// 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 s208: cursor-native `build_init_expr_ptr_from_flat` and
// `collect_init_expr_values_from_flat`. The previous `build_prefix_from_flat`
// `&InitExpr` branch decoded the inner InitExpr via `decode_expr` and
// dispatched to legacy `build_init_expr_ptr`; the cursor-native rewrite
// reads `typ` from edge(0) and walks the field aux cursors at edge(1..),
// resolving each field name via `field_c.name()` and value via
// `field_c.edge(0)` through `build_expr_from_flat`.
module ssa

import v2.ast
import v2.types

fn ip_ident(name string) ast.Expr {
    return ast.Expr(ast.Ident{
        name: name
    })
}

fn ip_num(value string) ast.Expr {
    return ast.Expr(ast.BasicLiteral{
        kind:  .number
        value: value
    })
}

fn make_init_ptr_fixture() []ast.File {
    mut stmts := [
        ast.Stmt(ast.ModuleStmt{
            name: 'main'
        }),
    ]
    stmts << ast.Stmt(ast.StructDecl{
        name:   'Point'
        fields: [
            ast.FieldDecl{
                name: 'x'
                typ:  ip_ident('int')
            },
            ast.FieldDecl{
                name: 'y'
                typ:  ip_ident('int')
            },
        ]
    })
    // fn make_point() { p := &Point{x: 1, y: 2} _ = p }
    stmts << ast.Stmt(ast.FnDecl{
        name:  'make_point'
        typ:   ast.FnType{
            return_type: ast.empty_expr
        }
        stmts: [
            ast.Stmt(ast.AssignStmt{
                op:  .decl_assign
                lhs: [ip_ident('p')]
                rhs: [
                    ast.Expr(ast.PrefixExpr{
                        op:   .amp
                        expr: ast.Expr(ast.InitExpr{
                            typ:    ip_ident('Point')
                            fields: [
                                ast.FieldInit{
                                    name:  'x'
                                    value: ip_num('1')
                                },
                                ast.FieldInit{
                                    name:  'y'
                                    value: ip_num('2')
                                },
                            ]
                        })
                    }),
                ]
            }),
        ]
    })
    return [
        ast.File{
            name:  'main.v'
            mod:   'main'
            stmts: stmts
        },
    ]
}

fn build_via_legacy_init_ptr(files []ast.File, env &types.Environment, name string) &Module {
    mut mod := Module.new(name)
    mut b := Builder.new_with_env(mod, env)
    b.register_fn_signatures(files[0])
    b.build_fn_bodies(files[0])
    return mod
}

fn build_via_flat_init_ptr(files []ast.File, env &types.Environment, name string) &Module {
    flat := ast.flatten_files(files)
    mut mod := Module.new(name)
    mut b := Builder.new_with_env(mod, env)
    b.register_fn_signatures_from_flat(flat.file_cursor(0))
    b.build_fn_bodies_from_flat(flat.file_cursor(0))
    return mod
}

fn test_build_init_expr_ptr_from_flat_matches_legacy() {
    files := make_init_ptr_fixture()
    env := types.Environment.new()
    mod_legacy := build_via_legacy_init_ptr(files, env, 'init_ptr_legacy')
    mod_flat := build_via_flat_init_ptr(files, env, 'init_ptr_flat')

    assert mod_legacy.funcs.len == mod_flat.funcs.len
    assert mod_legacy.blocks.len == mod_flat.blocks.len
    assert mod_legacy.instrs.len == mod_flat.instrs.len
    assert mod_legacy.values.len == mod_flat.values.len
}