// yt - A fully featured command line YouTube client
//
// Copyright (C) 2024 Benedikt Peetz <benedikt.peetz@b-peetz.de>
// SPDX-License-Identifier: GPL-3.0-or-later
//
// This file is part of Yt.
//
// You should have received a copy of the License along with this program.
// If not, see <https://www.gnu.org/licenses/gpl-3.0.txt>.

// The pyo3 `pyfunction` proc-macros call unsafe functions internally, which trigger this lint.
#![allow(unsafe_op_in_unsafe_fn)]
#![allow(clippy::missing_errors_doc)]

use std::env;
use std::io::stdout;
use std::{fs::File, io::Write};

use std::{path::PathBuf, sync::Once};

use crate::{duration::Duration, logging::setup_logging, wrapper::info_json::InfoJson};

use bytes::Bytes;
use log::{info, log_enabled, Level};
use pyo3::types::{PyString, PyTuple, PyTupleMethods};
use pyo3::{
    pyfunction,
    types::{PyAnyMethods, PyDict, PyDictMethods, PyList, PyListMethods, PyModule},
    wrap_pyfunction_bound, Bound, PyAny, PyResult, Python,
};
use serde::Serialize;
use serde_json::{Map, Value};
use url::Url;

pub mod duration;
pub mod logging;
pub mod wrapper;

#[cfg(test)]
mod tests;

/// Synchronisation helper, to ensure that we don't setup the logger multiple times
static SYNC_OBJ: Once = Once::new();

/// Add a logger to the yt-dlp options.
/// If you have an logger set (i.e. for rust), than this will log to rust
///
/// # Panics
/// This should never panic.
pub fn add_logger_and_sig_handler<'a>(
    opts: Bound<'a, PyDict>,
    py: Python<'_>,
) -> PyResult<Bound<'a, PyDict>> {
    setup_logging(py, "yt_dlp")?;

    let logging = PyModule::import_bound(py, "logging")?;
    let ytdl_logger = logging.call_method1("getLogger", ("yt_dlp",))?;

    // Ensure that all events are logged by setting the log level to NOTSET (we filter on rust's side)
    // Also use this static, to ensure that we don't configure the logger every time
    SYNC_OBJ.call_once(|| {
        // Disable the SIGINT (Ctrl+C) handler, python installs.
        // This allows the user to actually stop the application with Ctrl+C.
        // This is here because it can only be run in the main thread and this was here already.
        py.run_bound(
            "\
import signal
signal.signal(signal.SIGINT, signal.SIG_DFL)",
            None,
            None,
        )
        .expect("This code should always work");

        let config_opts = PyDict::new_bound(py);
        config_opts
            .set_item("level", 0)
            .expect("Setting this item should always work");

        logging
            .call_method("basicConfig", (), Some(&config_opts))
            .expect("This method exists");
    });

    // This was taken from `ytcc`, I don't think it is still applicable
    // ytdl_logger.setattr("propagate", false)?;
    // let logging_null_handler = logging.call_method0("NullHandler")?;
    // ytdl_logger.setattr("addHandler", logging_null_handler)?;

    opts.set_item("logger", ytdl_logger).expect("Should work");

    Ok(opts)
}

#[pyfunction]
#[allow(clippy::too_many_lines)]
#[allow(clippy::missing_panics_doc)]
#[allow(clippy::items_after_statements)]
#[allow(
    clippy::cast_possible_truncation,
    clippy::cast_sign_loss,
    clippy::cast_precision_loss
)]
pub fn progress_hook(py: Python<'_>, input: &Bound<'_, PyDict>) -> PyResult<()> {
    // Only add the handler, if the log-level is higher than Debug (this avoids covering debug
    // messages).
    // FIXME: We should actually just find a way to not cover printed messages. <2024-10-19>
    if log_enabled!(Level::Debug) {
        return Ok(());
    }

