#![allow(warnings)]

pub mod ffmpeg;
mod filter;

use self::filter::Filter;
use crate::{
	iotro::{intro, outro},
	render::ffmpeg::{Ffmpeg, FfmpegInput},
	time::{format_date, Time},
	Project, ProjectSourceMetadata, Resolution
};
use anyhow::{bail, Context};
use camino::{Utf8Path as Path, Utf8PathBuf as PathBuf};
use rational::Rational;
use std::{
	borrow::Cow,
	fs::{self, File},
	io::Write as _,
	process::{Command, Stdio}
};

const INTRO_LEN: Time = Time {
	seconds: 3,
	micros: 0
};
const OUTRO_LEN: Time = Time {
	seconds: 5,
	micros: 0
};
const TRANSITION: &str = "fadeblack";
const TRANSITION_LEN: Time = Time {
	seconds: 0,
	micros: 200_000
};

fn cmd() -> Command {
	let mut cmd = Command::new("busybox");
	cmd.arg("ash")
		.arg("-exuo")
		.arg("pipefail")
		.arg("-c")
		.arg("exec \"$0\" \"${@}\"");
	cmd
}

fn ffprobe() -> Command {
	let mut cmd = cmd();
	cmd.arg("ffprobe")
		.arg("-v")
		.arg("error")
		.arg("-of")
		.arg("default=noprint_wrappers=1:nokey=1");
	cmd
}

fn read_output(cmd: &mut Command) -> anyhow::Result<String> {
	let out = cmd.stderr(Stdio::inherit()).output()?;
	if !out.status.success() {
		bail!(
			"Executed command failed with exit status {:?}",
			out.status.code()
		);
	}
	String::from_utf8(out.stdout)
		.context("Command returned non-utf8 output")
		.map(|str| str.trim().into())
}

fn ffprobe_video(query: &str, input: &Path) -> anyhow::Result<String> {
	read_output(
		ffprobe()
			.arg("-select_streams")
			.arg("v:0")
			.arg("-show_entries")
			.arg(query)
			.arg(input)
	)
}

fn ffprobe_audio(query: &str, concat_input: &Path) -> anyhow::Result<String> {
	read_output(
		ffprobe()
			.arg("-select_streams")
			.arg("a:0")
			.arg("-show_entries")
			.arg(query)
			.arg("-safe")
			.arg("0")
			.arg("-f")
			.arg("concat")
			.arg(concat_input)
	)
}

pub(crate) struct Renderer<'a> {
	/// The directory with all the sources.
	directory: &'a Path,

	/// The slug (i.e. 23ws-malo2-231016).
	slug: String,
	/// The target directory.
	target: PathBuf
}

fn svg2mp4(svg: PathBuf, mp4: PathBuf, duration: Time) -> anyhow::Result<()> {
	let mut ffmpeg = Ffmpeg::new(mp4);
	ffmpeg.add_input(FfmpegInput {
		loop_input: true,
		..FfmpegInput::new(svg)
	});
	ffmpeg.add_filter(Filter::GenerateSilence {
		video: "0".into(),
		output: "out".into()
	});
	ffmpeg.set_filter_output("out");
	ffmpeg.set_duration(duration);
	ffmpeg.run()
}

fn svg2png(svg: &Path, png: &Path, size: usize) -> anyhow::Result<()> {
	let mut cmd = cmd();
	let size = size.to_string();
	cmd.arg("inkscape")
		.arg("-w")
		.arg(&size)
		.arg("-h")
		.arg(&size);
	cmd.arg(svg).arg("-o").arg(png);

	let status = cmd.status()?;
	if status.success() {
		Ok(())
	} else {
		bail!("inkscape failed with exit code {:?}", status.code())
	}
}

impl<'a> Renderer<'a> {
	pub(crate) fn new(directory: &'a Path, project: &Project) -> anyhow::Result<Self> {
		let slug = format!(
			"{}-{}",
			project.lecture.course,
			format_date(project.lecture.date)
		);
		let target = directory.join(&slug);
		fs::create_dir_all(&target)?;

		Ok(Self {
			directory,
			slug,
			target
		})
	}

	pub(crate) fn recording_mp4(&self) -> PathBuf {
		self.target.join("recording.mp4")
	}

	pub(crate) fn preprocess(&self, project: &mut Project) -> anyhow::Result<()> {
		assert!(!project.progress.preprocessed);

		let recording_txt = self.target.join("recording.txt");
		let mut file = File::create(&recording_txt)?;
		for filename in &project.source.files {
			writeln!(file, "file '{}'", self.directory.join(filename).to_string());
		}
		drop(file);

		println!("\x1B[1m ==> Concatenating Video and Normalising Audio ...\x1B[0m");
		let source_sample_rate =
			ffprobe_audio("stream=sample_rate", &recording_txt)?.parse()?;
		let recording_mp4 = self.recording_mp4();
		let mut ffmpeg = Ffmpeg::new(recording_mp4.clone());
		ffmpeg.add_input(FfmpegInput {
			concat: true,
			..FfmpegInput::new(recording_txt)
		});
		ffmpeg.enable_loudnorm();
		ffmpeg.run()?;

