/**
 * Copyright (c) 2017-2018 Tara Keeling
 *				 2020 Philippe G.
 *				 2021 Mumpf and Harry1999
 * 
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <stdbool.h>
#include <esp_heap_caps.h>
#include <esp_log.h>

#include "gds.h"
#include "gds_private.h"

#define SHADOW_BUFFER
#define USE_IRAM
#define PAGE_BLOCK 2048
#define ENABLE_WRITE 0x2c
#define MADCTL_MX 0x40
#define TFT_RGB_BGR 0x08

#define min(a, b) (((a) < (b)) ? (a) : (b))

static char TAG[] = "ILI9341";

enum { ILI9341, ILI9341_24 }; //ILI9341_24 for future use...

struct PrivateSpace {
    uint8_t *iRAM, *Shadowbuffer;
    struct {
        uint16_t Height, Width;
    } Offset;
    uint8_t MADCtl, PageSize;
    uint8_t Model;
};

// Functions are not declared to minimize # of lines

static void WriteByte(struct GDS_Device* Device, uint8_t Data) { Device->WriteData(Device, &Data, 1); }

static void SetColumnAddress(struct GDS_Device* Device, uint16_t Start, uint16_t End) {
    uint32_t Addr = __builtin_bswap16(Start) | (__builtin_bswap16(End) << 16);
    Device->WriteCommand(Device, 0x2A);
    Device->WriteData(Device, (uint8_t*)&Addr, 4);
}

static void SetRowAddress(struct GDS_Device* Device, uint16_t Start, uint16_t End) {
    uint32_t Addr = __builtin_bswap16(Start) | (__builtin_bswap16(End) << 16);
    Device->WriteCommand(Device, 0x2B);
    Device->WriteData(Device, (uint8_t*)&Addr, 4);
}

static void Update16(struct GDS_Device* Device) {
    struct PrivateSpace* Private = (struct PrivateSpace*)Device->Private;

#ifdef SHADOW_BUFFER
    uint32_t *optr = (uint32_t*)Private->Shadowbuffer, *iptr = (uint32_t*)Device->Framebuffer;
    int FirstCol = Device->Width / 2, LastCol = 0, FirstRow = -1, LastRow = 0;

    for(int r = 0; r < Device->Height; r++) {
        // look for change and update shadow (cheap optimization = width is always a multiple of 2)
        for(int c = 0; c < Device->Width / 2; c++, iptr++, optr++) {
            if(*optr != *iptr) {
                *optr = *iptr;
                if(c < FirstCol) FirstCol = c;
                if(c > LastCol) LastCol = c;
                if(FirstRow < 0) FirstRow = r;
                LastRow = r;
            }
        }

        // wait for a large enough window - careful that window size might increase by more than a line at once !
        if(FirstRow < 0 || ((LastCol - FirstCol + 1) * (r - FirstRow + 1) * 4 < PAGE_BLOCK && r != Device->Height - 1)) continue;

        FirstCol *= 2;
        LastCol = LastCol * 2 + 1;
        SetRowAddress(Device, FirstRow + Private->Offset.Height, LastRow + Private->Offset.Height);
        SetColumnAddress(Device, FirstCol + Private->Offset.Width, LastCol + Private->Offset.Width);
        Device->WriteCommand(Device, ENABLE_WRITE);

        int ChunkSize = (LastCol - FirstCol + 1) * 2;

        // own use of IRAM has not proven to be much better than letting SPI do its copy
        if(Private->iRAM) {
            uint8_t* optr = Private->iRAM;
            for(int i = FirstRow; i <= LastRow; i++) {
                memcpy(optr, Private->Shadowbuffer + (i * Device->Width + FirstCol) * 2, ChunkSize);
                optr += ChunkSize;
                if(optr - Private->iRAM <= (PAGE_BLOCK - ChunkSize) && i < LastRow) continue;
                Device->WriteData(Device, Private->iRAM, optr - Private->iRAM);
                optr = Private->iRAM;
            }
        } else
            for(int i = FirstRow; i <= LastRow; i++) {
                Device->WriteData(Device, Private->Shadowbuffer + (i * Device->Width + FirstCol) * 2, ChunkSize);
            }

