import parse       from './parse';
import Root        from './root';
import Rule        from './rule';
import AtRule      from './at-rule';
import Declaration from './declaration';
import warnOnce    from './warn-once';
import Comment     from './comment';
import Node        from './node';

function cleanSource(nodes) {
    return nodes.map( i => {
        if ( i.nodes ) i.nodes = cleanSource(i.nodes);
        delete i.source;
        return i;
    });
}

/**
 * @callback childCondition
 * @param {Node} node    - container child
 * @param {number} index - child index
 * @param {Node[]} nodes - all container children
 * @return {boolean}
 */

 /**
  * @callback childIterator
  * @param {Node} node    - container child
  * @param {number} index - child index
  * @return {false|undefined} returning `false` will break iteration
  */

/**
 * The {@link Root}, {@link AtRule}, and {@link Rule} container nodes
 * inherit some common methods to help work with their children.
 *
 * Note that all containers can store any content. If you write a rule inside
 * a rule, PostCSS will parse it.
 *
 * @extends Node
 * @abstract
 */
class Container extends Node {

    push(child) {
        child.parent = this;
        this.nodes.push(child);
        return this;
    }

    /**
     * Iterates through the container’s immediate children,
     * calling `callback` for each child.
     *
     * Returning `false` in the callback will break iteration.
     *
     * This method only iterates through the container’s immediate children.
     * If you need to recursively iterate through all the container’s descendant
     * nodes, use {@link Container#walk}.
     *
     * Unlike the for `{}`-cycle or `Array#forEach` this iterator is safe
     * if you are mutating the array of child nodes during iteration.
     * PostCSS will adjust the current index to match the mutations.
     *
     * @param {childIterator} callback - iterator receives each node and index
     *
     * @return {false|undefined} returns `false` if iteration was broke
     *
     * @example
     * const root = postcss.parse('a { color: black; z-index: 1 }');
     * const rule = root.first;
     *
     * for ( let decl of rule.nodes ) {
     *     decl.cloneBefore({ prop: '-webkit-' + decl.prop });
     *     // Cycle will be infinite, because cloneBefore moves the current node
     *     // to the next index
     * }
     *
     * rule.each(decl => {
     *     decl.cloneBefore({ prop: '-webkit-' + decl.prop });
     *     // Will be executed only for color and z-index
     * });
     */
    each(callback) {
        if ( !this.lastEach ) this.lastEach = 0;
        if ( !this.indexes ) this.indexes = { };

        this.lastEach += 1;
        let id = this.lastEach;
        this.indexes[id] = 0;

        if ( !this.nodes ) return undefined;

        let index, result;
        while ( this.indexes[id] < this.nodes.length ) {
            index  = this.indexes[id];
            result = callback(this.nodes[index], index);
            if ( result === false ) break;

            this.indexes[id] += 1;
        }

        delete this.indexes[id];

        return result;
    }

    /**
     * Traverses the container’s descendant nodes, calling callback
     * for each node.
     *
     * Like container.each(), this method is safe to use
     * if you are mutating arrays during iteration.
     *
     * If you only need to iterate through the container’s immediate children,
     * use {@link Container#each}.
     *
     * @param {childIterator} callback - iterator receives each node and index
     *
     * @return {false|undefined} returns `false` if iteration was broke
     *
     * @example
     * root.walk(node => {
     *   // Traverses all descendant nodes.
     * });
     */
    walk(callback) {
        return this.each( (child, i) => {
            let result = callback(child, i);
            if ( result !== false && child.walk ) {
                result = child.walk(callback);
            }
            return result;
        });
    }

