#include "web.h"
#include "db.h"
#include <leveldb/comparator.h>
#include <iomanip>

static inline std::string make_key(uint64_t timestamp) {
    std::stringstream key;
    key << "ts-";
    key << std::setfill('0') << std::setw(20) << timestamp;
    return key.str();
}

void web_handle_api_value(const boost::cmatch &match, struct mg_connection *conn) {
//    const struct mg_request_info *request_info = mg_get_request_info(conn);

    std::string sensor(match[1].str());
    uint64_t timestamp = std::stoul(match[2].str());
    char buf[1024];
    int count = mg_read(conn, buf, 1024);
    std::string value(buf, count);

    leveldb::DB *db = getDB(sensor);
    if (db == nullptr) {
        std::cout << "failed to get db for " << sensor << std::endl;
        mg_printf(conn, "HTTP/1.1 500 Internal Error\r\n\r\n");
        return;
    }

    std::cout << "sensor=" << sensor << " key=" << make_key(timestamp) << std::endl;
    db->Put(leveldb::WriteOptions(), make_key(timestamp), value);
    mg_printf(conn, "HTTP/1.1 200 Value received\r\n\r\n");
}

void web_handle_api_range(const boost::cmatch &match, struct mg_connection *conn) {
    static const leveldb::Comparator *cmp = leveldb::BytewiseComparator();

    std::string sensor(match[1].str());
    uint64_t start = std::stoul(match[2].str());
    uint64_t end = std::stoul(match[3].str());
    std::string key_start(std::move(make_key(start)));
    std::string key_end(std::move(make_key(end)));

    leveldb::DB *db = getDB(sensor);
    if (db == nullptr) {
        mg_printf(conn, "HTTP/1.1 500 Internal Error\r\n\r\n");
        return;
    }

    mg_printf(conn,
            "HTTP/1.1 200 Value received\r\n"
            "Content-Type: application/json; encoding=UTF-8\r\n"
            "\r\n");

    std::cout << "sensor=" << sensor << " start=" << start << " end=" << end << std::endl;

    std::ostringstream out;
    out << "{'sensor':'" << sensor << "', 'error':null, 'data':[";
    mg_write(conn, out.str().c_str(), out.str().size());

    leveldb::Iterator* it = db->NewIterator(leveldb::ReadOptions());
    bool first = true;
    std::ostringstream outbuf;
    for (it->Seek(key_start); 
            it->Valid() && cmp->Compare(it->key(), key_end) < 0;
            it->Next()) {
        const char *key = it->key().data();
        size_t key_size =  it->key().size();
        if (key_size != 20+3) {
            std::cerr << "invalid key" << std::endl;
            return;
        }

        unsigned int offset = 3; // "ts-"
        // skip zeros in timestamp
        while (offset < key_size-1 and *(key+offset) == '0')
            offset++;

        if (first)
            first = false;
        else
            outbuf << ',';

        outbuf << '[';
        outbuf.write(key+offset, key_size-offset);
        outbuf << ',';
        outbuf.write(it->value().data(), it->value().size());
        outbuf << ']';

        mg_write(conn, outbuf.str().c_str(), outbuf.tellp());
        outbuf.seekp(0);
    }
    mg_printf(conn, "]}\r\n");
    delete it;
}