        FirstCol = Device->Width / 2;
        LastCol = 0;
        FirstRow = -1;
    }
#else
    // always update by full lines
    SetColumnAddress(Device, Private->Offset.Width, Device->Width - 1);

    for(int r = 0; r < Device->Height; r += min(Private->PageSize, Device->Height - r)) {
        int Height = min(Private->PageSize, Device->Height - r);

        SetRowAddress(Device, Private->Offset.Height + r, Private->Offset.Height + r + Height - 1);
        Device->WriteCommand(Device, ENABLE_WRITE);

        if(Private->iRAM) {
            memcpy(Private->iRAM, Device->Framebuffer + r * Device->Width * 2, Height * Device->Width * 2);
            Device->WriteData(Device, Private->iRAM, Height * Device->Width * 2);
        } else {
            Device->WriteData(Device, Device->Framebuffer + r * Device->Width * 2, Height * Device->Width * 2);
        }
    }
#endif
}

static void Update24(struct GDS_Device* Device) {
    struct PrivateSpace* Private = (struct PrivateSpace*)Device->Private;

#ifdef SHADOW_BUFFER
    uint16_t *optr = (uint16_t*)Private->Shadowbuffer, *iptr = (uint16_t*)Device->Framebuffer;
    int FirstCol = (Device->Width * 3) / 2, LastCol = 0, FirstRow = -1, LastRow = 0;

    for(int r = 0; r < Device->Height; r++) {
        // look for change and update shadow (cheap optimization = width always / by 2)
        for(int c = 0; c < (Device->Width * 3) / 2; c++, optr++, iptr++) {
            if(*optr != *iptr) {
                *optr = *iptr;
                if(c < FirstCol) FirstCol = c;
                if(c > LastCol) LastCol = c;
                if(FirstRow < 0) FirstRow = r;
                LastRow = r;
            }
        }

        // do we have enough to send (cols are divided by 3/2)
        if(FirstRow < 0 || ((((LastCol - FirstCol + 1) * 2) / 3) * (r - FirstRow + 1) * 4 < PAGE_BLOCK && r != Device->Height - 1)) continue;

        FirstCol = (FirstCol * 2) / 3;
        LastCol = (LastCol * 2 + 1) / 3;
        SetRowAddress(Device, FirstRow + Private->Offset.Height, LastRow + Private->Offset.Height);
        SetColumnAddress(Device, FirstCol + Private->Offset.Width, LastCol + Private->Offset.Width);
        Device->WriteCommand(Device, ENABLE_WRITE);

        int ChunkSize = (LastCol - FirstCol + 1) * 3;

        // own use of IRAM has not proven to be much better than letting SPI do its copy
        if(Private->iRAM) {
            uint8_t* optr = Private->iRAM;
            for(int i = FirstRow; i <= LastRow; i++) {
                memcpy(optr, Private->Shadowbuffer + (i * Device->Width + FirstCol) * 3, ChunkSize);
                optr += ChunkSize;
                if(optr - Private->iRAM <= (PAGE_BLOCK - ChunkSize) && i < LastRow) continue;
                Device->WriteData(Device, Private->iRAM, optr - Private->iRAM);
                optr = Private->iRAM;
            }
        } else
            for(int i = FirstRow; i <= LastRow; i++) {
                Device->WriteData(Device, Private->Shadowbuffer + (i * Device->Width + FirstCol) * 3, ChunkSize);
            }

        FirstCol = (Device->Width * 3) / 2;
        LastCol = 0;
        FirstRow = -1;
    }
#else
    // always update by full lines
    SetColumnAddress(Device, Private->Offset.Width, Device->Width - 1);

    for(int r = 0; r < Device->Height; r += min(Private->PageSize, Device->Height - r)) {
        int Height = min(Private->PageSize, Device->Height - r);

        SetRowAddress(Device, Private->Offset.Height + r, Private->Offset.Height + r + Height - 1);
        Device->WriteCommand(Device, ENABLE_WRITE);

        if(Private->iRAM) {
            memcpy(Private->iRAM, Device->Framebuffer + r * Device->Width * 3, Height * Device->Width * 3);
            Device->WriteData(Device, Private->iRAM, Height * Device->Width * 3);
        } else {
            Device->WriteData(Device, Device->Framebuffer + r * Device->Width * 3, Height * Device->Width * 3);
        }
    }
#endif
}

