import Foundation
import JSONUtilities
import PathKit
import Version

extension Project {

    public func validate() throws {

        var errors: [SpecValidationError.ValidationError] = []
        func validateSettings(_ settings: Settings) -> [SpecValidationError.ValidationError] {
            var errors: [SpecValidationError.ValidationError] = []
            for group in settings.groups {
                if let settings = settingGroups[group] {
                    errors += validateSettings(settings)
                } else {
                    errors.append(.invalidSettingsGroup(group))
                }
            }

            for config in settings.configSettings.keys {
                if !configs.contains(where: { $0.name.lowercased().contains(config.lowercased()) }),
                   !options.disabledValidations.contains(.missingConfigs) {
                    errors.append(.invalidBuildSettingConfig(config))
                }
            }

            if settings.buildSettings.count == configs.count {
                var allConfigs = true
                outerLoop: for buildSetting in settings.buildSettings.keys {
                    var isConfig = false
                    for config in configs {
                        if config.name.lowercased().contains(buildSetting.lowercased()) {
                            isConfig = true
                            break
                        }
                    }
                    if !isConfig {
                        allConfigs = false
                        break outerLoop
                    }
                }

                if allConfigs {
                    errors.append(.invalidPerConfigSettings)
                }
            }
            return errors
        }

        errors += validateSettings(settings)

        for fileGroup in fileGroups {
            if !(basePath + fileGroup).exists {
                errors.append(.invalidFileGroup(fileGroup))
            }
        }

        for (name, package) in packages {
            if case let .local(path, _, _) = package, !(basePath + Path(path).normalize()).exists {
                errors.append(.invalidLocalPackage(name))
            }
        }

        for (config, configFile) in configFiles {
            if !options.disabledValidations.contains(.missingConfigFiles) && !(basePath + configFile).exists {
                errors.append(.invalidConfigFile(configFile: configFile, config: config))
            }
            if !options.disabledValidations.contains(.missingConfigs) && getConfig(config) == nil {
                errors.append(.invalidConfigFileConfig(config))
            }
        }

        if let configName = options.defaultConfig {
            if !configs.contains(where: { $0.name == configName }) {
                errors.append(.missingDefaultConfig(configName: configName))
            }
        }

        for settings in settingGroups.values {
            errors += validateSettings(settings)
        }

        for target in projectTargets {

            for (config, configFile) in target.configFiles {
                let configPath = basePath + configFile
                if !options.disabledValidations.contains(.missingConfigFiles) && !configPath.exists {
                    errors.append(.invalidTargetConfigFile(target: target.name, configFile: configPath.string, config: config))
                }
                if !options.disabledValidations.contains(.missingConfigs) && getConfig(config) == nil {
                    errors.append(.invalidConfigFileConfig(config))
                }
            }

            if let scheme = target.scheme {
                
                for configVariant in scheme.configVariants {
                    if configs.first(including: configVariant, for: .debug) == nil {
                        errors.append(.invalidTargetSchemeConfigVariant(
                            target: target.name,
                            configVariant: configVariant,
                            configType: .debug
                        ))
                    }
                    if configs.first(including: configVariant, for: .release) == nil {
                        errors.append(.invalidTargetSchemeConfigVariant(
                            target: target.name,
                            configVariant: configVariant,
                            configType: .release
                        ))
                    }
                }

                if scheme.configVariants.isEmpty {
                    if !configs.contains(where: { $0.type == .debug }) {
                        errors.append(.missingConfigForTargetScheme(target: target.name, configType: .debug))
                    }
                    if !configs.contains(where: { $0.type == .release }) {
                        errors.append(.missingConfigForTargetScheme(target: target.name, configType: .release))
                    }
                }

                for testTarget in scheme.testTargets {
                    if getTarget(testTarget.name) == nil {
                        // For test case of local Swift Package
                        if case .package(let name) = testTarget.targetReference.location, getPackage(name) != nil {
                            continue
                        }
                        errors.append(.invalidTargetSchemeTest(target: target.name, testTarget: testTarget.name))
                    }
                }

