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use crate::prelude::*;
use crate::commands::math::reducers::{reducer_for, Reduce};
use crate::commands::math::utils::run_with_function;
use nu_engine::WholeStreamCommand;
use nu_errors::ShellError;
use nu_protocol::{hir::Operator, Primitive, Signature, UntaggedValue, Value};
use bigdecimal::FromPrimitive;
pub struct SubCommand;
impl WholeStreamCommand for SubCommand {
fn name(&self) -> &str {
"math avg"
}
fn signature(&self) -> Signature {
Signature::build("math avg")
}
fn usage(&self) -> &str {
"Finds the average of a list of numbers or tables"
}
fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
run_with_function(args, average)
}
fn examples(&self) -> Vec<Example> {
vec![Example {
description: "Get the average of a list of numbers",
example: "echo [-50 100.0 25] | math avg",
result: Some(vec![UntaggedValue::decimal_from_float(
25.0,
Span::unknown(),
)
.into()]),
}]
}
}
fn to_byte(value: &Value) -> Option<Value> {
match &value.value {
UntaggedValue::Primitive(Primitive::Int(num)) => {
Some(UntaggedValue::Primitive(Primitive::Filesize(*num as u64)).into_untagged_value())
}
_ => None,
}
}
pub fn average(values: &[Value], name: &Tag) -> Result<Value, ShellError> {
let sum = reducer_for(Reduce::Summation);
let number = BigDecimal::from_usize(values.len()).ok_or_else(|| {
ShellError::labeled_error("nothing to average", "nothing to average", &name.span)
})?;
let total_rows = UntaggedValue::decimal(number);
let are_bytes = values
.get(0)
.ok_or_else(|| {
ShellError::unexpected("Cannot perform aggregate math operation on empty data")
})?
.is_filesize();
let total = if are_bytes {
to_byte(&sum(
UntaggedValue::int(0).into_untagged_value(),
values
.to_vec()
.iter()
.map(|v| match v {
Value {
value: UntaggedValue::Primitive(Primitive::Filesize(num)),
..
} => UntaggedValue::int(*num as i64).into_untagged_value(),
other => other.clone(),
})
.collect::<Vec<_>>(),
)?)
.ok_or_else(|| {
ShellError::labeled_error(
"could not convert to big decimal",
"could not convert to big decimal",
&name.span,
)
})
} else {
sum(UntaggedValue::int(0).into_untagged_value(), values.to_vec())
}?;
match total {
Value {
value: UntaggedValue::Primitive(Primitive::Filesize(num)),
..
} => {
let left = UntaggedValue::from(Primitive::Int(num as i64));
let result = nu_data::value::compute_values(Operator::Divide, &left, &total_rows);
match result {
Ok(UntaggedValue::Primitive(Primitive::Decimal(result))) => match result.to_u64() {
Some(number) => Ok(UntaggedValue::filesize(number).into_value(name)),
None => Err(ShellError::labeled_error(
"could not calculate average of non-integer or unrelated types",
"source",
name,
)),
},
Ok(_) => Err(ShellError::labeled_error(
"could not calculate average of non-integer or unrelated types",
"source",
name,
)),
Err((left_type, right_type)) => Err(ShellError::coerce_error(
left_type.spanned(name.span),
right_type.spanned(name.span),
)),
}
}
Value {
value: UntaggedValue::Primitive(Primitive::Duration(duration)),
..
} => {
let left = UntaggedValue::from(Primitive::Duration(duration));
let result = nu_data::value::compute_values(Operator::Divide, &left, &total_rows);
match result {
Ok(UntaggedValue::Primitive(Primitive::Duration(result))) => {
Ok(UntaggedValue::duration(result).into_value(name))
}
Ok(_) => Err(ShellError::labeled_error(
"could not calculate average of non-integer or unrelated types",
"source",
name,
)),
Err((left_type, right_type)) => Err(ShellError::coerce_error(
left_type.spanned(name.span),
right_type.spanned(name.span),
)),
}
}
Value {
value: UntaggedValue::Primitive(other),
..
} => {
let left = UntaggedValue::from(other);
let result = nu_data::value::compute_values(Operator::Divide, &left, &total_rows);
match result {
Ok(value) => Ok(value.into_value(name)),
Err((left_type, right_type)) => Err(ShellError::coerce_error(
left_type.spanned(name.span),
right_type.spanned(name.span),
)),
}
}
_ => Err(ShellError::labeled_error(
"could not calculate average of non-integer or unrelated types",
"source",
name,
)),
}
}
#[cfg(test)]
mod tests {
use super::ShellError;
use super::SubCommand;
#[test]
fn examples_work_as_expected() -> Result<(), ShellError> {
use crate::examples::test as test_examples;
test_examples(SubCommand {})
}
}
