// BLF LT1 PWM functions
// Copyright (C) 2023 Selene ToyKeeper
// SPDX-License-Identifier: GPL-3.0-or-later
#pragma once


void set_level_zero();

void set_level_ch1(uint8_t level);
void set_level_ch2(uint8_t level);
void set_level_both(uint8_t level);
void set_level_blend(uint8_t level);
//void set_level_auto(uint8_t level);  // redundant

#if 0  // gradual adjustments are disabled to save space
bool gradual_tick_ch1(uint8_t gt);
bool gradual_tick_ch2(uint8_t gt);
bool gradual_tick_both(uint8_t gt);
bool gradual_tick_blend(uint8_t gt);
//bool gradual_tick_auto(uint8_t gt);  // redundant
#endif


Channel channels[] = {
    { // channel 1 only
        .set_level    = set_level_ch1,
        //.gradual_tick = gradual_tick_ch1,
        .has_args     = 0
    },
    { // channel 2 only
        .set_level    = set_level_ch2,
        //.gradual_tick = gradual_tick_ch2,
        .has_args     = 0
    },
    { // both channels, tied together (max "200%" power)
        .set_level    = set_level_both,
        //.gradual_tick = gradual_tick_both,
        .has_args     = 0
    },
    { // both channels, manual blend (max "100%" power)
        .set_level    = set_level_blend,
        //.gradual_tick = gradual_tick_blend,
        .has_args     = 1
    },
    { // both channels, auto blend
        .set_level    = set_level_blend,
        //.gradual_tick = gradual_tick_blend,
        .has_args     = 1
    },
};

void set_level_zero() {
    // disable timer 0 overflow interrupt
    // (helps improve button press handling from Off state)
    TIMSK &= ~(1 << TOIE0);

    // turn off all LEDs
    ch1_dsm_lvl = 0;
    ch2_dsm_lvl = 0;
    CH1_PWM     = 0;
    CH2_PWM     = 0;
}

// wrap setting the dsm vars, to get a faster response
// (just setting *_dsm_lvl doesn't work well for strobes)
void set_hw_levels(PWM_DATATYPE ch1, PWM_DATATYPE ch2) {
    // set delta-sigma soft levels
    ch1_dsm_lvl = ch1;
    ch2_dsm_lvl = ch2;

    // set hardware PWM levels and init dsm loop
    CH1_PWM = ch1_pwm = ch1 >> 7;
    CH2_PWM = ch2_pwm = ch2 >> 7;

    // enable timer 0 overflow interrupt so DSM can work
    TIMSK |= (1 << TOIE0);
}

// delta-sigma modulation of PWM outputs
// happens on each Timer0 overflow (every 512 cpu clock cycles)
// uses 8-bit pwm w/ 7-bit dsm (0b 0PPP PPPP PDDD DDDD)
ISR(TIMER0_OVF_vect) {
    // set new hardware values first,
    // for best timing (reduce effect of interrupt jitter)
    CH1_PWM = ch1_pwm;
    CH2_PWM = ch2_pwm;

    // calculate next values, now that timing matters less

    // accumulate error
    ch1_dsm += (ch1_dsm_lvl & 0x007f);
    // next PWM = base PWM value + carry bit
    ch1_pwm  = (ch1_dsm_lvl >> 7) + (ch1_dsm > 0x7f);
    // clear carry bit
    ch1_dsm &= 0x7f;

    // repeat for other channels

    ch2_dsm += (ch2_dsm_lvl & 0x007f);
    ch2_pwm  = (ch2_dsm_lvl >> 7) + (ch2_dsm > 0x7f);
    ch2_dsm &= 0x7f;
}


void set_level_ch1(uint8_t level) {
    set_hw_levels(PWM_GET(pwm1_levels, level), 0);
}

void set_level_ch2(uint8_t level) {
    set_hw_levels(0, PWM_GET(pwm1_levels, level));
}

void set_level_both(uint8_t level) {
    PWM_DATATYPE pwm = PWM_GET(pwm1_levels, level);
    set_hw_levels(pwm, pwm);
}

void blend_helper(PWM_DATATYPE *warm, PWM_DATATYPE *cool, uint8_t level) {
    PWM_DATATYPE brightness = PWM_GET(pwm1_levels, level);
    uint8_t blend;
    if (channel_mode == CM_AUTO) {
        blend = 255 * (uint16_t)level / RAMP_SIZE;
        if (cfg.channel_mode_args[channel_mode] & 0b01000000)
            blend = 255 - blend;
    } else {
        blend = cfg.channel_mode_args[channel_mode];
    }

    calc_2ch_blend(warm, cool, brightness, DSM_TOP, blend);
}

void set_level_blend(uint8_t level) {
    PWM_DATATYPE warm, cool;
    blend_helper(&warm, &cool, level);
    set_hw_levels(warm, cool);
}

/*
void set_level_auto(uint8_t level) {
    PWM_DATATYPE warm, cool;
    blend_helper(&warm, &cool, level);
    set_hw_levels(warm, cool);
}
*/

///// "gradual tick" functions for smooth thermal regulation /////
// (and other smooth adjustments)

#if 0  // disabled to save space
///// bump each channel toward a target value /////
bool gradual_adjust(PWM_DATATYPE ch1, PWM_DATATYPE ch2) {
    // adjust multiple times based on current brightness
    // (so it adjusts faster/coarser when bright, slower/finer when dim)

    // higher shift = slower/finer adjustments
    const uint8_t shift = 9;  // ((255 << 7) >> 9) = 63 max
    uint8_t steps;

    steps = ch1_dsm_lvl >> shift;
    for (uint8_t i=0; i<=steps; i++)
        GRADUAL_ADJUST_SIMPLE(ch1, ch1_dsm_lvl);

    steps = ch2_dsm_lvl  >> shift;
    for (uint8_t i=0; i<=steps; i++)
        GRADUAL_ADJUST_SIMPLE(ch2, ch2_dsm_lvl);

    if ((ch1 == ch1_dsm_lvl)
     && (ch2 == ch2_dsm_lvl )) {
        return true;  // done
    }
    return false;  // not done yet
}

bool gradual_tick_ch1(uint8_t gt) {
    PWM_DATATYPE pwm = PWM_GET(pwm1_levels, gt);
    return gradual_adjust(pwm, 0);
}

bool gradual_tick_ch2(uint8_t gt) {
    PWM_DATATYPE pwm = PWM_GET(pwm1_levels, gt);
    return gradual_adjust(0, pwm);
}

bool gradual_tick_both(uint8_t gt) {
    PWM_DATATYPE pwm = PWM_GET(pwm1_levels, gt);
    return gradual_adjust(pwm, pwm);
}

bool gradual_tick_blend(uint8_t gt) {
    PWM_DATATYPE warm, cool;
    blend_helper(&warm, &cool, gt);
    return gradual_adjust(warm, cool);
}

/*
bool gradual_tick_auto(uint8_t gt) {
    PWM_DATATYPE warm, cool;
    blend_helper(&warm, &cool, gt);
    return gradual_adjust(warm, cool);
}
*/

#endif  // if 0