/*
 * MIT License
 *
 * Copyright (c) 2025 OpenCode
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <stdint.h>
#include "billing_face.h"
#include "watch.h"
#include "watch_utility.h"
#include "watch_common_display.h"
#include "watch_rtc.h"

// distant future for the background task: January 1, 2083.
// while the timer is running we schedule a task that will never fire, which
// keeps the watch from entering low energy mode and displaying stale data.
static const watch_date_time_t distant_future = {
    .unit = {0, 0, 0, 1, 1, 63}
};

#define BILLING_DEFAULT_RATE 2500 // 2500 monies/hour

// Billing math: RTC ticks at 128 Hz, rate in money, all 64-bit integer.
#define BILLING_TICKS_PER_HOUR (128u * 3600u)

static uint64_t billing_compute(uint32_t rate_money_per_hour, uint64_t elapsed_ticks) {
    return (uint64_t)rate_money_per_hour * elapsed_ticks / BILLING_TICKS_PER_HOUR;
}

// bottom display: money, saturated at 999999 when it no longer fits in 6 digits.
static uint32_t billing_display(uint64_t total) {
    return total > 999999u ? 999999u : (uint32_t)total;
}

// two most-significant digits of the rate
static uint32_t billing_rate_digits(uint32_t rate) {
    while (rate > 99) rate /= 10;
    return rate;
}

static inline void _button_beep(void) {
    if (movement_button_should_sound()) {
        watch_buzzer_play_note_with_volume(BUZZER_NOTE_C7, 50, movement_button_volume());
    }
}

static void _redraw(billing_state_t *state, rtc_counter_t now) {
    uint64_t elapsed = state->running ? ((uint64_t)now - (uint64_t)state->start_counter) : (uint64_t)state->paused_counter;
    uint64_t total_money = billing_compute(state->rate_money_per_hour, elapsed);

    // space-padded, not zero-padded — and full width, so stale digits clear
    char buf[8];
    sprintf(buf, "%6lu", (unsigned long)billing_display(total_money));
    watch_display_text(WATCH_POSITION_BOTTOM, buf);

    sprintf(buf, "%2lu", (unsigned long)billing_rate_digits(state->rate_money_per_hour));
    watch_display_text(WATCH_POSITION_TOP_RIGHT, buf);
}

static void _editor_inc_digit(billing_state_t *state) {
    uint32_t place = 1u;
    for (uint8_t i = state->cursor; i < 5; i++) place *= 10u;
    if (((state->rate_money_per_hour / place) % 10u) == 9) {
        state->rate_money_per_hour -= place * 9u; // 9 -> 0, no carry
    } else {
        state->rate_money_per_hour += place;
    }
}

static void _redraw_editor(billing_state_t *state, uint8_t subsecond) {
    uint32_t rate = state->rate_money_per_hour;
    char buf[14];
    sprintf(buf, "%06lu", (unsigned long)rate);
    watch_display_text(WATCH_POSITION_BOTTOM, buf);

    if (subsecond % 2) watch_display_character(' ', 4 + state->cursor);

    watch_display_text_with_fallback(WATCH_POSITION_TOP_LEFT, "RATE", "RA");
}

static void _show_bill_label(void) {
    watch_display_text_with_fallback(WATCH_POSITION_TOP_LEFT, "BILL", "BL");
}

static void _exit_editor(billing_state_t *state, rtc_counter_t now) {
    state->mode = 0;
    state->editor_quick = false;
    movement_request_tick_frequency(state->running ? 32 : 1);
    _show_bill_label();
    _redraw(state, now);
}

void billing_face_setup(uint8_t watch_face_index, void ** context_ptr) {
    (void) watch_face_index;
    if (*context_ptr == NULL) {
        *context_ptr = malloc(sizeof(billing_state_t));
        memset(*context_ptr, 0, sizeof(billing_state_t));
        billing_state_t *state = (billing_state_t *)*context_ptr;
        state->rate_money_per_hour = BILLING_DEFAULT_RATE;
    }
}

