#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#include <esp_log.h>

#include "eos.h"
#include "net.h"
#include "unicode.h"
#include "gsm.h"
#include "at_cmd.h"
#include "cell.h"

#define CTRL_Z      0x1a

static const char *TAG = "EOS SMS";

static char _pdu_in[2048];
static char _pdu_out[2048];

extern char *at_cmd_buf;

static ssize_t sms_encode(unsigned char *buffer, uint16_t buf_len, char *pdu, size_t pdu_size) {
    ucp_t ch;
    size_t pdu_len;
    ssize_t rv;
    int i;

    char *addr;
    uint8_t addr_type;
    size_t addr_len;

    uint8_t txt[GSM_UD_SIZE];
    size_t txt_len;

    uint16_t flags;

    if (buf_len < 2) return EOS_ERR_SIZE;
    flags = buffer[0] << 8;
    flags |= buffer[1];
    buffer += 2;
    buf_len -= 2;

    if (buf_len < 2) return EOS_ERR_SIZE;
    switch (buffer[0]) {
        case EOS_CELL_SMS_ADDRTYPE_INTL:
            addr_type = GSM_TON_INTERNATIONAL | GSM_NPI_TELEPHONE;
            break;

        case EOS_CELL_SMS_ADDRTYPE_OTHER:
            addr_type = GSM_TON_UNKNOWN | GSM_NPI_TELEPHONE;
            break;

        default:
            return EOS_ERR;
    }
    addr_len = buffer[1];
    addr = (char *)buffer + 2;

    if (buf_len < 2 + addr_len) return EOS_ERR_SIZE;
    buffer += 2 + addr_len;
    buf_len -= 2 + addr_len;

    i = 0;
    txt_len = 0;
    while (i < buf_len) {
        int _rv;

        if (buf_len - i < 4) {
            _rv = utf8_len_str(buffer + i);
            if (_rv < 0) return EOS_ERR;
            if (buf_len - i < _rv) return EOS_ERR_SIZE;
        }

        _rv = utf8_dec(buffer + i, &ch);
        if (_rv < 0) return EOS_ERR;
        if (ch >= 0xffff) return EOS_ERR;
        i += _rv;

        _rv = gsm_ucs2_to_7bit((char *)txt + txt_len, sizeof(txt) - txt_len, ch);
        if (_rv < 0) return EOS_ERR;
        txt_len += _rv;
    }

    if (pdu_size < 2) return EOS_ERR_SIZE;
    pdu_putc(pdu, 0);

    rv = gsm_sms_enc(pdu + 2, pdu_size - 2, addr, addr_len, addr_type, NULL, 0, txt, txt_len, GSM_ENC_7BIT, flags);
    if (rv < 0) return EOS_ERR;
    pdu_len = rv + 2;

    return pdu_len;
}

static ssize_t sms_decode(char *pdu, size_t pdu_len, unsigned char *buf, uint16_t buf_size) {
    uint16_t buf_len = 0;
    ssize_t rv;
    int i, j;

    char smsc_addr[GSM_ADDR_SIZE];
    size_t smsc_addr_len;
    uint8_t smsc_info, smsc_info_len, smsc_addr_type;

    char orig_addr[GSM_ADDR_SIZE];
    size_t orig_addr_len;
    uint8_t orig_addr_type;

    uint8_t udh[GSM_UDH_SIZE];
    size_t udh_len;

    uint8_t txt[GSM_UD_SIZE];
    size_t txt_len;
    uint8_t txt_enc;

    char smsc_timestamp[GSM_TS_SIZE];
    uint16_t flags;

    if (pdu_len < 2) return EOS_ERR_SIZE;
    rv = pdu_getc(pdu, &smsc_info);
    if (rv < 0) return rv;
    smsc_info_len = 2 * (smsc_info + 1);
    if (pdu_len < smsc_info_len) return EOS_ERR_SIZE;

    if (smsc_info > 1) {
        /* SMSC address - currently not used */
        pdu_putc(pdu, (smsc_info - 1) * 2);
        rv = gsm_addr_dec(pdu, pdu_len, smsc_addr, &smsc_addr_len, &smsc_addr_type);
        if (rv < 0) smsc_addr_len = 0;
    }

