import Foundation

// MARK: - Result type (Codable so /system/validate can return JSON)

struct StartupCheckResult: Codable {
    let name:    String
    let passed:  Bool
    let message: String
}

// MARK: - Validator

enum DaemonStartupValidator {

    static func run() -> [StartupCheckResult] {
        [
            checkXcode(),
            checkXcodebuild(),
            checkDevicectl(),
            checkSourcekitLSP(),
            checkTeamID(),
            checkSigningIdentity(),
            checkXcodeGen(),
        ]
    }

    // MARK: - Checks

    private static func checkXcode() -> StartupCheckResult {
        let exists = FileManager.default.fileExists(atPath: "/Applications/Xcode.app")
        return StartupCheckResult(
            name:    "Xcode Installation",
            passed:  exists,
            message: exists
                ? "Xcode found at /Applications/Xcode.app"
                : "Xcode not found — install from developer.apple.com or the App Store"
        )
    }

    private static func checkXcodebuild() -> StartupCheckResult {
        let result = shell("xcodebuild -version 2>/dev/null | head -1")
        let passed = result.contains("Xcode")
        return StartupCheckResult(
            name:    "xcodebuild",
            passed:  passed,
            message: passed
                ? result.trimmingCharacters(in: .whitespacesAndNewlines)
                : "xcodebuild not functional — run: xcode-select --install"
        )
    }

    private static func checkDevicectl() -> StartupCheckResult {
        let result = shell("xcrun devicectl --version 2>/dev/null")
        let passed = !result.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
        return StartupCheckResult(
            name:    "devicectl",
            passed:  passed,
            message: passed ? "devicectl available" : "devicectl not found — requires Xcode 15+"
        )
    }

    private static func checkSourcekitLSP() -> StartupCheckResult {
        let path = "/Applications/Xcode.app/Contents/Developer/Toolchains/" +
                   "XcodeDefault.xctoolchain/usr/bin/sourcekit-lsp"
        let exists = FileManager.default.fileExists(atPath: path)
        return StartupCheckResult(
            name:    "sourcekit-lsp",
            passed:  exists,
            message: exists ? "sourcekit-lsp found" : "sourcekit-lsp not found — completions unavailable"
        )
    }

    private static func checkTeamID() -> StartupCheckResult {
        let teamID = loadTeamID()
        let valid  = teamID.count == 10
            && teamID != "YOUR_10_CHAR_TEAM_ID"
            && teamID.allSatisfy({ $0.isLetter || $0.isNumber })
        return StartupCheckResult(
            name:    "Team ID",
            passed:  valid,
            message: valid
                ? "Team ID configured: \(teamID)"
                : "Team ID not set — edit ~/.padxcode/config.json"
        )
    }

    private static func checkSigningIdentity() -> StartupCheckResult {
        let result = shell(
            "security find-identity -v -p codesigning 2>/dev/null | grep 'Apple Development'"
        )
        let passed = !result.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
        let certName = result
            .components(separatedBy: "\"")
            .dropFirst()
            .first ?? "certificate present"
        return StartupCheckResult(
            name:    "Apple Development Certificate",
            passed:  passed,
            message: passed
                ? "Found: \(certName)"
                : "No Apple Development certificate — Xcode → Settings → Accounts → Manage Certificates"
        )
    }

    private static func checkXcodeGen() -> StartupCheckResult {
        let result = shell("which xcodegen 2>/dev/null")
            .trimmingCharacters(in: .whitespacesAndNewlines)
        let passed = !result.isEmpty
        return StartupCheckResult(
            name:    "XcodeGen",
            passed:  passed,
            message: passed
                ? "XcodeGen at \(result)"
                : "XcodeGen not found — brew install xcodegen"
        )
    }

    // MARK: - Shell helper

    @discardableResult
    private static func shell(_ command: String) -> String {
        let p = Process()
        p.executableURL = URL(fileURLWithPath: "/bin/zsh")
        p.arguments     = ["-lc", command]
        let pipe = Pipe()
        p.standardOutput = pipe
        p.standardError  = Pipe()
        try? p.run()
        p.waitUntilExit()
        return String(
            data:     pipe.fileHandleForReading.readDataToEndOfFile(),
            encoding: .utf8
        ) ?? ""
    }
}