// Camo mastery for checklist games. Users tick per-weapon milestones (max level,
// Gold, …); class tiers (Diamond) and overall tiers (Dark Matter) are derived.
// Post-launch weapons never gate a tier. They earn an achieved tier once their
// own base milestone is done, as DLC weapons do in Black Ops III and WWII.

export type Milestone = {
	key: string;
	label: string;
	description?: string;
	// limit to these weapon classes; every class when omitted
	classes?: string[];
	exceptWeapons?: string[];
	postLaunchOnly?: boolean;
};

export type Tier = {
	key: string;
	label: string;
	scope: 'class' | 'all';
	// a milestone key, or for `all` tiers also a class tier key
	requires: string;
	description?: string;
	classes?: string[];
	// class tiers only: the classes whose weapons a class depends on
	classRequirements?: Record<string, string[]>;
};

export type MasteryRules = {
	milestones: Milestone[];
	tiers: Tier[];
	classes: string[];
	steamApps: { id: number; label: string }[];
	rankCaps?: {
		player: { level: number; prestige: number };
		weaponPrestige: number;
		weaponLevelsByClass: Record<string, number>;
		weaponLevelOverrides?: Record<string, number>;
		sourceUrl?: string;
	};
};

export type Weapon = { id: number; name: string; category: string; postLaunch: boolean };
export type Count = { value: number; total: number; achieved: boolean };

export function appliesTo(milestone: Milestone, weapon: Weapon): boolean {
	if (milestone.postLaunchOnly && !weapon.postLaunch) return false;
	if (milestone.classes && !milestone.classes.includes(weapon.category)) return false;
	return !milestone.exceptWeapons?.includes(weapon.name);
}

function count(value: number, total: number): Count {
	return { value, total, achieved: total > 0 && value === total };
}

export function computeMastery(
	rules: MasteryRules,
	weapons: readonly Weapon[],
	isDone: (weaponId: number, milestone: string) => boolean
) {
	const milestones = new Map(rules.milestones.map((milestone) => [milestone.key, milestone]));
	const tiers = new Map(rules.tiers.map((tier) => [tier.key, tier]));
	const counted = (key: string, classes: readonly string[]) => {
		const milestone = milestones.get(key);
		return weapons.filter(
			(weapon) =>
				milestone &&
				!weapon.postLaunch &&
				classes.includes(weapon.category) &&
				appliesTo(milestone, weapon)
		);
	};
	const done = (list: readonly Weapon[], key: string) =>
		list.filter((weapon) => isDone(weapon.id, key)).length;

	const classTiers = new Map<string, Map<string, Count>>();
	for (const tier of rules.tiers) {
		if (tier.scope !== 'class') continue;
		const perClass = new Map<string, Count>();
		for (const name of tier.classes ?? rules.classes) {
			const members = counted(tier.requires, tier.classRequirements?.[name] ?? [name]);
			if (members.length) perClass.set(name, count(done(members, tier.requires), members.length));
		}
		classTiers.set(tier.key, perClass);
	}

	const allTiers = new Map<string, Count>();
	for (const tier of rules.tiers) {
		if (tier.scope !== 'all') continue;
		const perClass = classTiers.get(tier.requires);
		if (perClass) {
			const classes = [...perClass].filter(
				([name]) => !tier.classes || tier.classes.includes(name)
			);
			allTiers.set(
				tier.key,
				count(classes.filter(([, value]) => value.achieved).length, classes.length)
			);
		} else {
			const members = counted(tier.requires, tier.classes ?? rules.classes);
			allTiers.set(tier.key, count(done(members, tier.requires), members.length));
		}
	}

	// the per-weapon milestone at the bottom of a tier chain, e.g. darkMatter → diamond → gold
	const baseMilestone = (key: string): string => {
		const tier = tiers.get(key);
		return tier ? baseMilestone(tier.requires) : key;
	};

	function weaponTiers(weapon: Weapon): Tier[] {
		return rules.tiers.filter((tier) => {
			const base = baseMilestone(tier.key);
			const milestone = milestones.get(base);
			if (!milestone || !appliesTo(milestone, weapon)) return false;
			const achieved =
				tier.scope === 'class'
					? classTiers.get(tier.key)?.get(weapon.category)?.achieved
					: allTiers.get(tier.key)?.achieved &&
						(!tier.classes || tier.classes.includes(weapon.category));
			return !!achieved && (!weapon.postLaunch || isDone(weapon.id, base));
		});
	}

	return { classTiers, allTiers, weaponTiers };
}

export function summarizeGame(
	rules: MasteryRules,
	weapons: readonly Weapon[],
	achievementIds: readonly number[],
	isDone: (itemId: number, milestone: string) => boolean
) {
	const mastery = computeMastery(rules, weapons, isDone);
	return {
		achievements: count(
			achievementIds.filter((id) => isDone(id, 'done')).length,
			achievementIds.length
		),
		milestones: rules.milestones.map((milestone) => {
			const list = weapons.filter((weapon) => appliesTo(milestone, weapon));
			return {
				...milestone,
				...count(list.filter((weapon) => isDone(weapon.id, milestone.key)).length, list.length)
			};
		}),
		tiers: rules.tiers.map((tier) => {
			if (tier.scope === 'all') return { ...tier, ...mastery.allTiers.get(tier.key)! };
			const perClass = [...(mastery.classTiers.get(tier.key)?.values() ?? [])];
			return {
				...tier,
				...count(perClass.filter((value) => value.achieved).length, perClass.length)
			};
		}),
		mastery
	};
}