import type { Context, Hono } from "hono";
import { saveByPrefix } from "../mirror/queries.ts";
import { type Html, html } from "../pages/html.ts";
import {
	cacheFor,
	formatDate,
	notFound,
	openPublicRepo,
	type PageContext,
	type PublicRepo,
	page,
	relativeTime,
} from "../pages/layout.ts";
import { visibleReleases } from "../releases/releases.ts";
import { notify } from "../server/db.ts";
import { checkStamp, FILINGS_PER_HOUR, formStamp, ipHash, MAX_CHARS } from "./spam.ts";
import {
	addEntry,
	fileIssue,
	filingsSince,
	findIssue,
	hashToken,
	ISSUE_TYPES,
	type Issue,
	type IssueType,
	isBlocked,
	issueCounts,
	listIssues,
	threadEntries,
} from "./store.ts";

type Fields = Record<string, string>;
type Notice = { error?: string; draft?: string };

const TOKEN = /^[0-9a-f]{64}$/;
const FORM_FIELDS = ["title", "body", "type", "version", "name", "email", "website", "stamp"];
const unixNow = () => Math.floor(Date.now() / 1000);
// The same words whatever the reason, so a blocked address learns nothing more.
const BLOCKED = "This address can't post here.";

/** §23: the list, the filing form and the thread with its follow-up links. */
export function registerIssuePages(app: Hono, ctx: PageContext): void {
	app.get("/:repo/issues", (c) => {
		const repo = openPublicRepo(ctx, c.req.param("repo"));
		if (!repo) return notFound(c, ctx);
		const status = c.req.query("status") === "closed" ? "closed" : "open";
		cacheFor(c, false);
		return c.html(listPage(ctx, repo, status, c.req.query("q") ?? "", c.req.query("type") ?? ""));
	});

	app.get("/:repo/issues/new", (c) => {
		const repo = openPublicRepo(ctx, c.req.param("repo"));
		if (!repo) return notFound(c, ctx);
		const version = visibleReleases(ctx.kepr, repo.mirror, repo.settings.name)[0]?.version ?? "";
		return formPage(c, ctx, repo, { type: "bug", version }, "", 200);
	});

	app.post("/:repo/issues/new", async (c) => {
		const repo = openPublicRepo(ctx, c.req.param("repo"));
		if (!repo) return notFound(c, ctx);
		if (repo.settings.issuesPaused) return formPage(c, ctx, repo, {}, "", 403);
		const fields = await readFields(c, FORM_FIELDS);
		const now = unixNow();
		const refuse = (message: string, status: 400 | 403 | 429) =>
			formPage(c, ctx, repo, fields, message, status);
		// A bot that fills the hidden field learns nothing from the answer.
		if (fields.website !== "") return refuse("This issue could not be filed.", 400);
		const stamp = checkStamp(ctx.kepr, c, fields.stamp ?? "", now);
		if (stamp === "invalid") return refuse("This form expired. Please send it again.", 403);
		if (stamp === "too-fast") return refuse("That was quick. Please send it again.", 400);
		const title = fields.title?.trim() ?? "";
		const body = fields.body?.trim() ?? "";
		if (title === "" || body === "") return refuse("A title and what happened are needed.", 400);
		if (!ISSUE_TYPES.includes(fields.type as IssueType)) return refuse("Pick a type.", 400);
		if (Object.values(fields).some((value) => value.length > MAX_CHARS)) {
			return refuse(
				`Please keep each field under ${MAX_CHARS.toLocaleString("en-US")} characters.`,
				400,
			);
		}
		const hash = ipHash(ctx.kepr, c);
		if (isBlocked(ctx.kepr, hash)) return refuse(BLOCKED, 403);
		if (filingsSince(ctx.kepr, hash, now - 3600) >= FILINGS_PER_HOUR) {
			return refuse("Too many issues from here this hour. Please try again later.", 429);
		}
		const name = repo.settings.name;
		const filed = fileIssue(ctx.kepr, {
			repo: name,
			title,
			body,
			type: fields.type as IssueType,
			version: fields.version?.trim() ?? "",
			reporterName: fields.name?.trim() ?? "",
			contactEmail: fields.email?.trim() ?? "",
			ipHash: hash,
			filedAt: now,
		});
		notify(
			ctx.kepr,
			"issue_filed",
			`New issue ${name} #${filed.number}: ${title}`,
			`/admin/issues/${name}/${filed.number}`,
		);
		const link = `https://${ctx.domain}/${name}/issues/${filed.number}?token=${filed.token}`;
		privatePage(c);
		return c.html(
			page(ctx, {
				title: `issue #${filed.number} filed · ${name}`,
				description: "",
				path: c.req.path,
				body: html`${crumbs(name)}
<h1 class="file-page-title">Filed as
<a href="/${name}/issues/${filed.number}">#${filed.number}</a></h1>
<p>This is your private link for adding to the issue later. It is shown only this once,
so keep it; anyone who has it can post as you.</p>
<p class="issue-link mono"><a href="${link}">${link}</a></p>`,
			}),
		);
	});

