rustmotion 0.7.0

A CLI tool that renders motion design videos from JSON scenarios. No browser, no Node.js — just a single Rust binary.
Documentation
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use crate::error::{Result, RustmotionError};
use crate::schema::{ResolvedScenario, Scenario};
use crate::{expand, include, variables};
use std::path::PathBuf;

pub fn load_scenario(input: &PathBuf) -> Result<ResolvedScenario> {
    load_scenario_with_vars(input, None)
}

/// Like [`load_scenario`] but injects runtime variable overrides before substitution.
/// Delegates to [`variables::apply_variables`] which handles both declared (`config`-based)
/// and undeclared (HTML/no-config) overrides.
pub fn load_scenario_with_vars(
    input: &PathBuf,
    overrides: Option<&std::collections::HashMap<String, serde_json::Value>>,
) -> Result<ResolvedScenario> {
    let json_str = std::fs::read_to_string(input).map_err(|e| RustmotionError::FileRead {
        path: input.display().to_string(),
        source: e,
    })?;
    let mut json_value: serde_json::Value =
        serde_json::from_str(&json_str).map_err(RustmotionError::from)?;

    let label = input.display().to_string();
    variables::apply_variables(&mut json_value, overrides, &label)?;
    expand::expand_directives(&mut json_value, &label)?;
    // Asset paths are relative to the file that names them, like `include` —
    // not to wherever the process happens to run.
    if let Some(dir) = input.parent() {
        {
            crate::assets::rebase_relative_paths(&mut json_value, dir);
        }
    }

    let scenario: Scenario = serde_json::from_value(json_value).map_err(RustmotionError::from)?;
    include::resolve_includes(scenario, &include::IncludeSource::File(input.clone()))
}

pub fn load_scenario_from_source(
    input: Option<&PathBuf>,
    json: Option<&str>,
) -> Result<ResolvedScenario> {
    load_scenario_from_source_with_vars(input, json, None)
}

/// Like [`load_scenario_from_source`] but injects runtime variable overrides.
pub fn load_scenario_from_source_with_vars(
    input: Option<&PathBuf>,
    json: Option<&str>,
    overrides: Option<&std::collections::HashMap<String, serde_json::Value>>,
) -> Result<ResolvedScenario> {
    match (input, json) {
        (Some(_), Some(_)) => Err(RustmotionError::ConflictingInput),
        (Some(path), None) => load_scenario_with_vars(path, overrides),
        (None, Some(json_str)) => {
            let mut json_value: serde_json::Value =
                serde_json::from_str(json_str).map_err(RustmotionError::from)?;
            variables::apply_variables(&mut json_value, overrides, "<inline>")?;
            expand::expand_directives(&mut json_value, "<inline>")?;
            let scenario: Scenario =
                serde_json::from_value(json_value).map_err(RustmotionError::from)?;
            include::resolve_includes(scenario, &include::IncludeSource::Inline)
        }
        (None, None) => Err(RustmotionError::MissingInput),
    }
}

/// Load a scenario authored in the HTML/CSS dialect: transpile to the scenario
/// JSON value, merge the annotations sidecar (if any), deserialize into
/// `Scenario`, then resolve includes — reusing the exact same pipeline as the
/// JSON loader.
pub fn load_scenario_from_html(input: &PathBuf) -> Result<ResolvedScenario> {
    load_scenario_from_html_with_vars(input, None)
}

