import Foundation
import ArgumentParser

let log = ValidationLog()
var files: FileSystem!
var siteRoot: Element!

@main
struct CHGenerator: ParsableCommand {

    @Argument(help: "The path to the generator configuration file")
    var configPath: String

    mutating func run() throws {
        try generate(configPath: configPath)
    }
}

private func loadSiteData(in folder: URL) throws -> Element? {
    let log = MetadataInfoLogger(input: folder)
    print("--- SOURCE FILES -----------------------------------")
    let root = Element(atRoot: folder, log: log)
    print("                                                    ")
    log.printMetadataScanOverview()
    print("                                                    ")
    try log.writeResultsToFile(in: files.generatorInfoFolder)
    return root
}

private func loadConfiguration(at configPath: String) -> Configuration? {
    print("--- CONFIGURATION ----------------------------------")
    print("")
    print("    Configuration file: \(configPath)")
    let configUrl = URL(fileURLWithPath: configPath)
    let config: Configuration
    do {
        let data = try Data(contentsOf: configUrl)
        config = try JSONDecoder().decode(from: data)
    } catch {
        print("    Configuration error: \(error)")
        return nil
    }
    config.printOverview()
    print("                                                    ")
    return config
}

private func generate(configPath: String) throws {
    guard let configuration = loadConfiguration(at: configPath) else {
        return
    }

    files = .init(
        in: configuration.contentDirectory,
        to: configuration.outputDirectory,
        configuration: configuration)


    // 2. Scan site elements
    siteRoot = try loadSiteData(in: configuration.contentDirectory)
    guard siteRoot != nil else {
        return
    }
    let siteGenerator = try SiteGenerator()
    siteGenerator.generate(site: siteRoot)

    files.printGeneratedPages()
    files.printEmptyPages()
    files.printDraftPages()

    files.createImages()
    files.copyRequiredFiles()
    files.printExternalFiles()
    files.writeDetectedFileChangesToDisk()
}