use crate::layout;
use crate::x11;

use xkbcommon::xkb;

#[derive(Debug, Clone)]
pub enum KeyKind {
    Normal,
    Shift,
    Level3,
    Lock,
    Control,
    Alt,
    Super,
}

#[derive(Debug, Clone)]
pub struct KeyEntry {
    pub labels: [[String; 4]; 4],
    pub kind: KeyKind,
    pub dead: [[bool; 4]; 4],
    pub pos: layout::KeyPos,
}

#[derive(Debug, Clone)]
pub struct KeyData {
    pub keys: Vec<KeyEntry>,
    pub layouts: Vec<String>,
    pub is_iso: bool,
}

fn dead_display(name: &str) -> &'static str {
    match name.to_lowercase().as_str() {
        "dead_grave" => "`",
        "dead_acute" => "'",
        "dead_circumflex" => "^",
        "dead_tilde" => "~",
        "dead_macron" => "-",
        "dead_breve" => "u",
        "dead_abovedot" => ".",
        "dead_diaeresis" => "\"",
        "dead_caron" => "v",
        "dead_cedilla" => ",",
        "dead_ogonek" => "~",
        "dead_doubleacute" => "\"",
        "dead_stroke" => "/",
        "dead_hook" => "?",
        "dead_horn" => "?",
        "dead_psili" => "'",
        "dead_dasia" => "'",
        "dead_iota" => "i",
        "dead_voiced_sound" => "\"",
        "dead_semivoiced_sound" => "o",
        _ => "?",
    }
}

fn keysym_to_display(sym: xkb::Keysym) -> String {
    let utf8 = xkb::keysym_to_utf8(sym);
    let trimmed = utf8.trim().to_string();
    if !trimmed.is_empty() {
        let name = xkb::keysym_get_name(sym);
        if name.to_lowercase().starts_with("dead_") {
            return dead_display(&name).to_string();
        }
        return trimmed;
    }
    let name = xkb::keysym_get_name(sym);
    if name.to_lowercase().starts_with("dead_") {
        return dead_display(&name).to_string();
    }
    match sym {
        xkb::Keysym::Shift_L | xkb::Keysym::Shift_R => "Shift".into(),
        xkb::Keysym::ISO_Level3_Shift => "AltGr".into(),
        xkb::Keysym::Control_L | xkb::Keysym::Control_R => "Ctrl".into(),
        xkb::Keysym::Alt_L | xkb::Keysym::Alt_R => "Alt".into(),
        xkb::Keysym::Super_L | xkb::Keysym::Super_R => "Super".into(),
        xkb::Keysym::Menu => "Menu".into(),
        xkb::Keysym::Caps_Lock => "Caps".into(),
        xkb::Keysym::Tab => "Tab".into(),
        xkb::Keysym::Return => "Enter".into(),
        xkb::Keysym::Escape => "Esc".into(),
        xkb::Keysym::BackSpace => "Bksp".into(),
        xkb::Keysym::space => " ".into(),
        xkb::Keysym::Delete => "Del".into(),
        xkb::Keysym::Insert => "Ins".into(),
        xkb::Keysym::Home => "Home".into(),
        xkb::Keysym::End => "End".into(),
        xkb::Keysym::Page_Up => "PgUp".into(),
        xkb::Keysym::Page_Down => "PgDn".into(),
        xkb::Keysym::Up => "^".into(),
        xkb::Keysym::Down => "v".into(),
        xkb::Keysym::Left => "<".into(),
        xkb::Keysym::Right => ">".into(),
        xkb::Keysym::KP_Enter => "Enter".into(),
        xkb::Keysym::Num_Lock => "Num".into(),
        xkb::Keysym::Scroll_Lock => "Scrl".into(),
        xkb::Keysym::Pause => "Pause".into(),
        xkb::Keysym::Print => "PrtSc".into(),
        _ => name,
    }
}

fn detect_key_kind(syms: &[xkb::Keysym]) -> KeyKind {
    for &sym in syms {
        match sym {
            xkb::Keysym::Shift_L | xkb::Keysym::Shift_R => return KeyKind::Shift,
            xkb::Keysym::ISO_Level3_Shift => return KeyKind::Level3,
            xkb::Keysym::Caps_Lock => return KeyKind::Lock,
            xkb::Keysym::Control_L | xkb::Keysym::Control_R => return KeyKind::Control,
            xkb::Keysym::Alt_L | xkb::Keysym::Alt_R => return KeyKind::Alt,
            xkb::Keysym::Super_L | xkb::Keysym::Super_R => return KeyKind::Super,
            _ => {}
        }
    }
    KeyKind::Normal
}