    // ANSI ESCAPE CODES Wrappers {{{
    // see: https://en.wikipedia.org/wiki/ANSI_escape_code#Control_Sequence_Introducer_commands
    const CSI: &str = "\x1b[";
    fn clear_whole_line() {
        print!("{CSI}2K");
    }
    fn move_to_col(x: usize) {
        print!("{CSI}{x}G");
    }
    // }}}

    let input: Map<String, Value> = serde_json::from_str(&json_dumps(
        py,
        input
            .downcast::<PyAny>()
            .expect("Will always work")
            .to_owned(),
    )?)
    .expect("Python should always produce valid json");

    macro_rules! get {
        (@interrogate $item:ident, $type_fun:ident, $get_fun:ident, $name:expr) => {{
            let a = $item.get($name).expect(concat!(
                "The field '",
                stringify!($name),
                "' should exist."
            ));

            if a.$type_fun() {
                a.$get_fun().expect(
                    "The should have been checked in the if guard, so unpacking here is fine",
                )
            } else {
                panic!(
                    "Value {} => \n{}\n is not of type: {}",
                    $name,
                    a,
                    stringify!($type_fun)
                );
            }
        }};

        ($type_fun:ident, $get_fun:ident, $name1:expr, $name2:expr) => {{
            let a = get! {@interrogate input, is_object, as_object, $name1};
            let b = get! {@interrogate a, $type_fun, $get_fun, $name2};
            b
        }};

        ($type_fun:ident, $get_fun:ident, $name:expr) => {{
            get! {@interrogate input, $type_fun, $get_fun, $name}
        }};
    }

    macro_rules! default_get {
        (@interrogate $item:ident, $default:expr, $get_fun:ident, $name:expr) => {{
            let a = if let Some(field) = $item.get($name) {
                field.$get_fun().unwrap_or($default)
            } else {
                $default
            };
            a
        }};

        ($get_fun:ident, $default:expr, $name1:expr, $name2:expr) => {{
            let a = get! {@interrogate input, is_object, as_object, $name1};
            let b = default_get! {@interrogate a, $default, $get_fun, $name2};
            b
        }};

        ($get_fun:ident, $default:expr, $name:expr) => {{
            default_get! {@interrogate input, $default, $get_fun, $name}
        }};
    }

    macro_rules! c {
        ($color:expr, $format:expr) => {
            format!("\x1b[{}m{}\x1b[0m", $color, $format)
        };
    }

    fn format_bytes(bytes: u64) -> String {
        let bytes = Bytes::new(bytes);
        bytes.to_string()
    }

    fn format_speed(speed: f64) -> String {
        #[allow(clippy::cast_possible_truncation, clippy::cast_sign_loss)]
        let bytes = Bytes::new(speed.floor() as u64);
        format!("{bytes}/s")
    }

    let get_title = |add_extension: bool| -> String {
        match get! {is_string, as_str, "info_dict", "ext"} {
            "vtt" => {
                format!(
                    "Subtitles ({})",
                    default_get! {as_str, "<No Subtitle Language>", "info_dict", "name"}
                )
            }
            title_extension @ ("webm" | "mp4" | "m4a") => {
                if add_extension {
                    format!(
                        "{} ({})",
                        default_get! { as_str, "<No title>", "info_dict", "title"},
                        title_extension
                    )
                } else {
                    default_get! { as_str, "<No title>", "info_dict", "title"}.to_owned()
                }
            }
            other => panic!("The extension '{other}' is not yet implemented"),
        }
    };

    match get! {is_string, as_str, "status"} {
        "downloading" => {
            let elapsed = default_get! {as_f64, 0.0f64, "elapsed"};
            let eta = default_get! {as_f64, 0.0, "eta"};
            let speed = default_get! {as_f64, 0.0, "speed"};

            let downloaded_bytes = get! {is_u64, as_u64, "downloaded_bytes"};
            let total_bytes = {
                let total_bytes = default_get!(as_u64, 0, "total_bytes");
                if total_bytes == 0 {
                    let maybe_estimate = default_get!(as_u64, 0, "total_bytes_estimate");

                    if maybe_estimate == 0 {
                        // The download speed should be in bytes per second and the eta in seconds.
                        // Thus multiplying them gets us the raw bytes (which were estimated by `yt_dlp`, from their `info.json`)
                        let bytes_still_needed = (speed * eta).ceil() as u64;