static void SetLayout(struct GDS_Device* Device, struct GDS_Layout* Layout) {
    struct PrivateSpace* Private = (struct PrivateSpace*)Device->Private;
    ESP_LOGI(TAG, "SetLayout 197 HFlip=%d VFlip=%d Rotate=%d (1=true)", Layout->HFlip, Layout->VFlip, Layout->Rotate);
    //        D/CX RDX WRX D17-8 D7 D6 D5 D4 D3  D2 D1 D0 HEX
    //Command   0   1   ↑    XX  0  0  1  1  0   1  1  0  36h
    //Parameter 1   1   ↑    XX  MY MX MV ML BGR MH 0  0  00
    //Orientation 0: MADCtl = 0x80  =   1000 0000 (MY=1)
    if((Device->Height) > (Device->Width)) { //Resolution = 320x240
        Private->MADCtl = (1 << 7);          // 0x80 = default (no Rotation an no Flip)
        if(Layout->HFlip) {                  //Flip Horizontal
            int a = Private->MADCtl;
            Private->MADCtl = (a ^ (1 << 7));
        }
        if(Layout->Rotate) { //Rotate 180 degr.
            int a = Private->MADCtl;
            a = (a ^ (1 << 7));
            Private->MADCtl = (a ^ (1 << 6));
        }
        if(Layout->VFlip) { //Flip Vertical
            int a = Private->MADCtl;
            Private->MADCtl = (a ^ (1 << 6));
        }
    } else {                        //Resolution = 240x320
        Private->MADCtl = (1 << 5); // 0x20 = default (no Rotation an no Flip)
        if(Layout->HFlip) {         //Flip Horizontal
            int a = Private->MADCtl;
            Private->MADCtl = (a ^ (1 << 6));
        }
        if(Layout->Rotate) { //Rotate 180 degr.
            int a = Private->MADCtl;
            a = (a ^ (1 << 7));
            Private->MADCtl = (a ^ (1 << 6));
        }
        if(Layout->VFlip) { //Flip Vertical
            int a = Private->MADCtl;
            Private->MADCtl = (a ^ (1 << 7));
        }
    }

    Private->MADCtl = Layout->ColorSwap ? (Private->MADCtl | (1 << 3)) : (Private->MADCtl & ~(1 << 3));

    ESP_LOGI(TAG, "SetLayout 255 Private->MADCtl=%hhu", Private->MADCtl);

    Device->WriteCommand(Device, 0x36);
    WriteByte(Device, Private->MADCtl);

    Device->WriteCommand(Device, Layout->Invert ? 0x21 : 0x20);

#ifdef SHADOW_BUFFER
    // force a full refresh (almost ...)
    memset(Private->Shadowbuffer, 0xAA, Device->FramebufferSize);
#endif
}

static void DisplayOn(struct GDS_Device* Device) { Device->WriteCommand(Device, 0x29); }  //DISPON =0x29
static void DisplayOff(struct GDS_Device* Device) { Device->WriteCommand(Device, 0x28); } //DISPOFF=0x28

static void SetContrast(struct GDS_Device* Device, uint8_t Contrast) {
    Device->WriteCommand(Device, 0x51);
    WriteByte(Device, Contrast);

    Device->SetContrast = NULL;
    GDS_SetContrast(Device, Contrast);
    Device->SetContrast = SetContrast; // 0x00 value means the lowest brightness and 0xFF value means the highest brightness.
}

static bool Init(struct GDS_Device* Device) {
    struct PrivateSpace* Private = (struct PrivateSpace*)Device->Private;
    int Depth = (Device->Depth + 8 - 1) / 8;

    Private->PageSize = min(8, PAGE_BLOCK / (Device->Width * Depth));

#ifdef SHADOW_BUFFER
    Private->Shadowbuffer = malloc(Device->FramebufferSize);
    memset(Private->Shadowbuffer, 0xFF, Device->FramebufferSize);
#endif
#ifdef USE_IRAM
    Private->iRAM = heap_caps_malloc((Private->PageSize + 1) * Device->Width * Depth, MALLOC_CAP_INTERNAL | MALLOC_CAP_DMA);
#endif

    ESP_LOGI(TAG, "ILI9341 with bit default-depth %u, page %u, iRAM %p", Device->Depth, Private->PageSize, Private->iRAM);

    // Sleepout + Booster
    Device->WriteCommand(Device, 0x11);

