// Copyright 2014 Cognitect. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

goog.provide("com.cognitect.transit.impl.writer");
goog.require("com.cognitect.transit.util");
goog.require("com.cognitect.transit.caching");
goog.require("com.cognitect.transit.handlers");
goog.require("com.cognitect.transit.types");
goog.require("com.cognitect.transit.delimiters");
goog.require("goog.math.Long");

goog.scope(function () {

    var writer   = com.cognitect.transit.impl.writer,
        util     = com.cognitect.transit.util,
        caching  = com.cognitect.transit.caching,
        handlers = com.cognitect.transit.handlers,
        types    = com.cognitect.transit.types,
        d        = com.cognitect.transit.delimiters,
        Long     = goog.math.Long;

    writer.escape = function (string) {
        if (string.length > 0) {
            var c = string.charAt(0);
            if (c === d.ESC || c === d.SUB || c === d.RES) {
                return d.ESC + string;
            } else {
                return string;
            }
        } else {
            return string;
        }
    };

    /**
     * @constructor
     */
    writer.JSONMarshaller = function Transit$JSONMarshaller(opts) {
        this.opts = opts || {};
        this.preferStrings = this.opts["preferStrings"] != null ? this.opts["preferStrings"] : true;

        this.objectBuilder = this.opts["objectBuilder"] || null;

        this.handlers = new handlers.Handlers();

        var optsHandlers = this.opts["handlers"];
        if (optsHandlers) {
            if (util.isArray(optsHandlers) || !optsHandlers.forEach) {
                throw new Error("transit writer \"handlers\" option must be a map");
            }
            var self = this;
            optsHandlers.forEach(function (v, k) {
                if (k !== undefined) {
                    self.handlers.set(k, v);
                } else {
                    throw new Error("Cannot create handler for JavaScript undefined");
                }
            });
        }

        // Multiple JS context helper
        this.handlerForForeign = this.opts["handlerForForeign"];

        this.unpack = this.opts["unpack"] || function (x) {
                if (types.isArrayMap(x) && x.backingMap === null) {
                    return x._entries;
                } else {
                    return false;
                }
            };

        this.verbose = (this.opts && this.opts["verbose"]) || false;
    };

    writer.JSONMarshaller.prototype.handler = function (obj) {
        var h = this.handlers.get(handlers.constructor(obj));

        if (h != null) {
            return h;
        } else {
            var tag = obj && obj["transitTag"];
            if (tag) {
                return this.handlers.get(tag)
            } else {
                return null;
            }
        }
    };

    writer.JSONMarshaller.prototype.registerHandler = function (ctor, handler) {
        this.handlers.set(ctor, handler);
    };

    writer.JSONMarshaller.prototype.emitNil = function (asMapKey, cache) {
        if (asMapKey) {
            return this.emitString(d.ESC, "_", "", asMapKey, cache);
        } else {
            return null;
        }
    };

    writer.JSONMarshaller.prototype.emitString = function (prefix, tag, s, asMapKey, cache) {
        var string = prefix + tag + s;
        if (cache) {
            return cache.write(string, asMapKey);
        } else {
            return string;
        }
    };

    writer.JSONMarshaller.prototype.emitBoolean = function (b, asMapKey, cache) {
        if (asMapKey) {
            var s = b.toString();
            return this.emitString(d.ESC, "?", s[0], asMapKey, cache);
        } else {
            return b;
        }
    };

    writer.JSONMarshaller.prototype.emitInteger = function (i, asMapKey, cache) {
        if (i === Infinity) {
            return this.emitString(d.ESC, "z", "INF", asMapKey, cache);
        } else if (i === -Infinity) {
            return this.emitString(d.ESC, "z", "-INF", asMapKey, cache);
        } else if (isNaN(i)) {
            return this.emitString(d.ESC, "z", "NaN", asMapKey, cache);
        } else if (asMapKey || (typeof i === "string") || (i instanceof Long)) {
            return this.emitString(d.ESC, "i", i.toString(), asMapKey, cache);
        } else {
            return i;
        }
    };