fn is_keysym_dead(sym: xkb::Keysym) -> bool {
    xkb::keysym_get_name(sym).to_lowercase().starts_with("dead_")
}

pub fn level_from_x11_modmask(mask: u16) -> usize {
    let shift = mask & 0x01 != 0;
    let altgr = mask & 0x80 != 0;
    match (shift, altgr) {
        (false, false) => 0,
        (true, false) => 1,
        (false, true) => 2,
        (true, true) => 3,
    }
}

struct RawKey {
    name: String,
    labels: [[String; 4]; 4],
    dead: [[bool; 4]; 4],
    kind: KeyKind,
}

fn detect_is_iso(model: &str, keymap_has_lsgt: bool) -> bool {
    if model.contains("105") || model.contains("102") || model.contains("98") {
        return true;
    }
    if model.contains("101") || model.contains("104") || model.contains("106") {
        return false;
    }
    keymap_has_lsgt
}

pub fn compile_keymap(names: &x11::RuleNames) -> Result<KeyData, String> {
    let context = xkb::Context::new(xkb::CONTEXT_NO_FLAGS);

    let options = Some(names.options.clone());

    let keymap = xkb::Keymap::new_from_names(
        &context,
        &names.rules,
        &names.model,
        &names.layout,
        &names.variant,
        options,
        xkb::KEYMAP_COMPILE_NO_FLAGS,
    )
    .ok_or_else(|| "failed to compile keymap".to_string())?;

    let num_groups = keymap.num_layouts() as usize;

    let layouts: Vec<String> = if names.layout.is_empty() || num_groups <= 1 {
        vec![if names.layout.is_empty() {
            "default".into()
        } else {
            names.layout.clone()
        }]
    } else {
        let layout_parts: Vec<&str> = names.layout.split(',').collect();
        let variant_parts: Vec<&str> = if names.variant.is_empty() {
            vec![]
        } else {
            names.variant.split(',').collect()
        };
        layout_parts
            .iter()
            .enumerate()
            .map(|(i, l)| {
                let v = variant_parts.get(i).filter(|v| !v.is_empty());
                match v {
                    Some(v) => format!("{}({})", l, v),
                    None => l.to_string(),
                }
            })
            .collect()
    };

    layout::reset_default_pos();

    let mut raw = Vec::new();
    let mut has_lsgt = false;

    keymap.key_for_each(|km, kc| {
        let name = match km.key_get_name(kc) {
            Some(n) => n.to_string(),
            None => return,
        };

        if name == "LSGT" {
            has_lsgt = true;
        }

        let mut labels: [[String; 4]; 4] = Default::default();
        let mut dead = [[false; 4]; 4];
        let mut all_syms = Vec::new();

        for group in 0..num_groups.min(4) {
            for level in 0..4_u32 {
                let syms = km.key_get_syms_by_level(kc, group as u32, level);
                let li = level as usize;
                if syms.is_empty() {
                    labels[group][li] = String::new();
                } else {
                    let display: Vec<String> =
                        syms.iter().map(|&s| keysym_to_display(s)).collect();
                    labels[group][li] = display.join(" ");
                    dead[group][li] = syms.iter().any(|&s| is_keysym_dead(s));
                    all_syms.extend_from_slice(syms);
                }
            }
        }

        let kind = detect_key_kind(&all_syms);

        raw.push(RawKey { name, labels, dead, kind });
    });

    let is_iso = detect_is_iso(&names.model, has_lsgt);

    let keys: Vec<KeyEntry> = raw
        .into_iter()
        .filter(|k| !(k.name == "LSGT" && !is_iso))
        .map(|k| KeyEntry {
            pos: layout::resolve_position(&k.name, is_iso),
            labels: k.labels,
            dead: k.dead,
            kind: k.kind,
        })
        .collect();

    Ok(KeyData {
        keys,
        layouts,
        is_iso,
    })
}