		let width = ffprobe_video("stream=width", &recording_mp4)?.parse()?;
		let height = ffprobe_video("stream=height", &recording_mp4)?.parse()?;
		let source_res = match (width, height) {
			(3840, 2160) => Resolution::UHD,
			(2560, 1440) => Resolution::WQHD,
			(1920, 1080) => Resolution::FullHD,
			(1280, 720) => Resolution::HD,
			(640, 360) => Resolution::nHD,
			(width, height) => bail!("Unknown resolution: {width}x{height}")
		};
		project.source.metadata = Some(ProjectSourceMetadata {
			source_duration: ffprobe_video("format=duration", &recording_mp4)?.parse()?,
			source_fps: ffprobe_video("stream=r_frame_rate", &recording_mp4)?.parse()?,
			source_tbn: ffprobe_video("stream=time_base", &recording_mp4)?.parse()?,
			source_res,
			source_sample_rate
		});

		println!("\x1B[1m ==> Preparing assets ...\x1B[0m");

		// render intro to svg then mp4
		let intro_svg = self.target.join("intro.svg");
		fs::write(
			&intro_svg,
			intro(source_res, project.lecture.date)
				.to_string_pretty()
				.into_bytes()
		)?;
		let intro_mp4 = self.target.join("intro.mp4");
		svg2mp4(intro_svg, intro_mp4, Time {
			seconds: 3,
			micros: 0
		})?;

		// render outro to svg then mp4
		let outro_svg = self.target.join("outro.svg");
		fs::write(
			&outro_svg,
			outro(source_res).to_string_pretty().into_bytes()
		)?;
		let outro_mp4 = self.target.join("outro.mp4");
		svg2mp4(outro_svg, outro_mp4, Time {
			seconds: 5,
			micros: 0
		})?;

		// copy logo then render to png
		let logo_svg = self.target.join("logo.svg");
		fs::write(
			&logo_svg,
			include_bytes!(concat!(env!("CARGO_MANIFEST_DIR"), "/assets/logo.svg"))
		)?;
		let logo_png = self.target.join("logo.png");
		svg2png(&logo_svg, &logo_png, 150 * 1920 / source_res.width())?;

		// copy fastforward then render to png
		let fastforward_svg = self.target.join("fastforward.svg");
		fs::write(
			&fastforward_svg,
			include_bytes!(concat!(
				env!("CARGO_MANIFEST_DIR"),
				"/assets/fastforward.svg"
			))
		)?;
		let fastforward_png = self.target.join("fastforward.png");
		svg2png(
			&fastforward_svg,
			&fastforward_png,
			128 * 1920 / source_res.width()
		)?;

		Ok(())
	}

	pub(crate) fn render(&self, project: &mut Project) -> anyhow::Result<PathBuf> {
		let mut output = self.target.join(format!(
			"{}-{}p.mp4",
			self.slug,
			project.source.metadata.as_ref().unwrap().source_res.width()
		));
		let mut ffmpeg = Ffmpeg::new(output.clone());

		// add all of our inputs
		let intro = ffmpeg.add_input(FfmpegInput::new(self.target.join("intro.mp4")));
		let rec = ffmpeg.add_input(FfmpegInput::new(self.target.join("recording.mp4")));
		let outro = ffmpeg.add_input(FfmpegInput::new(self.target.join("outro.mp4")));
		let logo = ffmpeg.add_input(FfmpegInput::new(self.target.join("logo.png")));
		let ff = ffmpeg.add_input(FfmpegInput::new(self.target.join("fastforward.png")));

		let mut part1: Cow<'static, str> = intro.into();
		let mut part2: Cow<'static, str> = rec.into();
		let mut part3: Cow<'static, str> = outro.into();

		// trim the recording
		let rectrim = "rectrim";
		let start = project.source.start.unwrap();
		let duration = project.source.end.unwrap() - start;
		ffmpeg.add_filter(Filter::Trim {
			input: part2,
			start: Some(start),
			duration: Some(duration),
			output: rectrim.into()
		});
		part2 = rectrim.into();

		// TODO ff

		// TODO fade

		// concatenate everything
		let concat = "concat";
		ffmpeg.add_filter(Filter::Concat {
			inputs: vec![part1, part2, part3],
			n: 3,
			output: concat.into()
		});

		// overlay the logo
		let overlay = "overlay";
		ffmpeg.add_filter(Filter::Overlay {
			video_input: concat.into(),
			overlay_input: logo.into(),
			x: "main_w-overlay_w-130".into(),
			y: "main_h-overlay_h-65".into(),
			output: overlay.into()
		});

		// we're done :)
		ffmpeg.set_filter_output(overlay);
		ffmpeg.run()?;

		Ok(output)
	}
}