archival 0.18.1

//! Generates TypeScript declarations for a site's object definitions.
//!
//! This is the same traversal as [`crate::json_schema`] with a different
//! backend, but it describes a different thing. The JSON schema describes
//! *stored* objects, for editor and LLM validation: no `url` on files, no
//! `path`. This describes what a consumer of the built site sees - the same
//! shape a liquid template gets - so files carry their resolved `url` and top
//! level objects carry the injected `path` and `order`.
//!
//! The output is a self-contained module: it declares every type it references
//! and exports a single root interface, `ArchivalObjects`. It deliberately
//! knows nothing about who consumes it.

use crate::object_definition::{ObjectDefinition, ObjectDefinitions};
use crate::FieldType;
use std::collections::{HashMap, HashSet};

const HEADER: &str = "// AUTO-GENERATED by archival - do not edit.";

const ROOT_TYPE: &str = "ArchivalObjects";
const FILE_TYPE: &str = "ArchivalFile";
const META_TYPE: &str = "ArchivalMeta";

const PREAMBLE: &str = r#"/** An uploaded file. `url` is "" until something has been uploaded. */
export interface ArchivalFile {
  display_type: "image" | "video" | "audio" | "upload";
  filename: string;
  sha: string;
  mime: string;
  name?: string;
  description?: string;
  url: string;
}

/** A `meta` field: free-form TOML, converted to JSON. */
export type ArchivalMeta =
  | string
  | number
  | boolean
  | null
  | ArchivalMeta[]
  | { [key: string]: ArchivalMeta };"#;

/// archival injects these into every object read from its own file. A
/// definition that declares one of them is ignored in favor of the injected
/// value, so they are emitted from here rather than from `fields`.
const INJECTED: [&str; 2] = ["path", "order"];

/// Renders a TypeScript string literal. Delegating to serde_json keeps quoting
/// and escaping correct for object names we don't control.
fn ts_string(value: &str) -> String {
    serde_json::to_string(value).unwrap_or_else(|_| format!("\"{}\"", value))
}

fn is_identifier(name: &str) -> bool {
    let mut chars = name.chars();
    match chars.next() {
        Some(c) if c.is_ascii_alphabetic() || c == '_' || c == '$' => {}
        _ => return false,
    }
    chars.all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '$')
}

/// Reserved words are legal as property names, so only non-identifiers quote.
fn property_name(name: &str) -> String {
    if is_identifier(name) {
        name.to_string()
    } else {
        ts_string(name)
    }
}

fn pascal_case(name: &str) -> String {
    let joined: String = name
        .split(|c: char| !c.is_ascii_alphanumeric())
        .filter(|part| !part.is_empty())
        .map(|part| {
            let mut chars = part.chars();
            match chars.next() {
                Some(first) => format!("{}{}", first.to_ascii_uppercase(), chars.as_str()),
                None => String::new(),
            }
        })
        .collect();
    // A type name can't be empty or start with a digit.
    if joined
        .chars()
        .next()
        .is_some_and(|c| c.is_ascii_alphabetic())
    {
        joined
    } else {
        format!("Archival{}", joined)
    }
}

/// Hands out unique interface names, deterministically, so that two objects
/// whose names differ only in punctuation can't collide with each other or with
/// the types declared in the preamble.
struct Names {
    used: HashSet<String>,
}

impl Names {
    fn new() -> Self {
        Names {
            used: HashSet::from([
                ROOT_TYPE.to_string(),
                FILE_TYPE.to_string(),
                META_TYPE.to_string(),
            ]),
        }
    }

    fn take(&mut self, base: &str) -> String {
        let mut name = format!("{}Object", base);
        let mut n = 2;
        while self.used.contains(&name) {
            name = format!("{}Object{}", base, n);
            n += 1;
        }
        self.used.insert(name.clone());
        name
    }
}