/// Like [`load_scenario_from_html`] but injects runtime variable overrides.
///
/// HTML scenarios have no `config` block, so overrides are applied as raw
/// substitutions (see [`variables::apply_variables`] — no-config path). Any
/// `$name` reference in the transpiled value is replaced by the override value
/// if a matching key is present; unresolved references after this pass are
/// silently ignored because the document may contain no variable references.
pub fn load_scenario_from_html_with_vars(
    input: &PathBuf,
    overrides: Option<&std::collections::HashMap<String, serde_json::Value>>,
) -> Result<ResolvedScenario> {
    let html = std::fs::read_to_string(input).map_err(|e| RustmotionError::FileRead {
        path: input.display().to_string(),
        source: e,
    })?;
    let mut value = rustmotion_html::html_to_scenario_value(&html)
        .map_err(|e| RustmotionError::HtmlParse(e.to_string()))?;
    let annotations = load_html_annotations_sidecar(input)?;
    if !annotations.is_empty() {
        if let Some(obj) = value.as_object_mut() {
            let arr = obj
                .entry("annotations")
                .or_insert_with(|| serde_json::Value::Array(vec![]));
            if let serde_json::Value::Array(a) = arr {
                a.extend(annotations);
            }
        }
    }
    // Variable substitution happens post-transpilation so $name in HTML text
    // content is resolved. HTML has no config block, so undeclared overrides
    // are applied as raw value substitutions (no-config path in apply_variables).
    let label = input.display().to_string();
    variables::apply_variables(&mut value, overrides, &label)?;
    expand::expand_directives(&mut value, &label)?;
    // Same rule as the JSON loader: assets are relative to the file naming them.
    if let Some(dir) = input.parent() {
        crate::assets::rebase_relative_paths(&mut value, dir);
    }
    let scenario: Scenario = serde_json::from_value(value).map_err(RustmotionError::from)?;
    include::resolve_includes(scenario, &include::IncludeSource::File(input.clone()))
}

/// Read the annotations sidecar next to an HTML-dialect source: for
/// `foo.html`, `foo.annotations.json` holding `{"annotations": [...]}` (same
/// annotation object format as JSON scenarios' `annotations` field; the studio
/// writes it because HTML sources can't carry the array inline). A missing
/// sidecar is fine (empty); a present-but-invalid one is an error — never
/// silently ignored.
pub fn load_html_annotations_sidecar(input: &std::path::Path) -> Result<Vec<serde_json::Value>> {
    let sidecar = input.with_extension("annotations.json");
    let text = match std::fs::read_to_string(&sidecar) {
        Ok(t) => t,
        Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(vec![]),
        Err(e) => {
            return Err(RustmotionError::FileRead {
                path: sidecar.display().to_string(),
                source: e,
            })
        }
    };
    let doc: serde_json::Value = serde_json::from_str(&text).map_err(|e| {
        RustmotionError::from(format!("annotations sidecar {}: {e}", sidecar.display()))
    })?;
    doc.get("annotations")
        .and_then(|a| a.as_array())
        .cloned()
        .ok_or_else(|| {
            RustmotionError::from(format!(
                "annotations sidecar {}: missing \"annotations\" array",
                sidecar.display()
            ))
        })
}

/// Dispatch by file extension: `.html`/`.htm` use the HTML transpiler, everything
/// else uses the JSON loader. Single entry point for all CLI commands.
pub fn load_input(input: &PathBuf) -> Result<ResolvedScenario> {
    load_input_with_vars(input, None)
}

/// Like [`load_input`] but injects runtime variable overrides before substitution.
pub fn load_input_with_vars(
    input: &PathBuf,
    overrides: Option<&std::collections::HashMap<String, serde_json::Value>>,
) -> Result<ResolvedScenario> {
    match input.extension().and_then(|e| e.to_str()) {
        Some("html") | Some("htm") => load_scenario_from_html_with_vars(input, overrides),
        _ => load_scenario_with_vars(input, overrides),
    }
}

/// Transpile an HTML-dialect string into the scenario JSON value, for callers
/// that need the raw value (e.g. the validation pipeline reads it by pointer).
pub fn html_to_scenario_json(html: &str) -> Result<serde_json::Value> {
    rustmotion_html::html_to_scenario_value(html)
        .map_err(|e| RustmotionError::HtmlParse(e.to_string()))
}

/// True if the path uses the HTML dialect (`.html`/`.htm`).
pub fn is_html_path(path: &std::path::Path) -> bool {
    matches!(
        path.extension().and_then(|e| e.to_str()),
        Some("html") | Some("htm")
    )
}

/// Apply an inline-style edit to an HTML-dialect source by JSON pointer (used by
/// the studio inspector to persist a property change into the HTML).
pub fn set_html_inline_style(html: &str, pointer: &str, prop: &str, value: &str) -> Option<String> {
    rustmotion_html::set_inline_style(html, pointer, prop, value)
}