                        downloaded_bytes + bytes_still_needed
                    } else {
                        maybe_estimate
                    }
                } else {
                    total_bytes
                }
            };
            let percent: f64 = {
                if total_bytes == 0 {
                    100.0
                } else {
                    (downloaded_bytes as f64 / total_bytes as f64) * 100.0
                }
            };

            clear_whole_line();
            move_to_col(1);

            print!(
                "'{}' [{}/{} at {}] -> [{}/{} {}] ",
                c!("34;1", get_title(true)),
                c!("33;1", Duration::from(Some(elapsed))),
                c!("33;1", Duration::from(Some(eta))),
                c!("32;1", format_speed(speed)),
                c!("31;1", format_bytes(downloaded_bytes)),
                c!("31;1", format_bytes(total_bytes)),
                c!("36;1", format!("{:.02}%", percent))
            );
            stdout().flush()?;
        }
        "finished" => {
            println!("-> Finished downloading: '{}'", c!("34;1", get_title(true)));
        }
        "error" => {
            panic!("-> Error while downloading: {}", get_title(true))
        }
        other => unreachable!("'{other}' should not be a valid state!"),
    };

    Ok(())
}

pub fn add_hooks<'a>(opts: Bound<'a, PyDict>, py: Python<'_>) -> PyResult<Bound<'a, PyDict>> {
    if let Some(hooks) = opts.get_item("progress_hooks")? {
        let hooks = hooks.downcast::<PyList>()?;
        hooks.append(wrap_pyfunction_bound!(progress_hook, py)?)?;

        opts.set_item("progress_hooks", hooks)?;
    } else {
        // No hooks are set yet
        let hooks_list = PyList::new_bound(py, &[wrap_pyfunction_bound!(progress_hook, py)?]);

        opts.set_item("progress_hooks", hooks_list)?;
    }

    Ok(opts)
}

/// `extract_info(self, url, download=True, ie_key=None, extra_info=None, process=True, force_generic_extractor=False)`
///
/// Extract and return the information dictionary of the URL
///
/// Arguments:
/// @param url          URL to extract
///
/// Keyword arguments:
/// @param download     Whether to download videos
/// @param process      Whether to resolve all unresolved references (URLs, playlist items).
///                     Must be True for download to work
/// @param `ie_key`       Use only the extractor with this key
///
/// @param `extra_info`   Dictionary containing the extra values to add to the info (For internal use only)
/// @`force_generic_extractor`  Force using the generic extractor (Deprecated; use `ie_key`='Generic')
#[allow(clippy::unused_async)]
#[allow(clippy::missing_panics_doc)]
pub async fn extract_info(
    yt_dlp_opts: &Map<String, Value>,
    url: &Url,
    download: bool,
    process: bool,
) -> PyResult<InfoJson> {
    Python::with_gil(|py| {
        let opts = json_map_to_py_dict(yt_dlp_opts, py)?;

        let instance = get_yt_dlp(py, opts)?;
        let args = (url.as_str(),);

        let kwargs = PyDict::new_bound(py);
        kwargs.set_item("download", download)?;
        kwargs.set_item("process", process)?;

        let result = instance.call_method("extract_info", args, Some(&kwargs))?;

        // Remove the `<generator at 0xsome_hex>`, by setting it to null
        if !process {
            result.set_item("entries", ())?;
        }

        let result_str = json_dumps(py, result)?;

        if let Ok(confirm) = env::var("YT_STORE_INFO_JSON") {
            if confirm == "yes" {
                let mut file = File::create("output.info.json")?;
                write!(file, "{result_str}").unwrap();
            }
        }