    /**
     * Traverses the container’s descendant nodes, calling callback
     * for each declaration node.
     *
     * If you pass a filter, iteration will only happen over declarations
     * with matching properties.
     *
     * Like {@link Container#each}, this method is safe
     * to use if you are mutating arrays during iteration.
     *
     * @param {string|RegExp} [prop]   - string or regular expression
     *                                   to filter declarations by property name
     * @param {childIterator} callback - iterator receives each node and index
     *
     * @return {false|undefined} returns `false` if iteration was broke
     *
     * @example
     * root.walkDecls(decl => {
     *   checkPropertySupport(decl.prop);
     * });
     *
     * root.walkDecls('border-radius', decl => {
     *   decl.remove();
     * });
     *
     * root.walkDecls(/^background/, decl => {
     *   decl.value = takeFirstColorFromGradient(decl.value);
     * });
     */
    walkDecls(prop, callback) {
        if ( !callback ) {
            callback = prop;
            return this.walk( (child, i) => {
                if ( child.type === 'decl' ) {
                    return callback(child, i);
                }
            });
        } else if ( prop instanceof RegExp ) {
            return this.walk( (child, i) => {
                if ( child.type === 'decl' && prop.test(child.prop) ) {
                    return callback(child, i);
                }
            });
        } else {
            return this.walk( (child, i) => {
                if ( child.type === 'decl' && child.prop === prop ) {
                    return callback(child, i);
                }
            });
        }
    }

    /**
     * Traverses the container’s descendant nodes, calling callback
     * for each rule node.
     *
     * If you pass a filter, iteration will only happen over rules
     * with matching selectors.
     *
     * Like {@link Container#each}, this method is safe
     * to use if you are mutating arrays during iteration.
     *
     * @param {string|RegExp} [selector] - string or regular expression
     *                                     to filter rules by selector
     * @param {childIterator} callback   - iterator receives each node and index
     *
     * @return {false|undefined} returns `false` if iteration was broke
     *
     * @example
     * const selectors = [];
     * root.walkRules(rule => {
     *   selectors.push(rule.selector);
     * });
     * console.log(`Your CSS uses ${selectors.length} selectors`);
     */
    walkRules(selector, callback) {
        if ( !callback ) {
            callback = selector;

            return this.walk( (child, i) => {
                if ( child.type === 'rule' ) {
                    return callback(child, i);
                }
            });
        } else if ( selector instanceof RegExp ) {
            return this.walk( (child, i) => {
                if ( child.type === 'rule' && selector.test(child.selector) ) {
                    return callback(child, i);
                }
            });
        } else {
            return this.walk( (child, i) => {
                if ( child.type === 'rule' && child.selector === selector ) {
                    return callback(child, i);
                }
            });
        }
    }

    /**
     * Traverses the container’s descendant nodes, calling callback
     * for each at-rule node.
     *
     * If you pass a filter, iteration will only happen over at-rules
     * that have matching names.
     *
     * Like {@link Container#each}, this method is safe
     * to use if you are mutating arrays during iteration.
     *
     * @param {string|RegExp} [name]   - string or regular expression
     *                                   to filter at-rules by name
     * @param {childIterator} callback - iterator receives each node and index
     *
     * @return {false|undefined} returns `false` if iteration was broke
     *
     * @example
     * root.walkAtRules(rule => {
     *   if ( isOld(rule.name) ) rule.remove();
     * });
     *
     * let first = false;
     * root.walkAtRules('charset', rule => {
     *   if ( !first ) {
     *     first = true;
     *   } else {
     *     rule.remove();
     *   }
     * });
     */
    walkAtRules(name, callback) {
        if ( !callback ) {
            callback = name;
            return this.walk( (child, i) => {
                if ( child.type === 'atrule' ) {
                    return callback(child, i);
                }
            });
        } else if ( name instanceof RegExp ) {
            return this.walk( (child, i) => {
                if ( child.type === 'atrule' && name.test(child.name) ) {
                    return callback(child, i);
                }
            });
        } else {
            return this.walk( (child, i) => {
                if ( child.type === 'atrule' && child.name === name ) {
                    return callback(child, i);
                }
            });
        }
    }

    /**
     * Traverses the container’s descendant nodes, calling callback
     * for each comment node.
     *
     * Like {@link Container#each}, this method is safe
     * to use if you are mutating arrays during iteration.
     *
     * @param {childIterator} callback - iterator receives each node and index
     *
     * @return {false|undefined} returns `false` if iteration was broke
     *
     * @example
     * root.walkComments(comment => {
     *   comment.remove();
     * });
     */
    walkComments(callback) {
        return this.walk( (child, i) => {
            if ( child.type === 'comment' ) {
                return callback(child, i);
            }
        });
    }

