#include <stdio.h>
#include <string.h>
#include <limits.h>
#include "watch.h"
#include "movement.h"
#include "movement_config.h"

movement_state_t movement_state;
void * watch_face_contexts[MOVEMENT_NUM_FACES];
const int32_t movement_le_inactivity_deadlines[8] = {INT_MAX, 3600, 7200, 21600, 43200, 86400, 172800, 604800};
const int16_t movement_timeout_inactivity_deadlines[4] = {60, 120, 300, 1800};
movement_event_t event;

const int16_t movement_timezone_offsets[] = {
    -720,   //  0 : -12:00:00 (Baker Island Time)
    -660,   //  1 : -11:00:00 (Niue Time)
    -600,   //  2 : -10:00:00 (Hawaii-Aleutian Standard Time)
    -570,   //  3 :  -9:30:00 (Marquesas Islands Time)
    -540,   //  4 :  -9:00:00 (Alaska Standard Time)
    -480,   //  5 :  -8:00:00 (Pacific Standard Time)
    -420,   //  6 :  -7:00:00 (Mountain Standard Time)
    -360,   //  7 :  -6:00:00 (Central Standard Time)
    -300,   //  8 :  -5:00:00 (Eastern Standard Time)
    -270,   //  9 :  -4:30:00 (Venezuelan Standard Time)
    -240,   // 10 :  -4:00:00 (Atlantic Standard Time)
    -210,   // 11 :  -3:30:00 (Newfoundland Standard Time)
    -180,   // 12 :  -3:00:00 (Brasilia Time)
    -150,   // 13 :  -2:30:00 (Newfoundland Daylight Time)
    -120,   // 14 :  -2:00:00 (Fernando de Noronha Time)
    -60,    // 15 :  -1:00:00 (Azores Standard Time)
    0,      // 16 :   0:00:00 (UTC)
    60,     // 17 :   1:00:00 (Central European Time)
    120,    // 18 :   2:00:00 (South African Standard Time)
    180,    // 19 :   3:00:00 (Arabia Standard Time)
    210,    // 20 :   3:30:00 (Iran Standard Time)
    240,    // 21 :   4:00:00 (Georgia Standard Time)
    270,    // 22 :   4:30:00 (Afghanistan Time)
    300,    // 23 :   5:00:00 (Pakistan Standard Time)
    330,    // 24 :   5:30:00 (Indian Standard Time)
    345,    // 25 :   5:45:00 (Nepal Time)
    360,    // 26 :   6:00:00 (Kyrgyzstan time)
    390,    // 27 :   6:30:00 (Myanmar Time)
    420,    // 28 :   7:00:00 (Thailand Standard Time)
    480,    // 29 :   8:00:00 (China Standard Time, Australian Western Standard Time)
    525,    // 30 :   8:45:00 (Australian Central Western Standard Time)
    540,    // 31 :   9:00:00 (Japan Standard Time, Korea Standard Time)
    570,    // 32 :   9:30:00 (Australian Central Standard Time)
    600,    // 33 :  10:00:00 (Australian Eastern Standard Time)
    630,    // 34 :  10:30:00 (Lord Howe Standard Time)
    660,    // 35 :  11:00:00 (Solomon Islands Time)
    720,    // 36 :  12:00:00 (New Zealand Standard Time)
    765,    // 37 :  12:45:00 (Chatham Standard Time)
    780,    // 38 :  13:00:00 (Tonga Time)
    825,    // 39 :  13:45:00 (Chatham Daylight Time)
    840,    // 40 :  14:00:00 (Line Islands Time)
};

const char movement_valid_position_0_chars[] = " AaBbCcDdEeFGgHhIiJKLMNnOoPQrSTtUuWXYZ-='+\\/0123456789";
const char movement_valid_position_1_chars[] = " ABCDEFHlJLNORTtUX-='01378";

void cb_mode_btn_interrupt();
void cb_light_btn_interrupt();
void cb_alarm_btn_interrupt();
void cb_alarm_btn_extwake();
void cb_alarm_fired();
void cb_fast_tick();
void cb_tick();

