import {measureDistances} from "./compatibility.js";
import {getMovementHistory} from "./movement_tracking.js";
import {GenericSpeedProvider, SpeedProvider} from "./speed_provider.js";
import {settingsKey} from "./settings.js";
import {getAreaFromPositionAndShape, getTokenShape} from "./util.js";

export const availableSpeedProviders = {};
export let currentSpeedProvider = undefined;

function register(module, type, speedProvider) {
	const id = `${type}.${module.id}`;
	let providerInstance;
	if (speedProvider.prototype instanceof SpeedProvider) {
		providerInstance = new speedProvider(id);
	} else {
		console.warn(
			`Drag Ruler | The ${type} '${module.id}' uses the old, deprecated version of the Drag Ruler API. ` +
				"That old API will be removed in a future Drag Ruler version. " +
				`Please update the ${type} ${module.id} to stay compatible with future Drag Ruler versions.`,
		);
		speedProvider.id = id;
		speedProvider.usesRuler = () => true;
		providerInstance = speedProvider;
	}
	setupProvider(providerInstance);
}

function setupProvider(speedProvider) {
	if (speedProvider instanceof SpeedProvider) {
		const unreachableColor = {
			id: "unreachable",
			default: speedProvider.defaultUnreachableColor,
			name: "drag-ruler.settings.speedProviderSettings.color.unreachable.name",
		};
		for (const color of speedProvider.colors.concat([unreachableColor])) {
			game.settings.register(settingsKey, `speedProviders.${speedProvider.id}.color.${color.id}`, {
				config: false,
				scope: "client",
				type: Number,
				default: color.default,
			});
		}
		for (const setting of speedProvider.settings) {
			setting.config = false;
			game.settings.register(
				settingsKey,
				`speedProviders.${speedProvider.id}.setting.${setting.id}`,
				setting,
			);
		}
	}

	availableSpeedProviders[speedProvider.id] = speedProvider;
	game.settings.settings.get("drag-ruler.speedProvider").default = getDefaultSpeedProvider();
	updateSpeedProvider();
}

export function getDefaultSpeedProvider() {
	const providerIds = Object.keys(availableSpeedProviders);
	// Game systems take the highest precedence for the being the default
	const gameSystem = providerIds.find(key => key.startsWith("system."));
	if (gameSystem) return gameSystem;

	// If no game system is registered modules are next up.
	// For lack of a method to select the best module we're just falling back to taking the next best module
	// settingKeys should always be sorted the same way so this should achive a stable default
	const module = providerIds.find(key => key.startsWith("module."));
	if (module) return module;

	// If neither a game system or a module is found fall back to the native implementation
	return providerIds[0];
}

export function updateSpeedProvider() {
	// If the configured provider is registered use that one. If not use the default provider
	const configuredProvider = game.settings.get("drag-ruler", "speedProvider");
	currentSpeedProvider =
		availableSpeedProviders[configuredProvider] ??
		availableSpeedProviders[game.settings.settings.get("drag-ruler.speedProvider").default];
}

export function initApi() {
	const genericSpeedProviderInstance = new GenericSpeedProvider("native");
	setupProvider(genericSpeedProviderInstance);
}

export function getRangesFromSpeedProvider(token) {
	try {
		if (currentSpeedProvider instanceof Function) return currentSpeedProvider(token, 0x00ff00);
		const ranges = currentSpeedProvider.getRanges(token);
		for (const range of ranges) {
			range.color = game.settings.get(
				settingsKey,
				`speedProviders.${currentSpeedProvider.id}.color.${range.color}`,
			);
		}
		return ranges;
	} catch (e) {
		console.error(e);
		return [];
	}
}

export function getUnreachableColorFromSpeedProvider() {
	if (currentSpeedProvider instanceof Function) return 0xff0000;
	try {
		return game.settings.get(
			settingsKey,
			`speedProviders.${currentSpeedProvider.id}.color.unreachable`,
		);
	} catch (e) {
		console.error(e);
		return 0xff0000;
	}
}

export function getColorForDistanceAndToken(distance, token, ranges = null) {
	if (!ranges) {
		ranges = getRangesFromSpeedProvider(token);
	}
	if (ranges.length === 0) return null;
	const currentRange = ranges.reduce(
		(minRange, currentRange) => {
			if (distance <= currentRange.range && currentRange.range < minRange.range)
				return currentRange;
			return minRange;
		},
		{range: Infinity, color: getUnreachableColorFromSpeedProvider()},
	);
	return currentRange.color;
}

export function getMovedDistanceFromToken(token) {
	const terrainRulerAvailable = game.modules.get("terrain-ruler")?.active;
	const history = getMovementHistory(token);
	const segments = CONFIG.Canvas.rulerClass
		.dragRulerGetRaysFromWaypoints(history, {x: token.x, y: token.y})
		.map(ray => {
			return {ray};
		});
	const shape = getTokenShape(token);
	const distances = measureDistances(segments, token, shape, {
		enableTerrainRuler: terrainRulerAvailable,
	});
	// Sum up the distances
	return distances.reduce((acc, val) => acc + val, 0);
}

export function buildCostFunction(token, shape) {
	return (x, y, costOptions = {}) => {
		costOptions.token = token;
		const area = getAreaFromPositionAndShape({x, y}, shape);
		const costs = area.map(space => canvas.terrain.cost({x: space.x, y: space.y}, costOptions));
		return costs.reduce((max, current) => Math.max(max, current));
	};
}

export function registerModule(moduleId, speedProvider) {
	// Check if a module with the given id exists and is currently enabled
	const module = game.modules.get(moduleId);
	// If it doesn't the calling module did something wrong. Log a warning and ignore this module
	if (!module) {
		console.warn(
			`Drag Ruler | A module tried to register with the id "${moduleId}". However no active module with this id was found.` +
				"This api registration call was ignored. " +
				"If you are the author of that module please check that the id passed to `registerModule` matches the id in your manifest exactly." +
				"If this call was made form a game system instead of a module please use `registerSystem` instead.",
		);
		return;
	}
	// Using Drag Ruler's id is not allowed
	if (moduleId === "drag-ruler") {
		console.warn(
			`Drag Ruler | A module tried to register with the id "${moduleId}", which is not allowed. This api registration call was ignored. ` +
				"If you're the author of the module please use the id of your own module as it's specified in your manifest to register to this api. " +
				"If this call was made form a game system instead of a module please use `registerSystem` instead.",
		);
		return;
	}

	register(module, "module", speedProvider);
}

export function registerSystem(systemId, speedProvider) {
	const system = game.system;
	// If the current system id doesn't match the provided id something went wrong. Log a warning and ignore this module
	if (system.id != systemId) {
		console.warn(
			`Drag Ruler | A system tried to register with the id "${systemId}". However the active system has a different id.` +
				"This api registration call was ignored. " +
				"If you are the author of that system please check that the id passed to `registerSystem` matches the id in your manifest exactly." +
				"If this call was made form a module instead of a game system please use `registerModule` instead.",
		);
		return;
	}

	register(system, "system", speedProvider);
}