    /**
     * Inserts new nodes to the start of the container.
     *
     * @param {...(Node|object|string|Node[])} children - new nodes
     *
     * @return {Node} this node for methods chain
     *
     * @example
     * const decl1 = postcss.decl({ prop: 'color', value: 'black' });
     * const decl2 = postcss.decl({ prop: 'background-color', value: 'white' });
     * rule.append(decl1, decl2);
     *
     * root.append({ name: 'charset', params: '"UTF-8"' });  // at-rule
     * root.append({ selector: 'a' });                       // rule
     * rule.append({ prop: 'color', value: 'black' });       // declaration
     * rule.append({ text: 'Comment' })                      // comment
     *
     * root.append('a {}');
     * root.first.append('color: black; z-index: 1');
     */
    append(...children) {
        children.forEach(child => {
            let nodes = this.normalize(child, this.last);
            nodes.forEach(node => this.nodes.push(node));
        })
        return this;
    }

    /**
     * Inserts new nodes to the end of the container.
     *
     * @param {...(Node|object|string|Node[])} children - new nodes
     *
     * @return {Node} this node for methods chain
     *
     * @example
     * const decl1 = postcss.decl({ prop: 'color', value: 'black' });
     * const decl2 = postcss.decl({ prop: 'background-color', value: 'white' });
     * rule.prepend(decl1, decl2);
     *
     * root.append({ name: 'charset', params: '"UTF-8"' });  // at-rule
     * root.append({ selector: 'a' });                       // rule
     * rule.append({ prop: 'color', value: 'black' });       // declaration
     * rule.append({ text: 'Comment' })                      // comment
     *
     * root.append('a {}');
     * root.first.append('color: black; z-index: 1');
     */
    prepend(...children) {
        children = children.reverse();
        children.forEach(child => {
            let nodes = this.normalize(child, this.first, 'prepend').reverse();
            nodes.forEach(node => this.nodes.unshift(node))
            for ( let id in this.indexes ) {
                this.indexes[id] = this.indexes[id] + nodes.length;
            }
        })
        return this;
    }

    cleanRaws(keepBetween) {
        super.cleanRaws(keepBetween);
        if ( this.nodes ) {
          this.nodes.forEach(node => node.cleanRaws(keepBetween));
        }
    }

    /**
     * Insert new node before old node within the container.
     *
     * @param {Node|number} exist             - child or child’s index.
     * @param {Node|object|string|Node[]} add - new node
     *
     * @return {Node} this node for methods chain
     *
     * @example
     * rule.insertBefore(decl, decl.clone({ prop: '-webkit-' + decl.prop }));
     */
    insertBefore(exist, add) {
        exist = this.index(exist);

        let type  = exist === 0 ? 'prepend' : false;
        let nodes = this.normalize(add, this.nodes[exist], type).reverse();
        nodes.forEach(node => this.nodes.splice(exist, 0, node));

        let index;
        for ( let id in this.indexes ) {
            index = this.indexes[id];
            if ( exist <= index ) {
                this.indexes[id] = index + nodes.length;
            }
        }

        return this;
    }

    /**
     * Insert new node after old node within the container.
     *
     * @param {Node|number} exist             - child or child’s index
     * @param {Node|object|string|Node[]} add - new node
     *
     * @return {Node} this node for methods chain
     */
    insertAfter(exist, add) {
        exist = this.index(exist);

        let nodes = this.normalize(add, this.nodes[exist]).reverse();
        nodes.forEach(node =>  this.nodes.splice(exist + 1, 0, node))

        let index;
        for ( let id in this.indexes ) {
            index = this.indexes[id];
            if ( exist < index ) {
                this.indexes[id] = index + nodes.length;
            }
        }

        return this;
    }

    remove(child) {
        if ( typeof child !== 'undefined' ) {
            warnOnce('Container#remove is deprecated. ' +
                     'Use Container#removeChild');
            this.removeChild(child);
        } else {
            super.remove();
        }
        return this;
    }

