/*
 * Copyright 2015-2016 IBM Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import Foundation

public struct ActionToken {
    var actionName: String
    var actionCode: String
}

enum TokenState {
    case InStarComment
    case InSlashComment
    case Initial
    case inClass
    case inClassName
    case inClassQualifier
    case skippingBlock
    case parseAction
}

public class WhiskTokenizer {
    
    var atPath: String!
    var toPath: String!
    public var actions = [ActionToken]()
    
    public init(from: String, to: String) {
        atPath = from
        toPath = to
    }
    
    public func readXCodeProjectDirectory() throws {
        let dir: FileManager = FileManager.default
        
        if let enumerator: FileManager.DirectoryEnumerator = dir.enumerator(atPath: atPath) {
            
            while let item = enumerator.nextObject() as? NSString {
                
                var isDir = ObjCBool(false)
                let fullPath = atPath+"/\(item)"
                
                //print("===== inspecting \(fullPath)")
                if dir.fileExists(atPath: fullPath, isDirectory: &isDir) == true {
                    if isDir.boolValue == true {
                        
                    }  else if item.hasSuffix(".swift") {
                        
                        do {
                            let fileStr = try String(contentsOfFile: fullPath)
                            if let actionArray = getActions(str: fileStr) {
                                for action in actionArray {
                                    print("action: \(action.actionName), code: \(action.actionCode)")
                                    
                                    actions.append(action)
                                    
                                    do {
                                        let fileUrl = URL(fileURLWithPath: toPath+"/\(action.actionName).swift")
                                        try action.actionCode.write(to: fileUrl, atomically: false, encoding: String.Encoding.utf8)
                                    } catch {
                                        print("Error writing actions from Xcode \(error)")
                                    }
                                }
                            }
                            
                            
                        } catch {
                            print("Error \(error)")
                        }
                    }
                }
                
                
            }
            
        }
    }
    
    func getActions(str: String) -> [ActionToken]? {
        
        let scanner = Scanner(string: str)
        
        var line: NSString?
        var state = TokenState.Initial
        var actionArray: [ActionToken]? = [ActionToken]()
        var actionName = ""
        var actionCode = ""
        var leftBracketCount = 0
        var rightBracketCount = 0
        
        
        while scanner.scanUpToCharacters(from: CharacterSet.newlines, into: &line) {
            
            // print("Scan location is \(scanner.scanLocation)")
            
            guard let line = line else {
                print("Line is somehow null, quitting")
                return nil
            }
            
            var trimmedLine = line.trimmingCharacters(in: CharacterSet.whitespaces)
            
            //print("Inspecting line \(trimmedLine)")
            if trimmedLine.hasPrefix("//") {
                //print("Skipping comment")
            } else if trimmedLine.hasPrefix("/*") {
                state = TokenState.InStarComment
            } else {
                
                switch state {
                case .Initial:
                    if trimmedLine.hasPrefix("class") {
                        
                        let classStr = trimmedLine.components(separatedBy: ":")
                        if classStr.count > 1 {
                            
                            if classStr[1].range(of: "WhiskAction") != nil {
                                // get actionName
                                let classIndex = classStr[0].characters.index(classStr[0].startIndex, offsetBy: 6)
                                
                                actionName = classStr[0].substring(from: classIndex).trimmingCharacters(in: CharacterSet.whitespaces)
                                
                                state = TokenState.parseAction
                                var tok = trimmedLine.components(separatedBy: "{")
                                leftBracketCount = tok.count - 1
                                tok = trimmedLine.components(separatedBy: "}")
                                rightBracketCount = tok.count - 1
                            }
                            
                        }
                    } else {
                        //print("Don't care, looking for class")
                    }
                    
                case .parseAction:
                    
                    print("ParseAction: \(trimmedLine)")
                    
                    var lookingForLeftBracket = false
                    if leftBracketCount == 0 {
                        lookingForLeftBracket = true
                    }
                    var tok = trimmedLine.components(separatedBy: "{")
                    leftBracketCount = leftBracketCount + (tok.count - 1)
                    tok = trimmedLine.components(separatedBy: "}")
                    rightBracketCount = rightBracketCount + (tok.count - 1)
                    
                    if leftBracketCount == rightBracketCount {
                        
                        // drop extra bracket
                        let lastLine = String(trimmedLine.characters.dropLast())
                        
                        if lookingForLeftBracket == false {
                            actionCode = actionCode + "\n" + lastLine
                        }
                        
                        let newAction = ActionToken(actionName: actionName, actionCode: actionCode)
                        
                        actionArray?.append(newAction)
                        state = TokenState.Initial
                        actionName = ""
                        actionCode = ""
                        
                        leftBracketCount = 0
                        rightBracketCount = 0
                        
                        state = TokenState.Initial
                        
                    } else {
                        
                        let range = trimmedLine.range(of: "func run(")
                        if range != nil {
                            trimmedLine.replaceSubrange(range!, with: "func main(")
                        }
                        
                        if lookingForLeftBracket == false {
                            actionCode = actionCode + "\n"+trimmedLine
                        }
                    }
                    
                case .InStarComment:
                    if trimmedLine.hasSuffix("*/") {
                        state = TokenState.Initial
                    }
                default:
                    //print("Don't care")
                    break
                }
            }
            
        }
        
        if state == .parseAction {
            let code = String(actionCode.characters.dropLast())
            let newAction = ActionToken(actionName: actionName, actionCode: code)
            actionArray?.append(newAction)
            
        }
        
        return actionArray
    }
    
}