function IndentationToList(options) {
    'use strict';

    return Main(options);
    

    function Interpolate(template, variables) {
        var names = Object.keys(variables);
        var result = template;
        for (var i = 0, iTop = names.length; i < iTop; i++) {
            var name = names[i];
            var value = variables[name];
            var re = RegExp('\\b' + name + '\\b', 'g');
            result = result.replace(re, value);
        }
        return result;
    }

    function Parse(lineText, lineNumber, indent) {
        var aux = lineText.split(indent);
        var result = {
            'level': aux.length - 1,
            'label': aux.pop(),
            'line':  lineNumber
        };
        return result;
    }

    function InitOptions(options) {
        var defaultOptions = {
            indent: '  ',
            templates: {
                folder: '<li><label class="toggle" for="ID">FOLDER</label> <input type="checkbox" id="ID" /><ol>CONTENT</ol></li>',
                file: '<li class="file" href="">FILE</li>',
                folderWithoutContent: '<li><label for="ID">FOLDER</label> <input type="checkbox" id="ID" /></li>',
                contentWithoutFolder: '<ol>CONTENT</ol>'
            },
            text: ''
        };
        if (options.constructor.name !== 'Object') {
            options = {
                text: String(options)
            };
        }
        var result = {
            indent:    options.indent || defaultOptions.indent,
            templates: options.templates || defaultOptions.templates,
            text:      options.text
        };
        return result;
    }

    function InitLines(text) {
        var result = text.
            replace('\r\n', '\n').   // remove double line endings
            replace('\r', '\n').     // remove odd line endings
            split('\n').             // get lines
            filter(function(value) { // remove empty lines
                return value !== ''; 
            });
        result.push(''); // append an empty line
        return result;
    }

    function InitStack() {
        var result = {
            data: [],
            lastParent: null,
            lastChild: null
        };
        result.lastChild = result.data;
        return result;
    }

    function AddChild(stack, info, asSibling) {
        var last = asSibling ? stack.lastParent : stack.lastChild;
        info.parent = last;
        var node = [info];
        last.push(node);
        stack.lastParent = info.parent;
        stack.lastChild = node;
    }

    function ChildrenToHTML(stack, templates, contentWithoutFolder) {
        var last = stack.lastParent;
        var parent = last[0];
        var children = last.splice(1); // last.length === 1
        var items = [];
        for (var i = 0, iTop = children.length; i < iTop; i++) {
            var child = children[i];
            var isStringified = typeof child[0] === 'string';
            var isFolder = ! isStringified && child[0].label.search(/\/$/) >= 0;
            var isFile = ! isStringified && ! isFolder;
            var html;
            switch (true) {
                case isStringified:
                    html = child[0];
                break;

                case isFolder:
                    html = Interpolate(templates.folderWithoutContent, {ID: 'folder_' + child[0].line, FOLDER: child[0].label});
                break;
                
                case isFile:
                    html = Interpolate(templates.file, {FILE: child[0].label});
                break;
            }
            items.push(html);
        }
        var template = contentWithoutFolder ? templates.contentWithoutFolder : templates.folder;
        last[0] = Interpolate(template, {ID: 'folder_' + parent.line, FOLDER: parent.label, CONTENT: items.join('')});
        stack.lastParent = parent.parent;
        stack.lastChild = last;
    }

    function ParentsToHTML(stack, templates) {
        stack.data.pop();    // remove the last child (due to the last empty line)
        stack.data.unshift({ // prepend a fictitious parent to easily wrap up all real parents
            label: '',
            level: -1,
            line: '',
            parent: null
        });
        ChildrenToHTML(stack, templates, true);
        var result = stack.lastChild[0];
        return result;
    }

    function Main(options) {
        options = InitOptions(options);
        if (! options.text) {
            return '';
        }
        var lines = InitLines(options.text);
        var stack = InitStack();
        var level = -1;
        for (var i = 0, iTop = lines.length; i < iTop; i++) {
            var line = lines[i];
            var Parsed = Parse(line, i, options.indent);
            switch (true) {
                case Parsed.level > level:
                    AddChild(stack, Parsed);
                    level += 1; // go one level in
                break;

                case Parsed.level === level:
                    AddChild(stack, Parsed, true);
                break;

                case Parsed.level < level:
                    ChildrenToHTML(stack, options.templates);
                    level -= 1; // go only one level out, so that ChildrenToHTML can be called again (if any)
                    i -= 1;     // still need to process the current line
                break;
            }
        }
        // thanks to the last empty line, all children have been stringified by now
        var result = ParentsToHTML(stack, options.templates);
        return result;
    }

}

// SAMPLE TEXT
//---
// components/
//   login/
//     login.html
//     login.js
//   register/
//     register.html
//     register.js
//===

// SAMPLE USAGE
//---
// var text = document.getElementById('text').innerHTML;
// var converted = IndentationToList(text);
// document.getElementById('tree').innerHTML = converted;
//===

// CSS
//---
// See http://www.thecssninja.com/css/css-tree-menu for a suitable CSS
// Otherwise, try this, which I derived from that, by removing icons.
//---
// ol.tree
// {
//     padding: 0;
//     width: 300px;
// }
//     li
//     {
//         position: relative;
//         margin-left: -15px;
//         list-style: none;
//     }
//     li.file
//     {
//     }
//         li.file a
//         {
//             color: #4C4C4C;
//             padding-left: 21px;
//             text-decoration: none;
//             display: block;
//         }
//     li input
//     {
//         position: absolute;
//         left: 0;
//         margin-left: 0;
//         opacity: 0;
//         z-index: 2;
//         cursor: pointer;
//         height: 1em;
//         width: 1em;
//         top: 0;
//     }
//         li input + ol
//         {
//             margin: -0.938em 0 0 -44px; /* 15px */
//             height: 1em;
//         }
//         li input + ol > li { display: none; margin-left: -14px !important; padding-left: 1px; }
//   li label
//     {
//         display: block;
//     color:navy;
//     }
//     li label.toggle
//     {
//       cursor: pointer;
//       font-weight: 600;
//     }
//     li input:checked + ol
//     {
//         margin: -1.25em 0 0 -44px; /* 20px */
//         padding: 1.563em 0 0 80px;
//         height: auto;
//     }
//         li input:checked + ol > li { display: block; margin: 0 0 0.125em;  /* 2px */}
//         li input:checked + ol > li:last-child { margin: 0 0 0.063em; /* 1px */ }
//===