// Include Inkplate library to the sketch
#include "Inkplate.h"

// Including fonts
#include "Fonts/FreeSans12pt7b.h"
#include "Fonts/FreeSans9pt7b.h"

// Includes
#include <ctime>
#include <algorithm>
#include "Network.h"

char *ssid = "e-radionica.com";
char *pass = "croduino";
char *calendarURL = "https://calendar.google.com/calendar/ical/zvonimir3000%40gmail.com/private-bd11c7f112609813c4cd8e602de42f93/basic.ics";
int timeZone = 2;

// Delay between API calls
#define DELAY_MS 5000

// Variables to keep count of when to get new data, and when to just update time
int refreshes = 0;
const int refreshesToGet = 10;

// Initiate out Inkplate object
Inkplate display(INKPLATE_3BIT);

// Our networking functions, see Network.cpp for info
Network network;

// Variables for time and raw event info
char date[64];
char data[32000];

// For storing next 3 days info
char dates[32 * 3];

// Struct for storing calender event info
struct entry
{
    char name[128];
    char time[128];
    char location[128];
    int day;
    int timeStamp;
};

// Here we store calendar entries
int entriesNum = 0;
entry entries[128];

// Function for drawing calendar info
void drawInfo()
{
    // Setting font and color
    display.setTextColor(0, 7);
    display.setFont(&FreeSans12pt7b);
    display.setTextSize(1);

    display.setCursor(20, 20);

    // Find email in raw data
    char temp[64];
    char *start = strstr(data, "X-WR-CALNAME:");

    // If not found return
    if (!start)
        return;

    // Find where it ends
    start += 13;
    char *end = strchr(start, '\n');

    strncpy(temp, start, end - start - 1);
    temp[end - start - 1] = 0;

    // Print it
    display.println(temp);
}

// Drawing what time it is
void drawTime()
{
    // Initial text settings
    display.setTextColor(0, 7);
    display.setFont(&FreeSans12pt7b);
    display.setTextSize(1);

    display.setCursor(423, 20);

    // Our function to get time
    network.getTime(date);

    int t = date[16];
    date[16] = 0;
    display.println(date);
    date[16] = t;
}

// Draw lines in which to put events
void drawGrid()
{
    // upper left and low right coordinates
    int x1 = 3, y1 = 30;
    int x2 = 600 - 3, y2 = 798;

    // header size, for day info
    int header = 30;

    // Columns and rows
    int n = 1, m = 3;

    // Line drawing
    display.drawFastHLine(x1, y1 + header, x2 - x1, 0);
    for (int i = 0; i < n + 1; ++i)
    {
        display.drawFastHLine(x1, (int)((float)y1 + (float)i * (float)(y2 - y1) / (float)n), x2 - x1, 0);
    }
    for (int i = 0; i < m + 1; ++i)
    {
        display.drawFastVLine((int)((float)x1 + (float)i * (float)(x2 - x1) / (float)m), y1, y2 - y1, 0);
        display.setFont(&FreeSans9pt7b);

        // Display day info using time offset
        char temp[64];
        network.getTime(temp, i * 3600L * 24);
        temp[10] = 0;

        display.setCursor((int)((float)x1 + (float)i * (float)(x2 - x1) / (float)m) + 15, y1 + header - 6);
        display.println(temp);
    }
}

// Format event times, example 13:00 to 14:00
void getToFrom(char *dst, char *from, char *to, int *day, int *timeStamp)
{
    // ANSI C time struct
    struct tm ltm = {0}, ltm2 = {0};
    char temp[128], temp2[128];
    strncpy(temp, from, 16);
    temp[16] = 0;

    // https://github.com/esp8266/Arduino/issues/5141, quickfix
    memmove(temp + 5, temp + 4, 16);
    memmove(temp + 8, temp + 7, 16);
    memmove(temp + 14, temp + 13, 16);
    memmove(temp + 16, temp + 15, 16);
    temp[4] = temp[7] = temp[13] = temp[16] = '-';

    // time.h function
    strptime(temp, "%Y-%m-%dT%H-%M-%SZ", &ltm);

