pub enum DocEntry {
    Section(&'static str),
    Topic(&'static str, &'static str),
}

use DocEntry::{Section, Topic};

pub const DOCS: &[DocEntry] = &[
    // Getting Started
    Section("Getting Started"),
    Topic("Welcome", include_str!("../../docs/welcome.md")),
    Topic("Moving Around", include_str!("../../docs/navigation.md")),
    Topic(
        "How Does It Work?",
        include_str!("../../docs/how_it_works.md"),
    ),
    Topic(
        "Banks & Patterns",
        include_str!("../../docs/banks_patterns.md"),
    ),
    Topic("Stage / Commit", include_str!("../../docs/staging.md")),
    Topic("Using the Sequencer", include_str!("../../docs/grid.md")),
    Topic("Editing a Step", include_str!("../../docs/editing.md")),
    // Forth fundamentals
    Section("Forth"),
    Topic("About Forth", include_str!("../../docs/about_forth.md")),
    Topic("The Dictionary", include_str!("../../docs/dictionary.md")),
    Topic("The Stack", include_str!("../../docs/stack.md")),
    Topic("Creating Words", include_str!("../../docs/definitions.md")),
    Topic("Control Flow", include_str!("../../docs/control_flow.md")),
    Topic("The Prelude", include_str!("../../docs/prelude.md")),
    Topic("Oddities", include_str!("../../docs/oddities.md")),
    // Audio Engine
    Section("Audio Engine"),
    Topic("Introduction", include_str!("../../docs/engine_intro.md")),
    Topic("Settings", include_str!("../../docs/engine_settings.md")),
    Topic("Sources", include_str!("../../docs/engine_sources.md")),
    Topic("Samples", include_str!("../../docs/engine_samples.md")),
    Topic("Wavetables", include_str!("../../docs/engine_wavetable.md")),
    Topic("Filters", include_str!("../../docs/engine_filters.md")),
    Topic(
        "Modulation",
        include_str!("../../docs/engine_modulation.md"),
    ),
    Topic(
        "Distortion",
        include_str!("../../docs/engine_distortion.md"),
    ),
    Topic("Space & Time", include_str!("../../docs/engine_space.md")),
    Topic(
        "Audio-Rate Mod",
        include_str!("../../docs/engine_audio_modulation.md"),
    ),
    Topic("Words & Sounds", include_str!("../../docs/engine_words.md")),
    // MIDI
    Section("MIDI"),
    Topic("Introduction", include_str!("../../docs/midi_intro.md")),
    Topic("MIDI Output", include_str!("../../docs/midi_output.md")),
    Topic("MIDI Input", include_str!("../../docs/midi_input.md")),
    // Tutorials
    Section("Tutorials"),
    Topic("Randomness", include_str!("../../docs/tutorial_randomness.md")),
    Topic(
        "Notes & Harmony",
        include_str!("../../docs/tutorial_harmony.md"),
    ),
    Topic(
        "Generators",
        include_str!("../../docs/tutorial_generators.md"),
    ),
    Topic("Timing with at", include_str!("../../docs/tutorial_at.md")),
    Topic("Using Variables", include_str!("../../docs/tutorial_variables.md")),
];

pub fn topic_count() -> usize {
    DOCS.iter().filter(|e| matches!(e, Topic(_, _))).count()
}

pub fn get_topic(index: usize) -> Option<(&'static str, &'static str)> {
    DOCS.iter()
        .filter_map(|e| match e {
            Topic(name, content) => Some((*name, *content)),
            Section(_) => None,
        })
        .nth(index)
}

pub fn find_match(query: &str) -> Option<(usize, usize)> {
    let query = query.to_lowercase();
    for (topic_idx, (_, content)) in DOCS
        .iter()
        .filter_map(|e| match e {
            Topic(name, content) => Some((*name, *content)),
            Section(_) => None,
        })
        .enumerate()
    {
        for (line_idx, line) in content.lines().enumerate() {
            if line.to_lowercase().contains(&query) {
                return Some((topic_idx, line_idx));
            }
        }
    }
    None
}