var _ = require('underscore');

var pg  = require('./../pg');

function JsonFormat() {
    this.buffer = '';
    this.lastKnownResult = {};
}

JsonFormat.prototype = new pg('json');

JsonFormat.prototype._contentType = "application/json; charset=utf-8";

// jshint maxcomplexity:9
JsonFormat.prototype.formatResultFields = function(flds) {
  flds = flds || [];
  var nfields = {};
  for (var i=0; i<flds.length; ++i) {
    var f = flds[i];
    var cname = this.client.typeName(f.dataTypeID);
    var tname;
    if ( ! cname ) {
      tname = 'unknown(' + f.dataTypeID + ')';
    } else {
      if ( cname.match('bool') ) {
        tname = 'boolean';
      }
      else if ( cname.match(/int|float|numeric/) ) {
        tname = 'number';
      }
      else if ( cname.match(/text|char|unknown/) ) {
        tname = 'string';
      }
      else if ( cname.match(/date|time/) ) {
        tname = 'date';
      }
      else {
        tname = cname;
      }
      if ( tname && cname.match(/^_/) ) {
        tname += '[]';
      }
    }
    nfields[f.name] = { type: tname };
  }
  return nfields;
};

JsonFormat.prototype.startStreaming = function() {
    this.total_rows = 0;
    if (this.opts.beforeSink) {
        this.opts.beforeSink();
    }
    if (this.opts.callback) {
        this.buffer += this.opts.callback + '(';
    }
    this.buffer += '{"rows":[';
    this._streamingStarted = true;
};

JsonFormat.prototype.handleQueryRow = function(row, result) {
    if ( ! this._streamingStarted ) {
        this.startStreaming();
    }

    this.lastKnownResult = result;

    this.buffer += (this.total_rows++ ? ',' : '') + JSON.stringify(row, function (key, value) {
        if (value !== value) {
            return 'NaN';
        }

        if (value === Infinity) {
            return 'Infinity';
        }

        if (value === -Infinity) {
            return '-Infinity';
        }

        return value;
    });

    if (this.total_rows % (this.opts.bufferedRows || 1000)) {
        this.opts.sink.write(this.buffer);
        this.buffer = '';
    }
};

// jshint maxcomplexity:13
JsonFormat.prototype.handleQueryEnd = function(result) {
    if (this.error && !this._streamingStarted) {
        this.callback(this.error);
        return;
    }

    if ( this.opts.profiler ) {
        this.opts.profiler.done('gotRows');
    }

    if ( ! this._streamingStarted ) {
        this.startStreaming();
    }

    this.opts.total_time = (Date.now() - this.start_time)/1000;

    result = result || this.lastKnownResult || {};

    // Drop field description for skipped fields
    if (this.hasSkipFields) {
        var newfields = [];
        var sf = this.opts.skipfields;
        for (var i = 0; i < result.fields.length; i++) {
            var f = result.fields[i];
            if ( sf.indexOf(f.name) === -1 ) {
                newfields.push(f);
            }
        }
        result.fields = newfields;
    }

    var total_time = (Date.now() - this.start_time)/1000;

    var out = [
        '],', // end of "rows" array
        '"time":', JSON.stringify(total_time),
        ',"fields":', JSON.stringify(this.formatResultFields(result.fields)),
        ',"total_rows":', JSON.stringify(result.rowCount || this.total_rows)
    ];

    if (this.error) {
        out.push(',"error":', JSON.stringify([this.error.message]));
    }


    if ( result.notices && result.notices.length > 0 ) {
        var notices = {},
            severities = [];
        _.each(result.notices, function(notice) {
            var severity = notice.severity.toLowerCase() + 's';
            if (!notices[severity]) {
                severities.push(severity);
                notices[severity] = [];
            }
            notices[severity].push(notice.message);
        });
        _.each(severities, function(severity) {
            out.push(',');
            out.push(JSON.stringify(severity));
            out.push(':');
            out.push(JSON.stringify(notices[severity]));
        });
    }

    out.push('}');


    this.buffer += out.join('');

    if (this.opts.callback) {
        this.buffer += ')';
    }

    this.opts.sink.write(this.buffer);
    this.opts.sink.end();
    this.buffer = '';

    this.callback();
};

module.exports = JsonFormat;