shape/

display.rs

use std::fmt::Debug;
use std::fmt::Display;
use std::fmt::Write as _;

use super::helpers::quote_string;
use super::Shape;
use super::ShapeCase;
use crate::case_enum::Error;
use crate::helpers::quote_non_identifier;
use crate::name::Name;

const UNIT_OF_INDENTATION: &str = "  ";
const WRAP_COLUMN: usize = 60;

impl Shape {
    /// Returns a string representation of the [`Shape`].
    ///
    /// Please note: this display format does not imply an input syntax or
    /// parser for the shape language. To create new [`Shape`] elements, use the
    /// various `Shape::*` helper functions.
    #[must_use]
    pub fn pretty_print(&self) -> String {
        self.pretty_print_at_depth(0)
    }

    fn pretty_print_at_depth(&self, depth: usize) -> String {
        self.pretty_print_recursive(depth, Shape::pretty_print_at_depth)
    }

    /// Returns a string representation of the [`Shape`] with [`Name`] metadata
    /// included as `<shape> (aka <name1>, <name2>)` instead of just `<shape>`
    /// (which is what `pretty_print` would print). Note this extra verbosity
    /// may lead to more aggressive line breaking.
    #[must_use]
    pub fn pretty_print_with_names(&self) -> String {
        self.pretty_print_with_names_at_depth(0)
    }

    pub fn pretty_print_with_names_at_depth(&self, depth: usize) -> String {
        let pretty_shape =
            self.pretty_print_recursive(depth, Shape::pretty_print_with_names_at_depth);
        if self.names().count() == 0 {
            pretty_shape
        } else {
            let joined = self
                .names()
                .map(Name::to_string)
                .collect::<Vec<_>>()
                .join(", ");
            // Since the (aka ...) annotation trails multiline array and object
            // shapes, it often fits neatly into the otherwise mostly empty line
            // just after the closing ] or }.
            format!("{pretty_shape} (aka {joined})")
        }
    }

    #[allow(clippy::too_many_lines)]
    fn pretty_print_recursive(
        &self,
        depth: usize,
        print: impl Fn(&Shape, usize) -> String,
    ) -> String {
        fn print_flexible_wrapper(
            prefix: &str,
            pretty_children: impl IntoIterator<Item = String>,
            suffix: &str,
            depth: usize,
        ) -> String {
            let pretty_children = pretty_children.into_iter().collect::<Vec<_>>();

            // We may want to print the one-line version with some padding
            // inside the prefix/suffix, but we don't want that for the
            // multiline version, so we strip any padding before proceeding.
            let trimmed_prefix = prefix.trim();
            let trimmed_suffix = suffix.trim();

            if pretty_children.is_empty() {
                // If prefix was "{ " and suffix was " }", this prints "{}"
                // without the spaces when pretty_children is empty.
                return format!("{trimmed_prefix}{trimmed_suffix}");
            }

            if let (1, Some(only)) = (pretty_children.len(), pretty_children.first()) {
                // If there is only one child, always print it without
                // leading/trailing line breaks (though `prefix` and `suffix`
                // may include padding spaces, and `only` may print with its own
                // internal line breaks).
                return format!("{prefix}{only}{suffix}");
            }

            if pretty_children
                .iter()
                .all(|pretty| pretty.lines().count() <= 1)
            {
                // If all the children are single-line, and they fit within
                // WRAP_COLUMN columns, we may be able to print them all on one
                // line. Note we are using the untrimmed prefix and suffix,
                // since this is a place where padding spaces may be desired.
                //
                // By corollary, if the shape has any multiline children, the
                // whole shape needs to be printed with line breaks. We never
                // want to print mixed inline/multiline expressions, as in
                //
                //   [a, {
                //     blah: 1
                //   }, b, c, {
                //     whatever: true
                //   }]
                //
                // A human might be able to make this style readable, but
                // machine formatters that allow this hybrid line style tend to
                // produce unreadable monstrosities.
                let one_line = format!("{prefix}{}{suffix}", pretty_children.join(", "));
                if one_line.len() <= WRAP_COLUMN {
                    return one_line;
                }
                // If trying to print all the children on one line would exceed
                // WRAP_COLUMN columns, proceed to multi-line printing...
            }

            let mut result = format!("{trimmed_prefix}\n");
            let child_indent = UNIT_OF_INDENTATION.repeat(depth + 1);

            for pretty in &pretty_children {
                let _ = writeln!(result, "{child_indent}{pretty},");
            }

