import type {
	Creature,
	CreatureId,
	DailySpells,
	LegendaryBlock,
	SpellcastingBlock,
	TraitBlock,
} from "@initiative/domain";
import { creatureId, proficiencyBonus } from "@initiative/domain";
import { stripTags } from "./strip-tags.js";

const LEADING_DIGITS_REGEX = /^(\d+)/;

// --- Raw 5etools types (minimal, for parsing) ---

interface RawMonster {
	name: string;
	source: string;
	size: string[];
	type: string | { type: string; tags?: string[]; swarmSize?: string };
	alignment?: string[];
	ac: (number | { ac: number; from?: string[] } | { special: string })[];
	hp: { average?: number; formula?: string; special?: string };
	speed: Record<
		string,
		number | { number: number; condition?: string } | boolean
	>;
	str: number;
	dex: number;
	con: number;
	int: number;
	wis: number;
	cha: number;
	save?: Record<string, string>;
	skill?: Record<string, string>;
	senses?: string[];
	passive: number;
	resist?: (string | { special: string })[];
	immune?: (string | { special: string })[];
	vulnerable?: (string | { special: string })[];
	conditionImmune?: string[];
	languages?: string[];
	cr?: string | { cr: string };
	trait?: RawEntry[];
	action?: RawEntry[];
	bonus?: RawEntry[];
	reaction?: RawEntry[];
	legendary?: RawEntry[];
	legendaryActions?: number;
	legendaryActionsLair?: number;
	legendaryHeader?: string[];
	spellcasting?: RawSpellcasting[];
	initiative?: { proficiency?: number };
	_copy?: unknown;
}

interface RawEntry {
	name: string;
	entries: (string | RawEntryObject)[];
}

interface RawEntryObject {
	type: string;
	items?: (
		| string
		| { type: string; name?: string; entries?: (string | RawEntryObject)[] }
	)[];
	style?: string;
	name?: string;
	entries?: (string | RawEntryObject)[];
}

interface RawSpellcasting {
	name: string;
	headerEntries: string[];
	will?: string[];
	daily?: Record<string, string[]>;
	rest?: Record<string, string[]>;
	hidden?: string[];
	ability?: string;
	displayAs?: string;
	legendary?: Record<string, string[]>;
}

// --- Source mapping ---

let sourceDisplayNames: Record<string, string> = {};

export function setSourceDisplayNames(names: Record<string, string>): void {
	sourceDisplayNames = names;
}

// --- Size mapping ---

const SIZE_MAP: Record<string, string> = {
	T: "Tiny",
	S: "Small",
	M: "Medium",
	L: "Large",
	H: "Huge",
	G: "Gargantuan",
};

// --- Alignment mapping ---

const ALIGNMENT_MAP: Record<string, string> = {
	L: "Lawful",
	N: "Neutral",
	C: "Chaotic",
	G: "Good",
	E: "Evil",
	U: "Unaligned",
};

function formatAlignment(codes?: string[]): string {
	if (!codes || codes.length === 0) return "Unaligned";
	if (codes.length === 1 && codes[0] === "U") return "Unaligned";
	if (codes.length === 1 && codes[0] === "N") return "Neutral";
	return codes.map((c) => ALIGNMENT_MAP[c] ?? c).join(" ");
}

// --- Helpers ---

function formatSize(sizes: string[]): string {
	return sizes.map((s) => SIZE_MAP[s] ?? s).join(" or ");
}

function formatType(
	type:
		| string
		| {
				type: string | { choose: string[] };
				tags?: string[];
				swarmSize?: string;
		  },
): string {
	if (typeof type === "string") return capitalize(type);

	const baseType =
		typeof type.type === "string"
			? capitalize(type.type)
			: type.type.choose.map(capitalize).join(" or ");

	let result = baseType;
	if (type.tags && type.tags.length > 0) {
		const tagStrs = type.tags
			.filter((t): t is string => typeof t === "string")
			.map(capitalize);
		if (tagStrs.length > 0) {
			result += ` (${tagStrs.join(", ")})`;
		}
	}
	if (type.swarmSize) {
		const swarmSizeLabel = SIZE_MAP[type.swarmSize] ?? type.swarmSize;
		result = `Swarm of ${swarmSizeLabel} ${result}s`;
	}
	return result;
}

function capitalize(s: string): string {
	return s.charAt(0).toUpperCase() + s.slice(1);
}

