use crate::dry_run::ShellScript;
use crate::ffmpeg::FFmpegCommand;
use std::io::Result;
use std::path::{Path, PathBuf};
use std::fs;

pub fn merge_video_and_audio(video_path: &Path, audio_path: &Path, dry_run: bool, overwrite: bool) -> Result<PathBuf> {
    let origin_video_extension = video_path.extension().unwrap().to_str().unwrap();
    let origin_filename = format!("original.{}", &origin_video_extension);
    let origin_path = video_path.parent().unwrap().join(origin_filename);
    let output_path = video_path.with_extension("mp4");

    if dry_run {
        let mut script = ShellScript::new();
        script.add_comment("Rename original video file");
        script.add_variable("VIDEO_BACKUP", &origin_path);
        script.add_variable("VIDEO_OUTPUT", &output_path);
        script.add_command("mv \"$VIDEO_FILE\" \"$VIDEO_BACKUP\"");
        script.add_empty_line();
        script.add_comment("Merge video and audio");
        crate::dry_run::print_shell_script(&script);
        FFmpegCommand::new()
            .overwrite(overwrite)
            .input_var("VIDEO_BACKUP")
            .input_var("AUDIO_AAC")
            .codec("copy")
            .output_var("VIDEO_OUTPUT")
            .execute(true)?;
        return Ok(output_path);
    }

    println!("Renaming original video: {} -> {}", video_path.display(), origin_path.display());
    fs::rename(video_path, &origin_path)?;

    println!("Merging video and audio:");
    println!("  Video: {}", origin_path.display());
    println!("  Audio: {}", audio_path.display());
    println!("  Output: {}", output_path.display());
    FFmpegCommand::new()
        .overwrite(overwrite)
        .input(&origin_path)
        .input(audio_path)
        .codec("copy")
        .output(&output_path)
        .execute(false)?;

    println!("Merge completed: {}", output_path.display());
    Ok(output_path)
}