/**
 * Lawnchair!
 * --- 
 * clientside json store 
 *
 */
var Lawnchair = function (options, callback) {
    // ensure Lawnchair was called as a constructor
    if (!(this instanceof Lawnchair)) return new Lawnchair(options, callback);

    // lawnchair requires json 
    if (!JSON) throw 'JSON unavailable! Include http://www.json.org/json2.js to fix.'
    // options are optional; callback is not
    if (arguments.length <= 2 && arguments.length > 0) {
        callback = (typeof arguments[0] === 'function') ? arguments[0] : arguments[1];
        options  = (typeof arguments[0] === 'function') ? {} : arguments[0];
    } else {
        throw 'Incorrect # of ctor args!'
    }
    // TODO perhaps allow for pub/sub instead?
    if (typeof callback !== 'function') throw 'No callback was provided';
    
    // default configuration 
    this.record = options.record || 'record'  // default for records
    this.name   = options.name   || 'records' // default name for underlying store
    
    // mixin first valid  adapter
    var adapter
    // if the adapter is passed in we try to load that only
    if (options.adapter) {
        for (var i = 0, l = Lawnchair.adapters.length; i < l; i++) {
            if (Lawnchair.adapters[i].adapter === options.adapter) {
              adapter = Lawnchair.adapters[i].valid() ? Lawnchair.adapters[i] : undefined;
              break;
            }
        }
    // otherwise find the first valid adapter for this env
    } 
    else {
        for (var i = 0, l = Lawnchair.adapters.length; i < l; i++) {
            adapter = Lawnchair.adapters[i].valid() ? Lawnchair.adapters[i] : undefined
            if (adapter) break 
        }
    } 
    
    // we have failed 
    if (!adapter) throw 'No valid adapter.' 
    
    // yay! mixin the adapter 
    for (var j in adapter)  
        this[j] = adapter[j]
    
    // call init for each mixed in plugin
    for (var i = 0, l = Lawnchair.plugins.length; i < l; i++) 
        Lawnchair.plugins[i].call(this)

    // init the adapter 
    this.init(options, callback)
}

Lawnchair.adapters = [] 

/** 
 * queues an adapter for mixin
 * ===
 * - ensures an adapter conforms to a specific interface
 *
 */
Lawnchair.adapter = function (id, obj) {
    // add the adapter id to the adapter obj
    // ugly here for a  cleaner dsl for implementing adapters
    obj['adapter'] = id
    // methods required to implement a lawnchair adapter 
    var implementing = 'adapter valid init keys save batch get exists all remove nuke'.split(' ')
    ,   indexOf = this.prototype.indexOf
    // mix in the adapter   
    for (var i in obj) {
        if (indexOf(implementing, i) === -1) throw 'Invalid adapter! Nonstandard method: ' + i
    }
    // if we made it this far the adapter interface is valid 
	// insert the new adapter as the preferred adapter
	Lawnchair.adapters.splice(0,0,obj)
}

Lawnchair.plugins = []

/**
 * generic shallow extension for plugins
 * ===
 * - if an init method is found it registers it to be called when the lawnchair is inited 
 * - yes we could use hasOwnProp but nobody here is an asshole
 */ 
Lawnchair.plugin = function (obj) {
    for (var i in obj) 
        i === 'init' ? Lawnchair.plugins.push(obj[i]) : this.prototype[i] = obj[i]
}

/**
 * helpers
 *
 */
Lawnchair.prototype = {

    isArray: Array.isArray || function(o) { return Object.prototype.toString.call(o) === '[object Array]' },
    
    /**
     * this code exists for ie8... for more background see:
     * http://www.flickr.com/photos/westcoastlogic/5955365742/in/photostream
     */
    indexOf: function(ary, item, i, l) {
        if (ary.indexOf) return ary.indexOf(item)
        for (i = 0, l = ary.length; i < l; i++) if (ary[i] === item) return i
        return -1
    },

    // awesome shorthand callbacks as strings. this is shameless theft from dojo.
    lambda: function (callback) {
        return this.fn(this.record, callback)
    },

    // first stab at named parameters for terse callbacks; dojo: first != best // ;D
    fn: function (name, callback) {
        return typeof callback == 'string' ? new Function(name, callback) : callback
    },

