/*
 * Copyright (C) 2024 Jonni Liljamo <jonni@liljamo.com>
 *
 * This file is licensed under GPL-3.0-or-later, see NOTICE and LICENSE for
 * more information.
 */

use std::collections::HashMap;

use fancy_regex::Regex;

pub struct MkvInfo {
    pub title: String,
    pub year: usize,
    pub file_name: String,
}

impl MkvInfo {
    pub fn new(mkv: &matroska::Matroska, file_name: &str) -> MkvInfo {
        let metadata_title = mkv.info.title.clone();
        let (guessed_title, guessed_year) =
            guess_title_and_release_year(file_name, &metadata_title.clone().unwrap_or_default());

        let title = inquire::Text::new("Enter the title:")
            .with_initial_value(&guessed_title)
            .prompt()
            .unwrap();

        let year = inquire::CustomType::<usize>::new("Please enter the release year:")
            .with_starting_input(&guessed_year)
            .prompt()
            .unwrap();

        // Find the default video and audio tracks, which are needed for parts of the filename.
        let mut default_video_track = mkv.video_tracks().find(|track| track.default);
        if default_video_track.is_none() {
            default_video_track = mkv.video_tracks().nth(0);
        }
        let default_video_track_settings = match &default_video_track.unwrap().settings {
            matroska::Settings::Video(video_settings) => video_settings,
            _ => panic!("default video track did not have video settings"),
        };

        let mut default_audio_track = mkv.audio_tracks().find(|track| track.default);
        if default_audio_track.is_none() {
            default_audio_track = mkv.audio_tracks().nth(0);
        }
        let default_audio_track_settings = match &default_audio_track.unwrap().settings {
            matroska::Settings::Audio(audio_settings) => audio_settings,
            _ => panic!("default video track did not have audio settings"),
        };

        // "{T}.{Y}.{S}.{R}.{SRC}.{VC}.{AC}.mkv"
        let mut recommended_file_name = String::new();

        // T: Title, with spaces replaced with periods and take out various special characters.
        recommended_file_name += &title
            .replace(" ", ".")
            .replace("'", "")
            .replace(":", "")
            .replace("-", "");

        // Y: Release year.
        recommended_file_name += &format!(".{}", year);

        // S: Special, e.g. directors cut or extended.
        if let Some(special) = get_special(file_name) {
            recommended_file_name += &format!(".{}", special);
        }

        // R: Resolution, e.g. 360p, 720p, 1080p, 2160p.
        recommended_file_name += &format!(".{}p", get_resolution(default_video_track_settings));

        // SRC: Source, one of: BluRay, DVD, WebDL, Unknown.
        recommended_file_name += &format!(".{}", get_source(file_name));

        // VC: Video codec, the default or first one.
        let default_video_track_codec_id = default_video_track.unwrap().codec_id.clone();
        match default_video_track_codec_id.as_str() {
            "V_MPEG4/ISO/AVC" => recommended_file_name += ".x264",
            "V_MPEGH/ISO/HEVC" => recommended_file_name += ".x265",
            _ => panic!("unhandled video codec: '{}'", default_video_track_codec_id),
        }

        // AC: Audio codec, the default or first one.
        let default_audio_track_codec_id = default_audio_track.unwrap().codec_id.clone();
        match default_audio_track_codec_id.as_str() {
            "A_AAC" => recommended_file_name += ".AAC",
            "A_AC3" => recommended_file_name += ".DD",
            "A_EAC3" => recommended_file_name += ".DD+",
            "A_DTS" => recommended_file_name += ".DTS",
            _ => panic!("unhandled audio codec: '{}'", default_audio_track_codec_id),
        }

        match default_audio_track_settings.channels {
            0 => {} // Unknown
            2 => {} // Stereo, no need to mention
            6 => recommended_file_name += ".5.1",
            8 => recommended_file_name += ".7.1",
            _ => panic!(
                "unhandled amount of audio channels: '{}'",
                default_audio_track_settings.channels
            ),
        }

        // And last but not least, the file extension.
        recommended_file_name += ".mkv";

        // Last minute cleanup, e.g. double periods.
        recommended_file_name = recommended_file_name.replace("..", ".");

        let file_name = inquire::Text::new("File name:")
            .with_initial_value(&recommended_file_name)
            .prompt()
            .unwrap();

        MkvInfo {
            title,
            year,
            file_name,
        }
    }
}

/// Try to guess the title and release year from the file name and metadata title (if any).
fn guess_title_and_release_year(file_name: &str, metadata_title: &str) -> (String, String) {
    // !p at the end, because we don't want to match the resolution accidentally.
    let year_regex = Regex::new(r"\d{4}+(?!p)").unwrap();

    // First, let's find them from the file name.
    let mut fn_year_guess = String::new();
    let mut fn_title_guess = String::new();

    if let Some(year_match) = year_regex.find(file_name).unwrap() {
        // A possible year was found, great!
        fn_year_guess = year_match.as_str().to_string();
        // Now let's take all the text before it, and use that as the title guess.
        fn_title_guess = file_name[..year_match.start()]
            .replace(".", " ")
            .trim_end_matches("(") // Year might've been in parentheses
            .trim()
            .to_string();
    }