    rv = gsm_sms_dec(pdu + smsc_info_len, pdu_len - smsc_info_len, orig_addr, &orig_addr_len, &orig_addr_type, udh, &udh_len, txt, &txt_len, &txt_enc, smsc_timestamp, &flags);
    if ((rv == GSM_ERR_NOTSUPPORTED) || (txt_enc == GSM_ENC_8BIT)) {
        ESP_LOGE(TAG, "Message not supported: %s", pdu);
        return EOS_ERR_NOTSUPPORTED;
    }
    if (rv < 0) return EOS_ERR;

    if (buf_size < buf_len + 2) return EOS_ERR_SIZE;
    buf[0] = flags >> 8;
    buf[1] = flags;
    buf_len += 2;

    if (buf_size < buf_len + GSM_TS_SIZE) return EOS_ERR_SIZE;
    memcpy(buf + buf_len, smsc_timestamp, GSM_TS_SIZE);
    buf_len += GSM_TS_SIZE;

    if ((orig_addr_type & GSM_TON) == GSM_TON_ALPHANUMERIC) {
        if (buf_size < buf_len + 2) return EOS_ERR_SIZE;
        buf[buf_len] = EOS_CELL_SMS_ADDRTYPE_ALPHA;
        buf[buf_len + 1] = 0;
        buf_len += 2;

        i = 0;
        j = 0;
        while (i < orig_addr_len) {
            uint16_t ch;
            int _rv;

            _rv = gsm_7bit_to_ucs2((char *)orig_addr + i, orig_addr_len - i, &ch);
            if (_rv < 0) return EOS_ERR;
            i += _rv;

            if (buf_size - buf_len - j < 4) {
                _rv = utf8_len_ch(ch);
                if (_rv < 0) return EOS_ERR;
                if (buf_size - buf_len - j < _rv) return EOS_ERR_SIZE;
            }

            _rv = utf8_enc(ch, buf + buf_len + j);
            if (_rv < 0) return EOS_ERR;
            j += _rv;
        }
        buf[buf_len - 1] = j;
        buf_len += j;
    } else {
        if (buf_size < buf_len + 2) return EOS_ERR_SIZE;
        buf[buf_len] = ((orig_addr_type & GSM_TON) == GSM_TON_INTERNATIONAL) ? EOS_CELL_SMS_ADDRTYPE_INTL : EOS_CELL_SMS_ADDRTYPE_OTHER;
        buf[buf_len + 1] = orig_addr_len;
        buf_len += 2;

        if (buf_size < buf_len + orig_addr_len) return EOS_ERR_SIZE;
        memcpy(buf + buf_len, orig_addr, orig_addr_len);
        buf_len += orig_addr_len;
    }

    i = 0;
    j = 0;
    while (i < txt_len) {
        ucp_t ch;
        int _rv;

        if (txt_enc == GSM_ENC_7BIT) {
            uint16_t _ch;

            _rv = gsm_7bit_to_ucs2((char *)txt + i, txt_len - i, &_ch);
            if (_rv < 0) return EOS_ERR;
            ch = _ch;
        } else {
            if (txt_len - i < 2) return EOS_ERR_SIZE;
            if (txt_len - i < 4) {
                _rv = utf16_len_str(txt + i);
                if (_rv < 0) return EOS_ERR;
                if (txt_len - i < _rv) return EOS_ERR_SIZE;
            }
            _rv = utf16_dec(txt + i, &ch);
            if (_rv < 0) return EOS_ERR;
        }
        i += _rv;

        if (buf_size - buf_len - j < 4) {
            _rv = utf8_len_ch(ch);
            if (_rv < 0) return EOS_ERR;
            if (buf_size - buf_len - j < _rv) return EOS_ERR_SIZE;
        }

