SwiftLint/Plugins/SwiftLintCommandPlugin/SwiftLintCommandPlugin.swift

import Foundation
import PackagePlugin

private let commandsNotExpectingPaths: Set<String> = [
    "docs",
    "generate-docs",
    "baseline",
    "reporters",
    "rules",
    "version",
]

private let commandsWithoutCachPathOption: Set<String> = commandsNotExpectingPaths.union([
    "analyze",
])

@main
struct SwiftLintCommandPlugin: CommandPlugin {
    func performCommand(context: PluginContext, arguments: [String]) throws {
        try lintFiles(context: context, arguments: arguments)
    }
}

#if canImport(XcodeProjectPlugin)

import XcodeProjectPlugin

extension SwiftLintCommandPlugin: XcodeCommandPlugin {
    func performCommand(context: XcodePluginContext, arguments: [String]) throws {
        try lintFiles(context: context, arguments: arguments)
    }
}

#endif

extension SwiftLintCommandPlugin {
    private func lintFiles(context: some CommandContext, arguments: [String]) throws {
        guard !arguments.contains("--cache-path") else {
            Diagnostics.error("Caching is managed by the plugin and so setting `--cache-path` is not allowed")
            return
        }
        var argExtractor = ArgumentExtractor(arguments)
        let targetNames = argExtractor.extractOption(named: "target")
        let remainingArguments = argExtractor.remainingArguments

        if !commandsNotExpectingPaths.isDisjoint(with: remainingArguments) {
            try lintFiles(with: context, arguments: remainingArguments)
            return
        }
        guard !targetNames.isEmpty else {
            if let pathArgument = remainingArguments.last, FileManager.default.fileExists(atPath: pathArgument) {
                Diagnostics.remark("No targets provided. Files provided in path arguments will be linted.")
                try lintFiles(in: [], with: context, arguments: remainingArguments)
            } else {
                try lintFiles(with: context, arguments: remainingArguments)
            }
            return
        }
        for target in try context.targets(named: targetNames) {
            try lintFiles(in: target.paths, for: target.name, with: context, arguments: remainingArguments)
        }
    }

    private func lintFiles(in paths: [String] = ["."],
                           for targetName: String? = nil,
                           with context: some CommandContext,
                           arguments: [String]) throws {
        let process = Process()
        process.currentDirectoryURL = URL(fileURLWithPath: context.workingDirectory)
        process.executableURL = URL(fileURLWithPath: try context.tool)
        process.arguments = arguments
        if commandsWithoutCachPathOption.isDisjoint(with: arguments) {
            process.arguments! += ["--cache-path", context.cacheDirectory]
        }
        if commandsNotExpectingPaths.isDisjoint(with: arguments) {
            process.arguments! += paths
        }

        try process.run()
        process.waitUntilExit()

        let module = targetName.map { "\(context.subUnitName) '\($0)'" } ?? context.unitName
        switch process.terminationReason {
        case .exit:
            Diagnostics.remark("Finished running in \(module)")
        case .uncaughtSignal:
            Diagnostics.error("Got uncaught signal while running in \(module)")
        @unknown default:
            Diagnostics.error("Stopped running in \(module) due to unexpected termination reason")
        }

        if process.terminationStatus != EXIT_SUCCESS {
            Diagnostics.error("""
                Command found error violations or unsuccessfully stopped running with \
                exit code \(process.terminationStatus) in \(module)
                """
            )
        }
    }
}