/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
//! Barebones Watch Face for Rust + Mynewt on PineTime Smart Watch
#![no_std]                              //  Don't link with standard Rust library, which is not compatible with embedded systems
#![feature(trace_macros)]               //  Allow macro tracing: `trace_macros!(true)`
#![feature(concat_idents)]              //  Allow `concat_idents!()` macro used in `coap!()` macro
#![feature(proc_macro_hygiene)]         //  Allow Procedural Macros like `run!()`
#![feature(exclusive_range_pattern)]    //  Allow ranges like `0..128` in `match` statements

pub use watchface;  //  Export the Watch Face Framework

use core::{
    fmt::Write,
    ptr,
};
use macros::strn;
use watchface::lvgl::mynewt::{
    result::*,
    Strn,
};
use watchface::lvgl::{
    self,
    core::obj,
    themes::theme,
    widgets::label,
};
use watchface::{
    BluetoothState,
    String,
    WatchFace,
    WatchFaceState,
    WatchFaceTime,
    new_string,
    to_strn,
};

///////////////////////////////////////////////////////////////////////////////
//  Watch Face Definition

/// Barebones Watch Face with no frills
pub struct BarebonesWatchFace {
    /// Label for Time: "12:34"
    pub time_label:      lvgl::Ptr,
    /// Label for Date: "MON 22 MAY 2020"
    pub date_label:      lvgl::Ptr,
    /// Label for Bluetooth State (Bluetooth Icon)
    pub bluetooth_label: lvgl::Ptr,
    /// Label for Power Indicator (Charging & Battery)
    pub power_label:     lvgl::Ptr,
}

impl WatchFace for BarebonesWatchFace {

    ///////////////////////////////////////////////////////////////////////////////
    //  Create Watch Face

    /// Create the widgets for the Watch Face
    fn new() -> MynewtResult<Self> {
        //  Get the active screen
        let screen = watchface::get_active_screen();

        //  Get the large title font for showing the time
        let title_font = theme::get_font_title() ? ;

        //  Create the widgets
        let watch_face = Self {
            //  Create a Label for Time: "00:00"
            time_label: {
                let lbl = label::create(screen, ptr::null()) ? ;  //  `?` will terminate the function in case of error
                label::set_long_mode(lbl, label::LV_LABEL_LONG_BREAK) ? ;
                label::set_text(     lbl, strn!("00:00")) ? ;     //  strn creates a null-terminated string
                obj::set_width(      lbl, 240) ? ;
                obj::set_height(     lbl, 200) ? ;
                label::set_align(    lbl, label::LV_LABEL_ALIGN_CENTER) ? ;
                obj::align(          lbl, screen, obj::LV_ALIGN_CENTER, 0, -30) ? ;
                obj::set_style_local_text_font(lbl, label::LV_LABEL_PART_MAIN, obj::LV_STATE_DEFAULT, title_font) ? ;  //  Use large title font
                lbl  //  Return the label as time_label
            },

            //  Create a Label for Date: "MON 22 MAY 2020"
            date_label: {
                let lbl = label::create(screen, ptr::null()) ? ;
                label::set_long_mode(lbl, label::LV_LABEL_LONG_BREAK) ? ;
                obj::set_width(      lbl, 200) ? ;
                obj::set_height(     lbl, 200) ? ;
                label::set_text(     lbl, strn!("")) ? ;  //  strn creates a null-terminated string
                label::set_align(    lbl, label::LV_LABEL_ALIGN_CENTER) ? ;
                obj::align(          lbl, screen, obj::LV_ALIGN_CENTER, 0, 40) ? ;
                lbl  //  Return the label as date_label
            },

            //  Create a Label for Bluetooth State
            bluetooth_label: {
                let lbl = label::create(screen, ptr::null()) ? ;
                obj::set_width(     lbl, 50) ? ;
                obj::set_height(    lbl, 80) ? ;
                label::set_text(    lbl, strn!("")) ? ;  //  strn creates a null-terminated string
                label::set_recolor( lbl, true) ? ;
                label::set_align(   lbl, label::LV_LABEL_ALIGN_LEFT) ? ;
                obj::align(         lbl, screen, obj::LV_ALIGN_IN_TOP_LEFT, 0, 0) ? ;
                lbl  //  Return the label as bluetooth_label
            },

            //  Create a Label for Power Indicator
            power_label: {
                let lbl = label::create(screen, ptr::null()) ? ;
                obj::set_width(    lbl, 80) ? ;
                obj::set_height(   lbl, 20) ? ;
                label::set_text(   lbl, strn!("")) ? ;  //  strn creates a null-terminated string
                label::set_recolor(lbl, true) ? ;
                label::set_align(  lbl, label::LV_LABEL_ALIGN_RIGHT) ? ;
                obj::align(        lbl, screen, obj::LV_ALIGN_IN_TOP_RIGHT, 0, 0) ? ;
                lbl  //  Return the label as power_label
            },
        };
        //  Return the watch face
        Ok(watch_face)
    }

    ///////////////////////////////////////////////////////////////////////////////
    //  Update Watch Face

    /// Update the widgets in the Watch Face with the current state
    fn update(&mut self, state: &WatchFaceState) -> MynewtResult<()> {
        //  Populate the Time and Date Labels
        self.update_date_time(state) ? ;

