var Node = require("./node"),
    Selector = require("./selector"),
    MixinDefinition = require("./mixin-definition"),
    defaultFunc = require("../functions/default");

var MixinCall = function (elements, args, index, currentFileInfo, important) {
    this.selector = new Selector(elements);
    this.arguments = (args && args.length) ? args : null;
    this.index = index;
    this.currentFileInfo = currentFileInfo;
    this.important = important;
};
MixinCall.prototype = new Node();
MixinCall.prototype.type = "MixinCall";
MixinCall.prototype.accept = function (visitor) {
    if (this.selector) {
        this.selector = visitor.visit(this.selector);
    }
    if (this.arguments) {
        this.arguments = visitor.visitArray(this.arguments);
    }
};
MixinCall.prototype.eval = function (context) {
    var mixins, mixin, mixinPath, args, rules = [], match = false, i, m, f, isRecursive, isOneFound, rule,
        candidates = [], candidate, conditionResult = [], defaultResult, defFalseEitherCase=-1,
        defNone = 0, defTrue = 1, defFalse = 2, count, originalRuleset, noArgumentsFilter;

    function calcDefGroup(mixin, mixinPath) {
        var p, namespace;

        for (f = 0; f < 2; f++) {
            conditionResult[f] = true;
            defaultFunc.value(f);
            for(p = 0; p < mixinPath.length && conditionResult[f]; p++) {
                namespace = mixinPath[p];
                if (namespace.matchCondition) {
                    conditionResult[f] = conditionResult[f] && namespace.matchCondition(null, context);
                }
            }
            if (mixin.matchCondition) {
                conditionResult[f] = conditionResult[f] && mixin.matchCondition(args, context);
            }
        }
        if (conditionResult[0] || conditionResult[1]) {
            if (conditionResult[0] != conditionResult[1]) {
                return conditionResult[1] ?
                    defTrue : defFalse;
            }

            return defNone;
        }
        return defFalseEitherCase;
    }

    args = this.arguments && this.arguments.map(function (a) {
        return { name: a.name, value: a.value.eval(context) };
    });

    noArgumentsFilter = function(rule) {return rule.matchArgs(null, context);};

    for (i = 0; i < context.frames.length; i++) {
        if ((mixins = context.frames[i].find(this.selector, null, noArgumentsFilter)).length > 0) {
            isOneFound = true;

            // To make `default()` function independent of definition order we have two "subpasses" here.
            // At first we evaluate each guard *twice* (with `default() == true` and `default() == false`),
            // and build candidate list with corresponding flags. Then, when we know all possible matches,
            // we make a final decision.

            for (m = 0; m < mixins.length; m++) {
                mixin = mixins[m].rule;
                mixinPath = mixins[m].path;
                isRecursive = false;
                for(f = 0; f < context.frames.length; f++) {
                    if ((!(mixin instanceof MixinDefinition)) && mixin === (context.frames[f].originalRuleset || context.frames[f])) {
                        isRecursive = true;
                        break;
                    }
                }
                if (isRecursive) {
                    continue;
                }

                if (mixin.matchArgs(args, context)) {
                    candidate = {mixin: mixin, group: calcDefGroup(mixin, mixinPath)};

                    if (candidate.group!==defFalseEitherCase) {
                        candidates.push(candidate);
                    }

                    match = true;
                }
            }

            defaultFunc.reset();

            count = [0, 0, 0];
            for (m = 0; m < candidates.length; m++) {
                count[candidates[m].group]++;
            }

            if (count[defNone] > 0) {
                defaultResult = defFalse;
            } else {
                defaultResult = defTrue;
                if ((count[defTrue] + count[defFalse]) > 1) {
                    throw { type: 'Runtime',
                        message: 'Ambiguous use of `default()` found when matching for `'
                            + this.format(args) + '`',
                        index: this.index, filename: this.currentFileInfo.filename };
                }
            }

            for (m = 0; m < candidates.length; m++) {
                candidate = candidates[m].group;
                if ((candidate === defNone) || (candidate === defaultResult)) {
                    try {
                        mixin = candidates[m].mixin;
                        if (!(mixin instanceof MixinDefinition)) {
                            originalRuleset = mixin.originalRuleset || mixin;
                            mixin = new MixinDefinition("", [], mixin.rules, null, false);
                            mixin.originalRuleset = originalRuleset;
                        }
                        Array.prototype.push.apply(
                            rules, mixin.evalCall(context, args, this.important).rules);
                    } catch (e) {
                        throw { message: e.message, index: this.index, filename: this.currentFileInfo.filename, stack: e.stack };
                    }
                }
            }

            if (match) {
                if (!this.currentFileInfo || !this.currentFileInfo.reference) {
                    for (i = 0; i < rules.length; i++) {
                        rule = rules[i];
                        if (rule.markReferenced) {
                            rule.markReferenced();
                        }
                    }
                }
                return rules;
            }
        }
    }
    if (isOneFound) {
        throw { type:    'Runtime',
            message: 'No matching definition was found for `' + this.format(args) + '`',
            index:   this.index, filename: this.currentFileInfo.filename };
    } else {
        throw { type:    'Name',
            message: this.selector.toCSS().trim() + " is undefined",
            index:   this.index, filename: this.currentFileInfo.filename };
    }
};
MixinCall.prototype.format = function (args) {
    return this.selector.toCSS().trim() + '(' +
        (args ? args.map(function (a) {
            var argValue = "";
            if (a.name) {
                argValue += a.name + ":";
            }
            if (a.value.toCSS) {
                argValue += a.value.toCSS();
            } else {
                argValue += "???";
            }
            return argValue;
        }).join(', ') : "") + ")";
};
module.exports = MixinCall;