    // create start and end event structs
    struct tm event, event2;
    time_t epoch = mktime(&ltm) + (time_t)timeZone * 3600L;
    gmtime_r(&epoch, &event);
    strncpy(dst, asctime(&event) + 11, 5);

    dst[5] = '-';

    strncpy(temp2, to, 16);
    temp2[16] = 0;

    // Same as above

    // https://github.com/esp8266/Arduino/issues/5141, quickfix
    memmove(temp2 + 5, temp2 + 4, 16);
    memmove(temp2 + 8, temp2 + 7, 16);
    memmove(temp2 + 14, temp2 + 13, 16);
    memmove(temp2 + 16, temp2 + 15, 16);
    temp2[4] = temp2[7] = temp2[13] = temp2[16] = '-';

    strptime(temp2, "%Y-%m-%dT%H-%M-%SZ", &ltm2);

    time_t epoch2 = mktime(&ltm2) + (time_t)timeZone * 3600L;
    gmtime_r(&epoch2, &event2);
    strncpy(dst + 6, asctime(&event2) + 11, 5);

    dst[11] = 0;

    char day0[64], day1[64], day2[64];

    // Find UNIX timestamps for next days to see where to put event
    network.getTime(day0, 0);
    network.getTime(day1, 24 * 3600);
    network.getTime(day2, 48 * 3600);

    *timeStamp = epoch;

    network.getTime(temp);
    if (strncmp(day0, asctime(&event), 10) == 0)
        *day = 0;
    else if (strncmp(day1, asctime(&event), 10) == 0)
        *day = 1;
    else if (strncmp(day2, asctime(&event), 10) == 0)
        *day = 2;
    else // event not in next 3 days, don't display
        *day = -1;
}

// Function to drw event
bool drawEvent(entry *event, int day, int beginY, int maxHeigth, int *heigthNeeded)
{
    // Upper left coordintes
    int x1 = 3 + 4 + (594 / 3) * day;
    int y1 = beginY + 3;

    // Setting text font
    display.setFont(&FreeSans12pt7b);

    int n = 0;
    char line[128];

    // Insert line brakes into setTextColor
    int lastSpace = -100;
    display.setCursor(x1, beginY + 22);
    for (int i = 0; i < min((size_t)64, strlen(event->name)); ++i)
    {

        line[n] = event->name[i];
        if (line[n] == ' ')
            lastSpace = n;
        line[++n] = 0;

        int16_t xt1, yt1;
        uint16_t w, h;

        display.getTextBounds(line, 0, 0, &xt1, &yt1, &w, &h);

        // Char out of bounds, put in next line
        if (w > 590 / 3 - 20)
        {
            // if there was a space 5 chars before, break line there
            if (n - lastSpace < 5)
            {
                i -= n - lastSpace - 1;
                line[lastSpace] = 0;
            }

            display.setCursor(x1, display.getCursorY());
            display.println(line);

            line[0] = 0;
            n = 0;
        }
    }

    // display last line
    display.setCursor(x1, display.getCursorY());
    display.println(line);

    display.setCursor(x1, display.getCursorY());
    display.setFont(&FreeSans9pt7b);

    // Print time
    // also, if theres a location print it
    if (strlen(event->location) != 1)
    {
        display.println(event->time);

        display.setCursor(x1, display.getCursorY());
        display.print(event->location);
    }
    else
    {
        display.print(event->time);
    }

    // Draw event rect bounds
    display.drawRoundRect(x1 - 2, y1, 590 / 3 - 2, display.getCursorY() + 5 - y1, 10, 0);

    // Set how high is the event
    *heigthNeeded = display.getCursorY() + 10 - y1;

    // Return is it overflowing
    return display.getCursorY() < maxHeigth - 5;
}

// Struct event comparison function, by timestamp
int cmp(const void *a, const void *b)
{

    entry *entryA = (entry *)a;
    entry *entryB = (entry *)b;

    return (entryA->timeStamp - entryB->timeStamp);
}

// Main data drawing data
void drawData()
{
    long i = 0;
    long n = strlen(data);

