MZN to BRL converter

The tool converts Mozambican Metical (MZN) to Brazilian Real (BRL) using a current exchange rate. It serves travelers, importers, exporters, and finance staff who need quick, auditable conversions for budgeting, invoicing, and payments. Users input an amount in MZN and receive the BRL equivalent, with either an auto-fetched rate or a supplied rate. The goal is precise numeric results, transparent rounding, and clear handling of edge cases.
Assumptions: rate data is sourced from a credible provider and reflects near real-time market quotes where possible.

Core Logic & Features: Required: amount_mzn (numeric, non-negative); rate (numeric, BRL per MZN, optional if auto_rate is enabled); auto_rate (boolean, default true). Outputs: amount_brl (numeric, BRL) and formatted_brl (string, e.g., R$ 1.23). Optional/advanced: locale-aware formatting, last-rate audit timestamp, and support for overriding with a manual rate. Differentiator: minimal inputs for reliable BRL value with explicit rounding rules suitable for budgeting and invoicing.

Inputs & Outputs: Inputs: amount_mzn (number, units MZN, required, sample 1000, validation >= 0); rate (number, units BRL per MZN, optional when auto_rate is true); auto_rate (boolean, optional, default true). Outputs: amount_brl (number, units BRL, 2 decimals); formatted_brl (string, currency-formatted). Validation enforces numeric types and non-negative amounts; if rate is missing and auto_rate is false, error is raised.

Algorithms & Calculations: Core formula: amount_brl = amount_mzn × rate. If rate is absent and auto_rate is enabled, fetch latest_rate from a rate_provider and apply. Round to two decimal places using standard half-up rule. Output formatted string using BRL conventions unless locale overrides are provided.
Errors & Edge Cases: Negative amount_mzn or non-numeric inputs trigger validation errors. If rate data is unavailable and auto_rate is true, fall back to last-known rate or raise a data-unavailable error. If rate equals zero, output zero with a warning in logs. Very large values are clamped to prevent overflow. Exclusions: no reverse conversion, no multi-currency baskets, no settlement guarantees.
Industry/Region & Localization: Currencies follow ISO 4217 codes MZN and BRL; BRL formatting uses Brazilian conventions (R$ symbol, two decimals) by default, with optional locale-based overrides for decimal separators and symbol placement.
Assumptions & Exclusions: Assumes rate data is trustworthy and that the user reviews the rate before finalizing any financial action. Not a payment processor or trading tool; focuses solely on simple, auditable MZN→BRL conversions for budgeting and invoicing.