var OKCMS = (function(){
  
  var adminRoot = window.location.pathname.split("/")[1]
  var adminDB = [ "", adminRoot, "index.json" ].join("/")
  
  var OKCMS = function(opt){
    this.opt = Object.assign({
      ready: function(){},
    }, opt || {})
    this.fetch()
  }
  OKCMS.prototype.fetch = function(){
    $.ajax({
      url: adminDB,
      type: "GET",
      success: this.load.bind(this)
    })
  }
  OKCMS.prototype.load = function(data){
    this.data = data
    // data.meta
    // data.resources by type
    // data.resources[types].type
    // data.resources[types].spec
    // data.resources[types].groupBy
    // data.resources[types].descending
    // data.resources[types].data[]
    // data.resources[types].data[0][groupBy][group]
    var resources = this.resources = {}
    this.types = Object.keys(data.resources)
    this.types.forEach(function(type){
      var resource = data.resources[type]
      resources[resource.type] = resource
      resource.lookup = {}
      if (resource.groupBy) {
        var group_lookup = resource.data[0][resource.groupBy]
        var groups = Object.keys(group_lookup)
        resource.index = []
        groups.forEach(function(group){
          var list = group_lookup[group]
          list.forEach(function(record){
            resource.lookup[record.id] = record
            resource.index.push(record)
          })
        })
      }
      else {
        resource.data.forEach(function(record){
          resource.lookup[record.id] = record
        })
      }
    })
    this.opt.ready && this.opt.ready()
  }
  OKCMS.prototype.getResource = function(type){
    var resource = this.resources[type]
    if (! resource) throw new Error ("Resource not found: " + type)
    return resource
  }
  OKCMS.prototype.index = function(type){
    var resource = this.getResource(type)
    return resource.index
  }
  OKCMS.prototype.groups = function(type){
    var resource = this.getResource(type)
    return resource.data[0][resource.groupBy]
  }
  OKCMS.prototype.keys = function(type){
    var index = this.index(type)
    var keys = index.map(function(rec){
      return rec.id
    })
    return keys
  }
  OKCMS.prototype.spec = function(type){
    var resource = this.getResource(type)
    return resource.spec
  }
  OKCMS.prototype.get = function(type, id){
    var resource = this.getResource(type)
    if (id in resource.index) {
      return resource.index[id]
    }
    throw new Error ("Key not found: " + type + ":" + id)
  }
  OKCMS.prototype.new = function(type){
    var resource = this.resource(type)
    var spec = this.spec(type)
    var record = {}
    Object.keys(spec).forEach(function(key){
      var field = spec[key]
      switch (field.type) {
        case 'foreign-key':
          record[key] = ""
          break
        
        case 'enum':
          record[key] = field.values[0]
          break

        case 'meta':
          if (key === "__index") {
            record[key] = resource.index.length
          }
          else if (key === "dateCreated") {
            record[key] = (new Date ()).toUTCString()
          }
          else {
            record[key] = "" // ???
          }
          break
        
        case 'date':
          record[key] = new Date
          break
        
        case 'flag':
          record[key] = false
          break
        
        case 'link-list':
        case 'gallery':
        case 'media':
          record[key] = []
          break

        case 'image':
        case 'video':
          record[key] = {}
          break

        case 'number':
          record[key] = 0
          break

        case 'string':
        case 'text':
        default:
          record[key] = ""
          break
      }
    })
    return record
  }
  OKCMS.prototype.enum_keys = function(type, field){
    var spec = this.spec(type)
    var field = spec[field]
    if (! field) throw new Error ("No such field: " + field)
    if (field.type == "enum") {
      return field.options
    }
    else if (field.type == "foreign-key") {
      return this.keys(field.key)
    }
  }
  OKCMS.prototype.save = function(type, data, cb){
    if (! data.id) {
      this.create(type, data, cb)
    } else {
      this.update(type, data, cb)
    }
  }
  OKCMS.prototype.create = function(type, data, cb){
    var resource = this.getResource(type)
    if (! data.title) {
      throw new Error ("Title field is empty")
    }
    if (! data.id) {
      data.id = slugify( data.title )
    }
    $.ajax({
      url: [ "", adminRoot, type ].join("/"),
      type: "POST",
      success: function(){
        cb && cb()
      }
    })
  }
  OKCMS.prototype.update = function(type, data, cb){
    var resource = this.getResource(type)
    var id = data.id
    
    // /admin/:type/:id/
    $.ajax({
      url: [ "", adminRoot, type, id ].join("/"),
      type: "PUT",
      data: data,
      success: function(){
        cb && cb()
      }
    })
  }
  OKCMS.prototype.destroy = function(type, id, cb){
    $.ajax({
      url: [ "", adminRoot, type, id ].join("/"),
      type: "DELETE",
      success: function(){
        cb && cb()
      }
    })
  }

  function slugify (s){
    return (s || "").toLowerCase().replace(/\s/g,"-").replace(/[^-_a-zA-Z0-9]/g, '-').replace(/-+/g, "-")
  }

})()