                if !options.disabledValidations.contains(.missingTestPlans) {
                    let invalidTestPlans: [TestPlan] = scheme.testPlans.filter { !(basePath + $0.path).exists }
                    errors.append(contentsOf: invalidTestPlans.map{ .invalidTestPlan($0) })
                }
            }

            for script in target.buildScripts {
                if case let .path(pathString) = script.script {
                    let scriptPath = basePath + pathString
                    if !scriptPath.exists {
                        errors.append(.invalidBuildScriptPath(target: target.name, name: script.name, path: scriptPath.string))
                    }
                }
            }

            errors += validateSettings(target.settings)

            for buildToolPlugin in target.buildToolPlugins {
                if packages[buildToolPlugin.package] == nil {
                    errors.append(.invalidPluginPackageReference(plugin: buildToolPlugin.plugin, package: buildToolPlugin.package))
                }
            }
        }

        for target in aggregateTargets {
            for dependency in target.targets {
                if getProjectTarget(dependency) == nil {
                    errors.append(.invalidTargetDependency(target: target.name, dependency: dependency))
                }
            }
        }

        for target in targets {
            var uniqueDependencies = Set<Dependency>()

            for dependency in target.dependencies {
                let dependencyValidationErrors = try validate(dependency, in: target)
                errors.append(contentsOf: dependencyValidationErrors)

                if uniqueDependencies.contains(dependency) {
                    errors.append(.duplicateDependencies(target: target.name, dependencyReference: dependency.reference))
                } else {
                    uniqueDependencies.insert(dependency)
                }
            }

            for source in target.sources {
                let sourcePath = basePath + source.path
                if !source.optional && !sourcePath.exists {
                    errors.append(.invalidTargetSource(target: target.name, source: sourcePath.string))
                }
            }
            
            if target.supportedDestinations != nil, target.platform == .watchOS {
                errors.append(.unexpectedTargetPlatformForSupportedDestinations(target: target.name, platform: target.platform))
            }
            
            if let supportedDestinations = target.supportedDestinations,
               target.type.isApp,
               supportedDestinations.contains(.watchOS) {
                errors.append(.containsWatchOSDestinationForMultiplatformApp(target: target.name))
            }

            if target.supportedDestinations?.contains(.macOS) == true,
               target.supportedDestinations?.contains(.macCatalyst) == true {
                
                errors.append(.multipleMacPlatformsInSupportedDestinations(target: target.name))
            }
            
            if target.supportedDestinations?.contains(.macCatalyst) == true,
               target.platform != .iOS, target.platform != .auto {
                
                errors.append(.invalidTargetPlatformForSupportedDestinations(target: target.name))
            }
            
            if target.platform != .auto, target.platform != .watchOS,
               let supportedDestination = SupportedDestination(rawValue: target.platform.rawValue),
               target.supportedDestinations?.contains(supportedDestination) == false {
                
                errors.append(.missingTargetPlatformInSupportedDestinations(target: target.name, platform: target.platform))
            }
        }

        for projectReference in projectReferences {
            if !(basePath + projectReference.path).exists {
                errors.append(.invalidProjectReferencePath(projectReference))
            }
        }

        for scheme in schemes {
            errors.append(
                contentsOf: scheme.build.targets.compactMap { validationError(for: $0.target, in: scheme, action: "build") }
            )
            if let action = scheme.run, let config = action.config, getConfig(config) == nil {
                errors.append(.invalidSchemeConfig(scheme: scheme.name, config: config))
            }

            if !options.disabledValidations.contains(.missingTestPlans) {
                let invalidTestPlans: [TestPlan] = scheme.test?.testPlans.filter { !(basePath + $0.path).exists } ?? []
                errors.append(contentsOf: invalidTestPlans.map{ .invalidTestPlan($0) })
            }

            let defaultPlanCount = scheme.test?.testPlans.filter { $0.defaultPlan }.count ?? 0
            if (defaultPlanCount > 1) {
                errors.append(.multipleDefaultTestPlans)
            }

