import Foundation
import PackagePlugin

@main
struct VersionPlugin: BuildToolPlugin {
    func createBuildCommands(context: PluginContext, target _: Target) async throws -> [Command] {
        let outputPath = context.pluginWorkDirectory.appending("Version.swift")

        return [
            .buildCommand(
                displayName: "Generate Version.swift",
                executable: .init("/usr/bin/env"),
                arguments: [
                    "swift", "-e",
                    """
                    import Foundation

                    func getVersion() -> String {
                        // Priority 1: Environment variable (CI)
                        if let envVersion = ProcessInfo.processInfo.environment["AXE_VERSION"] {
                            return envVersion
                        }

                        // Priority 2: Git describe (local development)
                        let gitProcess = Process()
                        gitProcess.executableURL = URL(fileURLWithPath: "/usr/bin/git")
                        gitProcess.arguments = ["describe", "--tags", "--always", "--dirty"]

                        let pipe = Pipe()
                        gitProcess.standardOutput = pipe
                        gitProcess.standardError = Pipe()

                        do {
                            try gitProcess.run()
                            gitProcess.waitUntilExit()

                            if gitProcess.terminationStatus == 0 {
                                let data = pipe.fileHandleForReading.readDataToEndOfFile()
                                if let version = String(data: data, encoding: .utf8)?.trimmingCharacters(in: .whitespacesAndNewlines) {
                                    return version.isEmpty ? "dev" : version
                                }
                            }
                        } catch {
                            // Git command failed
                        }

                        // Priority 3: Fallback
                        return "dev"
                    }

                    let version = getVersion()
                    let content = "// Auto-generated by VersionPlugin\\nlet VERSION = \\"\\(version)\\""

                    try content.write(toFile: "\\(CommandLine.arguments[1])", atomically: true, encoding: .utf8)
                    """,
                    outputPath.string,
                ],
                environment: [:],
                inputFiles: [],
                outputFiles: [outputPath]
            ),
        ]
    }
}