    // returns a unique identifier (by way of Backbone.localStorage.js)
    // TODO investigate smaller UUIDs to cut on storage cost
    uuid: function () {
        var S4 = function () {
            return (((1+Math.random())*0x10000)|0).toString(16).substring(1);
        }
        return (S4()+S4()+"-"+S4()+"-"+S4()+"-"+S4()+"-"+S4()+S4()+S4());
    },

    // a classic iterator
    each: function (callback) {
        var cb = this.lambda(callback)
        // iterate from chain
        if (this.__results) {
            for (var i = 0, l = this.__results.length; i < l; i++) cb.call(this, this.__results[i], i) 
        }  
        // otherwise iterate the entire collection 
        else {
            this.all(function(r) {
                for (var i = 0, l = r.length; i < l; i++) cb.call(this, r[i], i)
            })
        }
        return this
    }
// --
};
// window.name code courtesy Remy Sharp: http://24ways.org/2009/breaking-out-the-edges-of-the-browser
Lawnchair.adapter('window-name', (function(index, store) {
    if (typeof window==='undefined') {
        window = { top: { } }; // node/optimizer compatibility
    }

    var data = window.top.name ? JSON.parse(window.top.name) : {}

    return {

        valid: function () {
            return typeof window.top.name != 'undefined' 
        },

        init: function (options, callback) {
            data[this.name] = data[this.name] || {index:[],store:{}}
            index = data[this.name].index
            store = data[this.name].store
            this.fn(this.name, callback).call(this, this)
        },

        keys: function (callback) {
            this.fn('keys', callback).call(this, index)
            return this
        },

        save: function (obj, cb) {
            // data[key] = value + ''; // force to string
            // window.top.name = JSON.stringify(data);
            var key = obj.key || this.uuid()
            this.exists(key, function(exists) {
                if (!exists) {
                    if (obj.key) delete obj.key
                    index.push(key)
                }
                store[key] = obj
                window.top.name = JSON.stringify(data) // TODO wow, this is the only diff from the memory adapter
                if (cb) {
                    obj.key = key
                    this.lambda(cb).call(this, obj)
                }
            })
            return this
        },

        batch: function (objs, cb) {
            var r = []
            for (var i = 0, l = objs.length; i < l; i++) {
                this.save(objs[i], function(record) {
                    r.push(record)
                })
            }
            if (cb) this.lambda(cb).call(this, r)
            return this
        },
        
        get: function (keyOrArray, cb) {
            var r;
            if (this.isArray(keyOrArray)) {
                r = []
                for (var i = 0, l = keyOrArray.length; i < l; i++) {
                    r.push(store[keyOrArray[i]]) 
                }
            } else {
                r = store[keyOrArray]
                if (r) r.key = keyOrArray
            }
            if (cb) this.lambda(cb).call(this, r)
            return this 
        },
        
        exists: function (key, cb) {
            this.lambda(cb).call(this, !!(store[key]))
            return this
        },

        all: function (cb) {
            var r = []
            for (var i = 0, l = index.length; i < l; i++) {
                var obj = store[index[i]]
                obj.key = index[i]
                r.push(obj)
            }
            this.fn(this.name, cb).call(this, r)
            return this
        },
        
        remove: function (keyOrArray, cb) {
            var del = this.isArray(keyOrArray) ? keyOrArray : [keyOrArray]
            for (var i = 0, l = del.length; i < l; i++) {
                delete store[del[i]]
                index.splice(this.indexOf(index, del[i]), 1)
            }
            window.top.name = JSON.stringify(data)
            if (cb) this.lambda(cb).call(this)
            return this
        },

        nuke: function (cb) {
            store = {}
            index = []
            window.top.name = JSON.stringify(data)
            if (cb) this.lambda(cb).call(this)
            return this 
        }
    }
/////
})())
/**
 * dom storage adapter 
 * === 
 * - originally authored by Joseph Pecoraro
 *
 */ 
//
// TODO does it make sense to be chainable all over the place?
// chainable: nuke, remove, all, get, save, all    
// not chainable: valid, keys
//
Lawnchair.adapter('dom', (function() {
    var storage = window.localStorage
    // the indexer is an encapsulation of the helpers needed to keep an ordered index of the keys
    var indexer = function(name) {
        return {
            // the key
            key: name + '._index_',
            // returns the index
            all: function() {
				var a  = storage.getItem(this.key)
				if (a) {
					a = JSON.parse(a)
				}
                if (a === null) storage.setItem(this.key, JSON.stringify([])) // lazy init
                return JSON.parse(storage.getItem(this.key))
            },
            // adds a key to the index
            add: function (key) {
                var a = this.all()
                a.push(key)
                storage.setItem(this.key, JSON.stringify(a))
            },
            // deletes a key from the index
            del: function (key) {
                var a = this.all(), r = []
                // FIXME this is crazy inefficient but I'm in a strata meeting and half concentrating
                for (var i = 0, l = a.length; i < l; i++) {
                    if (a[i] != key) r.push(a[i])
                }
                storage.setItem(this.key, JSON.stringify(r))
            },
            // returns index for a key
            find: function (key) {
                var a = this.all()
                for (var i = 0, l = a.length; i < l; i++) {
                    if (key === a[i]) return i 
                }
                return false
            }
        }
    }
    