        Ok(serde_json::from_str(&result_str)
            .expect("Python should be able to produce correct json"))
    })
}

/// # Panics
/// Only if python fails to return a valid URL.
pub fn unsmuggle_url(smug_url: &Url) -> PyResult<Url> {
    Python::with_gil(|py| {
        let utils = get_yt_dlp_utils(py)?;
        let url = utils
            .call_method1("unsmuggle_url", (smug_url.as_str(),))?
            .downcast::<PyTuple>()?
            .get_item(0)?;

        let url: Url = url
            .downcast::<PyString>()?
            .to_string()
            .parse()
            .expect("Python should be able to return a valid url");

        Ok(url)
    })
}

/// Download a given list of URLs.
/// Returns the paths they were downloaded to.
///
/// # Panics
/// Only if `yt_dlp` changes their `info_json` schema.
pub async fn download(
    urls: &[Url],
    download_options: &Map<String, Value>,
) -> PyResult<Vec<PathBuf>> {
    let mut out_paths = Vec::with_capacity(urls.len());

    for url in urls {
        info!("Started downloading url: '{}'", url);
        let info_json = extract_info(download_options, url, true, true).await?;

        // Try to work around yt-dlp type weirdness
        let result_string = if let Some(filename) = info_json.filename {
            filename
        } else {
            info_json.requested_downloads.expect("This must exist")[0]
                .filename
                .clone()
        };

        out_paths.push(result_string);
        info!("Finished downloading url: '{}'", url);
    }

    Ok(out_paths)
}

fn json_map_to_py_dict<'a>(
    map: &Map<String, Value>,
    py: Python<'a>,
) -> PyResult<Bound<'a, PyDict>> {
    let json_string = serde_json::to_string(&map).expect("This must always work");

    let python_dict = json_loads(py, json_string)?;

    Ok(python_dict)
}

fn json_dumps(py: Python<'_>, input: Bound<'_, PyAny>) -> PyResult<String> {
    //     json.dumps(yt_dlp.sanitize_info(input))

    let yt_dlp = get_yt_dlp(py, PyDict::new_bound(py))?;
    let sanitized_result = yt_dlp.call_method1("sanitize_info", (input,))?;

    let json = PyModule::import_bound(py, "json")?;
    let dumps = json.getattr("dumps")?;

    let output = dumps.call1((sanitized_result,))?;

    let output_str = output.extract::<String>()?;

    Ok(output_str)
}

fn json_loads_str<T: Serialize>(py: Python<'_>, input: T) -> PyResult<Bound<'_, PyDict>> {
    let string = serde_json::to_string(&input).expect("Correct json must be pased");

    json_loads(py, string)
}

fn json_loads(py: Python<'_>, input: String) -> PyResult<Bound<'_, PyDict>> {
    //     json.loads(input)

    let json = PyModule::import_bound(py, "json")?;
    let dumps = json.getattr("loads")?;

    let output = dumps.call1((input,))?;

    Ok(output
        .downcast::<PyDict>()
        .expect("This should always be a PyDict")
        .clone())
}

fn get_yt_dlp_utils(py: Python<'_>) -> PyResult<Bound<'_, PyAny>> {
    let yt_dlp = PyModule::import_bound(py, "yt_dlp")?;
    let utils = yt_dlp.getattr("utils")?;

    Ok(utils)
}
fn get_yt_dlp<'a>(py: Python<'a>, opts: Bound<'a, PyDict>) -> PyResult<Bound<'a, PyAny>> {
    // Unconditionally set a logger
    let opts = add_logger_and_sig_handler(opts, py)?;
    let opts = add_hooks(opts, py)?;

    let yt_dlp = PyModule::import_bound(py, "yt_dlp")?;
    let youtube_dl = yt_dlp.call_method1("YoutubeDL", (opts,))?;

    Ok(youtube_dl)
}