
                            typ:   ast.Expr(ast.Ident{
                                name: 'int'
                            })
                            value: ast.Expr(ast.BasicLiteral{
                                kind:  .number
                                value: '7'
                            })
                        },
                    ]
                }),
            ]
        },
    ]
}

// register_consts_and_globals_from_flat on a file with no const/global decls
// must produce zero new entries — same as register_consts_and_globals.
fn test_register_consts_and_globals_from_flat_empty_file_matches_legacy() {
    files := [
        ast.File{
            name:  'empty.v'
            mod:   'main'
            stmts: [ast.Stmt(ast.ModuleStmt{
                name: 'main'
            })]
        },
    ]
    flat := ast.flatten_files(files)

    env := types.Environment.new()

    mut mod_legacy := Module.new('cg_empty_legacy')
    mut b_legacy := Builder.new_with_env(mod_legacy, env)
    b_legacy.register_consts_and_globals(files[0])

    mut mod_flat := Module.new('cg_empty_flat')
    mut b_flat := Builder.new_with_env(mod_flat, env)
    b_flat.register_consts_and_globals_from_flat(flat.file_cursor(0))

    // No const/global decls -> no new globals on either side.
    assert mod_legacy.globals.len == mod_flat.globals.len
    assert b_legacy.const_values.len == b_flat.const_values.len
}

// register_consts_and_globals_from_flat on a file with one ConstDecl + one
// GlobalDecl must register identical entries via both code paths.
fn test_register_consts_and_globals_from_flat_matches_legacy_for_consts_and_globals() {
    files := make_consts_and_globals_fixture()
    flat := ast.flatten_files(files)

    env := types.Environment.new()

    mut mod_legacy := Module.new('cg_mix_legacy')
    mut b_legacy := Builder.new_with_env(mod_legacy, env)
    b_legacy.register_consts_and_globals(files[0])

    mut mod_flat := Module.new('cg_mix_flat')
    mut b_flat := Builder.new_with_env(mod_flat, env)
    b_flat.register_consts_and_globals_from_flat(flat.file_cursor(0))

    // Both paths registered one const + one global => 2 globals each.
    assert mod_legacy.globals.len == mod_flat.globals.len
    assert mod_legacy.globals.len == 2
    for i in 0 .. mod_legacy.globals.len {
        assert mod_legacy.globals[i].name == mod_flat.globals[i].name
    }
    // const_values map must match for the answer constant.
    assert b_legacy.const_values.len == b_flat.const_values.len
    assert 'answer' in b_legacy.const_values
    assert 'answer' in b_flat.const_values
    assert b_legacy.const_values['answer'] == b_flat.const_values['answer']
    assert b_legacy.const_values['answer'] == 42
}