            let suffix_indent = UNIT_OF_INDENTATION.repeat(depth);
            let _ = write!(result, "{suffix_indent}{trimmed_suffix}");

            result
        }

        match self.case() {
            ShapeCase::Bool(Some(b)) => b.to_string(),
            ShapeCase::Bool(None) => "Bool".to_string(),
            ShapeCase::String(Some(s)) => quote_string(s.as_str()),
            ShapeCase::String(None) => "String".to_string(),
            ShapeCase::Int(Some(i)) => i.to_string(),
            ShapeCase::Int(None) => "Int".to_string(),
            ShapeCase::Float => "Float".to_string(),
            ShapeCase::Null => "null".to_string(), // No typo: JSON null is lowercase.

            ShapeCase::Unknown => "Unknown".to_string(),

            // There may be some argument for using lower-case "none" here,
            // since None is not a reserved/built-in GraphQL type name like
            // Bool, String, Int, and Float are, so someone could define a
            // custom GraphQL None type that would collide with this Shape name.
            ShapeCase::None => "None".to_string(),

            ShapeCase::Array { prefix, tail } => {
                let mut pretty_prefix = prefix
                    .iter()
                    .map(|shape| print(shape, depth + 1))
                    .collect::<Vec<_>>();

                if !tail.is_none() {
                    let pretty_tail =
                        print_flexible_wrapper("List<", [print(tail, depth + 1)], ">", depth);

                    if pretty_prefix.is_empty() {
                        // If there is no prefix, then the tail is the whole
                        // list, so we can return pretty_tail as-is.
                        return pretty_tail;
                    }

                    // If the List<S> notation appears at the end of an array
                    // with a non-empty prefix, use ...List<S> to indicate it is
                    // not just a single element, but governs the whole rest of
                    // the array.
                    pretty_prefix.push(format!("...{pretty_tail}"));
                }

                print_flexible_wrapper("[", pretty_prefix, "]", depth)
            }

            ShapeCase::Object { fields, rest } => {
                let mut sorted_properties = fields
                    .iter()
                    .map(|(key, value)| (key, print(value, depth + 1)))
                    .collect::<Vec<_>>();
                sorted_properties.sort_by_key(|(key, _)| key.as_str());

                let mut pretty_properties = sorted_properties
                    .into_iter()
                    .map(|(key, value)| format!("{}: {value}", quote_non_identifier(key)))
                    .collect::<Vec<_>>();

                if !rest.is_none() {
                    let pretty_rest =
                        print_flexible_wrapper("Dict<", [print(rest, depth + 1)], ">", depth);

                    if pretty_properties.is_empty() {
                        // If there are no fields, then the rest is the whole
                        // object, so we can return pretty_rest as-is.
                        return pretty_rest;
                    }

                    // If the Dict<S> notation appears at the end of an object
                    // with a non-empty fields, use ...Dict<S> to indicate it is
                    // not just a single property, but governs all dynamic
                    // fields of the object.
                    pretty_properties.push(format!("...{pretty_rest}"));
                }

                print_flexible_wrapper(
                    // If the object is printed as a single line, the
                    // opening and closing braces will have this extra space
                    // of padding. If the object is broken onto multiple
                    // lines, this extra padding will be removed.
                    "{ ",
                    pretty_properties,
                    " }",
                    depth,
                )
            }

            ShapeCase::One(shapes) => {
                let pretty = print_flexible_wrapper(
                    "One<",
                    shapes
                        .iter()
                        .map(|child_shape| print(child_shape, depth + 1)),
                    ">",
                    depth,
                );

                // The empty `One<>` union represents an unsatisfiable shape
                // like TypeScript's `never` type, so that's how we print it.
                if pretty == "One<>" {
                    "Never".to_string()
                } else {
                    pretty
                }
            }

            ShapeCase::All(shapes) => print_flexible_wrapper(
                "All<",
                shapes
                    .iter()
                    .map(|child_shape| print(child_shape, depth + 1)),
                ">",
                depth,
            ),

            ShapeCase::Name(name, _weak) => name.to_string(),

            ShapeCase::Error(Error {
                message, partial, ..
            }) => print_flexible_wrapper(
                "Error<",
                std::iter::once(quote_string(message.as_str()))
                    .chain(partial.iter().map(|p| print(p, depth + 1))),
                ">",
                depth,
            ),
        }
    }
}

impl Debug for Shape {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "Shape({})", self.pretty_print_with_names())
    }
}

impl Display for Shape {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.pretty_print())
    }
}