//! Minimal status LED driver for the CMDR keyboard.

use rp2040_hal::{
    gpio::AnyPin,
    pio::{PIO, PIOExt, StateMachineIndex, UninitStateMachine},
};
use smart_leds::{RGB8, SmartLedsWrite};
use ws2812_pio::Ws2812Direct;

const COLOR_OFF: RGB8 = RGB8 { r: 0, g: 0, b: 0 };
const COLOR_GREEN: RGB8 = RGB8 { r: 10, g: 7, b: 0 };
const COLOR_BLUE: RGB8 = RGB8 { r: 10, g: 4, b: 10 };
const COLOR_ORANGE: RGB8 = RGB8 { r: 5, g: 10, b: 0 };
const COLOR_RED: RGB8 = RGB8 { r: 20, g: 0, b: 0 };
const COLOR_PURPLE: RGB8 = RGB8 { r: 0, g: 10, b: 10 };
const BREATH_PERIOD_MS: u32 = 3200;

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum StatusMode {
    Off,
    Active,
    Idle,
    Suspended,
    Error,
    Bootloader,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct StatusSummary {
    pub caps_lock_active: bool,
    pub sticky_armed: bool,
    pub sticky_latched: bool,
    pub usb_initialized: bool,
    pub usb_active: bool,
    pub usb_suspended: bool,
    pub idle_mode: bool,
}

impl StatusSummary {
    pub const fn new(
        caps_lock_active: bool,
        sticky_armed: bool,
        sticky_latched: bool,
        usb_initialized: bool,
        usb_active: bool,
        usb_suspended: bool,
        idle_mode: bool,
    ) -> Self {
        Self {
            caps_lock_active,
            sticky_armed,
            sticky_latched,
            usb_initialized,
            usb_active,
            usb_suspended,
            idle_mode,
        }
    }
}

pub struct StatusLed<P, SM, I>
where
    I: AnyPin<Function = P::PinFunction>,
    P: PIOExt,
    SM: StateMachineIndex,
{
    ws2812_direct: Ws2812Direct<P, SM, I>,
    current_mode: StatusMode,
    mode_started_at: Option<u32>,
}

impl<P, SM, I> StatusLed<P, SM, I>
where
    I: AnyPin<Function = P::PinFunction>,
    P: PIOExt,
    SM: StateMachineIndex,
{
    pub fn new(
        pin: I,
        pio: &mut PIO<P>,
        sm: UninitStateMachine<(P, SM)>,
        clock_freq: fugit::HertzU32,
    ) -> Self {
        let mut led = Self {
            ws2812_direct: Ws2812Direct::new(pin, pio, sm, clock_freq),
            current_mode: StatusMode::Off,
            mode_started_at: None,
        };
        led.write_color(COLOR_OFF);
        led
    }

    pub fn update(&mut self, mode: StatusMode) {
        self.current_mode = mode;
        self.mode_started_at = None;
        let color = mode_color(mode, 0);
        self.write_color(color);
    }

    pub fn apply_summary(&mut self, summary: StatusSummary, current_time_ms: u32) {
        let mode = summary_to_mode(summary);
        let elapsed = if self.current_mode != mode {
            self.current_mode = mode;
            self.mode_started_at = Some(current_time_ms);
            0
        } else {
            let start = self.mode_started_at.unwrap_or(current_time_ms);
            current_time_ms.saturating_sub(start)
        };
        let base_color = mode_color(mode, elapsed);
        let color = highlight_color(summary).unwrap_or(base_color);
        self.write_color(color);
    }

    fn write_color(&mut self, color: RGB8) {
        let _ = self.ws2812_direct.write([color].iter().copied());
    }
}

fn summary_to_mode(summary: StatusSummary) -> StatusMode {
    if summary.usb_suspended {
        StatusMode::Suspended
    } else if !summary.usb_initialized {
        StatusMode::Off
    } else if summary.idle_mode {
        StatusMode::Idle
    } else if summary.usb_active {
        StatusMode::Active
    } else {
        StatusMode::Off
    }
}

fn highlight_color(summary: StatusSummary) -> Option<RGB8> {
    if summary.sticky_latched {
        Some(COLOR_PURPLE)
    } else if summary.sticky_armed {
        Some(COLOR_BLUE)
    } else if summary.caps_lock_active {
        Some(COLOR_ORANGE)
    } else {
        None
    }
}

fn mode_color(mode: StatusMode, elapsed_ms: u32) -> RGB8 {
    match mode {
        StatusMode::Off => COLOR_OFF,
        StatusMode::Active => COLOR_GREEN,
        StatusMode::Idle => breathe(COLOR_GREEN, elapsed_ms, BREATH_PERIOD_MS),
        StatusMode::Suspended => blink(COLOR_BLUE, elapsed_ms, 2000),
        StatusMode::Error => COLOR_RED,
        StatusMode::Bootloader => COLOR_PURPLE,
    }
}

fn blink(color: RGB8, elapsed_ms: u32, period_ms: u32) -> RGB8 {
    if period_ms == 0 {
        return color;
    }
    let phase = (elapsed_ms / (period_ms / 2).max(1)) % 2;
    if phase == 0 { color } else { COLOR_OFF }
}

fn breathe(color: RGB8, elapsed_ms: u32, period_ms: u32) -> RGB8 {
    if period_ms == 0 {
        return color;
    }
    let period = period_ms.max(1);
    let time_in_period = (elapsed_ms % period) as f32;
    let period_f = period as f32;
    let phase = time_in_period / period_f;
    let brightness = if phase < 0.5 {
        1.0 - (phase * 2.0)
    } else {
        (phase - 0.5) * 2.0
    };
    let clamped = brightness.max(0.0).min(1.0);
    let ramp = (clamped * 255.0 + 0.5) as u8;
    scale_color(color, ramp)
}

fn scale_color(color: RGB8, factor: u8) -> RGB8 {
    RGB8 {
        r: (u16::from(color.r) * u16::from(factor) / 255) as u8,
        g: (u16::from(color.g) * u16::from(factor) / 255) as u8,
        b: (u16::from(color.b) * u16::from(factor) / 255) as u8,
    }
}