Mountain/ExtensionManagement/

Scanner.rs

//! # Extension Scanner (ExtensionManagement)
//!
//! Contains the logic for scanning directories on the filesystem to discover
//! installed extensions by reading their `package.json` manifests, and for
//! collecting default configuration values from all discovered extensions.
//!
//! ## RESPONSIBILITIES
//!
//! ### 1. Extension Discovery
//! - Scan registered extension paths for valid extensions
//! - Read and parse `package.json` manifest files
//! - Validate extension metadata and structure
//! - Build `ExtensionDescriptionStateDTO` for each discovered extension
//!
//! ### 2. Configuration Collection
//! - Extract default configuration values from extension
//!   `contributes.configuration`
//! - Merge configuration properties from all extensions
//! - Handle nested configuration objects recursively
//! - Detect and prevent circular references
//!
//! ### 3. Error Handling
//! - Gracefully handle unreadable directories
//! - Skip extensions with invalid package.json
//! - Log warnings for partial scan failures
//! - Continue scanning even when some paths fail
//!
//! ## ARCHITECTURAL ROLE
//!
//! The Extension Scanner is part of the **Extension Management** subsystem:
//!
//! ```text
//! Startup ──► ScanPaths ──► Scanner ──► Extensions Map ──► ApplicationState
//! ```
//!
//! ### Position in Mountain
//! - `ExtensionManagement` module: Extension discovery and metadata
//! - Used during application startup to populate extension registry
//! - Provides data to `Cocoon` for extension host initialization
//!
//! ### Dependencies
//! - `CommonLibrary::FileSystem`: ReadDirectory and ReadFile effects
//! - `CommonLibrary::Error::CommonError`: Error handling
//! - `ApplicationRunTime`: Effect execution
//! - `ApplicationState`: Extension storage
//!
//! ### Dependents
//! - `InitializationData::ConstructExtensionHostInitializationData`: Sends
//!   extensions to Cocoon
//! - `MountainEnvironment::ScanForExtensions`: Public API for extension
//!   scanning
//! - `ApplicationState::Internal::ScanExtensionsWithRecovery`: Robust scanning
//!   wrapper
//!
//! ## SCANNING PROCESS
//!
//! 1. **Path Resolution**: Get scan paths from
//!    `ApplicationState.Extension.Registry.ExtensionScanPaths`
//! 2. **Directory Enumeration**: For each path, read directory entries
//! 3. **Manifest Detection**: Look for `package.json` in each subdirectory
//! 4. **Parsing**: Deserialize `package.json` into
//!    `ExtensionDescriptionStateDTO`
//! 5. **Augmentation**: Add `ExtensionLocation` (disk path) to metadata
//! 6. **Storage**: Insert into `ApplicationState.Extension.ScannedExtensions`
//!    map
//!
//! ## CONFIGURATION MERGING
//!
//! `CollectDefaultConfigurations()` extracts default values from all
//! extensions' `contributes.configuration.properties` and merges them into a
//! single JSON object:
//!
//! - Handles nested `.` notation (e.g., `editor.fontSize`)
//! - Recursively processes nested `properties` objects
//! - Detects circular references to prevent infinite loops
//! - Returns a flat map of configuration keys to default values
//!
//! ## ERROR HANDLING
//!
//! - **Directory Read Failures**: Logged as warnings, scanning continues
//! - **Invalid package.json**: Skipped with warning, scanning continues
//! - **IO Errors**: Logged, operation continues or fails gracefully
//!
//! ## PERFORMANCE
//!
//! - Scans are performed asynchronously via `ApplicationRunTime`
//! - Each directory read is a separate filesystem operation
//! - Large extension directories may impact startup time
//! - Consider caching scan results for development workflows
//!
//! ## VS CODE REFERENCE
//!
//! Borrowed from VS Code's extension management:
//! - `vs/workbench/services/extensions/common/extensionPoints.ts` -
//!   Configuration contribution
//! - `vs/platform/extensionManagement/common/extensionManagementService.ts` -
//!   Extension scanning
//!
//! ## TODO
//!
//! - [ ] Implement concurrent scanning for multiple paths
//! - [ ] Add extension scan caching with invalidation
//! - [ ] Implement extension validation rules (required fields, etc.)
//! - [ ] Add scan progress reporting for UI feedback
//! - [ ] Support extension scanning in subdirectories (recursive)
//!
//! ## MODULE CONTENTS
//!
//! - [`ScanDirectoryForExtensions`]: Scan a single directory for extensions
//! - [`CollectDefaultConfigurations`]: Merge configuration defaults from all
//!   extensions
//! - `process_configuration_properties`: Recursive configuration property
//! processor