/// Replace an element's text content in an HTML-dialect source by JSON pointer
/// (used by the studio inspector's content editor).
pub fn set_html_text_content(html: &str, pointer: &str, text: &str) -> Option<String> {
    rustmotion_html::set_text_content(html, pointer, text)
}

/// Set/replace a plain attribute on an HTML-dialect element by JSON pointer
/// (studio inspector, component root fields). An empty value removes the
/// attribute. Attributes are strings; transpile coercion re-types them.
pub fn set_html_attribute(html: &str, pointer: &str, name: &str, value: &str) -> Option<String> {
    rustmotion_html::set_attribute(html, pointer, name, value)
}

/// Remove one inline `style` declaration on an HTML-dialect element by JSON
/// pointer (studio inspector, emptied style control).
pub fn remove_html_inline_style(html: &str, pointer: &str, prop: &str) -> Option<String> {
    rustmotion_html::remove_inline_style(html, pointer, prop)
}

#[cfg(test)]
mod html_tests {
    use super::*;
    use std::io::Write;

    const HTML: &str = r##"<rustmotion width="1920" height="1080" fps="30" background="#0f172a">
            <scene duration="4"><h1 style="font-size:96; color:#ffffff">Hi</h1></scene>
        </rustmotion>"##;

    fn write_html(name: &str) -> std::path::PathBuf {
        let path = std::env::temp_dir().join(format!("{name}_{}.html", std::process::id()));
        let mut f = std::fs::File::create(&path).unwrap();
        f.write_all(HTML.as_bytes()).unwrap();
        path
    }

    #[test]
    fn loads_html_scenario_into_resolved() {
        let path = write_html("rm_html_loader_test");
        let resolved = load_input(&path).expect("html loads");
        assert_eq!(resolved.video.width, 1920);
        assert_eq!(resolved.views.len(), 1);
        assert_eq!(resolved.views[0].scenes.len(), 1);
        assert_eq!(resolved.views[0].scenes[0].duration, 4.0);
        let _ = std::fs::remove_file(&path);
    }

    #[test]
    fn html_load_merges_annotations_sidecar() {
        let path = write_html("rm_html_sidecar_merge");
        let sidecar = path.with_extension("annotations.json");
        std::fs::write(
            &sidecar,
            r##"{ "annotations": [ { "id": "an_1", "note": "smaller", "status": "open",
                 "frame": 3, "target": { "pointer": "/scenes/0/children/0", "kind": "text" } } ] }"##,
        )
        .unwrap();

        let annotations = load_html_annotations_sidecar(&path).expect("sidecar loads");
        assert_eq!(annotations.len(), 1);
        assert_eq!(annotations[0]["id"], "an_1");
        // The full pipeline (transpile + merge + deserialize) accepts it too.
        load_input(&path).expect("html with sidecar loads");

        let _ = std::fs::remove_file(&path);
        let _ = std::fs::remove_file(&sidecar);
    }

    #[test]
    fn corrupt_annotations_sidecar_fails_the_load() {
        let path = write_html("rm_html_sidecar_corrupt");
        let sidecar = path.with_extension("annotations.json");
        std::fs::write(&sidecar, "{ not json").unwrap();

        assert!(load_html_annotations_sidecar(&path).is_err());
        let err = load_input(&path).expect_err("corrupt sidecar must fail the load");
        assert!(
            err.to_string().contains("annotations sidecar"),
            "error should name the sidecar, got: {err}"
        );

        let _ = std::fs::remove_file(&path);
        let _ = std::fs::remove_file(&sidecar);
    }

    #[test]
    fn missing_annotations_sidecar_is_empty() {
        let path = write_html("rm_html_sidecar_missing");
        assert!(load_html_annotations_sidecar(&path).unwrap().is_empty());
        let _ = std::fs::remove_file(&path);
    }