    writer.JSONMarshaller.prototype.emitDouble = function (d, asMapKey, cache) {
        if (asMapKey) {
            return this.emitString(d.ESC, "d", d, asMapKey, cache);
        } else {
            return d;
        }
    };

    writer.JSONMarshaller.prototype.emitBinary = function (b, asMapKey, cache) {
        return this.emitString(d.ESC, "b", b, asMapKey, cache);
    };

    writer.JSONMarshaller.prototype.emitQuoted = function (em, obj, cache) {
        if (em.verbose) {
            var ret = {},
                k = this.emitString(d.ESC_TAG, "'", "", true, cache);
            ret[k] = writer.marshal(this, obj, false, cache);
            return ret;
        } else {
            return [this.emitString(d.ESC_TAG, "'", "", true, cache), writer.marshal(this, obj, false, cache)];
        }
    };

    writer.emitObjects = function (em, iterable, cache) {
        var ret = [];
        if (util.isArray(iterable)) {
            for (var i = 0; i < iterable.length; i++) {
                ret.push(writer.marshal(em, iterable[i], false, cache));
            }
        } else {
            iterable.forEach(function (v, i) {
                ret.push(writer.marshal(em, v, false, cache));
            });
        }
        return ret;
    };

    writer.emitArray = function (em, iterable, skip, cache) {
        return writer.emitObjects(em, iterable, cache);
    };

    writer.isStringableKey = function (em, k) {
        if (typeof k !== "string") {
            var h = em.handler(k);
            return h && h.tag(k).length === 1;
        } else {
            return true;
        }
    };

    /**
     * Returns true if map-like obj parameter has only stringable keys -
     * strings, symbols or keywords. If false, obj is a cmap value.
     * @param em
     * @param obj
     * @returns {boolean}
     */
    writer.stringableKeys = function (em, obj) {
        var arr = em.unpack(obj),
            stringableKeys = true;

        if (arr) {
            for (var i = 0; i < arr.length; i += 2) {
                stringableKeys = writer.isStringableKey(em, arr[i]);
                if (!stringableKeys) {
                    break;
                }
            }
            return stringableKeys;
        } else if (obj.keys) {
            var iter = obj.keys(),
                step = null;

            if (iter.next) {
                step = iter.next();
                while (!step.done) {
                    stringableKeys = writer.isStringableKey(em, step.value);
                    if (!stringableKeys) {
                        break;
                    }
                    step = iter.next();
                }
                return stringableKeys;
            }
        }

        if (obj.forEach) {
            obj.forEach(function (v, k) {
                stringableKeys = stringableKeys && writer.isStringableKey(em, k);
            });
            return stringableKeys;
        } else {
            throw new Error("Cannot walk keys of object type " + handlers.constructor(obj).name);
        }
    };

    /**
     * Returns true if x is an Object instance from a different JavaScript
     * context.
     * @param x
     * @returns {boolean}
     */
    writer.isForeignObject = function (x) {
        if (x.constructor["transit$isObject"]) {
            return true;
        }

        var ret = x.constructor.toString();

        ret = ret.substr('function '.length);
        ret = ret.substr(0, ret.indexOf('('));
        isObject = ret == "Object";

        if (typeof Object.defineProperty != "undefined") {
            Object.defineProperty(x.constructor, "transit$isObject", {
                value: isObject,
                enumerable: false
            });
        } else {
            x.constructor["transit$isObject"] = isObject;
        }

        return isObject;
    };

    writer.emitMap = function (em, obj, skip, cache) {
        var arr = null, rep = null, tag = null, ks = null, i = 0;