    // reset count
    entriesNum = 0;

    // Search raw data for events
    while (i < n && strstr(data + i, "BEGIN:VEVENT"))
    {
        // Find next event start and end
        i = strstr(data + i, "BEGIN:VEVENT") - data + 12;
        char *end = strstr(data + i, "END:VEVENT");

        // Find all relevant event data
        char *summary = strstr(data + i, "SUMMARY:") + 8;
        char *location = strstr(data + i, "LOCATION:") + 9;
        char *timeStart = strstr(data + i, "DTSTART:") + 8;
        char *timeEnd = strstr(data + i, "DTEND:") + 6;

        if (summary && summary < end)
        {
            strncpy(entries[entriesNum].name, summary, strchr(summary, '\n') - summary);
            entries[entriesNum].name[strchr(summary, '\n') - summary] = 0;
        }
        if (location && location < end)
        {
            strncpy(entries[entriesNum].location, location, strchr(location, '\n') - location);
            entries[entriesNum].location[strchr(location, '\n') - location] = 0;
        }
        if (timeStart && timeStart < end && timeEnd < end)
        {
            getToFrom(entries[entriesNum].time, timeStart, timeEnd, &entries[entriesNum].day, &entries[entriesNum].timeStamp);
        }
        ++entriesNum;
    }

    // Sort entries by time
    qsort(entries,
          entriesNum,
          sizeof(entry),
          cmp);

    // Events displayed and overflown counters
    int columns[3] = {0};
    bool clogged[3] = {0};
    int cloggedCount[3] = {0};

    // Displaying events one by one
    for (int i = 0; i < entriesNum; ++i)
    {
        // If column overflowed just add event to not shown
        if (entries[i].day != -1 && clogged[entries[i].day])
            ++cloggedCount[entries[i].day];
        if (entries[i].day == -1 || clogged[entries[i].day])
            continue;

        // We store hot much height did one event take up
        int shift = 0;
        bool s = drawEvent(&entries[i], entries[i].day, columns[entries[i].day] + 64, 800 - 4, &shift);

        columns[entries[i].day] += shift;

        // If it overflowed, set column to clogged and add one event as not shown
        if (!s)
        {
            ++cloggedCount[entries[i].day];
            clogged[entries[i].day] = 1;
        }
    }

    // Display not shown events info
    for (int i = 0; i < 3; ++i)
    {
        if (clogged[i])
        {
            display.fillRoundRect(6 + i * (594 / 3), 800 - 24, (594 / 3) - 5, 20, 10, 0);
            display.setCursor(10, 800 - 6);
            display.setTextColor(7, 0);
            display.setFont(&FreeSans9pt7b);
            display.print(cloggedCount[i]);
            display.print(" more events");
        }
    }
}

void setup()
{
    Serial.begin(115200);

    // Initial display settings
    display.begin();

    display.clearDisplay();
    display.clean();
    display.setRotation(1);
    display.setTextWrap(false);
    display.setTextColor(0, 7);

    // Welcome screen
    display.setCursor(5, 230);
    display.setTextSize(2);
    display.println(F("Welcome to Inkplate 6 Google Calendar example!"));
    display.setCursor(5, 250);
    display.println(F("Connecting to WiFi..."));
    display.display();

    delay(5000);
    network.begin();
    // Our begin function
    network.begin();
}

void loop()
{
    // Keep trying to get data if it fails the first time
    if (refreshes % refreshesToGet == 0)
        while (!network.getData(data))
        {
            Serial.println("Failed getting data, retrying");
            delay(1000);
        }

    // Initial screen clearing
    display.clearDisplay();

    // Drawing all data, functions for that are above
    if (refreshes % refreshesToGet == 0)
    {
        drawInfo();
        drawGrid();
        drawData();
    }
    drawTime();

    // Actually display all data
    if (refreshes % refreshesToGet == 0)
        display.display();
    else
        display.partialUpdate();

    // Increment refreshes
    ++refreshes;

    // Go to sleep before checking again
    esp_sleep_enable_timer_wakeup(1000L * DELAY_MS);
    (void)esp_light_sleep_start();
}