fn field_type(field: &FieldType) -> String {
    match field {
        // The alias name is a naming convenience in the object definition
        // file; the value is
        // the aliased type.
        FieldType::Alias(alias) => field_type(&alias.0),
        FieldType::String | FieldType::Markdown => "string | null".to_string(),
        // Secrets are strings that templates never see. Carriers and other
        // server side consumers do see them - see the note in the CLI help.
        FieldType::Secret => "string | null".to_string(),
        FieldType::Number => "number | null".to_string(),
        FieldType::Boolean => "boolean | null".to_string(),
        // Dates are ISO 8601 strings once serialized; TOML datetimes have no
        // JSON equivalent.
        FieldType::Date => "string | null".to_string(),
        FieldType::Enum(values) => {
            if values.is_empty() {
                "string | null".to_string()
            } else {
                let variants: Vec<String> = values.iter().map(|v| ts_string(v)).collect();
                format!("{} | null", variants.join(" | "))
            }
        }
        FieldType::Image | FieldType::Video | FieldType::Audio | FieldType::Upload => {
            format!("{} | null", FILE_TYPE)
        }
        FieldType::Meta => format!("{} | null", META_TYPE),
        FieldType::Oneof(options) => {
            if options.is_empty() {
                return "null".to_string();
            }
            let branches: Vec<String> = options
                .iter()
                .map(|option| {
                    format!(
                        "{{ type: {}; value: {} }}",
                        ts_string(&option.name),
                        field_type(&option.r#type)
                    )
                })
                .collect();
            format!("{} | null", branches.join(" | "))
        }
    }
}

/// Emits `definition` and, recursively, its children. Returns the interface
/// name to refer to it by.
///
/// `injected` is true only for objects read from their own toml file. Child
/// objects live inside their parent's file, so they get no `path` or `order`.
fn emit_object(
    base: &str,
    definition: &ObjectDefinition,
    injected: bool,
    names: &mut Names,
    out: &mut Vec<String>,
) -> String {
    let type_name = names.take(base);
    // Reserve this object's slot so it is emitted before its children.
    let slot = out.len();
    out.push(String::new());

    let mut members: Vec<String> = Vec::new();
    if injected {
        members.push("  /** `<object name>/<file name>` this object was read from. */".to_string());
        members.push("  path: string;".to_string());
        members.push("  /** The object's `order`, or null when it is unordered. */".to_string());
        members.push("  order: number | null;".to_string());
    }
    for (field, field_definition) in &definition.fields {
        if injected && INJECTED.contains(&field.as_str()) {
            continue;
        }
        if let Some(description) = &field_definition.description {
            members.push(doc_comment(description, "  "));
        }
        members.push(format!(
            "  {}: {};",
            property_name(field),
            field_type(&field_definition.r#type)
        ));
    }
    for (child, child_definition) in &definition.children {
        let child_type = emit_object(
            &format!("{}{}", base, pascal_case(child)),
            child_definition,
            false,
            names,
            out,
        );
        // Repeated from the child's own interface: this is the member a
        // consumer hovers, so it is where the description is worth having.
        if let Some(description) = &child_definition.description {
            members.push(doc_comment(description, "  "));
        }
        // Children default to an empty list rather than null.
        members.push(format!("  {}: {}[];", property_name(child), child_type));
    }

    let mut doc = if injected {
        String::new()
    } else {
        "// Child objects are read from their parent's file, so they have no path/order.\n"
            .to_string()
    };
    if let Some(description) = &definition.description {
        doc.push_str(&doc_comment(description, ""));
        doc.push('\n');
    }
    out[slot] = format!(
        "{}export interface {} {{\n{}\n}}",
        doc,
        type_name,
        members.join("\n")
    );
    type_name
}

/// Renders a schema description as a JSDoc comment indented to `indent`.
fn doc_comment(description: &str, indent: &str) -> String {
    // A description is arbitrary prose from objects.toml, so it can contain the
    // sequence that would end the comment early.
    let description = description.replace("*/", "*\\/");
    let mut lines = description.lines();
    let first = lines.next().unwrap_or_default();
    match lines.next() {
        None => format!("{indent}/** {first} */"),
        Some(second) => {
            let rest = std::iter::once(first)
                .chain(std::iter::once(second))
                .chain(lines)
                .map(|line| format!("{indent} * {line}").trim_end().to_string())
                .collect::<Vec<_>>()
                .join("\n");
            format!("{indent}/**\n{rest}\n{indent} */")
        }
    }
}

/// Generates the full declaration file for a site.
///
/// `root_objects` names the objects backed by a single `objects/<name>.toml`
/// (see [`crate::site::Site::root_objects`]); everything else is a list. An
/// object with no files on disk reads as an empty list, so it is typed as one.
pub fn generate_typescript_defs(
    objects: &ObjectDefinitions,
    root_objects: &HashSet<String>,
) -> String {
    let mut names = Names::new();
    let mut declarations: Vec<String> = Vec::new();
    let mut members: Vec<String> = Vec::new();
    let mut types: HashMap<&String, String> = HashMap::new();

    for (name, definition) in objects {
        let type_name = emit_object(
            &pascal_case(name),
            definition,
            true,
            &mut names,
            &mut declarations,
        );
        types.insert(name, type_name);
    }
    for (name, definition) in objects {
        let type_name = &types[name];
        let is_root = root_objects.contains(name);
        if let Some(description) = &definition.description {
            members.push(doc_comment(description, "  "));
        }
        members.push(format!(
            "  {}: {}{};",
            property_name(name),
            type_name,
            if is_root { "" } else { "[]" }
        ));
    }