    /**
     * Removes node from the container and cleans the parent properties
     * from the node and its children.
     *
     * @param {Node|number} child - child or child’s index
     *
     * @return {Node} this node for methods chain
     *
     * @example
     * rule.nodes.length  //=> 5
     * rule.removeChild(decl);
     * rule.nodes.length  //=> 4
     * decl.parent        //=> undefined
     */
    removeChild(child) {
        child = this.index(child);
        this.nodes[child].parent = undefined;
        this.nodes.splice(child, 1);

        let index;
        for ( let id in this.indexes ) {
            index = this.indexes[id];
            if ( index >= child ) {
                this.indexes[id] = index - 1;
            }
        }

        return this;
    }

    /**
     * Removes all children from the container
     * and cleans their parent properties.
     *
     * @return {Node} this node for methods chain
     *
     * @example
     * rule.removeAll();
     * rule.nodes.length //=> 0
     */
    removeAll() {
        this.nodes.forEach(node =>  node.parent = undefined)
        this.nodes = [];
        return this;
    }

    /**
     * Passes all declaration values within the container that match pattern
     * through callback, replacing those values with the returned result
     * of callback.
     *
     * This method is useful if you are using a custom unit or function
     * and need to iterate through all values.
     *
     * @param {string|RegExp} pattern      - replace pattern
     * @param {object} opts                - options to speed up the search
     * @param {string|string[]} opts.props - an array of property names
     * @param {string} opts.fast           - string that’s used
     *                                       to narrow down values and speed up
                                             the regexp search
     * @param {function|string} callback   - string to replace pattern
     *                                       or callback that returns a new
     *                                       value.
     *                                       The callback will receive
     *                                       the same arguments as those
     *                                       passed to a function parameter
     *                                       of `String#replace`.
     *
     * @return {Node} this node for methods chain
     *
     * @example
     * root.replaceValues(/\d+rem/, { fast: 'rem' }, string => {
     *   return 15 * parseInt(string) + 'px';
     * });
     */
    replaceValues(pattern, opts, callback) {
        if ( !callback ) {
            callback = opts;
            opts = { };
        }

        this.walkDecls( decl => {
            if ( opts.props && opts.props.indexOf(decl.prop) === -1 ) return;
            if ( opts.fast  && decl.value.indexOf(opts.fast) === -1 ) return;

            decl.value = decl.value.replace(pattern, callback);
        });

        return this;
    }

    /**
     * Returns `true` if callback returns `true`
     * for all of the container’s children.
     *
     * @param {childCondition} condition - iterator returns true or false.
     *
     * @return {boolean} is every child pass condition
     *
     * @example
     * const noPrefixes = rule.every(i => i.prop[0] !== '-');
     */
    every(condition) {
        return this.nodes.every(condition);
    }

    /**
     * Returns `true` if callback returns `true` for (at least) one
     * of the container’s children.
     *
     * @param {childCondition} condition - iterator returns true or false.
     *
     * @return {boolean} is some child pass condition
     *
     * @example
     * const hasPrefix = rule.some(i => i.prop[0] === '-');
     */
    some(condition) {
        return this.nodes.some(condition);
    }

    /**
     * Returns a `child`’s index within the {@link Container#nodes} array.
     *
     * @param {Node} child - child of the current container.
     *
     * @return {number} child index
     *
     * @example
     * rule.index( rule.nodes[2] ) //=> 2
     */
    index(child) {
        if ( typeof child === 'number' ) {
            return child;
        } else {
            return this.nodes.indexOf(child);
        }
    }

    /**
     * The container’s first child.
     *
     * @type {Node}
     *
     * @example
     * rule.first == rules.nodes[0];
     */
    get first() {
        if ( !this.nodes ) return undefined;
        return this.nodes[0];
    }