    // adapter api 
    return {
    
        // ensure we are in an env with localStorage 
        valid: function () {
            return !!storage && function() {
              // in mobile safari if safe browsing is enabled, window.storage
              // is defined but setItem calls throw exceptions.
              var success = true
              var value = Math.random()
              try {
                storage.setItem(value, value)
              } catch (e) {
                success = false
              }
              storage.removeItem(value)
              return success
            }()
        },

        init: function (options, callback) {
            this.indexer = indexer(this.name)
            if (callback) this.fn(this.name, callback).call(this, this)  
        },
        
        save: function (obj, callback) {
            var key = obj.key ? this.name + '.' + obj.key : this.name + '.' + this.uuid()
            // if the key is not in the index push it on
            if (this.indexer.find(key) === false) this.indexer.add(key)
            // now we kil the key and use it in the store colleciton    
            delete obj.key;
            storage.setItem(key, JSON.stringify(obj))
            obj.key = key.slice(this.name.length + 1)
            if (callback) {
                this.lambda(callback).call(this, obj)
            }
            return this
        },

        batch: function (ary, callback) {
            var saved = []
            // not particularily efficient but this is more for sqlite situations
            for (var i = 0, l = ary.length; i < l; i++) {
                this.save(ary[i], function(r){
                    saved.push(r)
                })
            }
            if (callback) this.lambda(callback).call(this, saved)
            return this
        },
       
        // accepts [options], callback
        keys: function(callback) {
            if (callback) { 
                var name = this.name
                ,   keys = this.indexer.all().map(function(r){ return r.replace(name + '.', '') })
                this.fn('keys', callback).call(this, keys)
            }
            return this // TODO options for limit/offset, return promise
        },
        
        get: function (key, callback) {
            if (this.isArray(key)) {
                var r = []
                for (var i = 0, l = key.length; i < l; i++) {
                    var k = this.name + '.' + key[i]
                    var obj = storage.getItem(k)
                    if (obj) {
						obj = JSON.parse(obj)
                        obj.key = key[i]
                        r.push(obj)
                    } 
                }
                if (callback) this.lambda(callback).call(this, r)
            } else {
                var k = this.name + '.' + key
                var  obj = storage.getItem(k)
                if (obj) {
					obj = JSON.parse(obj)
					obj.key = key
				}
                if (callback) this.lambda(callback).call(this, obj)
            }
            return this
        },

        exists: function (key, cb) {
            var exists = this.indexer.find(this.name+'.'+key) === false ? false : true ;
            this.lambda(cb).call(this, exists);
            return this;
        },
        // NOTE adapters cannot set this.__results but plugins do
        // this probably should be reviewed
        all: function (callback) {
            var idx = this.indexer.all()
            ,   r   = []
            ,   o
            ,   k
            for (var i = 0, l = idx.length; i < l; i++) {
                k     = idx[i] //v
                o     = JSON.parse(storage.getItem(k))
                o.key = k.replace(this.name + '.', '')
                r.push(o)
            }
            if (callback) this.fn(this.name, callback).call(this, r)
            return this
        },
        
        remove: function (keyOrObj, callback) {
            var key = this.name + '.' + ((keyOrObj.key) ? keyOrObj.key : keyOrObj)
            this.indexer.del(key)
            storage.removeItem(key)
            if (callback) this.lambda(callback).call(this)
            return this
        },
        
        nuke: function (callback) {
            this.all(function(r) {
                for (var i = 0, l = r.length; i < l; i++) {
                    this.remove(r[i]);
                }
                if (callback) this.lambda(callback).call(this)
            })
            return this 
        }
}})());