import { page } from "$app/state";
import { avatarUrl } from "$lib/avatar";

export function resolveOgreUrl(baseUrl?: string): string {
	if (baseUrl) return baseUrl;
	try {
		return page.data.publicConfig?.ogreUrl ?? "";
	} catch {
		return "";
	}
}

export function resolveAppUrl(appUrl?: string): string {
	if (appUrl) return appUrl.replace(/\/+$/, "");
	try {
		return page.url.origin;
	} catch {
		return "https://tangled.org";
	}
}

const ogAvatarUrl = (did: string | undefined, appUrl?: string): string | undefined =>
	did ? `${resolveAppUrl(appUrl)}${avatarUrl(did, 256, "jpeg")}` : undefined;

export interface OgRepoPayload {
	type: "repository";
	repoName: string;
	ownerHandle: string;
	stars?: number;
	pulls?: number;
	issues?: number;
	createdAt?: string;
	avatarUrl?: string;
	languages?: { color: string; percentage: number }[];
}

export interface OgIssuePayload {
	type: "issue";
	repoName: string;
	ownerHandle: string;
	authorHandle: string;
	title: string;
	issueNumber: number | string;
	status: "open" | "closed";
	avatarUrl?: string;
	authorAvatarUrl?: string;
	commentCount?: number;
	createdAt: string;
}

export interface OgPullPayload {
	type: "pullRequest";
	repoName: string;
	ownerHandle: string;
	authorHandle: string;
	title: string;
	pullRequestNumber: number | string;
	status: "open" | "closed" | "merged";
	avatarUrl?: string;
	authorAvatarUrl?: string;
	commentCount?: number;
	createdAt: string;
}

export type OgPayload = OgRepoPayload | OgIssuePayload | OgPullPayload;

export function encodeOgPayload(payload: OgPayload): string {
	const entries = Object.entries(payload).filter(
		([_, v]) => v != null && v !== "" && !(Array.isArray(v) && v.length === 0)
	);
	const json = JSON.stringify(Object.fromEntries(entries));
	if (typeof Buffer !== "undefined") {
		return Buffer.from(json, "utf-8").toString("base64url");
	}
	const bytes = new TextEncoder().encode(json);
	let bin = "";
	for (let i = 0; i < bytes.length; i++) bin += String.fromCharCode(bytes[i]);
	return btoa(bin).replace(/\+/g, "-").replace(/\//g, "_").replace(/=+$/, "");
}

export function ogCardUrl(payload: OgPayload, baseUrl?: string): string {
	return `${resolveOgreUrl(baseUrl)}/card?payload=${encodeOgPayload(payload)}`;
}

export function repoCard(
	repo: { name: string; ownerHandle: string; ownerDid?: string; createdAt?: string },
	counts?: { stars?: number; pulls?: number; issues?: number } | null,
	baseUrl?: string,
	languages?: { color: string; percentage: number }[] | null,
	appUrl?: string
): string {
	return ogCardUrl(
		{
			type: "repository",
			repoName: repo.name,
			ownerHandle: repo.ownerHandle,
			stars: counts?.stars,
			pulls: counts?.pulls,
			issues: counts?.issues,
			createdAt: repo.createdAt,
			avatarUrl: ogAvatarUrl(repo.ownerDid, appUrl),
			languages: languages ?? undefined
		},
		baseUrl
	);
}

export function issueCard(
	repo: { name: string; ownerHandle: string; ownerDid?: string },
	issue: {
		title: string;
		issueNumber?: number | string;
		rkey?: string;
		state?: string;
		createdAt: string;
		author?: { handle?: string; avatar?: string; did?: string };
		authorHandle?: string;
		authorDid?: string;
		commentCount?: number;
	},
	baseUrl?: string,
	appUrl?: string
): string {
	const authorHandle = issue.author?.handle || issue.authorHandle || "";
	const authorDid = issue.author?.did || issue.authorDid;
	return ogCardUrl(
		{
			type: "issue",
			repoName: repo.name,
			ownerHandle: repo.ownerHandle,
			authorHandle,
			title: issue.title || "Issue",
			issueNumber: issue.issueNumber ?? issue.rkey ?? "",
			status: issue.state === "closed" ? "closed" : "open",
			createdAt: issue.createdAt,
			avatarUrl: ogAvatarUrl(repo.ownerDid, appUrl),
			authorAvatarUrl: issue.author?.avatar || ogAvatarUrl(authorDid, appUrl),
			commentCount: issue.commentCount
		},
		baseUrl
	);
}

export function pullCard(
	repo: { name: string; ownerHandle: string; ownerDid?: string },
	pull: {
		title?: string;
		rkey: string;
		state?: "open" | "closed" | "merged";
		createdAt: string;
		author?: { handle?: string; did?: string };
	},
	commentCount?: number,
	baseUrl?: string,
	appUrl?: string
): string {
	return ogCardUrl(
		{
			type: "pullRequest",
			repoName: repo.name,
			ownerHandle: repo.ownerHandle,
			authorHandle: pull.author?.handle || "",
			title: pull.title || "Pull Request",
			pullRequestNumber: pull.rkey,
			status: pull.state ?? "open",
			createdAt: pull.createdAt,
			avatarUrl: ogAvatarUrl(repo.ownerDid, appUrl),
			authorAvatarUrl: ogAvatarUrl(pull.author?.did, appUrl),
			commentCount
		},
		baseUrl
	);
}