        if ((obj.constructor === Object) ||
            (obj.forEach != null) ||
            (em.handlerForForeign && writer.isForeignObject(obj))) {
            if (em.verbose) {
                if (obj.forEach != null) {
                    if (writer.stringableKeys(em, obj)) {
                        var ret = {};
                        obj.forEach(function (v, k) {
                            ret[writer.marshal(em, k, true, false)] = writer.marshal(em, v, false, cache);
                        });
                        return ret;
                    } else {
                        arr = em.unpack(obj);
                        rep = [];
                        tag = em.emitString(d.ESC_TAG, "cmap", "", true, cache);
                        if (arr) {
                            for (; i < arr.length; i += 2) {
                                rep.push(writer.marshal(em, arr[i], false, false));
                                rep.push(writer.marshal(em, arr[i + 1], false, cache));
                            }
                        } else {
                            obj.forEach(function (v, k) {
                                rep.push(writer.marshal(em, k, false, false));
                                rep.push(writer.marshal(em, v, false, cache));
                            });
                        }
                        ret = {};
                        ret[tag] = rep;
                        return ret;
                    }
                } else {
                    ks = util.objectKeys(obj);
                    ret = {};
                    for (; i < ks.length; i++) {
                        ret[writer.marshal(em, ks[i], true, false)] = writer.marshal(em, obj[ks[i]], false, cache);
                    }
                    return ret;
                }
            } else {
                if (obj.forEach != null) {
                    if (writer.stringableKeys(em, obj)) {
                        arr = em.unpack(obj);
                        ret = ["^ "];
                        if (arr) {
                            for (; i < arr.length; i += 2) {
                                ret.push(writer.marshal(em, arr[i], true, cache));
                                ret.push(writer.marshal(em, arr[i + 1], false, cache));
                            }
                        } else {
                            obj.forEach(function (v, k) {
                                ret.push(writer.marshal(em, k, true, cache));
                                ret.push(writer.marshal(em, v, false, cache));
                            });
                        }
                        return ret;
                    } else {
                        arr = em.unpack(obj);
                        rep = [];
                        tag = em.emitString(d.ESC_TAG, "cmap", "", true, cache);
                        if (arr) {
                            for (; i < arr.length; i += 2) {
                                rep.push(writer.marshal(em, arr[i], false, cache));
                                rep.push(writer.marshal(em, arr[i + 1], false, cache));
                            }
                        } else {
                            obj.forEach(function (v, k) {
                                rep.push(writer.marshal(em, k, false, cache));
                                rep.push(writer.marshal(em, v, false, cache));
                            });
                        }
                        return [tag, rep];
                    }
                } else {
                    ret = ["^ "];
                    ks = util.objectKeys(obj);
                    for (; i < ks.length; i++) {
                        ret.push(writer.marshal(em, ks[i], true, cache));
                        ret.push(writer.marshal(em, obj[ks[i]], false, cache));
                    }
                    return ret;
                }
            }
        } else if (em.objectBuilder != null) {
            return em.objectBuilder(obj, function (k) {
                    return writer.marshal(em, k, true, cache);
                },
                function (v) {
                    return writer.marshal(em, v, false, cache);
                });
        } else {
            var name = handlers.constructor(obj).name,
                err = new Error("Cannot write " + name);
            err.data = {obj: obj, type: name};
            throw err;
        }
    };

    writer.emitTaggedMap = function (em, tag, rep, skip, cache) {
        if (em.verbose) {
            var ret = {};
            ret[em.emitString(d.ESC_TAG, tag, "", true, cache)] = writer.marshal(em, rep, false, cache);
            return ret;
        } else {
            return [em.emitString(d.ESC_TAG, tag, "", true, cache), writer.marshal(em, rep, false, cache)];
        }
    };

