#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <string>
#include <unistd.h>
#include "inverter.h"
#include "tools.h"
#include "main.h"

#include <fcntl.h>
#include <termios.h>

cInverter::cInverter(std::string devicename, int qpiri, int qpiws, int qmod, int qpigs) {
    device = devicename;
    status1[0] = 0;
    status2[0] = 0;
    warnings[0] = 0;
    mode = 0;
    buf_qpiri = qpiri;
    buf_qpiws = qpiws;
    buf_qmod = qmod;
    buf_qpigs = qpigs;
    lprintf("INVERTER: Initialized with buffer sizes - QPIRI:%d QPIWS:%d QMOD:%d QPIGS:%d", 
            buf_qpiri, buf_qpiws, buf_qmod, buf_qpigs);
}

string *cInverter::GetQpigsStatus() {
    m.lock();
    string *result = new string(status1);
    m.unlock();
    return result;
}

string *cInverter::GetQpiriStatus() {
    m.lock();
    string *result = new string(status2);
    m.unlock();
    return result;
}

string *cInverter::GetWarnings() {
    m.lock();
    string *result = new string(warnings);
    m.unlock();
    return result;
}

void cInverter::SetMode(char newmode) {
    m.lock();
    if (mode && newmode != mode)
        ups_status_changed = true;
    mode = newmode;
    m.unlock();
}

int cInverter::GetMode() {
    int result;
    m.lock();

    switch (mode) {
        case 'P': result = 1;   break;  // Power_On
        case 'S': result = 2;   break;  // Standby
        case 'L': result = 3;   break;  // Line
        case 'B': result = 4;   break;  // Battery
        case 'F': result = 5;   break;  // Fault
        case 'H': result = 6;   break;  // Power_Saving
        default:  result = 0;   break;  // Unknown
    }

    m.unlock();
    return result;
}

bool cInverter::query(const char *cmd, int replysize) {
    time_t started;
    int fd;
    int i=0, n;

    fd = open(this->device.data(), O_RDWR | O_NONBLOCK);
    if (fd == -1) {
        lprintf("INVERTER: Unable to open device file (errno=%d %s)", errno, strerror(errno));
        sleep(5);
        return false;
    }


    // Once connected, set the baud rate and other serial config (Don't rely on this being correct on the system by default...)
    speed_t baud = B2400;

    // Speed settings (in this case, 2400 8N1)
    struct termios settings;
    tcgetattr(fd, &settings);

    cfsetospeed(&settings, baud);      // baud rate
    cfsetispeed(&settings, baud);      // input baud rate
    settings.c_cflag &= ~PARENB;       // no parity
    settings.c_cflag &= ~CSTOPB;       // 1 stop bit
    settings.c_cflag &= ~CSIZE;
    settings.c_cflag |= CS8 | CLOCAL;  // 8 bits
    // settings.c_lflag = ICANON;         // canonical mode
    settings.c_oflag &= ~OPOST;        // raw output

    tcsetattr(fd, TCSANOW, &settings); // apply the settings
    
    // CRITICAL: Flush both input and output buffers to clear any residual data
    tcflush(fd, TCIOFLUSH);
    
    // Wait a bit for the device to settle after flush
    usleep(100000); // 100ms delay

    // Clear internal buffer
    memset(buf, 0, sizeof(buf));

    // ---------------------------------------------------------------

    // Generating CRC for a command
    uint16_t crc = cal_crc_half((uint8_t*)cmd, strlen(cmd));
    n = strlen(cmd);
    memcpy(&buf, cmd, n);
    lprintf("INVERTER: Current CRC: %X %X", crc >> 8, crc & 0xff);

    buf[n++] = crc >> 8;
    buf[n++] = crc & 0xff;
    buf[n++] = 0x0d;

    //send a command
    int written = write(fd, &buf, n);
    if (written != n) {
        lprintf("INVERTER: %s write failed (wrote %d of %d bytes)", cmd, written, n);
        close(fd);
        return false;
    }
    
    // Flush output to ensure command is sent
    tcdrain(fd);
    