    // set flip modes & contrast
    GDS_SetContrast(Device, 0x7f);
    struct GDS_Layout Layout = {};
    Device->SetLayout(Device, &Layout);

    // set screen depth (16/18) *** INTERFACE PIXEL FORMAT: 0x66=18 bit; 0x55=16 bit
    Device->WriteCommand(Device, 0x3A);
    if(Private->Model == ILI9341_24)
        WriteByte(Device, Device->Depth == 24 ? 0x66 : 0x55);
    else
        WriteByte(Device, Device->Depth == 24 ? 0x66 : 0x55);

    ESP_LOGI(TAG, "ILI9341_Init 312 device-depth %u, 0x66/0x55=0x%X", Device->Depth, Device->Depth == 24 ? 0x66 : 0x55);

    // no Display Inversion (INVOFF=0x20 INVON=0x21)
    Device->WriteCommand(Device, 0x20);

    //Gamma Correction: Enable next two line and enabel one of the Test0x Section... or build you own 15 Parameter...
    Device->WriteCommand(Device, 0xF2);
    WriteByte(Device, 0x03); // 3Gamma Function: Disable = default (0x02), Enable (0x03)
    Device->WriteCommand(Device, 0x26);
    WriteByte(Device, 0x01); // Gamma curve selected (0x01, 0x02, 0x04, 0x08) - A maximum of 4 fixed gamma curves can be selected
    //Gamma Correction Test01
    Device->WriteCommand(Device, 0xE0); // Positive Gamma Correction (15 Parameter)
    WriteByte(Device, 0x0F);
    WriteByte(Device, 0x31);
    WriteByte(Device, 0x2B);
    WriteByte(Device, 0x0C);
    WriteByte(Device, 0x0E);
    WriteByte(Device, 0x08);
    WriteByte(Device, 0x4E);
    WriteByte(Device, 0xF1);
    WriteByte(Device, 0x37);
    WriteByte(Device, 0x07);
    WriteByte(Device, 0x10);
    WriteByte(Device, 0x03);
    WriteByte(Device, 0x0E);
    WriteByte(Device, 0x09);
    WriteByte(Device, 0x00);
    Device->WriteCommand(Device, 0xE1); // Negative Gamma Correction (15 Parameter)
    WriteByte(Device, 0x00);
    WriteByte(Device, 0x0E);
    WriteByte(Device, 0x14);
    WriteByte(Device, 0x03);
    WriteByte(Device, 0x11);
    WriteByte(Device, 0x07);
    WriteByte(Device, 0x31);
    WriteByte(Device, 0xC1);
    WriteByte(Device, 0x48);
    WriteByte(Device, 0x08);
    WriteByte(Device, 0x0F);
    WriteByte(Device, 0x0C);
    WriteByte(Device, 0x31);
    WriteByte(Device, 0x36);
    WriteByte(Device, 0x0F);

    // gone with the wind
    Device->DisplayOn(Device);
    Device->Update(Device);

    return true;
}

static const struct GDS_Device ILI9341_X = {
    .DisplayOn = DisplayOn,
    .DisplayOff = DisplayOff,
    .SetLayout = SetLayout,
    .Update = Update16,
    .Init = Init,
    .Mode = GDS_RGB565,
    .Depth = 16,
};

struct GDS_Device* ILI9341_Detect(sys_display_config* Driver, struct GDS_Device* Device) {
    uint8_t Model;
    int Depth = 16; // 16bit colordepth

    if(Driver->common.driver == sys_display_drivers_ILI9341)
        Model = ILI9341;
    else if(Driver->common.driver == sys_display_drivers_ILI9341_24)
        Model = ILI9341_24;
    else
        return NULL;

    if(!Device) Device = calloc(1, sizeof(struct GDS_Device));

    *Device = ILI9341_X;
    Depth = Driver->common.bitDepth != 0 ? Driver->common.bitDepth : Depth;
    struct PrivateSpace* Private = (struct PrivateSpace*)Device->Private;
    Private->Model = Model;
    ESP_LOGI(TAG, "ILI9341_Detect 391 Driver= %s   Depth=%d", Model == ILI9341 ? "ILI9341" : "ILI9341_24", Depth);

    if(Depth == 18) {
        Device->Mode = GDS_RGB888;
        Device->Depth = 24;
        Device->Update = Update24;
    }

    if(Model == ILI9341_24) Device->SetContrast = SetContrast;

    return Device;
}