        _rv = utf8_enc(ch, buf + buf_len + j);
        if (_rv < 0) return EOS_ERR;
        j += _rv;
    }
    if (buf_size < buf_len + j + 1) return EOS_ERR_SIZE;
    buf[buf_len + j] = '\0';
    buf_len += j + 1;

    return buf_len;
}

void eos_cell_sms_handler(unsigned char mtype, unsigned char *buffer, uint16_t buf_len) {
    int rv;

    buffer++;
    buf_len--;
    switch (mtype) {
        case EOS_CELL_MTYPE_SMS_LIST: {
            if (buf_len < 1) return;

            rv = snprintf(at_cmd_buf, AT_SIZE_CMD_BUF, "AT+CMGL=%d\r", buffer[0]);
            if ((rv < 0) || (rv >= AT_SIZE_CMD_BUF)) return;

            rv = eos_modem_take(1000);
            if (rv) return;

            at_cmd(at_cmd_buf);
            do {
                unsigned char *buf;
                uint16_t buf_len;

                char *pdu = _pdu_in;
                size_t pdu_size = sizeof(_pdu_in);
                size_t pdu_len;
                ssize_t _rv;

                rv = at_expect("^\\+CMGL: [0-9]+,[0-9],.*,[0-9]+$", "^OK", 1000);
                if (rv) break;

                rv = eos_modem_readln(pdu, pdu_size, 1000);
                if (rv) break;

                pdu_len = strlen(pdu);

                buf = eos_net_alloc();
                buf[0] = EOS_CELL_MTYPE_SMS | EOS_CELL_MTYPE_SMS_LIST_ITEM;
                _rv = sms_decode(pdu, pdu_len, buf + 1, EOS_NET_SIZE_BUF - 1);
                if (_rv < 0) {
                    eos_net_free(buf);
                    continue;
                }

                buf_len = _rv;
                eos_net_send(EOS_NET_MTYPE_CELL, buf, buf_len + 1);
            } while (1);

            eos_modem_give();
            break;
        }

        case EOS_CELL_MTYPE_SMS_MSG: {
            char b[4];

            char *pdu = _pdu_in;
            size_t pdu_size = sizeof(_pdu_in);
            size_t pdu_len;
            ssize_t _rv;

            _rv = sms_encode(buffer, buf_len, pdu, pdu_size);
            if (_rv < 0) return;

            pdu_len = _rv;
            if (pdu_size < pdu_len + 2) return;
            pdu[pdu_len] = CTRL_Z;
            pdu[pdu_len + 1] = '\0';

            rv = snprintf(at_cmd_buf, AT_SIZE_CMD_BUF, "AT+CMGS=%d\r", pdu_len / 2);
            if ((rv < 0) || (rv >= AT_SIZE_CMD_BUF)) return;

            rv = eos_modem_take(1000);
            if (rv) return;

            at_cmd(at_cmd_buf);
            // wait for: '> ' (0d 0a 3e 20)
            eos_modem_read(b, 4, 1000);
            at_cmd(pdu);
            rv = at_expect("^\\+CMGS: [0-9]+", "^ERROR", 5000);
            if (!rv) rv = at_expect("^OK", "^ERROR", 1000);

            eos_modem_give();
            break;
        }
    }
}

static void sms_received_handler(char *urc, regmatch_t m[]) {
    char cmd[32];
    unsigned char *buf;
    uint16_t buf_len;
    int ref, rv;

    char *pdu = _pdu_out;
    size_t pdu_size = sizeof(_pdu_out);
    size_t pdu_len;
    ssize_t _rv;

    sscanf(urc + m[1].rm_so, "%d", &ref);

    rv = snprintf(cmd, sizeof(cmd), "AT+CMGR=%d\r", ref);
    if ((rv < 0) || (rv >= sizeof(cmd))) return;

    at_cmd(cmd);

    rv = at_expect("^\\+CMGR: [0-9],.*,[0-9]+$", "^ERROR", 1000);
    if (rv) return;

    rv = eos_modem_readln(pdu, pdu_size, 1000);
    if (rv) return;

    pdu_len = strlen(pdu);

    rv = at_expect("^OK", NULL, 1000);

    buf = eos_net_alloc();
    buf[0] = EOS_CELL_MTYPE_SMS | EOS_CELL_MTYPE_SMS_MSG;
    _rv = sms_decode(pdu, pdu_len, buf + 1, EOS_NET_SIZE_BUF - 1);
    if (_rv < 0) {
        eos_net_free(buf);
        return;
    }

    buf_len = _rv;
    eos_net_send(EOS_NET_MTYPE_CELL, buf, buf_len + 1);
}

void eos_cell_sms_init(void) {
    at_urc_insert("^\\+CMTI: .*,([0-9]+)$", sms_received_handler, REG_EXTENDED);
}