        //  Populate the Bluetooth Label
        self.update_bluetooth(state) ? ;

        //  Populate the Power Label
        self.update_power(state) ? ;
        Ok(())
    }
}

impl BarebonesWatchFace {

    ///////////////////////////////////////////////////////////////////////////////
    //  Update Watch Face

    /// Populate the Time and Date Labels with the time and date
    fn update_date_time(&self, state: &WatchFaceState) -> MynewtResult<()> {
        //  Format the time as "12:34" and set the label
        let mut buf = new_string();
        write!(
            &mut buf,         //  Write the formatted text
            "{:02}:{:02}\0",  //  Must terminate Rust strings with null
            state.time.hour,
            state.time.minute
        ).expect("time fail");

        label::set_text(      //  Set the label
            self.time_label, 
            &to_strn(&buf)
        ) ? ;

        //  Get the short day name and short month name
        let day   = get_day_name(&state.time);
        let month = get_month_name(&state.time);

        //  Format the date as "MON 22 MAY 2020" and set the label
        let mut buf = new_string();
        write!(
            &mut buf,           //  Write the formatted text
            "{} {} {} {}\n\0",  //  Must terminate Rust strings with null
            day,
            state.time.day,
            month,
            state.time.year
        ).expect("date fail");

        label::set_text(        //  Set the label
            self.date_label, 
            &to_strn(&buf)
        ) ? ;
        Ok(())
    }    
    
    /// Populate the Bluetooth Label with the Bluetooth State (Bluetooth Icon)
    fn update_bluetooth(&self, state: &WatchFaceState) -> MynewtResult<()> {
        if state.bluetooth == BluetoothState::BLUETOOTH_STATE_DISCONNECTED {
            //  If Bluetooth is disconnected, leave the label empty
            label::set_text(
                self.bluetooth_label, 
                strn!("")
            ) ? ;
        } else {
            //  Compute the color of the Bluetooth icon
            let color = 
                match &state.bluetooth {
                    BluetoothState::BLUETOOTH_STATE_INACTIVE     => "#000000",  //  Black
                    BluetoothState::BLUETOOTH_STATE_ADVERTISING  => "#0000ff",  //  Blue
                    BluetoothState::BLUETOOTH_STATE_DISCONNECTED => "#ff0000",  //  Red
                    BluetoothState::BLUETOOTH_STATE_CONNECTED    => "#00ff00",  //  Green
                };

            //  Format the Bluetooth status and set the label
            let mut buf = new_string();
            write!(
                &mut buf,              //  Write the formatted text
                "{} \u{F293}#\0",      //  LV_SYMBOL_BLUETOOTH. Must terminate Rust strings with null.
                color
            ).expect("bt fail");

            label::set_text(           //  Set the label
                self.bluetooth_label, 
                &to_strn(&buf)
            ) ? ;
        }
        Ok(())
    }

    /// Populate the Power Label with the Power Indicator (Charging & Battery)
    fn update_power(&self, state: &WatchFaceState) -> MynewtResult<()> {
        //  Get the active screen
        let screen = watchface::get_active_screen();

        //  Compute the percentage power
        let percentage = convert_battery_voltage(state.millivolts);

        //  Compute the colour for the charging symbol
        let color =                                                     //  Charging color
            if percentage <= 20                        { "#f2495c" }    //  Low Battery
            else if state.powered && !(state.charging) { "#73bf69" }    //  Full Battery
            else                                       { "#fade2a" };   //  Mid Battery

        let symbol =                         //  Charging symbol
            if state.powered { "\u{F0E7}" }  //  LV_SYMBOL_CHARGE
            else             { " " };

        //  Format the Power Indicator and set the label
        let mut buf = new_string();
        write!(
            &mut buf,                    //  Write the formatted text
            "{} {}%{}#\nRUST ({}mV)\0",  //  Must terminate Rust strings with null
            color,
            percentage,
            symbol,
            state.millivolts
        ).expect("batt fail");

        label::set_text(
            self.power_label, 
            &to_strn(&buf)
        ) ? ; 
        obj::align(
            self.power_label, screen, 
            obj::LV_ALIGN_IN_TOP_RIGHT, 0, 0
        ) ? ;
        Ok(())
    }

}

///////////////////////////////////////////////////////////////////////////////
//  Date Time Functions

/// Get month short name
fn get_month_name(time: &WatchFaceTime) -> String {
    String::from(
        match time.month {
            1  => "JAN",
            2  => "FEB",
            3  => "MAR",
            4  => "APR",
            5  => "MAY",
            6  => "JUN",
            7  => "JUL",
            8  => "AUG",
            9  => "SEP",
            10 => "OCT",
            11 => "NOV",
            12 => "DEC",
            _  => "???",
        }    
    )
}

/// Get day short name
fn get_day_name(time: & WatchFaceTime) -> String {
    String::from(
        match time.day_of_week {
            0  => "SUN",
            1  => "MON",
            2  => "TUE",
            3  => "WED",
            4  => "THU",
            5  => "FRI",
            6  => "SAT",
            _  => "???",
        }
    )
}

///////////////////////////////////////////////////////////////////////////////
//  Battery Functions

/// Convert battery voltage to percentage
fn convert_battery_voltage(_voltage: u32) -> i32 {
    50  //  TODO
}