SwiftLint/Source/SwiftLintFramework/Rules/VariableNameMinLengthRule.swift

//
//  VariableNameMinLengthRule.swift
//  SwiftLint
//
//  Created by Mickaël Morier on 04/11/2015.
//  Copyright © 2015 Realm. All rights reserved.
//

import SourceKittenFramework
import SwiftXPC

public struct VariableNameMinLengthRule: ASTRule, ParameterizedRule {
    public init() {
        self.init(parameters: [
            RuleParameter(severity: .Warning, value: 3),
            RuleParameter(severity: .Error, value: 2)
        ])
    }

    public init(parameters: [RuleParameter<Int>]) {
        self.parameters = parameters
    }

    public let parameters: [RuleParameter<Int>]

    public static let description = RuleDescription(
        identifier: "variable_name_min_length",
        name: "Variable Name Min Length Rule",
        description: "Variable name should not be too short.",
        nonTriggeringExamples: [
            "let myLet = 0",
            "var myVar = 0",
            "private let _myLet = 0"
        ],
        triggeringExamples: [
            "let i = 0",
            "var id = 0",
            "private let _i = 0"
        ]
    )

    public func validateFile(file: File,
        kind: SwiftDeclarationKind,
        dictionary: XPCDictionary) -> [StyleViolation] {
            let variableKinds: [SwiftDeclarationKind] = [
                .VarClass,
                .VarGlobal,
                .VarInstance,
                .VarLocal,
                .VarParameter,
                .VarStatic
            ]
            if !variableKinds.contains(kind) {
                return []
            }
            guard let name = dictionary["key.name"] as? String,
                let offset = (dictionary["key.offset"] as? Int64).flatMap({ Int($0) }) else {
                    return []
            }
            return name.violationsForNameAtLocation(Location(file: file, offset: offset),
                dictionary: dictionary, ruleDescription: self.dynamicType.description,
                parameters: self.parameters)
    }
}

extension String {
    private func violationsForNameAtLocation(location: Location, dictionary: XPCDictionary,
                                             ruleDescription: RuleDescription,
                                             parameters: [RuleParameter<Int>]) -> [StyleViolation] {
        if characters.first == "$" {
            // skip block variables
            return []
        }
        let name = nameStrippingLeadingUnderscoreIfPrivate(dictionary)
        for parameter in parameters.reverse() where name.characters.count < parameter.value {
            return [StyleViolation(ruleDescription: ruleDescription,
                severity: parameter.severity,
                location: location,
                reason: "Variable name should be \(parameter.value) characters " +
                        "or more: currently \(name.characters.count) characters")]
        }
        return []
    }
}