    /**
     * The container’s last child.
     *
     * @type {Node}
     *
     * @example
     * rule.last == rule.nodes[rule.nodes.length - 1];
     */
    get last() {
        if ( !this.nodes ) return undefined;
        return this.nodes[this.nodes.length - 1];
    }

    normalize(nodes, sample) {
        if ( typeof nodes === 'string' ) {
            nodes = cleanSource(parse(nodes).nodes);
        } else if ( !Array.isArray(nodes) ) {
            if ( nodes.type === 'root' ) {
                nodes = nodes.nodes;
            } else if ( nodes.type ) {
                nodes = [nodes];
            } else if ( nodes.prop ) {
                if ( typeof nodes.value === 'undefined' ) {
                    throw new Error('Value field is missed in node creation');
                } else if ( typeof nodes.value !== 'string' ) {
                    nodes.value = String(nodes.value);
                }
                nodes = [new Declaration(nodes)];
            } else if ( nodes.selector ) {
                nodes = [new Rule(nodes)];
            } else if ( nodes.name ) {
                nodes = [new AtRule(nodes)];
            } else if ( nodes.text ) {
                nodes = [new Comment(nodes)];
            } else {
                throw new Error('Unknown node type in node creation');
            }
        }

        let processed = nodes.map( i => {
            if ( typeof i.raws === 'undefined' ) i = this.rebuild(i);

            if ( i.parent ) i = i.clone();
            if ( typeof i.raws.before === 'undefined' ) {
                if ( sample && typeof sample.raws.before !== 'undefined' ) {
                    i.raws.before = sample.raws.before.replace(/[^\s]/g, '');
                }
            }
            i.parent = this;
            return i;
        });

        return processed;
    }

    rebuild(node, parent) {
        let fix;
        if ( node.type === 'root' ) {
            fix = new Root();
        } else if ( node.type === 'atrule' ) {
            fix = new AtRule();
        } else if ( node.type === 'rule' ) {
            fix = new Rule();
        } else if ( node.type === 'decl' ) {
            fix = new Declaration();
        } else if ( node.type === 'comment' ) {
            fix = new Comment();
        }

        for ( let i in node ) {
            if ( i === 'nodes' ) {
                fix.nodes = node.nodes.map( j => this.rebuild(j, fix) );
            } else if ( i === 'parent' && parent ) {
                fix.parent = parent;
            } else if ( node.hasOwnProperty(i) ) {
                fix[i] = node[i];
            }
        }

        return fix;
    }

    eachInside(callback) {
        warnOnce('Container#eachInside is deprecated. ' +
                 'Use Container#walk instead.');
        return this.walk(callback);
    }

    eachDecl(prop, callback) {
        warnOnce('Container#eachDecl is deprecated. ' +
                 'Use Container#walkDecls instead.');
        return this.walkDecls(prop, callback);
    }

    eachRule(selector, callback) {
        warnOnce('Container#eachRule is deprecated. ' +
                 'Use Container#walkRules instead.');
        return this.walkRules(selector, callback);
    }

    eachAtRule(name, callback) {
        warnOnce('Container#eachAtRule is deprecated. ' +
                 'Use Container#walkAtRules instead.');
        return this.walkAtRules(name, callback);
    }

    eachComment(callback) {
        warnOnce('Container#eachComment is deprecated. ' +
                 'Use Container#walkComments instead.');
        return this.walkComments(callback);
    }

    get semicolon() {
        warnOnce('Node#semicolon is deprecated. Use Node#raws.semicolon');
        return this.raws.semicolon;
    }

    set semicolon(val) {
        warnOnce('Node#semicolon is deprecated. Use Node#raws.semicolon');
        this.raws.semicolon = val;
    }

    get after() {
        warnOnce('Node#after is deprecated. Use Node#raws.after');
        return this.raws.after;
    }

    set after(val) {
        warnOnce('Node#after is deprecated. Use Node#raws.after');
        this.raws.after = val;
    }

    /**
     * @memberof Container#
     * @member {Node[]} nodes - an array containing the container’s children
     *
     * @example
     * const root = postcss.parse('a { color: black }');
     * root.nodes.length           //=> 1
     * root.nodes[0].selector      //=> 'a'
     * root.nodes[0].nodes[0].prop //=> 'color'
     */

}

export default Container;