use std::{path::PathBuf, sync::Arc};

use CommonLibrary::{
	Effect::ApplicationRunTime::ApplicationRunTime as _,
	Error::CommonError::CommonError,
	FileSystem::{DTO::FileTypeDTO::FileTypeDTO, ReadDirectory::ReadDirectory, ReadFile::ReadFile},
};
use serde_json::{Map, Value};
use tauri::Manager;

use crate::{
	ApplicationState::{
		DTO::ExtensionDescriptionStateDTO::ExtensionDescriptionStateDTO,
		State::ApplicationState::ApplicationState,
	},
	Environment::Utility,
	RunTime::ApplicationRunTime::ApplicationRunTime,
	dev_log,
};

/// Directory names that are never extensions themselves even though they
/// sit at the top level of `extensions/`. VS Code's shipped tree keeps
/// TypeScript type declarations in `types/`, build output in `out/`, and a
/// flat `node_modules/` for shared dependencies. Scanning into those emits
/// noise like `[ExtensionScanner] Could not read package.json at
/// .../out/package.json` on every boot; callers use `ExtensionScanDenyList` to
/// skip them without losing the ability to scan *nested* `node_modules` inside
/// a real extension (e.g. a language server's bundled deps).
const EXTENSION_SCAN_DENY_LIST:&[&str] = &["types", "out", "node_modules", "test", ".vscode-test", ".git"];

/// Test-only extensions that only serve the upstream VS Code test harness.
/// Excluded unless `Test=1` is set, because they
/// pollute the registry with events nobody listens for and drag down boot
/// time on every user session.
const TEST_ONLY_EXTENSIONS:&[&str] = &[
	"vscode-api-tests",
	"vscode-test-resolver",
	"vscode-colorize-tests",
	"vscode-colorize-perf-tests",
	"vscode-notebook-tests",
];

fn IncludeTestExtensions() -> bool { matches!(std::env::var("Test").as_deref(), Ok("1") | Ok("true")) }

fn IsDeniedDirectory(Name:&str) -> bool { EXTENSION_SCAN_DENY_LIST.iter().any(|Denied| *Denied == Name) }

fn IsTestOnlyExtension(Name:&str) -> bool { TEST_ONLY_EXTENSIONS.iter().any(|TestOnly| *TestOnly == Name) }

/// Return `true` if the given scan path represents a user-writable extension
/// directory (i.e. where `extensions:install` drops VSIX payloads), not a
/// bundled "built-in" path that ships with the app.
///
/// VS Code's sidebar categorises installed extensions by `IsBuiltin`:
/// `true` appears under **Built-in**, `false` under **Installed**
/// (accessible via `@installed`). Previously this classifier was
/// hardcoded to `true` for every scan path, so user-installed VSIXes
/// showed up under Built-in and `@installed` was empty.
///
/// The canonical user extension root on macOS/Linux is `~/.land/extensions`
/// (VS Code's equivalent is `~/.vscode/extensions`). We also honour a
/// `Lodge` override in case callers remap it.
///
/// Everything else - the Mountain build's own `Resources/extensions`,
/// Sky's `Static/Application/extensions`, the VS Code submodule's
/// `Dependency/…/extensions` - is treated as built-in.
fn IsUserExtensionScanPath(DirectoryPath:&std::path::Path) -> bool {
	let Normalised = match DirectoryPath.canonicalize() {
		Ok(Canonical) => Canonical,

