retiretui_engine 0.2.0

Plan model, tax engine, and projection for RetireTui.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134

use crate::params::TaxTables;
use crate::plan::{Issue, Plan, TreatmentClass, push_issue};
use crate::project::plan_inflation;

use super::targets::conversion_window;
use super::{OptimizeOptions, RATE_EPSILON};

/// Checks the shared constraints, plus the bracket when one is targeted.
pub(super) fn check_options(
    plan: &Plan,
    tables: &TaxTables,
    options: &OptimizeOptions,
    bracket_rate: Option<f64>,
) -> Vec<Issue> {
    let mut issues = Vec::new();
    check_accounts(plan, options, &mut issues);
    if let Some(rate) = bracket_rate {
        check_bracket(plan, tables, rate, &mut issues);
    }
    if conversion_window(plan, options).is_empty() {
        push_issue(
            &mut issues,
            "options.start_year",
            "the conversion window is empty",
        );
    }
    if options.headroom < 0 {
        push_issue(&mut issues, "options.headroom", "must not be negative");
    }
    check_ceilings(plan, tables, options, &mut issues);
    for (path, cap) in [
        ("options.annual_max", options.annual_max),
        ("options.total_max", options.total_max),
    ] {
        if cap.is_some_and(|cap| cap <= 0) {
            push_issue(&mut issues, path, "must be positive when present");
        }
    }
    issues
}

fn check_accounts(plan: &Plan, options: &OptimizeOptions, issues: &mut Vec<Issue>) {
    let destination_owner = match plan.account(&options.destination) {
        None => {
            push_issue(
                issues,
                "options.destination",
                format!("unknown account `{}`", options.destination),
            );
            None
        }
        Some(account) if account.treatment() != TreatmentClass::Roth => {
            push_issue(issues, "options.destination", "must be a Roth account");
            None
        }
        Some(account) => Some(account.owner.clone()),
    };
    if options.sources.is_empty() {
        push_issue(
            issues,
            "options.sources",
            "no deferred account to convert from: name one, or convert into a Roth whose owner holds one",
        );
    }
    for (i, source) in options.sources.iter().enumerate() {
        let path = format!("options.sources[{i}]");
        match plan.account(source) {
            None => push_issue(issues, path, format!("unknown account `{source}`")),
            Some(account) if account.treatment() != TreatmentClass::Deferred => {
                push_issue(issues, path, "must be a tax-deferred account");
            }
            Some(account) => {
                if destination_owner
                    .as_deref()
                    .is_some_and(|owner| owner != account.owner)
                {
                    push_issue(issues, path, "must share the destination's owner");
                }
            }
        }
    }
}

fn check_ceilings(
    plan: &Plan,
    tables: &TaxTables,
    options: &OptimizeOptions,
    issues: &mut Vec<Issue>,
) {
    if let Some(tier) = options.irmaa_tier {
        if plan.medicare.is_none() {
            push_issue(
                issues,
                "options.irmaa_tier",
                "requires a [medicare] section in the plan",
            );
        }
        let tiers = tables
            .params_for(plan.plan.start_year, &plan_inflation(plan))
            .irmaa
            .len();
        if usize::from(tier) >= tiers {
            push_issue(
                issues,
                "options.irmaa_tier",
                format!("only {tiers} tiers exist"),
            );
        }
    }
    if options.max_magi.is_some_and(|max| max <= 0) {
        push_issue(issues, "options.max_magi", "must be positive when present");
    }
}

fn check_bracket(plan: &Plan, tables: &TaxTables, rate: f64, issues: &mut Vec<Issue>) {
    let params = tables.params_for(plan.plan.start_year, &plan_inflation(plan));
    let brackets = params.brackets.for_status(plan.household.filing);
    match brackets
        .iter()
        .position(|bracket| (bracket.rate - rate).abs() < RATE_EPSILON)
    {
        None => push_issue(
            issues,
            "options.bracket_rate",
            format!("no bracket with rate {rate}"),
        ),
        Some(index) if index + 1 == brackets.len() => push_issue(
            issues,
            "options.bracket_rate",
            "the top bracket has no ceiling to fill",
        ),
        Some(_) => {}
    }
}