    // Clear buffer again before reading
    memset(buf, 0, sizeof(buf));
    time(&started);

    do {
        n = read(fd, (void*)buf+i, replysize-i);
        if (n < 0) {
            if (time(NULL) - started > 2) {
                lprintf("INVERTER: %s read timeout", cmd);
                break;
            } else {
                usleep(10000); // 10ms
                continue;
            }
        }
        
        if (n > 0) {
            i += n;
            // Check if we've received the terminator
            if (i > 0 && buf[i-1] == 0x0d) {
                lprintf("INVERTER: %s received terminator at byte %d", cmd, i);
                break;
            }
        }

    } while (i<replysize && (time(NULL) - started < 3));
    close(fd);

    if (i > 0) {

        lprintf("INVERTER: %s reply size (%d bytes, expected %d)", cmd, i, replysize);

        // Dump raw buffer for debugging
        if (debugFlag) {
            lprintf("INVERTER: Raw buffer hex dump (first 50 bytes):");
            for(int x = 0; x < (i < 50 ? i : 50); x++) {
                fprintf(stderr, "%02X ", buf[x]);
                if ((x+1) % 16 == 0) fprintf(stderr, "\n");
            }
            fprintf(stderr, "\n");
        }

        if (buf[0]!='(' ) {
            lprintf("INVERTER: %s: incorrect start byte (got 0x%02X, expected '(').  Buffer: %s", cmd, buf[0], buf);
            return false;
        }
        
        if (buf[i-1]!=0x0d) {
            lprintf("INVERTER: %s: incorrect stop byte (got 0x%02X at pos %d, expected CR).  Buffer: %s", cmd, buf[i-1], i-1, buf);
            return false;
        }
        
        if (!(CheckCRC(buf, i))) {
            lprintf("INVERTER: %s: CRC Failed!  Reply size: %d  Buffer: %s", cmd, i, buf);
            return false;
        }

        buf[i-3] = '\0'; //nullterminating on first CRC byte
        lprintf("INVERTER: %s: %d bytes read: %s", cmd, i, buf);

        lprintf("INVERTER: %s query finished", cmd);
        
        // If expected size doesn't match actual size, log it
        if (i != replysize) {
            lprintf("INVERTER: WARNING - %s actual size (%d) differs from configured size (%d)", cmd, i, replysize);
            lprintf("INVERTER: SUGGESTION - Update inverter.conf to set the buffer size to %d", i);
        }
        
        return true;
    } else {
        lprintf("INVERTER: %s reply too short (%d bytes)", cmd, i);
        return false;
    }
}

void cInverter::poll() {
    int n,j;
    
    fprintf(stderr, "[POLL] Thread started, runOnce=%s\n", runOnce ? "true" : "false");

    while (true) {

        // Reading mode
        if (!ups_qmod_changed) {
            fprintf(stderr, "[POLL] Reading QMOD...\n");
            if (query("QMOD", buf_qmod)) {
                SetMode(buf[1]);
                ups_qmod_changed = true;
                fprintf(stderr, "[POLL] QMOD completed\n");
            }
        }

        // reading status (QPIGS)
        if (!ups_qpigs_changed) {
            fprintf(stderr, "[POLL] Reading QPIGS...\n");
            if (query("QPIGS", buf_qpigs)) {
                m.lock();
                strcpy(status1, (const char*)buf+1);
                m.unlock();
                ups_qpigs_changed = true;
                fprintf(stderr, "[POLL] QPIGS completed\n");
            }
        }

        // Reading QPIRI status
        if (!ups_qpiri_changed) {
            fprintf(stderr, "[POLL] Reading QPIRI...\n");
            if (query("QPIRI", buf_qpiri)) {
                m.lock();
                strcpy(status2, (const char*)buf+1);
                m.unlock();
                ups_qpiri_changed = true;
                fprintf(stderr, "[POLL] QPIRI completed\n");
            }
        }

        // Get any device warnings...
        if (!ups_qpiws_changed) {
            fprintf(stderr, "[POLL] Reading QPIWS...\n");
            if (query("QPIWS", buf_qpiws)) {
                m.lock();
                strcpy(warnings, (const char*)buf+1);
                m.unlock();
                ups_qpiws_changed = true;
                fprintf(stderr, "[POLL] QPIWS completed\n");
            }
        }

