JsonParser.swift

//
//  JsonParser.swift
//  ModelGen
//
//  Created by Heberti Almeida on 2017-05-10.
//  Copyright © 2017 ModelGen. All rights reserved.
//

import Foundation
import StencilSwiftKit
import PathKit

public typealias JSON = [String: Any]

public final class JsonParser {
  public var json: JSON = [:]
  public var properties = [SchemaProperty]()
  public var customKeyProperties: [SchemaProperty] {
    return properties.filter { $0.hasCustomJsonKey }

  }

  public var nonCustomKeyProperties: [SchemaProperty] {
    return properties.filter { !$0.hasCustomJsonKey }
  }
  
  public var nonOptionalProperties: [SchemaProperty] {
    return properties.filter { !$0.isOptional }
  }
  
  public var optionalProperties: [SchemaProperty] {
    return properties.filter { $0.isOptional }
  }
  
  public var immutableProperties: [SchemaProperty] {
    return properties.filter { !$0.isMutable }
  }
  
  public var mutableProperties: [SchemaProperty] {
    return properties.filter { $0.isMutable }
  }

  public init() {}

  public func parseFile(at path: Path) throws {
    currentFile = path
    do {
      guard let json = try JSONSerialization.jsonObject(with: try path.read(), options: []) as? JSON else {
        throw JsonParserError.invalidFile(reason: "Invalid structure.")
      }
      self.json = json
    } catch let error as JsonParserError {
      throw error
    } catch let error {
      throw JsonParserError.invalidFile(reason: error.localizedDescription)
    }
  }
}

// MARK: Parser

func render(output: OutputDestination, template: String, lang: String, path: Path) throws {
  guard path.isDirectory else {
    do {
      try parse(output: output, template: template, lang: lang, path: path)
    } catch let error {
      printError(error.localizedDescription, showFile: true)
    }
    printSuccess("Finished generation.")
    exit(0)
  }

  let paths = try path.children().filter { $0.extension == "json" }
  paths.forEach { path in
    do {
      try parse(output: output, template: template, lang: lang, path: path)
    } catch let error {
      printError(error.localizedDescription, showFile: true)
    }
  }
  printSuccess("Finished generation of \(paths.count) files.")
}

/// Parse specs and generate files based on json
///
/// - Parameters:
///   - output: Output destination of generated files
///   - template: Stencil template
///   - lang: Language to generate files
///   - path: Spec path, folder or file.json
/// - Throws: Error if something happens
func parse(output: OutputDestination, template: String, lang: String, path: Path) throws {
  let parser = JsonParser()
  var finalOutput = output
  jsonAbsolutePath = Path(NSString(string: path.description).deletingLastPathComponent)

  do {
    try parser.parseFile(at: path)

    let language = Language(rawValue: lang) ?? .swift
    let tempatePath = try validate(template)
    let template = try StencilSwiftTemplate(templateString: tempatePath.read(), environment: stencilSwiftEnvironment())
    let context = try parser.stencilContextFor(language)
    let enriched = try StencilContext.enrich(context: context, parameters: [])
    let rendered = try template.render(enriched)

    let out = Path(output.description)
    guard out.isDirectory else {
      output.write(content: rendered, onlyIfChanged: true)
      return
    }
    guard let title = parser.json["title"] as? String else {
      throw JsonParserError.missingTitle
    }
    let finalPath = Path(output.description) + "\(title.uppercaseFirst() + language.fileExtension)"
    finalOutput = .file(finalPath)
    finalOutput.write(content: rendered, onlyIfChanged: true)
  } catch let error {
    printError(error.localizedDescription, showFile: true, file: path.description)
  }
}