		Err(_) => DirectoryPath.to_path_buf(),
	};

	// `${Lodge}` explicit override takes priority.
	if let Ok(Override) = std::env::var("Lodge") {
		if !Override.is_empty() && Normalised == std::path::PathBuf::from(&Override) {
			return true;
		}
	}

	// `${HOME}/.land/extensions` is the default user-scope root - used by
	// `VsixInstaller::InstallVsix` for local VSIX drops and by the scan
	// path list in `ScanPathConfigure`.
	if let Ok(Home) = std::env::var("HOME") {
		let UserRoot = std::path::PathBuf::from(Home).join(".land/extensions");

		if Normalised == UserRoot {
			return true;
		}
	}

	false
}

/// Scans a single directory for valid extensions.
///
/// This function iterates through a given directory, looking for subdirectories
/// that contain a `package.json` file. It then attempts to parse this file
/// into an `ExtensionDescriptionStateDTO`.
pub async fn ScanDirectoryForExtensions(
	ApplicationHandle:tauri::AppHandle,

	DirectoryPath:PathBuf,
) -> Result<Vec<ExtensionDescriptionStateDTO>, CommonError> {
	// Decide up-front whether this scan path contributes built-ins or user
	// extensions. Built-ins are ones shipped inside the Mountain/Sky/VS Code
	// bundle; the `~/.land/extensions` root is user-space.
	let IsUserPath = IsUserExtensionScanPath(&DirectoryPath);

	let RunTime = ApplicationHandle.state::<Arc<ApplicationRunTime>>().inner().clone();

	let mut FoundExtensions = Vec::new();

	// Distinguish "directory does not exist" (first-run, no user extensions
	// installed yet - perfectly normal) from a real I/O failure. Only the
	// latter deserves a `warn:` prefix; the former is debug-level noise.
	match DirectoryPath.try_exists() {
		Ok(false) => {
			dev_log!(
				"extensions",
				"[ExtensionScanner] Extension path '{}' does not exist, skipping (no extensions installed here)",
				DirectoryPath.display()
			);

			return Ok(Vec::new());
		},

		Err(error) => {
			dev_log!(
				"extensions",
				"[ExtensionScanner] Could not stat extension path '{}': {} - skipping",
				DirectoryPath.display(),
				error
			);

			return Ok(Vec::new());
		},

		Ok(true) => {},
	}

	let TopLevelEntries = match RunTime.Run(ReadDirectory(DirectoryPath.clone())).await {
		Ok(entries) => entries,

		Err(error) => {
			dev_log!(
				"extensions",
				"warn: [ExtensionScanner] Could not read extension directory '{}': {}. Skipping.",
				DirectoryPath.display(),
				error
			);

			return Ok(Vec::new());
		},
	};

	dev_log!(
		"extensions",
		"[ExtensionScanner] Directory '{}' contains {} top-level entries",
		DirectoryPath.display(),
		TopLevelEntries.len()
	);

	let mut parse_failures = 0usize;

	let mut missing_package_json = 0usize;

	let mut denied_directory_count = 0usize;

	let mut test_extension_skips = 0usize;

	let AllowTestExtensions = IncludeTestExtensions();

	for (EntryName, FileType) in TopLevelEntries {
		if FileType == FileTypeDTO::Directory {
			// BATCH-18: skip scanner traversal into directories that are
			// build output / shared deps, not extensions.
			if IsDeniedDirectory(&EntryName) {
				denied_directory_count += 1;

				continue;
			}

			if !AllowTestExtensions && IsTestOnlyExtension(&EntryName) {
				test_extension_skips += 1;

				continue;
			}

			let PotentialExtensionPath = DirectoryPath.join(EntryName);

			let PackageJsonPath = PotentialExtensionPath.join("package.json");