        // If runOnce mode and all data collected, exit the thread
        if (runOnce && ups_qmod_changed && ups_qpigs_changed && ups_qpiri_changed && ups_qpiws_changed) {
            fprintf(stderr, "[POLL] All data collected, exiting (run-once mode)\n");
            return;
        }

        fprintf(stderr, "[POLL] Flags: QMOD=%d QPIGS=%d QPIRI=%d QPIWS=%d, sleeping...\n", 
                ups_qmod_changed.load(), ups_qpigs_changed.load(), 
                ups_qpiri_changed.load(), ups_qpiws_changed.load());

        sleep(2);
    }
}

void cInverter::ExecuteCmd(const string cmd) {
    // Sending any command raw
    if (query(cmd.data(), 7)) {
        m.lock();
        strcpy(status2, (const char*)buf+1);
        m.unlock();
    }
}

uint16_t cInverter::cal_crc_half(uint8_t *pin, uint8_t len) {
    uint16_t crc;

    uint8_t da;
    uint8_t *ptr;
    uint8_t bCRCHign;
    uint8_t bCRCLow;

    uint16_t crc_ta[16]= {
        0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7,
        0x8108,0x9129,0xa14a,0xb16b,0xc18c,0xd1ad,0xe1ce,0xf1ef
    };

    ptr=pin;
    crc=0;

    while(len--!=0) {
        da=((uint8_t)(crc>>8))>>4;
        crc<<=4;
        crc^=crc_ta[da^(*ptr>>4)];
        da=((uint8_t)(crc>>8))>>4;
        crc<<=4;
        crc^=crc_ta[da^(*ptr&0x0f)];
        ptr++;
    }

    bCRCLow = crc;
    bCRCHign= (uint8_t)(crc>>8);

    if(bCRCLow==0x28||bCRCLow==0x0d||bCRCLow==0x0a)
        bCRCLow++;
    if(bCRCHign==0x28||bCRCHign==0x0d||bCRCHign==0x0a)
        bCRCHign++;

    crc = ((uint16_t)bCRCHign)<<8;
    crc += bCRCLow;
    return(crc);
}

bool cInverter::CheckCRC(unsigned char *data, int len) {
    uint16_t crc = cal_crc_half(data, len-3);
    return data[len-3]==(crc>>8) && data[len-2]==(crc&0xff);
}

// Auto-discover the correct buffer size for a command by reading until CR
int cInverter::query_auto(const char *cmd, int max_size) {
    time_t started;
    int fd;
    int i=0, n;
    unsigned char temp_buf[1024];
    
    memset(temp_buf, 0, sizeof(temp_buf));

    fd = open(this->device.data(), O_RDWR | O_NONBLOCK);
    if (fd == -1) {
        lprintf("INVERTER: Unable to open device file for auto-discovery");
        return -1;
    }

    // Configure serial port
    speed_t baud = B2400;
    struct termios settings;
    tcgetattr(fd, &settings);
    cfsetospeed(&settings, baud);
    cfsetispeed(&settings, baud);
    settings.c_cflag &= ~PARENB;
    settings.c_cflag &= ~CSTOPB;
    settings.c_cflag &= ~CSIZE;
    settings.c_cflag |= CS8 | CLOCAL;
    settings.c_oflag &= ~OPOST;
    tcsetattr(fd, TCSANOW, &settings);
    
    // Flush all buffers
    tcflush(fd, TCIOFLUSH);
    usleep(200000); // 200ms delay to ensure clean state

    // Generate and send command with CRC
    uint16_t crc = cal_crc_half((uint8_t*)cmd, strlen(cmd));
    n = strlen(cmd);
    memcpy(&temp_buf, cmd, n);
    temp_buf[n++] = crc >> 8;
    temp_buf[n++] = crc & 0xff;
    temp_buf[n++] = 0x0d;

    write(fd, &temp_buf, n);
    tcdrain(fd);
    
