'use strict';

function hexdump(ab, offset, len, opts) {
	if (!opts) {
		opts = {};
	}
	var ui8 = new Uint8Array(ab.buffer || ab, offset || ab.byteOffset, len || ab.byteLength);
	var bytecount = 0;
	var head = '        0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F';
	var trail;
	var str = [].slice
		.call(ui8)
		.map(function(i) {
			var h = i.toString(16);
			if (h.length < 2) {
				h = '0' + h;
			}
			return h;
		})
		.join('')
		.match(/.{1,2}/g)
		.join(' ')
		.match(/.{1,48}/g)
		.map(function(str) {
			var lead = bytecount.toString(16);
			bytecount += 16;

			while (lead.length < 7) {
				lead = '0' + lead;
			}

			while (str.length < 48) {
				str += ' ';
			}

			if (opts.C) {
				return (
					lead +
					' ' +
					str +
					' |' +
					str
						.replace(/ /g, '')
						.match(/.{1,2}/g)
						.map(function(ch) {
							var c = String.fromCharCode(parseInt(ch, 16));
							if (!/[ -~]/.test(c)) {
								c = '.';
							}
							return c;
						})
						.join('') +
					'|'
				);
			} else {
				return lead + ' ' + str;
			}
		})
		.join('\n');

	trail = (len || ab.byteLength).toString(16);
	while (trail.length < 7) {
		trail = '0' + trail;
	}
	return head + '\n' + str + '\n' + trail;
}

module.exports = hexdump;