/**
 * @fileoverview Operator linebreak - enforces operator linebreak style of two types: after and before
 * @author Benoît Zugmeyer
 * @copyright 2015 Benoît Zugmeyer. All rights reserved.
 */

"use strict";

var assign = require("object-assign"),
    astUtils = require("../ast-utils");

//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------

module.exports = function(context) {

    var usedDefaultGlobal = !context.options[0];
    var globalStyle = context.options[0] || "after";
    var options = context.options[1] || {};
    var styleOverrides = options.overrides ? assign({}, options.overrides) : {};

    if (usedDefaultGlobal && !styleOverrides["?"]) {
        styleOverrides["?"] = "before";
    }

    if (usedDefaultGlobal && !styleOverrides[":"]) {
        styleOverrides[":"] = "before";
    }

    //--------------------------------------------------------------------------
    // Helpers
    //--------------------------------------------------------------------------

    /**
     * Checks the operator placement
     * @param {ASTNode} node The node to check
     * @param {ASTNode} leftSide The node that comes before the operator in `node`
     * @private
     * @returns {void}
     */
    function validateNode(node, leftSide) {
        var leftToken = context.getLastToken(leftSide);
        var operatorToken = context.getTokenAfter(leftToken);

        // When the left part of a binary expression is a single expression wrapped in
        // parentheses (ex: `(a) + b`), leftToken will be the last token of the expression
        // and operatorToken will be the closing parenthesis.
        // The leftToken should be the last closing parenthesis, and the operatorToken
        // should be the token right after that.
        while (operatorToken.value === ")") {
            leftToken = operatorToken;
            operatorToken = context.getTokenAfter(operatorToken);
        }

        var rightToken = context.getTokenAfter(operatorToken);
        var operator = operatorToken.value;
        var style = styleOverrides[operator] || globalStyle;

        // if single line
        if (astUtils.isTokenOnSameLine(leftToken, operatorToken) &&
                astUtils.isTokenOnSameLine(operatorToken, rightToken)) {

            return;

        } else if (!astUtils.isTokenOnSameLine(leftToken, operatorToken) &&
                !astUtils.isTokenOnSameLine(operatorToken, rightToken)) {

            // lone operator
            context.report(node, {
                line: operatorToken.loc.end.line,
                column: operatorToken.loc.end.column
            }, "Bad line breaking before and after '" + operator + "'.");

        } else if (style === "before" && astUtils.isTokenOnSameLine(leftToken, operatorToken)) {

            context.report(node, {
                line: operatorToken.loc.end.line,
                column: operatorToken.loc.end.column
            }, "'" + operator + "' should be placed at the beginning of the line.");

        } else if (style === "after" && astUtils.isTokenOnSameLine(operatorToken, rightToken)) {

            context.report(node, {
                line: operatorToken.loc.end.line,
                column: operatorToken.loc.end.column
            }, "'" + operator + "' should be placed at the end of the line.");

        } else if (style === "none") {

            context.report(node, {
                line: operatorToken.loc.end.line,
                column: operatorToken.loc.end.column
            }, "There should be no line break before or after '" + operator + "'");

        }
    }

    /**
     * Validates a binary expression using `validateNode`
     * @param {BinaryExpression|LogicalExpression|AssignmentExpression} node node to be validated
     * @returns {void}
     */
    function validateBinaryExpression(node) {
        validateNode(node, node.left);
    }

    //--------------------------------------------------------------------------
    // Public
    //--------------------------------------------------------------------------

    return {
        "BinaryExpression": validateBinaryExpression,
        "LogicalExpression": validateBinaryExpression,
        "AssignmentExpression": validateBinaryExpression,
        "VariableDeclarator": function(node) {
            if (node.init) {
                validateNode(node, node.id);
            }
        },
        "ConditionalExpression": function(node) {
            validateNode(node, node.test);
            validateNode(node, node.consequent);
        }
    };
};

module.exports.schema = [
    {
        "enum": ["after", "before", "none", null]
    },
    {
        "type": "object",
        "properties": {
            "overrides": {
                "type": "object",
                "properties": {
                    "anyOf": {
                        "type": "string",
                        "enum": ["after", "before", "none"]
                    }
                }
            }
        },
        "additionalProperties": false
    }
];