// 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 the cursor-native rewrite of `build_postfix_from_flat`.
// Covers the three op kinds that don't need wrapper-unwrap setup: `x++`,
// `x--` (ident inc/dec branch — direct `c.name()` lookup) and the fallthrough
// path where the operand isn't an ident/selector/index (delegates straight to
// `build_expr_from_flat`). Selector/index `++` are exercised indirectly by the
// hello smoke + broader test suite; the wrapper-unwrap (`!`/`?`) branch is
// pinned by the option/result test paths.
module ssa

import v2.ast
import v2.token
import v2.types

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

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

fn make_postfix_fixture() []ast.File {
    mut stmts := [
        ast.Stmt(ast.ModuleStmt{
            name: 'main'
        }),
    ]
    // fn inc_then_ret() int { x := 0 x++ return x }
    stmts << ast.Stmt(ast.FnDecl{
        name:  'inc_then_ret'
        typ:   ast.FnType{
            return_type: pf_ident('int')
        }
        stmts: [
            ast.Stmt(ast.AssignStmt{
                op:  .decl_assign
                lhs: [pf_ident('x')]
                rhs: [pf_num('0')]
            }),
            ast.Stmt(ast.ExprStmt{
                expr: ast.Expr(ast.PostfixExpr{
                    op:   .inc
                    expr: pf_ident('x')
                })
            }),
            ast.Stmt(ast.ReturnStmt{
                exprs: [pf_ident('x')]
            }),
        ]
    })
    // fn dec_then_ret() int { y := 5 y-- return y }
    stmts << ast.Stmt(ast.FnDecl{
        name:  'dec_then_ret'
        typ:   ast.FnType{
            return_type: pf_ident('int')
        }
        stmts: [
            ast.Stmt(ast.AssignStmt{
                op:  .decl_assign
                lhs: [pf_ident('y')]
                rhs: [pf_num('5')]
            }),
            ast.Stmt(ast.ExprStmt{
                expr: ast.Expr(ast.PostfixExpr{
                    op:   .dec
                    expr: pf_ident('y')
                })
            }),
            ast.Stmt(ast.ReturnStmt{
                exprs: [pf_ident('y')]
            }),
        ]
    })
    return [
        ast.File{
            name:  'main.v'
            mod:   'main'
            stmts: stmts
        },
    ]
}

fn build_via_legacy_postfix(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_postfix(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_postfix_from_flat_matches_legacy() {
    _ = token.Token.inc
    files := make_postfix_fixture()
    env := types.Environment.new()
    mod_legacy := build_via_legacy_postfix(files, env, 'postfix_legacy')
    mod_flat := build_via_flat_postfix(files, env, 'postfix_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
}