function extractAc(ac: RawMonster["ac"]): {
	value: number;
	source?: string;
} {
	const first = ac[0];
	if (typeof first === "number") {
		return { value: first };
	}
	if ("special" in first) {
		// Variable AC (e.g. spell summons) — parse leading number if possible
		const match = LEADING_DIGITS_REGEX.exec(first.special);
		return {
			value: match ? Number(match[1]) : 0,
			source: first.special,
		};
	}
	return {
		value: first.ac,
		source: first.from ? stripTags(first.from.join(", ")) : undefined,
	};
}

function formatSpeed(speed: RawMonster["speed"]): string {
	const parts: string[] = [];
	for (const [mode, value] of Object.entries(speed)) {
		if (mode === "canHover") continue;
		if (typeof value === "boolean") continue;

		let numStr: string;
		let condition = "";
		if (typeof value === "number") {
			numStr = `${value} ft.`;
		} else {
			numStr = `${value.number} ft.`;
			if (value.condition) {
				condition = ` ${value.condition}`;
			}
		}

		if (mode === "walk") {
			parts.push(`${numStr}${condition}`);
		} else {
			parts.push(`${mode} ${numStr}${condition}`);
		}
	}
	return parts.join(", ");
}

function formatSaves(save?: Record<string, string>): string | undefined {
	if (!save) return undefined;
	return Object.entries(save)
		.map(([key, val]) => `${key.toUpperCase()} ${val}`)
		.join(", ");
}

function formatSkills(skill?: Record<string, string>): string | undefined {
	if (!skill) return undefined;
	return Object.entries(skill)
		.map(([key, val]) => `${capitalize(key)} ${val}`)
		.join(", ");
}

function formatDamageList(
	items?: (string | Record<string, unknown>)[],
): string | undefined {
	if (!items || items.length === 0) return undefined;
	return items
		.map((item) => {
			if (typeof item === "string") return capitalize(stripTags(item));
			if (typeof item.special === "string") return stripTags(item.special);
			// Handle conditional entries like { vulnerable: [...], note: "..." }
			const damageTypes = (Object.values(item).find((v) => Array.isArray(v)) ??
				[]) as string[];
			const note = typeof item.note === "string" ? ` ${item.note}` : "";
			return damageTypes.map((d) => capitalize(stripTags(d))).join(", ") + note;
		})
		.join(", ");
}

function formatConditionImmunities(
	items?: (string | { conditionImmune?: string[]; note?: string })[],
): string | undefined {
	if (!items || items.length === 0) return undefined;
	return items
		.flatMap((c) => {
			if (typeof c === "string") return [capitalize(stripTags(c))];
			if (c.conditionImmune) {
				const conds = c.conditionImmune.map((ci) => capitalize(stripTags(ci)));
				const note = c.note ? ` ${c.note}` : "";
				return conds.map((ci) => `${ci}${note}`);
			}
			return [];
		})
		.join(", ");
}

function renderListItem(item: string | RawEntryObject): string | undefined {
	if (typeof item === "string") {
		return `• ${stripTags(item)}`;
	}
	if (item.name && item.entries) {
		return `• ${stripTags(item.name)}: ${renderEntries(item.entries)}`;
	}
	return undefined;
}

function renderEntryObject(entry: RawEntryObject, parts: string[]): void {
	if (entry.type === "list") {
		for (const item of entry.items ?? []) {
			const rendered = renderListItem(item);
			if (rendered) parts.push(rendered);
		}
	} else if (entry.type === "item" && entry.name && entry.entries) {
		parts.push(`${stripTags(entry.name)}: ${renderEntries(entry.entries)}`);
	} else if (entry.entries) {
		parts.push(renderEntries(entry.entries));
	}
}

function renderEntries(entries: (string | RawEntryObject)[]): string {
	const parts: string[] = [];
	for (const entry of entries) {
		if (typeof entry === "string") {
			parts.push(stripTags(entry));
		} else {
			renderEntryObject(entry, parts);
		}
	}
	return parts.join(" ");
}

function normalizeTraits(raw?: RawEntry[]): TraitBlock[] | undefined {
	if (!raw || raw.length === 0) return undefined;
	return raw.map((t) => ({
		name: stripTags(t.name),
		text: renderEntries(t.entries),
	}));
}

function normalizeSpellcasting(
	raw?: RawSpellcasting[],
): SpellcastingBlock[] | undefined {
	if (!raw || raw.length === 0) return undefined;

	return raw.map((sc) => {
		const block: {
			name: string;
			headerText: string;
			atWill?: string[];
			daily?: DailySpells[];
			restLong?: DailySpells[];
		} = {
			name: stripTags(sc.name),
			headerText: sc.headerEntries.map((e) => stripTags(e)).join(" "),
		};

