module TS.SpaceTac {
    const POOL_SHIP_NAMES = [
        "Zert",
        "Ob'tec",
        "Paayk",
        "Fen_amr",
        "TempZst",
        "croNt",
        "Appn",
        "Vertix",
        "Opan-vel",
        "Yz-aol",
        "Arkant",
        "PNX",
    ]

    /**
     * Random generator of secondary missions that can be taken from 
     */
    export class MissionGenerator {
        universe: Universe
        around: StarLocation
        random: RandomGenerator
        equipment_generator: LootGenerator

        constructor(universe: Universe, around: StarLocation, random = RandomGenerator.global) {
            this.universe = universe;
            this.around = around;
            this.random = random;
            this.equipment_generator = new LootGenerator(this.random);
        }

        /**
         * Generate a single mission
         */
        generate(): Mission {
            let generators = [
                bound(this, "generateEscort"),
                bound(this, "generateCleanLocation"),
            ];

            let generator = this.random.choice(generators);
            let result = generator();
            if (result.value) {
                result.reward = this.generateReward(result.value);
            }
            return result;
        }

        /**
         * Generate a new ship that may be used in a mission
         */
        generateShip(level: number) {
            let generator = new ShipGenerator(this.random);
            let result = generator.generate(level, null, true);
            result.name = `${this.random.choice(POOL_SHIP_NAMES)}-${this.random.randInt(10, 999)}`;
            return result;
        }

        /**
         * Try to generate an equipment of given value
         */
        tryGenerateEquipmentReward(value: number): Equipment | null {
            let minvalue = value * 0.8;
            let maxvalue = value * 1.2;
            let qualities = [EquipmentQuality.FINE, EquipmentQuality.PREMIUM, EquipmentQuality.LEGENDARY];

            let candidates: Equipment[] = [];
            for (let pass = 0; pass < 10; pass++) {
                let equipment: Equipment | null;
                let level = 1;
                do {
                    let quality = qualities[this.random.weighted([15, 12, 2])];
                    equipment = this.equipment_generator.generate(level, quality);
                    if (equipment && equipment.getPrice() >= minvalue && equipment.getPrice() <= maxvalue) {
                        candidates.push(equipment);
                    }
                    level += 1;
                } while (equipment && equipment.getPrice() < maxvalue * 1.5 && level < 20);
            }

            if (candidates.length > 0) {
                return this.random.choice(candidates);
            } else {
                return null;
            }
        }

        /**
         * Generate a reward
         */
        generateReward(value: number): MissionReward {
            if (this.random.bool()) {
                let equipment = this.tryGenerateEquipmentReward(value);
                if (equipment) {
                    return equipment;
                } else {
                    return value;
                }
            } else {
                return value;
            }
        }

        /**
         * Helper to set the difficulty of a mission
         */
        setDifficulty(mission: Mission, base_value: number, fight_level: number) {
            let level_diff = fight_level - this.around.star.level;
            let code = (level_diff > 0) ? MissionDifficulty.hard : (level_diff < 0 ? MissionDifficulty.easy : MissionDifficulty.normal);
            let value = fight_level * (base_value + base_value * 0.1 * clamp(level_diff, -5, 5));
            mission.setDifficulty(code, Math.round(value));
        }

        /**
         * Generate an escort mission
         */
        generateEscort(): Mission {
            let mission = new Mission(this.universe);
            let dest_star = this.random.choice(this.around.star.getNeighbors());
            let destination = this.random.choice(dest_star.locations);
            let ship = this.generateShip(dest_star.level);
            mission.addPart(new MissionPartEscort(mission, destination, ship));
            mission.title = `Escort a ship to a level ${dest_star.level} system`;
            this.setDifficulty(mission, 1000, dest_star.level);
            return mission;
        }

        /**
         * Generate a clean location mission
         */
        generateCleanLocation(): Mission {
            let mission = new Mission(this.universe);
            let dest_star = this.random.choice(this.around.star.getNeighbors().concat([this.around.star]));
            let here = (dest_star == this.around.star);
            let choices = dest_star.locations;
            if (here) {
                choices = choices.filter(loc => loc != this.around);
            }
            let destination = this.random.choice(choices);
            mission.addPart(new MissionPartCleanLocation(mission, destination));
            mission.addPart(new MissionPartGoTo(mission, this.around, "Go back to collect your reward"));
            mission.title = `Defeat a level ${destination.star.level} fleet in ${here ? "this" : "a nearby"} system`;
            this.setDifficulty(mission, here ? 300 : 500, dest_star.level);
            return mission;
        }
    }
}