			// Per-candidate-directory probe, fires for every top-level
			// entry the scanner inspects (203 lines per session). The
			// accepted / rejected disposition is already covered by the
			// `ext-scan` tag below.
			dev_log!(
				"ext-scan-verbose",
				"[ExtensionScanner] Checking for package.json in: {}",
				PotentialExtensionPath.display()
			);

			match RunTime.Run(ReadFile(PackageJsonPath.clone())).await {
				Ok(PackageJsonContent) => {
					// Parse to a dynamic JSON value first so we can resolve
					// VS Code NLS placeholders (`%key%` strings referencing
					// `package.nls.json` entries) across every typed field.
					// Without this the UI renders literal `%command.clone%`,
					// `%displayName%`, etc. in the Command Palette and menus.
					let mut ManifestValue:Value = match serde_json::from_slice::<Value>(&PackageJsonContent) {
						Ok(v) => v,

						Err(error) => {
							parse_failures += 1;

							dev_log!(
								"extensions",
								"warn: [ExtensionScanner] Failed to parse package.json at '{}': {}",
								PotentialExtensionPath.display(),
								error
							);

							continue;
						},
					};

					// BATCH-18: only report "no bundle" when the manifest
					// actually contains `%placeholder%` strings that need
					// substitution. Many shipped extensions (js-debug-companion,
					// js-profile-table) publish English-only manifests with no
					// placeholders - surfacing a warning there is misleading
					// because the UI renders correctly with the raw fields.
					let ManifestUsesPlaceholders = ManifestContainsNLSPlaceholders(&ManifestValue);

					if let Some(NLSMap) =
						LoadNLSBundle(&RunTime, &PotentialExtensionPath, ManifestUsesPlaceholders).await
					{
						let mut Replaced = 0u32;

						let mut Unresolved = 0u32;

						ResolveNLSPlaceholdersInner(&mut ManifestValue, &NLSMap, &mut Replaced, &mut Unresolved);

						dev_log!(
							"nls",
							"[LandFix:NLS] {} → {} replaced, {} unresolved placeholders",
							PotentialExtensionPath.display(),
							Replaced,
							Unresolved
						);
					}

					match serde_json::from_value::<ExtensionDescriptionStateDTO>(ManifestValue) {
						Ok(mut Description) => {
							// Augment the description with its location on disk.
							Description.ExtensionLocation =
								serde_json::to_value(url::Url::from_directory_path(&PotentialExtensionPath).unwrap())
									.unwrap_or(Value::Null);

							// Construct identifier from publisher.name if not set
							if Description.Identifier == Value::Null
								|| Description.Identifier == Value::Object(Default::default())
							{
								let Id = if Description.Publisher.is_empty() {
									Description.Name.clone()
								} else {
									format!("{}.{}", Description.Publisher, Description.Name)
								};

								Description.Identifier = serde_json::json!({ "value": Id });
							}

							// Classify the extension by the scan path it came from.
							// Built-in extensions ship in the Mountain/Sky/VS Code
							// bundle; user extensions live under
							// `~/.land/extensions` (written by
							// `VsixInstaller::InstallVsix`). Hardcoding `true`
							// here (the previous behaviour) made every VSIX
							// install appear under **Built-in** in the
							// Extensions sidebar and left `@installed` empty
							// because the default query filters for User-scope
							// extensions only.
							Description.IsBuiltin = !IsUserPath;

							// Boot-time exec-bit heal for user-scope extensions.
							// Runs only against `~/.land/extensions/<id>/` (built-in
							// trees ship with correct modes from the bundle). Walks
							// `bin/`, `server/`, `tools/`, etc., promotes 0o644 →
							// 0o755 on files matching ELF / Mach-O / shebang magic.
							// One-shot per boot - cheap (a couple stat + read(4) calls
							// per file in those directories), and recovers extensions
							// installed before the in-extractor exec-bit fix landed
							// without forcing the user to reinstall.
							#[cfg(unix)]
							if IsUserPath {
								crate::ExtensionManagement::VsixInstaller::HealExecutableBits(&PotentialExtensionPath);
							}

							dev_log!(
								"ext-scan",
								"[ExtScan] accept path={} is_user={} is_builtin={} id={}",
								PotentialExtensionPath.display(),
								IsUserPath,
								Description.IsBuiltin,
								Description
									.Identifier
									.get("value")
									.and_then(|V| V.as_str())
									.unwrap_or("<unknown>")
							);