void billing_face_activate(void *context) {
    billing_state_t *state = (billing_state_t *)context;
    watch_clear_colon();
    _show_bill_label();
    movement_request_tick_frequency(state->running ? 32 : 1);
    if (state->running) {
        movement_schedule_background_task(distant_future);
    }
}

bool billing_face_loop(movement_event_t event, void *context) {
    billing_state_t *state = (billing_state_t *)context;
    rtc_counter_t now = watch_rtc_get_counter();

    switch (event.event_type) {
        case EVENT_ACTIVATE:
            if (state->mode == 1) _redraw_editor(state, 0);
            else _redraw(state, now);
            break;
        case EVENT_TICK:
            if (state->mode == 1) {
                if (state->editor_quick) _editor_inc_digit(state);
                _redraw_editor(state, event.subsecond);
            } else {
                _redraw(state, now);
            }
            break;
        case EVENT_ALARM_BUTTON_DOWN:
            if (state->mode == 1) {
                _button_beep();
                _editor_inc_digit(state);
                _redraw_editor(state, 0);
            } else {
                _button_beep();
                if (state->running) {
                    state->paused_counter = now - state->start_counter;
                    state->running = false;
                    movement_cancel_background_task();
                    movement_request_tick_frequency(1);
                } else {
                    state->start_counter = now - state->paused_counter;
                    state->running = true;
                    movement_request_tick_frequency(32);
                    movement_schedule_background_task(distant_future);
                }
                _redraw(state, now);
            }
            break;
        case EVENT_ALARM_LONG_PRESS:
            if (state->mode == 1) {
                state->editor_quick = true;
                movement_request_tick_frequency(8);
            }
            break;
        case EVENT_ALARM_LONG_UP:
            if (state->mode == 1) {
                state->editor_quick = false;
                movement_request_tick_frequency(4);
            }
            break;
        case EVENT_LIGHT_BUTTON_DOWN:
            if (state->mode == 1) {
                state->cursor = (uint8_t)((state->cursor + 1) % 6);
                _redraw_editor(state, 0);
            } else if (!state->running) {
                // reset the timer while stopped (matches the stopwatch face)
                state->start_counter = 0;
                state->paused_counter = 0;
                _redraw(state, now);
            }
            break;
        case EVENT_LIGHT_LONG_PRESS:
            if (state->mode == 1) {
                _exit_editor(state, now);
            } else {
                // enter the rate editor
                state->mode = 1;
                state->cursor = 0;
                state->saved_rate = state->rate_money_per_hour;
                state->editor_quick = false;
                movement_request_tick_frequency(4);
                _redraw_editor(state, 0);
            }
            break;
        case EVENT_MODE_BUTTON_UP:
            if (state->mode == 1) {
                // Mode confirms and exits the editor, staying on this face.
                _exit_editor(state, now);
                return true;
            }
            return movement_default_loop_handler(event);
        case EVENT_TIMEOUT:
            if (state->mode == 1) {
                // walked away mid-edit: discard the edit and leave the editor,
                // so we don't idle at 4 Hz forever with a half-entered rate
                state->rate_money_per_hour = state->saved_rate;
                _exit_editor(state, now);
            }
            // otherwise stay on screen, just like the stopwatch face
            break;
        case EVENT_LOW_ENERGY_UPDATE:
            if (state->mode == 0) {
                if (!state->running) {
                    // show a blank display so it's clear we're in sleep mode
                    watch_display_text(WATCH_POSITION_BOTTOM, "------");
                } else {
                    _redraw(state, now);
                }
            }
            break;
        default:
            return movement_default_loop_handler(event);
    }

    return true;
}

void billing_face_resign(void *context) {
    (void) context;
    movement_cancel_background_task();
    movement_request_tick_frequency(1);
}