            if let action = scheme.test, let config = action.config, getConfig(config) == nil {
                errors.append(.invalidSchemeConfig(scheme: scheme.name, config: config))
            }
            errors.append(
                contentsOf: scheme.test?.targets.compactMap { validationError(for: $0.targetReference, in: scheme, action: "test") } ?? []
            )
            errors.append(
                contentsOf: scheme.test?.coverageTargets.compactMap { validationError(for: $0, in: scheme, action: "test") } ?? []
            )
            if let action = scheme.profile, let config = action.config, getConfig(config) == nil {
                errors.append(.invalidSchemeConfig(scheme: scheme.name, config: config))
            }
            if let action = scheme.analyze, let config = action.config, getConfig(config) == nil {
                errors.append(.invalidSchemeConfig(scheme: scheme.name, config: config))
            }
            if let action = scheme.archive, let config = action.config, getConfig(config) == nil {
                errors.append(.invalidSchemeConfig(scheme: scheme.name, config: config))
            }
        }

        if !errors.isEmpty {
            throw SpecValidationError(errors: errors)
        }
    }

    public func validateMinimumXcodeGenVersion(_ xcodeGenVersion: Version) throws {
        if let minimumXcodeGenVersion = options.minimumXcodeGenVersion, xcodeGenVersion < minimumXcodeGenVersion {
            throw SpecValidationError(errors: [SpecValidationError.ValidationError.invalidXcodeGenVersion(minimumVersion: minimumXcodeGenVersion, version: xcodeGenVersion)])
        }
    }

    // Returns error if the given dependency from target is invalid.
    private func validate(_ dependency: Dependency, in target: Target) throws -> [SpecValidationError.ValidationError] {
        var errors: [SpecValidationError.ValidationError] = []

        switch dependency.type {
            case .target:
                let dependencyTargetReference = try TargetReference(dependency.reference)

                switch dependencyTargetReference.location {
                case .local:
                    if getProjectTarget(dependency.reference) == nil {
                        errors.append(.invalidTargetDependency(target: target.name, dependency: dependency.reference))
                    }
                case .project(let dependencyProjectName):
                    if getProjectReference(dependencyProjectName) == nil {
                        errors.append(.invalidTargetDependency(target: target.name, dependency: dependency.reference))
                    }
                }
            case .sdk:
                let path = Path(dependency.reference)
                if !dependency.reference.contains("/") {
                    switch path.extension {
                    case "framework"?,
                            "tbd"?,
                            "dylib"?:
                        break
                    default:
                        errors.append(.invalidSDKDependency(target: target.name, dependency: dependency.reference))
                    }
                }
            case .package:
                if packages[dependency.reference] == nil {
                    errors.append(.invalidSwiftPackage(name: dependency.reference, target: target.name))
                }
            default: break
        }

        return errors
    }

    /// Returns a descriptive error if the given target reference was invalid otherwise `nil`.
    private func validationError(for targetReference: TargetReference, in scheme: Scheme, action: String) -> SpecValidationError.ValidationError? {
        switch targetReference.location {
        case .local where getProjectTarget(targetReference.name) == nil:
            return .invalidSchemeTarget(scheme: scheme.name, target: targetReference.name, action: action)
        case .project(let project) where getProjectReference(project) == nil:
            return .invalidProjectReference(scheme: scheme.name, reference: project)
        case .local, .project:
            return nil
        }
    }
    
    /// Returns a descriptive error if the given target reference was invalid otherwise `nil`.
    private func validationError(for testableTargetReference: TestableTargetReference, in scheme: Scheme, action: String) -> SpecValidationError.ValidationError? {
        switch testableTargetReference.location {
        case .local where getProjectTarget(testableTargetReference.name) == nil:
            return .invalidSchemeTarget(scheme: scheme.name, target: testableTargetReference.name, action: action)
        case .project(let project) where getProjectReference(project) == nil:
            return .invalidProjectReference(scheme: scheme.name, reference: project)
        case .package(let package) where getPackage(package) == nil:
            return .invalidLocalPackage(package)
        case .local, .project, .package:
            return nil
        }
    }
}