							FoundExtensions.push(Description);
						},

						Err(error) => {
							parse_failures += 1;

							dev_log!(
								"extensions",
								"warn: [ExtensionScanner] Failed to parse package.json for extension at '{}': {}",
								PotentialExtensionPath.display(),
								error
							);

							dev_log!(
								"ext-scan",
								"[ExtScan] skip path={} reason=parse-failure err={}",
								PotentialExtensionPath.display(),
								error
							);
						},
					}
				},

				Err(error) => {
					missing_package_json += 1;

					dev_log!(
						"extensions",
						"warn: [ExtensionScanner] Could not read package.json at '{}': {}",
						PackageJsonPath.display(),
						error
					);

					dev_log!(
						"ext-scan",
						"[ExtScan] skip path={} reason=no-package-json err={}",
						PotentialExtensionPath.display(),
						error
					);
				},
			}
		}
	}

	dev_log!(
		"extensions",
		"[ExtensionScanner] Directory '{}' scan done: {} parsed, {} parse-failures, {} missing package.json, {} \
		 denied-dirs, {} test-extensions-skipped (Test={})",
		DirectoryPath.display(),
		FoundExtensions.len(),
		parse_failures,
		missing_package_json,
		denied_directory_count,
		test_extension_skips,
		AllowTestExtensions,
	);

	Ok(FoundExtensions)
}

/// Walk a manifest value and return true as soon as any `%placeholder%` string
/// is encountered. Used to decide whether a missing `package.nls.json` bundle
/// is a real problem or a shipped-as-English extension.
fn ManifestContainsNLSPlaceholders(Value:&Value) -> bool {
	match Value {
		serde_json::Value::String(Text) => {
			Text.len() >= 2 && Text.starts_with('%') && Text.ends_with('%') && !Text[1..Text.len() - 1].contains('%')
		},

		serde_json::Value::Array(Items) => Items.iter().any(ManifestContainsNLSPlaceholders),

		serde_json::Value::Object(Object) => Object.values().any(ManifestContainsNLSPlaceholders),

		_ => false,
	}
}

/// Load an extension's NLS bundle (`package.nls.json`) into a `{key → string}`
/// map. Returns `None` if the bundle is absent or unreadable; placeholders stay
/// as-is in that case. Entries can be bare strings or `{message, comment}`
/// objects - we only keep `message`.
///
/// The `PlaceholdersNeeded` flag downgrades the "no bundle" warning when the
/// caller already proved the manifest has no `%placeholder%` entries to
/// resolve - in that case the bundle is optional and its absence is benign
/// (BATCH-18).
async fn LoadNLSBundle(
	RunTime:&Arc<ApplicationRunTime>,

	ExtensionPath:&PathBuf,

	PlaceholdersNeeded:bool,
) -> Option<Map<String, Value>> {
	let NLSPath = ExtensionPath.join("package.nls.json");

	let Content = match RunTime.Run(ReadFile(NLSPath.clone())).await {
		Ok(Bytes) => Bytes,

		Err(Error) => {
			if PlaceholdersNeeded {
				dev_log!("nls", "[LandFix:NLS] no bundle for {} ({})", ExtensionPath.display(), Error);
			} else {
				dev_log!(
					"nls",
					"[LandFix:NLS] {} has no placeholders, no bundle needed",
					ExtensionPath.display()
				);
			}

			return None;
		},
	};

	let Parsed:Value = match serde_json::from_slice(&Content) {
		Ok(V) => V,

		Err(Error) => {
			dev_log!("nls", "warn: [LandFix:NLS] failed to parse {}: {}", NLSPath.display(), Error);

			return None;
		},
	};

	let Object = Parsed.as_object()?;

	let mut Resolved = Map::with_capacity(Object.len());

	for (Key, RawValue) in Object {
		let Text = if let Some(s) = RawValue.as_str() {
			Some(s.to_string())
		} else if let Some(obj) = RawValue.as_object() {
			obj.get("message").and_then(|m| m.as_str()).map(|s| s.to_string())
		} else {
			None
		};

		if let Some(t) = Text {
			Resolved.insert(Key.clone(), Value::String(t));
		}
	}

	dev_log!(
		"nls",
		"[LandFix:NLS] loaded {} keys for {}",
		Resolved.len(),
		ExtensionPath.display()
	);