static inline void _movement_reset_inactivity_countdown() {
    movement_state.le_mode_ticks = movement_le_inactivity_deadlines[movement_state.settings.bit.le_interval];
    movement_state.timeout_ticks = movement_timeout_inactivity_deadlines[movement_state.settings.bit.to_interval];
}

static inline void _movement_enable_fast_tick_if_needed() {
    if (!movement_state.fast_tick_enabled) {
        movement_state.fast_ticks = 0;
        watch_rtc_register_periodic_callback(cb_fast_tick, 128);
    }
}

static inline void _movement_disable_fast_tick_if_possible() {
    if ((movement_state.light_ticks == -1) && ((movement_state.light_down_timestamp + movement_state.mode_down_timestamp + movement_state.alarm_down_timestamp) == 0)) {
        movement_state.fast_tick_enabled = false;
        watch_rtc_disable_periodic_callback(128);
    }
}

void _movement_handle_background_tasks() {
    for(uint8_t i = 0; i < MOVEMENT_NUM_FACES; i++) {
        // For each face, if the watch face wants a background task...
        if (watch_faces[i].wants_background_task != NULL && watch_faces[i].wants_background_task(&movement_state.settings, watch_face_contexts[i])) {
            // ...we give it one. pretty straightforward!
            movement_event_t background_event = { EVENT_BACKGROUND_TASK, 0 };
            watch_faces[i].loop(background_event, &movement_state.settings, watch_face_contexts[i]);
        }
    }
    movement_state.needs_background_tasks_handled = false;
}

void movement_request_tick_frequency(uint8_t freq) {
    if (freq == 128) return; // Movement uses the 128 Hz tick internally
    RTC->MODE2.INTENCLR.reg = 0xFE; // disable all callbacks except the 128 Hz one
    movement_state.subsecond = 0;
    movement_state.tick_frequency = freq;
    watch_rtc_register_periodic_callback(cb_tick, freq);
}

void movement_illuminate_led() {
    if (movement_state.settings.bit.led_duration) {
        watch_set_led_color(movement_state.settings.bit.led_red_color ? (0xF | movement_state.settings.bit.led_red_color << 4) : 0,
                            movement_state.settings.bit.led_green_color ? (0xF | movement_state.settings.bit.led_green_color << 4) : 0);
        movement_state.light_ticks = (movement_state.settings.bit.led_duration * 2 - 1) * 128;
        _movement_enable_fast_tick_if_needed();
    }
}

void movement_move_to_face(uint8_t watch_face_index) {
    movement_state.watch_face_changed = true;
    movement_state.next_watch_face = watch_face_index;
}

void movement_move_to_next_face() {
    movement_move_to_face((movement_state.current_watch_face + 1) % MOVEMENT_NUM_FACES);
}

void app_init() {
    memset(&movement_state, 0, sizeof(movement_state));

    movement_state.settings.bit.led_green_color = 0xF;
    movement_state.settings.bit.button_should_sound = true;
    movement_state.settings.bit.le_interval = 1;
    movement_state.settings.bit.led_duration = 1;
    movement_state.settings.bit.time_zone = 16; // default to GMT
    movement_state.light_ticks = -1;
    _movement_reset_inactivity_countdown();
}

void app_wake_from_backup() {
    movement_state.settings.reg = watch_get_backup_data(0);
}

void app_setup() {
    watch_store_backup_data(movement_state.settings.reg, 0);

    static bool is_first_launch = true;

    if (is_first_launch) {
        for(uint8_t i = 0; i < MOVEMENT_NUM_FACES; i++) {
            watch_face_contexts[i] = NULL;
            is_first_launch = false;
        }

