import {Unit} from "../../lifecycle/Unit"
import {Logging} from "../../service/Logging";
import {Singleton, Inject} from "../../di/decorator/injection"
import {CommandLine} from "./CommandLine"
import {UsageDirective} from "../directive/UsageDirective";
import {Directive} from "../Directive";
import {ShellDirective} from "../directive/ShellDirective";
import {TemplateDirective} from "../directive/TemplateDirective";
import {RunDirective} from "../directive/RunDirective";

/**
 * Unit that takes the place of the final unit in the application that handles
 * invocations from the command line.
 */
@Singleton()
export class CommandLineApplication extends Unit {
    /** The unit that was replaced by the CLI app. */
    private static replacement?: typeof Unit

    /** Set the replaced unit. */
    public static setReplacement(unitClass?: typeof Unit) {
        this.replacement = unitClass
    }

    /** Get the replaced unit. */
    public static getReplacement() {
        return this.replacement
    }

    @Inject()
    protected readonly cli!: CommandLine

    @Inject()
    protected readonly logging!: Logging

    constructor() { super() }

    public async up() {
        this.cli.registerDirective(UsageDirective)
        this.cli.registerDirective(ShellDirective)
        this.cli.registerDirective(TemplateDirective)
        this.cli.registerDirective(RunDirective)

        const argv = process.argv.slice(2)
        const match = this.cli.getDirectives()
            .map(dirCls => this.make<Directive>(dirCls))
            .firstWhere(dir => dir.matchesKeyword(argv[0]))

        if ( match ) {
            await match.invoke(argv.slice(1))
        } else {
            const usage = this.make<UsageDirective>(UsageDirective)
            await usage.handle(process.argv)
        }
    }
}