    let root = format!(
        "/** Every object in the site, keyed by name. */\nexport interface {} {{\n{}\n}}",
        ROOT_TYPE,
        members.join("\n")
    );

    let mut sections = vec![HEADER.to_string(), PREAMBLE.to_string()];
    sections.extend(declarations);
    sections.push(root);
    format!("{}\n", sections.join("\n\n"))
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::object_definition::ObjectDefinition;
    use anyhow::Result;
    use ordermap::OrderMap;

    fn defs(toml: &str) -> Result<ObjectDefinitions> {
        ObjectDefinition::from_source(toml, &OrderMap::new())
    }

    fn generate(toml: &str, roots: &[&str]) -> Result<String> {
        let roots: HashSet<String> = roots.iter().map(|r| r.to_string()).collect();
        Ok(generate_typescript_defs(&defs(toml)?, &roots))
    }

    #[test]
    fn empty_site() -> Result<()> {
        let out = generate("", &[])?;
        assert!(out.contains("export interface ArchivalObjects {"));
        assert!(out.contains("export interface ArchivalFile {"));
        Ok(())
    }

    #[test]
    fn scalar_fields() -> Result<()> {
        let out = generate(
            r#"
            [posts]
            title = "string"
            body = "markdown"
            views = "number"
            draft = "boolean"
            published = "date"
            token = "secret"
            "#,
            &[],
        )?;
        assert!(out.contains("title: string | null;"), "{}", out);
        assert!(out.contains("body: string | null;"));
        assert!(out.contains("views: number | null;"));
        assert!(out.contains("draft: boolean | null;"));
        assert!(out.contains("published: string | null;"));
        assert!(out.contains("token: string | null;"));
        Ok(())
    }

    #[test]
    fn injects_path_and_order_on_top_level_objects_only() -> Result<()> {
        let out = generate(
            r#"
            [events]
            name = "string"
            [events.tickets]
            url = "string"
            "#,
            &[],
        )?;
        assert!(out.contains("export interface EventsObject {"));
        assert!(out.contains("  path: string;"));
        assert!(out.contains("  order: number | null;"));
        // The child interface must carry neither.
        let child = out
            .split("export interface EventsTicketsObject {")
            .nth(1)
            .expect("no child interface")
            .split("}")
            .next()
            .unwrap();
        assert!(!child.contains("path:"), "child had path: {}", child);
        assert!(!child.contains("order:"), "child had order: {}", child);
        assert!(out.contains("tickets: EventsTicketsObject[];"));
        Ok(())
    }

    #[test]
    fn lists_roots_and_absent_objects() -> Result<()> {
        let out = generate(
            r#"
            [posts]
            title = "string"
            [settings]
            contact = "string"
            "#,
            &["settings"],
        )?;
        assert!(out.contains("posts: PostsObject[];"), "{}", out);
        assert!(out.contains("settings: SettingsObject;"), "{}", out);
        Ok(())
    }

    #[test]
    fn enums_become_literal_unions() -> Result<()> {
        let out = generate(
            r#"
            [posts]
            genre = ["emo", "metal"]
            "#,
            &[],
        )?;
        assert!(out.contains(r#"genre: "emo" | "metal" | null;"#), "{}", out);
        Ok(())
    }

    #[test]
    fn files_and_meta() -> Result<()> {
        let out = generate(
            r#"
            [posts]
            hero = "image"
            clip = "video"
            attachment = "upload"
            extra = "meta"
            "#,
            &[],
        )?;
        assert!(out.contains("hero: ArchivalFile | null;"));
        assert!(out.contains("clip: ArchivalFile | null;"));
        assert!(out.contains("attachment: ArchivalFile | null;"));
        assert!(out.contains("extra: ArchivalMeta | null;"));
        Ok(())
    }

    #[test]
    fn oneofs_become_discriminated_unions() -> Result<()> {
        let out = generate(
            r#"
            [posts]
            [[posts.media]]
            name = "video"
            type = "video"
            [[posts.media]]
            name = "link"
            type = "string"
            "#,
            &[],
        )?;
        assert!(
            out.contains(
                r#"media: { type: "video"; value: ArchivalFile | null } | { type: "link"; value: string | null } | null;"#
            ),
            "{}",
            out
        );
        Ok(())
    }