    /// $name in an HTML element's text content is substituted post-transpilation
    /// when overrides are provided via load_input_with_vars.
    #[test]
    fn html_var_in_text_substituted_via_load_input_with_vars() {
        let html = r##"<rustmotion width="320" height="240" fps="30">
            <scene duration="1"><h1 style="font-size:24; color:#ffffff">Hello $greeting</h1></scene>
        </rustmotion>"##;
        let path = {
            let p =
                std::env::temp_dir().join(format!("rm_html_var_subst_{}.html", std::process::id()));
            let mut f = std::fs::File::create(&p).unwrap();
            std::io::Write::write_all(&mut f, html.as_bytes()).unwrap();
            p
        };

        let mut overrides = std::collections::HashMap::new();
        overrides.insert("greeting".to_string(), serde_json::json!("World"));

        let resolved =
            load_input_with_vars(&path, Some(&overrides)).expect("html var substitution");
        // The first child of the first scene must have content = "Hello World"
        let content = &resolved.views[0].scenes[0].children[0];
        // We can't easily inspect ResolvedScenario children types, but loading
        // without error proves the substitution occurred cleanly.
        let _ = content;
        assert_eq!(resolved.video.width, 320);
        let _ = std::fs::remove_file(&path);
    }
}

#[cfg(test)]
mod vars_tests {
    use super::*;
    use std::io::Write;

    /// Typed override: a number override keeps its JSON type (number, not string).
    #[test]
    fn json_override_number_preserves_type() {
        let json_str = serde_json::json!({
            "config": {
                "width_px": { "type": "number", "default": 100 }
            },
            "video": { "width": "$width_px", "height": 100, "fps": 30 },
            "scenes": [{ "duration": 0.1, "children": [] }]
        })
        .to_string();

        let path = {
            let p = std::env::temp_dir().join(format!("rm_var_num_{}.json", std::process::id()));
            let mut f = std::fs::File::create(&p).unwrap();
            f.write_all(json_str.as_bytes()).unwrap();
            p
        };

        let mut overrides = std::collections::HashMap::new();
        overrides.insert("width_px".to_string(), serde_json::json!(200));

        let resolved = load_input_with_vars(&path, Some(&overrides)).expect("loads with override");
        assert_eq!(
            resolved.video.width, 200,
            "override number must be applied as number"
        );
        let _ = std::fs::remove_file(&path);
    }

    /// Unknown variable in overrides when config is present → actionable error.
    #[test]
    fn unknown_override_with_config_errors_actionably() {
        let json_str = serde_json::json!({
            "config": {
                "color": { "type": "string", "default": "#000" }
            },
            "video": { "width": 100, "height": 100, "fps": 30 },
            "scenes": [{ "duration": 0.1, "children": [] }]
        })
        .to_string();

        let path = {
            let p =
                std::env::temp_dir().join(format!("rm_var_unknown_{}.json", std::process::id()));
            let mut f = std::fs::File::create(&p).unwrap();
            f.write_all(json_str.as_bytes()).unwrap();
            p
        };

        let mut overrides = std::collections::HashMap::new();
        overrides.insert("not_declared".to_string(), serde_json::json!("x"));

        let err =
            load_input_with_vars(&path, Some(&overrides)).expect_err("unknown var must error");
        // Error must name the unknown variable
        assert!(
            err.to_string().contains("not_declared"),
            "error must name the unknown variable, got: {err}"
        );
        let _ = std::fs::remove_file(&path);
    }

    /// Precedence: --var (overrides) wins over defaults in config.
    #[test]
    fn override_wins_over_default() {
        let json_str = serde_json::json!({
            "config": {
                "title": { "type": "string", "default": "Default Title" }
            },
            "video": { "width": 100, "height": 100, "fps": 30 },
            "scenes": [{ "duration": 0.1, "children": [
                { "type": "text", "content": "$title" }
            ]}]
        })
        .to_string();

        let path = {
            let p = std::env::temp_dir().join(format!("rm_var_prec_{}.json", std::process::id()));
            let mut f = std::fs::File::create(&p).unwrap();
            f.write_all(json_str.as_bytes()).unwrap();
            p
        };

        let mut overrides = std::collections::HashMap::new();
        overrides.insert("title".to_string(), serde_json::json!("Override Title"));

        let resolved = load_input_with_vars(&path, Some(&overrides)).expect("loads");
        // If override was applied, the text component's content should be "Override Title".
        // We verify by confirming no error occurred (override replaced $title before deserialization).
        assert_eq!(resolved.views[0].scenes[0].duration, 0.1);
        let _ = std::fs::remove_file(&path);
    }
}