    writer.emitEncoded = function (em, h, tag, rep, obj, asMapKey, cache) {
        if (tag.length === 1) {
            if (typeof rep === "string") {
                return em.emitString(d.ESC, tag, rep, asMapKey, cache);
            } else if (asMapKey || em.preferStrings) {
                var vh = em.verbose && h.getVerboseHandler();
                if (vh) {
                    tag = vh.tag(obj);
                    rep = vh.stringRep(obj, vh);
                } else {
                    rep = h.stringRep(obj, h);
                }
                if (rep !== null) {
                    return em.emitString(d.ESC, tag, rep, asMapKey, cache);
                } else {
                    var err = new Error("Tag \"" + tag + "\" cannot be encoded as string");
                    err.data = {tag: tag, rep: rep, obj: obj};
                    throw err;
                }
            } else {
                return writer.emitTaggedMap(em, tag, rep, asMapKey, cache);
            }
        } else {
            return writer.emitTaggedMap(em, tag, rep, asMapKey, cache);
        }
    };

    writer.marshal = function (em, obj, asMapKey, cache) {
        var h = em.handler(obj) || (em.handlerForForeign ? em.handlerForForeign(obj, em.handlers) : null),
            tag = h ? h.tag(obj) : null,
            rep = h ? h.rep(obj) : null;

        if (h != null && tag != null) {
            switch (tag) {
                case "_":
                    return em.emitNil(asMapKey, cache);
                    break;
                case "s":
                    return em.emitString("", "", writer.escape(rep), asMapKey, cache);
                    break;
                case "?":
                    return em.emitBoolean(rep, asMapKey, cache);
                    break;
                case "i":
                    return em.emitInteger(rep, asMapKey, cache);
                    break;
                case "d":
                    return em.emitDouble(rep, asMapKey, cache);
                    break;
                case "b":
                    return em.emitBinary(rep, asMapKey, cache);
                    break;
                case "'":
                    return em.emitQuoted(em, rep, cache);
                    break;
                case "array":
                    return writer.emitArray(em, rep, asMapKey, cache);
                    break;
                case "map":
                    return writer.emitMap(em, rep, asMapKey, cache);
                    break;
                default:
                    return writer.emitEncoded(em, h, tag, rep, obj, asMapKey, cache);
                    break;
            }
        } else {
            var name = handlers.constructor(obj).name,
                err = new Error("Cannot write " + name);
            err.data = {obj: obj, type: name};
            throw err;
        }
    };

    writer.maybeQuoted = function (em, obj) {
        var h = em.handler(obj) || (em.handlerForForeign ? em.handlerForForeign(obj, em.handlers) : null);

        if (h != null) {
            if (h.tag(obj).length === 1) {
                return types.quoted(obj);
            } else {
                return obj;
            }
        } else {
            var name = handlers.constructor(obj).name,
                err = new Error("Cannot write " + name);
            err.data = {obj: obj, type: name};
            throw err;
        }
    };

    writer.marshalTop = function (em, obj, asMapKey, cache) {
        return JSON.stringify(writer.marshal(em, writer.maybeQuoted(em, obj), asMapKey, cache));
    };

    /**
     * @constructor
     */
    writer.Writer = function Transit$Writer(marshaller, options) {
        this._marshaller = marshaller;
        this.options = options || {};
        if (this.options["cache"] === false) {
            this.cache = null;
        } else {
            this.cache = this.options["cache"] ? this.options["cache"] : new caching.WriteCache();
        }
    };

    writer.Writer.prototype.marshaller = function () {
        return this._marshaller;
    };
    writer.Writer.prototype["marshaller"] = writer.Writer.prototype.marshaller;

    writer.Writer.prototype.write = function (obj, opts) {
        var ret = null,
            ropts = opts || {},
            asMapKey = ropts["asMapKey"] || false,
            cache = this._marshaller.verbose ? false : this.cache;

        if (ropts["marshalTop"] === false) {
            ret = writer.marshal(this._marshaller, obj, asMapKey, cache)
        } else {
            ret = writer.marshalTop(this._marshaller, obj, asMapKey, cache)
        }
        if (this.cache != null) {
            this.cache.clear();
        }
        return ret;
    };
    writer.Writer.prototype["write"] = writer.Writer.prototype.write;

    writer.Writer.prototype.register = function (type, handler) {
        this._marshaller.registerHandler(type, handler);
    };
    writer.Writer.prototype["register"] = writer.Writer.prototype.register;

});