    #[test]
    fn resolves_editor_type_aliases() -> Result<()> {
        let source = r#"
            [posts]
            hero = "hero_image"
            "#;
        let mut editor_types = OrderMap::new();
        editor_types.insert(
            "hero_image".to_string(),
            crate::manifest::ManifestEditorType {
                alias_of: "image".to_string(),
                validate: vec![],
                editor_url: String::new(),
            },
        );
        let definitions = ObjectDefinition::from_source(source, &editor_types)?;
        let out = generate_typescript_defs(&definitions, &HashSet::new());
        assert!(out.contains("hero: ArchivalFile | null;"), "{}", out);
        Ok(())
    }

    #[test]
    fn sanitizes_names() -> Result<()> {
        let out = generate(
            r#"
            ["my-object"]
            "weird key" = "string"
            "#,
            &[],
        )?;
        assert!(out.contains("export interface MyObjectObject {"), "{}", out);
        assert!(out.contains(r#""weird key": string | null;"#), "{}", out);
        assert!(out.contains(r#""my-object": MyObjectObject[];"#), "{}", out);
        Ok(())
    }

    #[test]
    fn allocates_around_name_collisions() -> Result<()> {
        let out = generate(
            r#"
            [posts]
            title = "string"
            ["posts-2"]
            title = "string"
            "#,
            &[],
        )?;
        assert!(out.contains("export interface PostsObject {"), "{}", out);
        assert!(out.contains("export interface Posts2Object {"), "{}", out);
        Ok(())
    }

    #[test]
    fn never_shadows_the_preamble_types() -> Result<()> {
        let out = generate(
            r#"
            ["archival_file"]
            a = "string"
            ["archival_meta"]
            b = "string"
            "#,
            &[],
        )?;
        // ArchivalFile/ArchivalMeta are declared in the preamble; the objects
        // must get suffixed names rather than redeclaring them.
        assert_eq!(out.matches("export interface ArchivalFile {").count(), 1);
        assert!(
            out.contains("export interface ArchivalFileObject {"),
            "{}",
            out
        );
        assert!(
            out.contains("export interface ArchivalMetaObject {"),
            "{}",
            out
        );
        Ok(())
    }

    #[test]
    fn is_deterministic() -> Result<()> {
        let toml = r#"
            [posts]
            title = "string"
            [posts.tags]
            name = "string"
            [settings]
            contact = "string"
            "#;
        assert_eq!(
            generate(toml, &["settings"])?,
            generate(toml, &["settings"])?
        );
        Ok(())
    }

    #[test]
    fn descriptions_become_jsdoc() -> Result<()> {
        let out = generate(
            r#"
            # A blog post.
            [posts]
            # The headline.
            title = "string"
            body = "markdown"
            # When it was written.
            # Rendered with the `date` filter.
            published = "date"
            "#,
            &[],
        )?;
        assert!(
            out.contains("/** A blog post. */\nexport interface"),
            "{out}"
        );
        assert!(
            out.contains("  /** The headline. */\n  title: string | null;"),
            "{out}"
        );
        // Multi-line descriptions become a block comment.
        assert!(
            out.contains(
                "  /**\n   * When it was written.\n   * Rendered with the `date` filter.\n   */\n  published: string | null;"
            ),
            "{out}"
        );
        // Undescribed fields get no comment.
        assert!(out.contains("\n  body: string | null;"), "{out}");
        Ok(())
    }

    #[test]
    fn object_descriptions_reach_every_place_they_are_referenced() -> Result<()> {
        let out = generate(
            r#"
            # A blog post.
            [posts]
            title = "string"
            # Related links.
            [posts.links]
            url = "string"
            "#,
            &[],
        )?;
        // On the child's interface, on the member that holds it...
        assert!(
            out.contains("/** Related links. */\nexport interface PostsLinksObject {"),
            "{out}"
        );
        assert!(
            out.contains("  /** Related links. */\n  links: PostsLinksObject[];"),
            "{out}"
        );
        // ...and for a top-level object, on the root interface's member too.
        assert!(
            out.contains("  /** A blog post. */\n  posts: PostsObject[];"),
            "{out}"
        );
        Ok(())
    }

    #[test]
    fn a_description_cannot_end_its_own_comment() -> Result<()> {
        let out = generate(
            r#"
            [posts]
            # Not a terminator: */ still inside.
            title = "string"
            "#,
            &[],
        )?;
        assert!(out.contains(r"*\/ still inside."), "{out}");
        // Exactly one comment opened and one closed on that line.
        let line = out
            .lines()
            .find(|l| l.contains("still inside"))
            .expect("description not emitted");
        assert_eq!(line.matches("*/").count(), 1, "{line}");
        Ok(())
    }
}