#!/usr/bin/env node

var fs = require('fs');
var os = require('os');
var path = require('path');
var isAbsolutePath = require('path-is-absolute');
var Table = require('cli-table');
var program = require('commander');
var debug = require('debug')('json2csv:cli');
var json2csv = require('../lib/json2csv');
var parseLdJson = require('../lib/parse-ldjson');
var pkg = require('../package');

program
  .version(pkg.version)
  .option('-i, --input <input>', 'Path and name of the incoming json file. If not provided, will read from stdin.')
  .option('-o, --output [output]', 'Path and name of the resulting csv file. Defaults to stdout.')
  .option('-f, --fields <fields>', 'Specify the fields to convert.')
  .option('-l, --fieldList [list]', 'Specify a file with a list of fields to include. One field per line.')
  .option('-d, --delimiter [delimiter]', 'Specify a delimiter other than the default comma to use.')
  .option('-v, --defaultValue [defaultValue]', 'Specify a default value other than empty string.')
  .option('-e, --eol [value]', 'Specify an EOL value after each row.')
  .option('-z, --newLine [value]', 'Specify an new line value for separating rows.')
  .option('-q, --quote [value]', 'Specify an alternate quote value.')
  .option('-n, --no-header', 'Disable the column name header')
  .option('-F, --flatten', 'Flatten nested objects')
  .option('-u, --unwindPath <paths>', 'Creates multiple rows from a single JSON document similar to MongoDB unwind.')
  .option('-L, --ldjson', 'Treat the input as Line-Delimited JSON.')
  .option('-p, --pretty', 'Use only when printing to console. Logs output in pretty tables.')
  .option('-a, --include-empty-rows', 'Includes empty rows in the resulting CSV output.')
  .option('-b, --with-bom', 'Includes BOM character at the beginning of the csv.')
  .parse(process.argv);

function getFields(callback) {
  var fields;

  if (program.fieldList) {
    fs.readFile(program.fieldList, 'utf8', function (err, data) {
      if (err) {
        return callback(err);
      }

      data.replace(/\r\n|\n\r|\r|\n/g, os.EOL);
      fields = data.split(os.EOL);
      callback(null, fields);
    });
  } else {
    fields = program.fields ? program.fields.split(',') : undefined;
    callback(null, fields);
  }
}

function getInput(callback) {
  var input, isAbsolute, rows;

  if (program.input) {
    isAbsolute = isAbsolutePath(program.input);
    input = require(isAbsolute ? program.input : path.join(process.cwd(), program.input));

    return callback(null, input);
  }

  input = '';
  process.stdin.resume();
  process.stdin.setEncoding('utf8');

  process.stdin.on('data', function (chunk) {
    input += chunk;
  });
  process.stdin.on('error', function (err) {
    debug('Could not read from stdin', err);
  });
  process.stdin.on('end', function () {
    if (program.ldjson) {
      rows = parseLdJson(input);
    } else {
      rows = JSON.parse(input);
    }

    callback(null, rows);
  });
}

function logPretty(csv) {
  var lines = csv.split(os.EOL);
  var table = new Table({
    head: lines[0].split(','),
    colWidths: lines[0].split('","').map(function (elem) {
      return elem.length * 2;
    })
  });

  for (var i = 1; i < lines.length; i++) {
    table.push(lines[i].split(','));
  }
  return table.toString();
}

getFields(function (err, fields) {
  if (err) {
    throw new Error('Cannot read fields from file ' + program.fieldList);
  }

  getInput(function (inputError, input) {
    if (inputError) {
      throw new Error('Couldn\'t get the input: ' + inputError);
    }

    var opts = {
      data: input,
      fields: fields,
      hasCSVColumnTitle: program.header,
      quotes: program.quote,
      defaultValue: program.defaultValue,
      flatten: program.flatten,
      includeEmptyRows: program.includeEmptyRows,
      withBOM: program.withBom
    };

    if (program.delimiter) {
      opts.del = program.delimiter;
    }

    if (program.eol) {
      opts.eol = program.eol;
    }

    if (program.newLine) {
      opts.newLine = program.newLine;
    }

    if (program.unwindPath) {
      opts.unwindPath = program.unwindPath.split(',');
    }

    var csv = json2csv(opts);

    if (program.output) {
      fs.writeFile(program.output, csv, function (writeError) {
        if (writeError) {
          throw new Error('Cannot save to ' + program.output + ': ' + writeError);
        }

        debug(program.input + ' successfully converted to ' + program.output);
      });
    } else {
      // don't fail if piped to e.g. head
      process.stdout.on('error', function (error) {
        if (error.code === 'EPIPE') {
          process.exit();
        }
      })

      /*eslint-disable no-console */
      if (program.pretty) {
        console.log(logPretty(csv));
      } else {
        console.log(csv);
      }
      /*eslint-enable no-console */
    }
  });
});