// 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.
module ast

import v2.token

fn string_inter_test_expr() Expr {
    return Expr(Ident{
        name: 'value'
    })
}

fn string_inter_test_literal(width int, precision int) Expr {
    return Expr(StringInterLiteral{
        kind:   .v
        values: ['value=', '']
        inters: [
            StringInter{
                format:       .decimal
                width:        width
                precision:    precision
                expr:         string_inter_test_expr()
                format_expr:  empty_expr
                resolved_fmt: '%d'
            },
        ]
    })
}

fn assert_string_inter_roundtrip(files []File, width int, precision int) {
    assert files.len == 1
    assert files[0].stmts.len == 2
    assert files[0].stmts[1] is ExprStmt
    expr_stmt := files[0].stmts[1] as ExprStmt
    assert expr_stmt.expr is StringInterLiteral
    lit := expr_stmt.expr as StringInterLiteral
    assert lit.inters.len == 1
    assert lit.inters[0].width == width
    assert lit.inters[0].precision == precision
}

fn test_string_inter_width_precision_survive_flat_roundtrip_losslessly() {
    width := 1_000_000
    precision := -1_000_000
    mut b := new_flat_builder()
    b.append_file(File{
        name:  'string_inter.v'
        mod:   'string_inter'
        stmts: [
            Stmt(ModuleStmt{
                name: 'string_inter'
            }),
            Stmt(ExprStmt{
                expr: string_inter_test_literal(width, precision)
            }),
        ]
    })
    assert_string_inter_roundtrip(b.flat.to_files(), width, precision)
}

fn test_emit_string_inter_by_ids_preserves_large_width_precision() {
    width := 900_000
    precision := -900_000
    mut b := new_flat_builder()
    b.append_file(File{
        name:  'string_inter_direct.v'
        mod:   'string_inter'
        stmts: [
            Stmt(ModuleStmt{
                name: 'string_inter'
            }),
        ]
    })
    expr_id := b.emit_expr(string_inter_test_expr())
    format_expr_id := b.emit_expr(empty_expr)
    inter_id :=
        b.emit_string_inter_by_ids(.decimal, width, precision, expr_id, format_expr_id, '%d')
    lit_id := b.emit_string_inter_literal_by_ids(.v, ['value=', ''], [inter_id], token.Pos{})
    stmt_id := b.emit_expr_stmt_by_id(lit_id)
    b.append_file_stmts(0, [stmt_id])
    assert_string_inter_roundtrip(b.flat.to_files(), width, precision)
}