    // Clear buffer for reading
    memset(temp_buf, 0, sizeof(temp_buf));
    time(&started);

    // Read until we find CR (0x0d) or timeout
    while (i < max_size && (time(NULL) - started < 5)) {
        n = read(fd, temp_buf+i, 1); // Read one byte at a time
        if (n > 0) {
            i += n;
            // Found the terminator
            if (temp_buf[i-1] == 0x0d) {
                lprintf("INVERTER: Auto-discovery for %s: found CR at byte %d", cmd, i);
                break;
            }
        } else {
            usleep(10000); // 10ms between reads
        }
    }
    
    close(fd);
    
    // Validate the response
    if (i > 0 && temp_buf[0] == '(' && temp_buf[i-1] == 0x0d) {
        lprintf("INVERTER: Auto-discovery for %s successful: %d bytes", cmd, i);
        return i;
    } else {
        lprintf("INVERTER: Auto-discovery for %s failed (read %d bytes)", cmd, i);
        
        // Dump what we received for debugging
        if (i > 0) {
            lprintf("INVERTER: Received data (hex):");
            for(int x = 0; x < i; x++) {
                fprintf(stderr, "%02X ", temp_buf[x]);
            }
            fprintf(stderr, "\n");
            lprintf("INVERTER: Received data (ascii):");
            for(int x = 0; x < i; x++) {
                fprintf(stderr, "%c", (temp_buf[x] >= 32 && temp_buf[x] < 127) ? temp_buf[x] : '.');
            }
            fprintf(stderr, "\n");
        }
        
        return -1;
    }
}

// Auto-discover buffer sizes for all commands
void cInverter::AutoDiscoverBufferSizes() {
    printf("\n=== AUTO-DISCOVERY MODE ===\n");
    printf("Testing inverter to find correct buffer sizes...\n\n");
    
    int qmod_size = query_auto("QMOD", 20);
    if (qmod_size > 0) {
        printf("✓ QMOD buffer size: %d\n", qmod_size);
    } else {
        printf("✗ QMOD auto-discovery failed\n");
    }
    sleep(1);
    
    int qpigs_size = query_auto("QPIGS", 150);
    if (qpigs_size > 0) {
        printf("✓ QPIGS buffer size: %d\n", qpigs_size);
    } else {
        printf("✗ QPIGS auto-discovery failed\n");
    }
    sleep(1);
    
    int qpiri_size = query_auto("QPIRI", 150);
    if (qpiri_size > 0) {
        printf("✓ QPIRI buffer size: %d\n", qpiri_size);
    } else {
        printf("✗ QPIRI auto-discovery failed\n");
    }
    sleep(1);
    
    int qpiws_size = query_auto("QPIWS", 100);
    if (qpiws_size > 0) {
        printf("✓ QPIWS buffer size: %d\n", qpiws_size);
    } else {
        printf("✗ QPIWS auto-discovery failed\n");
    }
    
    printf("\n=== SUGGESTED CONFIGURATION ===\n");
    printf("Update your /etc/inverter/inverter.conf with these values:\n\n");
    if (qmod_size > 0) printf("qmod=%d\n", qmod_size);
    if (qpigs_size > 0) printf("qpigs=%d\n", qpigs_size);
    if (qpiri_size > 0) printf("qpiri=%d\n", qpiri_size);
    if (qpiws_size > 0) printf("qpiws=%d\n", qpiws_size);
    printf("\n");
    
    // Output in parsable format for scripts
    printf("DISCOVERY_QMOD=%d\n", qmod_size > 0 ? qmod_size : 5);
    printf("DISCOVERY_QPIGS=%d\n", qpigs_size > 0 ? qpigs_size : 110);
    printf("DISCOVERY_QPIRI=%d\n", qpiri_size > 0 ? qpiri_size : 98);
    printf("DISCOVERY_QPIWS=%d\n", qpiws_size > 0 ? qpiws_size : 36);
    printf("DISCOVERY_SUCCESS=%s\n", (qmod_size > 0 && qpigs_size > 0 && qpiri_size > 0 && qpiws_size > 0) ? "true" : "false");
}