//
//  StringsFileGenerator.swift
//  
//
//  Created by Thibaut Schmitt on 04/01/2022.
//

import Foundation
import ToolCore

class StringsFileGenerator {
    
    // MARK: - Strings Files
    
    static func writeStringsFiles(sections: [Section],
                                  langs: [String],
                                  defaultLang: String,
                                  tags: [String],
                                  outputPath: String,
                                  inputFilenameWithoutExt: String) {
        var stringsFilesContent = [String: String]()
        for lang in langs {
            stringsFilesContent[lang] = Self.generateStringsFileContent(lang: lang,
                                                                        defaultLang: defaultLang,
                                                                        tags: tags,
                                                                        sections: sections)
        }
        
        // Write strings file content
        langs.forEach { lang in
            guard let fileContent = stringsFilesContent[lang] else { return }
            
            let stringsFilePath = "\(outputPath)/\(lang).lproj/\(inputFilenameWithoutExt).strings"
            let stringsFilePathURL = URL(fileURLWithPath: stringsFilePath)
            do {
                try fileContent.write(to: stringsFilePathURL, atomically: false, encoding: .utf8)
            } catch (let error) {
                let error = StringiumError.writeFile(error.localizedDescription, stringsFilePath)
                print(error.description)
                Stringium.exit(withError: error)
            }
        }
    }
    
    static func generateStringsFileContent(lang: String,
                                           defaultLang: String,
                                           tags inputTags: [String],
                                           sections: [Section]) -> String {
        var stringsFileContent = """
        /**
         * Apple Strings File
         * Generated by ResgenSwift \(ResgenSwiftVersion)
         * Language: \(lang)
         */\n
        """
        
        sections.forEach { section in
            // Check that at least one string will be generated
            guard section.hasOneOrMoreMatchingTags(tags: inputTags) else {
                return // Go to next section
            }
            
            stringsFileContent += "\n/********** \(section.name) **********/\n\n"
            section.definitions.forEach { definition in
                var skipDefinition = false // Set to true if not matching tag
                let translationOpt: String? = {
                    // If no matching tag => skip
                    if definition.hasOneOrMoreMatchingTags(inputTags: inputTags) == false {
                        skipDefinition = true
                        return nil
                    }
                    
                    // If tags contains `noTranslationTag` => get default lang
                    if definition.tags.contains(Stringium.noTranslationTag) {
                        return definition.translations[defaultLang]
                    }
                    
                    // Else: get specific lang
                    return definition.translations[lang]
                }()
                
                if let translation = translationOpt {
                    stringsFileContent += "\"\(definition.name)\" = \"\(translation)\";\n\n"
                } else if skipDefinition == false {
                    let error = StringiumError.langNotDefined(lang, definition.name, definition.reference != nil)
                    print(error.description)
                    Stringium.exit(withError: error)
                }
            }
        }
        
        return stringsFileContent
    }
    
    // MARK: - Extension file
    
    static func writeExtensionFiles(sections: [Section],
                                    defaultLang lang: String,
                                    tags: [String],
                                    staticVar: Bool,
                                    inputFilename: String,
                                    extensionName: String,
                                    extensionFilePath: String,
                                    extensionSuffix: String) {
        // Get extension content
        let extensionFileContent = Self.getExtensionContent(sections: sections,
                                                            defaultLang: lang,
                                                            tags: tags,
                                                            staticVar: staticVar,
                                                            inputFilename: inputFilename,
                                                            extensionName: extensionName,
                                                            extensionSuffix: extensionSuffix)
        
        // Write content
        let extensionFilePathURL = URL(fileURLWithPath: extensionFilePath)
        do {
            try extensionFileContent.write(to: extensionFilePathURL, atomically: false, encoding: .utf8)
        } catch (let error) {
            let error = StringiumError.writeFile(extensionFilePath, error.localizedDescription)
            print(error.description)
            Stringium.exit(withError: error)
        }
    }
    
    // MARK: - Extension content
    
    static func getExtensionContent(sections: [Section],
                                    defaultLang lang: String,
                                    tags: [String],
                                    staticVar: Bool,
                                    inputFilename: String,
                                    extensionName: String,
                                    extensionSuffix: String) -> String {
        [
            Self.getHeader(stringsFilename: inputFilename, extensionClassname: extensionName),
            Self.getEnumKey(sections: sections, tags: tags, extensionSuffix: extensionSuffix),
            Self.getProperties(sections: sections, defaultLang: lang, tags: tags, staticVar: staticVar),
            Self.getFooter()
        ]
            .joined(separator: "\n")
    }
    
    // MARK: - Extension part
    
    private static func getHeader(stringsFilename: String, extensionClassname: String) -> String {
        """
        // Generated by ResgenSwift.Strings.\(Stringium.toolName) \(ResgenSwiftVersion)
        
        import UIKit
        
        fileprivate let kStringsFileName = "\(stringsFilename)"
        
        extension \(extensionClassname) {
        """
    }
    
    private static func getEnumKey(sections: [Section], tags: [String], extensionSuffix: String) -> String {
        var enumDefinition = "\n    enum Key\(extensionSuffix.uppercasedFirst()): String {\n"
        
        sections.forEach { section in
            // Check that at least one string will be generated
            guard section.hasOneOrMoreMatchingTags(tags: tags) else {
                return // Go to next section
            }
            
            section.definitions.forEach { definition in
                guard definition.hasOneOrMoreMatchingTags(inputTags: tags) == true else {
                    return // Go to next definition
                }
                debugPrint("Found definition")
                enumDefinition += "        case \(definition.name) = \"\(definition.name)\"\n"
            }
        }
        
        enumDefinition += "    }"
        
        return enumDefinition
    }
    
    private static func getProperties(sections: [Section], defaultLang lang: String, tags: [String], staticVar: Bool) -> String {
        sections.compactMap { section in
            // Check that at least one string will be generated
            guard section.hasOneOrMoreMatchingTags(tags: tags) else {
                return nil // Go to next section
            }
            
            var res = "\n    // MARK: - \(section.name)\n"
            res += section.definitions.compactMap { definition in
                guard definition.hasOneOrMoreMatchingTags(inputTags: tags) == true else {
                    return nil // Go to next definition
                }
                
                if staticVar {
                    return "\n\(definition.getNSLocalizedStringStaticProperty(forLang: lang))"
                }
                return "\n\(definition.getNSLocalizedStringProperty(forLang: lang))"
            }
            .joined(separator: "\n")
            return res
        }
        .joined(separator: "\n")
    }
    
    private static func getFooter() -> String {
        """
        }
        
        """
    }
}