        // set up the 1 minute alarm (for background tasks and low power updates)
        watch_date_time alarm_time;
        alarm_time.reg = 0;
        alarm_time.unit.second = 59; // after a match, the alarm fires at the next rising edge of CLK_RTC_CNT, so 59 seconds lets us update at :00
        watch_rtc_register_alarm_callback(cb_alarm_fired, alarm_time, ALARM_MATCH_SS);
    }
    if (movement_state.le_mode_ticks != -1) {
        watch_disable_extwake_interrupt(BTN_ALARM);

        watch_enable_external_interrupts();
        watch_register_interrupt_callback(BTN_MODE, cb_mode_btn_interrupt, INTERRUPT_TRIGGER_BOTH);
        watch_register_interrupt_callback(BTN_LIGHT, cb_light_btn_interrupt, INTERRUPT_TRIGGER_BOTH);
        watch_register_interrupt_callback(BTN_ALARM, cb_alarm_btn_interrupt, INTERRUPT_TRIGGER_BOTH);

        watch_enable_buzzer();
        watch_enable_leds();
        watch_enable_display();

        movement_request_tick_frequency(1);

        for(uint8_t i = 0; i < MOVEMENT_NUM_FACES; i++) {
            watch_faces[i].setup(&movement_state.settings, &watch_face_contexts[i]);
        }

        watch_faces[movement_state.current_watch_face].activate(&movement_state.settings, watch_face_contexts[movement_state.current_watch_face]);
        event.subsecond = 0;
        event.event_type = EVENT_ACTIVATE;
    }
}

void app_prepare_for_standby() {
}

void app_wake_from_standby() {
}

bool app_loop() {
    if (movement_state.watch_face_changed) {
        if (movement_state.settings.bit.button_should_sound) {
            // low note for nonzero case, high note for return to watch_face 0
            watch_buzzer_play_note(movement_state.next_watch_face ? BUZZER_NOTE_C7 : BUZZER_NOTE_C8, 50);
        }
        watch_faces[movement_state.current_watch_face].resign(&movement_state.settings, watch_face_contexts[movement_state.current_watch_face]);
        movement_state.current_watch_face = movement_state.next_watch_face;
        watch_clear_display();
        watch_faces[movement_state.current_watch_face].activate(&movement_state.settings, watch_face_contexts[movement_state.current_watch_face]);
        event.subsecond = 0;
        event.event_type = EVENT_ACTIVATE;
        movement_state.watch_face_changed = false;
    }

    // if the LED should be off, turn it off
    if (movement_state.light_ticks == 0) {
        // unless the user is holding down the LIGHT button, in which case, give them more time.
        if (watch_get_pin_level(BTN_LIGHT)) {
            movement_state.light_ticks = 1;
        } else {
            watch_set_led_off();
            movement_state.light_ticks = -1;
            _movement_disable_fast_tick_if_possible();
        }
    }

    // handle background tasks, if the alarm handler told us we need to
    if (movement_state.needs_background_tasks_handled) _movement_handle_background_tasks();

    // if we have timed out of our low energy mode countdown, enter low energy mode.
    if (movement_state.le_mode_ticks == 0) {
        movement_state.le_mode_ticks = -1;
        watch_register_extwake_callback(BTN_ALARM, cb_alarm_btn_extwake, true);
        event.event_type = EVENT_NONE;
        event.subsecond = 0;

        // this is a little mini-runloop.
        // as long as le_mode_ticks is -1 (i.e. we are in low energy mode), we wake up here, update the screen, and go right back to sleep.
        while (movement_state.le_mode_ticks == -1) {
            // we also have to handle background tasks here in the mini-runloop
            if (movement_state.needs_background_tasks_handled) _movement_handle_background_tasks();

            event.event_type = EVENT_LOW_ENERGY_UPDATE;
            watch_faces[movement_state.current_watch_face].loop(event, &movement_state.settings, watch_face_contexts[movement_state.current_watch_face]);
            watch_enter_sleep_mode();
        }
        // as soon as le_mode_ticks is reset by the extwake handler, we bail out of the loop and reactivate ourselves.
        event.event_type = EVENT_ACTIVATE;
        // this is a hack tho: waking from sleep mode, app_setup does get called, but it happens before we have reset our ticks.
        // need to figure out if there's a better heuristic for determining how we woke up.
        app_setup();
    }

    static bool can_sleep = true;

    if (event.event_type) {
        event.subsecond = movement_state.subsecond;
        can_sleep = watch_faces[movement_state.current_watch_face].loop(event, &movement_state.settings, watch_face_contexts[movement_state.current_watch_face]);
        event.event_type = EVENT_NONE;
    }