		const hidden = new Set(sc.hidden ?? []);

		if (sc.will && !hidden.has("will")) {
			block.atWill = sc.will.map((s) => stripTags(s));
		}

		if (sc.daily) {
			block.daily = parseDailyMap(sc.daily);
		}

		if (sc.rest) {
			block.restLong = parseDailyMap(sc.rest);
		}

		return block;
	});
}

function parseDailyMap(map: Record<string, string[]>): DailySpells[] {
	return Object.entries(map).map(([key, spells]) => {
		const each = key.endsWith("e");
		const uses = Number.parseInt(each ? key.slice(0, -1) : key, 10);
		return {
			uses,
			each,
			spells: spells.map((s) => stripTags(s)),
		};
	});
}

function normalizeLegendary(
	raw?: RawEntry[],
	monster?: RawMonster,
): LegendaryBlock | undefined {
	if (!raw || raw.length === 0) return undefined;

	const name = monster?.name ?? "creature";
	const count = monster?.legendaryActions ?? 3;
	const preamble = `${name} can take ${count} Legendary Actions, choosing from the options below. Only one Legendary Action can be used at a time and only at the end of another creature's turn. ${name} regains spent Legendary Actions at the start of its turn.`;

	return {
		preamble,
		entries: raw.map((e) => ({
			name: stripTags(e.name),
			text: renderEntries(e.entries),
		})),
	};
}

function extractCr(cr: string | { cr: string } | undefined): string {
	if (cr === undefined) return "—";
	return typeof cr === "string" ? cr : cr.cr;
}

function makeCreatureId(source: string, name: string): CreatureId {
	const slug = name
		.toLowerCase()
		.replaceAll(/[^a-z0-9]+/g, "-")
		.replaceAll(/(^-|-$)/g, "");
	return creatureId(`${source.toLowerCase()}:${slug}`);
}

/**
 * Normalizes raw 5etools bestiary JSON into domain Creature[].
 */
export function normalizeBestiary(raw: { monster: RawMonster[] }): Creature[] {
	// Filter out _copy entries (reference another source's monster) and
	// monsters missing required fields (ac, hp, size, type)
	const monsters = raw.monster.filter((m) => {
		if (m._copy) return false;
		return (
			Array.isArray(m.ac) &&
			m.ac.length > 0 &&
			m.hp !== undefined &&
			Array.isArray(m.size) &&
			m.size.length > 0 &&
			m.type !== undefined
		);
	});
	const creatures: Creature[] = [];
	for (const m of monsters) {
		try {
			creatures.push(normalizeMonster(m));
		} catch {
			// Skip monsters with unexpected data shapes
		}
	}
	return creatures;
}

function normalizeMonster(m: RawMonster): Creature {
	const crStr = extractCr(m.cr);
	const ac = extractAc(m.ac);

	return {
		id: makeCreatureId(m.source, m.name),
		name: m.name,
		source: m.source,
		sourceDisplayName: sourceDisplayNames[m.source] ?? m.source,
		size: formatSize(m.size),
		type: formatType(m.type),
		alignment: formatAlignment(m.alignment),
		ac: ac.value,
		acSource: ac.source,
		hp: {
			average: m.hp.average ?? 0,
			formula: m.hp.formula ?? m.hp.special ?? "",
		},
		speed: formatSpeed(m.speed),
		abilities: {
			str: m.str,
			dex: m.dex,
			con: m.con,
			int: m.int,
			wis: m.wis,
			cha: m.cha,
		},
		cr: crStr,
		initiativeProficiency: m.initiative?.proficiency ?? 0,
		proficiencyBonus: proficiencyBonus(crStr),
		passive: m.passive,
		savingThrows: formatSaves(m.save),
		skills: formatSkills(m.skill),
		resist: formatDamageList(m.resist),
		immune: formatDamageList(m.immune),
		vulnerable: formatDamageList(m.vulnerable),
		conditionImmune: formatConditionImmunities(m.conditionImmune),
		senses:
			m.senses && m.senses.length > 0
				? m.senses.map((s) => stripTags(s)).join(", ")
				: undefined,
		languages:
			m.languages && m.languages.length > 0
				? m.languages.join(", ")
				: undefined,
		traits: normalizeTraits(m.trait),
		actions: normalizeTraits(m.action),
		bonusActions: normalizeTraits(m.bonus),
		reactions: normalizeTraits(m.reaction),
		legendaryActions: normalizeLegendary(m.legendary, m),
		spellcasting: normalizeSpellcasting(m.spellcasting),
	};
}