    // Second, let's find guesses from the metadata title, if one is set.
    let mut md_year_guess = String::new();
    let mut md_title_guess = String::new();

    if !metadata_title.is_empty() {
        // This is just slimmed down from the file name guessing.
        if let Some(year_match) = year_regex.find(metadata_title).unwrap() {
            md_year_guess = year_match.as_str().to_string();
            md_title_guess = metadata_title[..year_match.start()]
                .trim_end_matches("(") // Year might've been in parentheses
                .trim()
                .to_string();
        }
    }

    // Then let's decide which of each of these is correct.
    let mut year_guess = String::new();
    if !fn_year_guess.is_empty() && !md_year_guess.is_empty() {
        // Both were found, prefer metadata.
        year_guess = md_year_guess;
    } else if fn_year_guess.is_empty() && !md_year_guess.is_empty() {
        // Only metadata was found.
        year_guess = md_year_guess;
    } else if !fn_year_guess.is_empty() && md_year_guess.is_empty() {
        // Only file name was found.
        year_guess = fn_year_guess;
    }

    let mut title_guess = String::new();
    if !fn_title_guess.is_empty() && !md_title_guess.is_empty() {
        if fn_title_guess == md_title_guess {
            title_guess = md_title_guess;
        } else {
            let title_options = vec![md_title_guess, fn_title_guess];
            title_guess = inquire::Select::new("Which of these titles is better?", title_options)
                .prompt()
                .unwrap();
        }
    } else if fn_title_guess.is_empty() && !md_title_guess.is_empty() {
        // Only metadata was found.
        title_guess = md_title_guess;
    } else if !fn_title_guess.is_empty() && md_title_guess.is_empty() {
        // Only file name was found.
        title_guess = fn_title_guess;
    }

    (title_guess, year_guess)
}

/// Get possible special kind for the file.
///
/// Tries to guess it and place the cursor on the right option.
fn get_special(file_name: &str) -> Option<String> {
    // Map with special feature kind mapped to ways it could be written in the file name.
    let mut special_option_pairs = HashMap::new();
    special_option_pairs.insert("DIRECTORS.CUT", vec!["directors.cut", "directors cut"]);
    special_option_pairs.insert("EXTENDED", vec!["extended"]);
    special_option_pairs.insert("OPEN.MATTE", vec!["open.matte", "open matte"]);
    special_option_pairs.insert("REMASTERED", vec!["remastered"]);
    special_option_pairs.insert("RESTORED", vec!["restored"]);
    special_option_pairs.insert("THEATER", vec!["theater"]);
    special_option_pairs.insert("UNRATED", vec!["unrated"]);

    let mut special_matched = None;
    'outer: for (special_kind, options) in &special_option_pairs {
        for o in options {
            if file_name.to_lowercase().contains(o) {
                special_matched = Some(special_kind);
                break 'outer;
            }
        }
    }

    if inquire::Confirm::new("Is this a special feature?")
        .with_default(special_matched.is_some())
        .prompt()
        .unwrap()
    {
        let mut special_options = special_option_pairs
            .keys()
            .map(|key| key.to_string())
            .collect::<Vec<_>>();
        special_options.sort();

        let mut match_pos = 0;
        if let Some(special_kind) = special_matched {
            match_pos = special_options
                .iter()
                .position(|s| s == special_kind)
                .unwrap();
        }
        let special_ans = inquire::Select::new("What kind of special feature?", special_options)
            .with_starting_cursor(match_pos)
            .prompt();
        match special_ans {
            Ok(special) => Some(special),
            Err(_) => panic!("something went wrong while asking for special value"),
        }
    } else {
        None
    }
}

/// Get the resolution of the file.
fn get_resolution(video_settings: &matroska::Video) -> u64 {
    // NOTE: Kinda dumb logic to figure out a sane value for the resolution field.
    //       There's a lot of "theater aspect" content which is normal 1080p in width
    //       but has a height of like 1769. I still want that labeled 1080p.
    match video_settings.pixel_height {
        360 => 360,
        720 => 720,
        1080 => 1080,
        2160 => 2160,
        _ => match video_settings.pixel_width {
            480 => 360,
            1280 => 720,
            1920 => 1080,
            3840 => 2160,
            _ => video_settings.pixel_height,
        },
    }
}

/// Get the source of the file.
///
/// Tries to guess it and place the cursor on the right option.
fn get_source(file_name: &str) -> String {
    // Map with source kind mapped to ways it could be written in the file name.
    let mut source_option_pairs = HashMap::new();
    source_option_pairs.insert("BluRay", vec!["bluray", "blu.ray", "blu-ray"]);
    source_option_pairs.insert("DVD", vec!["dvd"]);
    source_option_pairs.insert("WebDL", vec!["webdl", "web.dl", "web-dl"]);
    source_option_pairs.insert("Unknown", vec![]);

    let mut source_matched = None;
    'outer: for (source_kind, options) in &source_option_pairs {
        for o in options {
            if file_name.to_lowercase().contains(o) {
                source_matched = Some(source_kind);
                break 'outer;
            }
        }
    }

    let mut source_options = source_option_pairs
        .keys()
        .map(|key| key.to_string())
        .collect::<Vec<_>>();
    source_options.sort();

    let mut match_pos = 0;
    if let Some(source_kind) = source_matched {
        match_pos = source_options
            .iter()
            .position(|s| s == source_kind)
            .unwrap();
    }

    inquire::Select::new("What is the source of this file?", source_options)
        .with_starting_cursor(match_pos)
        .prompt()
        .unwrap()
}