    // if we have timed out of our timeout countdown, give the app a hint that they can resign.
    if (movement_state.timeout_ticks == 0) {
        event.event_type = EVENT_TIMEOUT;
        event.subsecond = movement_state.subsecond;
        watch_faces[movement_state.current_watch_face].loop(event, &movement_state.settings, watch_face_contexts[movement_state.current_watch_face]);
        event.event_type = EVENT_NONE;
    }

    event.subsecond = 0;

    return can_sleep && (movement_state.light_ticks == 0);
}

movement_event_type_t _figure_out_button_event(bool pin_level, movement_event_type_t button_down_event_type, uint8_t *down_timestamp) {
    if (pin_level) {
        // handle rising edge
        _movement_enable_fast_tick_if_needed();
        *down_timestamp = movement_state.fast_ticks + 1;
        return button_down_event_type;
    } else {
        // this line is hack but it handles the situation where the light button was held for more than 10 seconds.
        // fast tick is disabled by then, and the LED would get stuck on since there's no one left decrementing light_ticks.
        if (movement_state.light_ticks == 1) movement_state.light_ticks = 0;
        // now that that's out of the way, handle falling edge
        uint16_t diff = movement_state.fast_ticks - *down_timestamp;
        *down_timestamp = 0;
        _movement_disable_fast_tick_if_possible();
        // any press over a half second is considered a long press.
        if (diff > 64) return button_down_event_type + 2;
        else return button_down_event_type + 1;
    }
}

void cb_light_btn_interrupt() {
    bool pin_level = watch_get_pin_level(BTN_LIGHT);
    _movement_reset_inactivity_countdown();
    event.event_type = _figure_out_button_event(pin_level, EVENT_LIGHT_BUTTON_DOWN, &movement_state.light_down_timestamp);
}

void cb_mode_btn_interrupt() {
    bool pin_level = watch_get_pin_level(BTN_MODE);
    _movement_reset_inactivity_countdown();
    event.event_type = _figure_out_button_event(pin_level, EVENT_MODE_BUTTON_DOWN, &movement_state.mode_down_timestamp);
}

void cb_alarm_btn_interrupt() {
    bool pin_level = watch_get_pin_level(BTN_ALARM);
    _movement_reset_inactivity_countdown();
    event.event_type = _figure_out_button_event(pin_level, EVENT_ALARM_BUTTON_DOWN, &movement_state.alarm_down_timestamp);
}

void cb_alarm_btn_extwake() {
    // wake up!
    _movement_reset_inactivity_countdown();
}

void cb_alarm_fired() {
    movement_state.needs_background_tasks_handled = true;
}

void cb_fast_tick() {
    movement_state.fast_ticks++;
    if (movement_state.light_ticks > 0) movement_state.light_ticks--;
    // this is just a fail-safe; fast tick should be disabled as soon as the button is up and/or the LED times out.
    // but if for whatever reason it isn't, this forces the fast tick off after 10 seconds.
    if (movement_state.fast_ticks >= 1280) watch_rtc_disable_periodic_callback(128);
}

void cb_tick() {
    event.event_type = EVENT_TICK;
    watch_date_time date_time = watch_rtc_get_date_time();
    if (date_time.unit.second != movement_state.last_second) {
        // TODO: can we consolidate these two ticks?
        if (movement_state.settings.bit.le_interval && movement_state.le_mode_ticks > 0) movement_state.le_mode_ticks--;
        if (movement_state.timeout_ticks > 0) movement_state.timeout_ticks--;

        movement_state.last_second = date_time.unit.second;
        movement_state.subsecond = 0;
    } else {
        movement_state.subsecond++;
    }
}