class ContentDescription {
    public name : string;
    public group : ContentUnit | ContentGroup;
    public description : Say | ((description : ContentDescription, group : ContentUnit | ContentGroup) => Say);
    private saidCount = 0;

    public constructor (name : string, group : ContentUnit | ContentGroup) {
        this.name = name;
        this.group = group;
    }

    public getScore () {
        return (this.group).getScore();
    }

    public getDescription (group : ContentUnit | ContentGroup) : Say {
        this.saidCount++;
        if (typeof this.description == "function") {
            return this.description(this, group);
        }
        return this.description;
    }

    public setDescription (description : Say | string | ((description : ContentDescription, group : ContentUnit | ContentGroup) => Say) ) {
        if (!(description instanceof Say)) {
            this.description = new Say(description);
        } else {
            this.description = description;
        }
        return this;
    }

    public static pickDescriptions (cda : Array<ContentDescription>, target : ContentGroup | ContentUnit) : Array<Say> {
        let a = cda.slice();
        let groups = [];
        for (let i = 0; i < a.length; i++) {
            let randomIndex = Math.floor(Math.random() * (a.length - i)) + i;
            let temp = a[i];
            a[i] = a[randomIndex];
            a[randomIndex] = temp;
        }

        // After shuffling the list, descriptions with the highest scores go at the top, and between those the ones with the lowest saidCounts go first
        // If multiple descriptions have the same score/saidCount, they are picked randomly due to the previous shuffling.
        a.sort((a : ContentDescription, b : ContentDescription) => {
            // Division by saidCount for now, to increase rotativity of descriptions
            // Reduce precision on final number to decrease the likelihood of printing the same descriptions always in the same order
            let precision = 5;
            let scoreA = Math.floor(precision * a.getScore() / (a.saidCount + 1)) / precision;
            let scoreB = Math.floor(precision * b.getScore() / (b.saidCount + 1)) / precision;
            if (scoreA != scoreB) return scoreB - scoreA;
            return 0;
        });

        a.forEach(description => {
            groups.push(description.group);
        });

        let matches = (<any> target).matchAgainst(<any> groups);
        if (matches != undefined) {
            let result = [];
            matches.forEach(i => {
                result.push(a[i].getDescription(target));
                result.push(new Say(" "));
            });
            return result;
        } else {
            console.warn("No description available for", target);
            return [new Say("Warning: No description available for the current situation. Please report so it can be corrected.")];
        }
    }
}