package com.ankurm.dbmigrations;

import java.io.IOException;
import java.io.UncheckedIOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.time.Instant;

/**
 * Writes a named transcript under {@code docs/output/} while the test that produced it runs.
 * Every console-line quoted in the companion article for this module comes from one of these
 * files, and the file is only ever written by a test assertion — never hand-typed.
 *
 * See docs/15-production-checklist.md for how this module's real output is regenerated.
 */
public final class Transcript {

    private static final Path OUTPUT_DIR = Paths.get("docs", "output");

    private final StringBuilder buffer = new StringBuilder();
    private final String name;

    private Transcript(String name) {
        this.name = name;
    }

    public static Transcript start(String name, String heading) {
        Transcript t = new Transcript(name);
        t.line("=".repeat(Math.min(78, heading.length() + 4)));
        t.line(heading);
        t.line("=".repeat(Math.min(78, heading.length() + 4)));
        t.line("captured: " + Instant.now());
        t.line("");
        return t;
    }

    public Transcript line(String text) {
        buffer.append(text).append(System.lineSeparator());
        System.out.println(text);
        return this;
    }

    public Transcript section(String title) {
        line("");
        line("-- " + title + " --");
        return this;
    }

    public void write() {
        try {
            Files.createDirectories(OUTPUT_DIR);
            Path target = OUTPUT_DIR.resolve(name + ".txt");
            Files.writeString(target, buffer.toString(), StandardOpenOption.CREATE,
                    StandardOpenOption.TRUNCATE_EXISTING);
        }
        catch (IOException ex) {
            throw new UncheckedIOException(ex);
        }
    }
}