	Some(Resolved)
}

/// Internal NLS walker that also counts substitutions made vs. unresolved
/// placeholders it saw, so the outer scanner can log a one-line summary per
/// extension.
fn ResolveNLSPlaceholdersInner(Value:&mut Value, NLS:&Map<String, Value>, Replaced:&mut u32, Unresolved:&mut u32) {
	match Value {
		serde_json::Value::String(Text) => {
			if Text.len() >= 2 && Text.starts_with('%') && Text.ends_with('%') {
				let Key = &Text[1..Text.len() - 1];

				if !Key.is_empty() && !Key.contains('%') {
					if let Some(Replacement) = NLS.get(Key).and_then(|v| v.as_str()) {
						*Text = Replacement.to_string();
						*Replaced += 1;
					} else {
						*Unresolved += 1;
					}
				}
			}
		},

		serde_json::Value::Array(Items) => {
			for Item in Items {
				ResolveNLSPlaceholdersInner(Item, NLS, Replaced, Unresolved);
			}
		},

		serde_json::Value::Object(Map) => {
			for (_, FieldValue) in Map {
				ResolveNLSPlaceholdersInner(FieldValue, NLS, Replaced, Unresolved);
			}
		},

		_ => {},
	}
}

/// A helper function to extract default configuration values from all
/// scanned extensions.
pub fn CollectDefaultConfigurations(State:&ApplicationState) -> Result<Value, CommonError> {
	let mut MergedDefaults = Map::new();

	let Extensions = State
		.Extension
		.ScannedExtensions
		.ScannedExtensions
		.lock()
		.map_err(Utility::ErrorMapping::MapApplicationStateLockErrorToCommonError)?;

	for Extension in Extensions.values() {
		if let Some(contributes) = Extension.Contributes.as_ref().and_then(|v| v.as_object()) {
			if let Some(configuration) = contributes.get("configuration").and_then(|v| v.as_object()) {
				if let Some(properties) = configuration.get("properties").and_then(|v| v.as_object()) {
					// NESTED OBJECT HANDLING: Recursively process configuration properties
					self::process_configuration_properties(&mut MergedDefaults, "", properties, &mut Vec::new())?;
				}
			}
		}
	}

	Ok(Value::Object(MergedDefaults))
}

/// RECURSIVE CONFIGURATION PROCESSING: Handle nested object structures
fn process_configuration_properties(
	merged_defaults:&mut serde_json::Map<String, Value>,

	current_path:&str,

	properties:&serde_json::Map<String, Value>,

	visited_keys:&mut Vec<String>,
) -> Result<(), CommonError> {
	for (key, value) in properties {
		// Build the full path for this property
		let full_path = if current_path.is_empty() {
			key.clone()
		} else {
			format!("{}.{}", current_path, key)
		};

		// Check for circular references
		if visited_keys.contains(&full_path) {
			return Err(CommonError::Unknown {
				Description:format!("Circular reference detected in configuration properties: {}", full_path),
			});
		}

		visited_keys.push(full_path.clone());

		if let Some(prop_details) = value.as_object() {
			// Check if this is a nested object structure
			if let Some(nested_properties) = prop_details.get("properties").and_then(|v| v.as_object()) {
				// Recursively process nested properties
				self::process_configuration_properties(merged_defaults, &full_path, nested_properties, visited_keys)?;
			} else if let Some(default_value) = prop_details.get("default") {
				// Handle regular property with default value
				merged_defaults.insert(full_path.clone(), default_value.clone());
			}
		}

		// Remove current key from visited keys
		visited_keys.retain(|k| k != &full_path);
	}

	Ok(())
}