	app.get("/:repo/issues/:n{[0-9]{1,9}}", (c) => {
		const repo = openPublicRepo(ctx, c.req.param("repo"));
		const issue = repo && findIssue(ctx.kepr, repo.settings.name, Number(c.req.param("n")));
		if (!repo || !issue) return notFound(c, ctx);
		const token = c.req.query("token");
		if (token === undefined) {
			cacheFor(c, false);
			return c.html(threadPage(c, ctx, repo, issue, null, {}));
		}
		privatePage(c);
		return c.html(threadPage(c, ctx, repo, issue, token, {}));
	});

	app.post("/:repo/issues/:n{[0-9]{1,9}}", async (c) => {
		const repo = openPublicRepo(ctx, c.req.param("repo"));
		const issue = repo && findIssue(ctx.kepr, repo.settings.name, Number(c.req.param("n")));
		if (!repo || !issue) return notFound(c, ctx);
		const { token = "", body = "", stamp = "" } = await readFields(c, ["token", "body", "stamp"]);
		privatePage(c);
		const refuse = (error: string, status: 400 | 403) =>
			c.html(threadPage(c, ctx, repo, issue, token, { error, draft: body }), status);
		if (!ownsIssue(issue, token))
			return refuse("This follow-up link does not match the issue.", 403);
		const check = checkStamp(ctx.kepr, c, stamp, unixNow());
		if (check === "invalid") return refuse("This form expired. Please send it again.", 403);
		if (check === "too-fast") return refuse("That was quick. Please send it again.", 400);
		if (isBlocked(ctx.kepr, ipHash(ctx.kepr, c))) return refuse(BLOCKED, 403);
		const text = body.trim();
		if (text === "") return refuse("Write something to add.", 400);
		if (text.length > MAX_CHARS) {
			return refuse(`Please keep it under ${MAX_CHARS.toLocaleString("en-US")} characters.`, 400);
		}
		const entry = addEntry(ctx.kepr, issue.id, "reporter", text, unixNow());
		notify(
			ctx.kepr,
			"issue_followup",
			`Follow-up on ${repo.settings.name} #${issue.number}: ${issue.title}`,
			`/admin/issues/${repo.settings.name}/${issue.number}`,
		);
		return c.redirect(
			`/${repo.settings.name}/issues/${issue.number}?token=${token}#entry-${entry}`,
			303,
		);
	});
}

async function readFields(c: Context, names: string[]): Promise<Fields> {
	const form = await c.req.parseBody();
	const fields: Fields = {};
	for (const name of names) {
		const value = form[name];
		fields[name] = typeof value === "string" ? value : "";
	}
	return fields;
}

function ownsIssue(issue: Issue, token: string): boolean {
	return TOKEN.test(token) && issue.token_hash === hashToken(token);
}

// A page carrying a token or a form stamp is never cached, and its URL never leaks as a referrer.
function privatePage(c: Context): void {
	c.header("Cache-Control", "no-store");
	c.header("Referrer-Policy", "no-referrer");
}

function crumbs(repo: string): Html {
	return html`<p class="breadcrumb mono">
<a href="/${repo}">${repo}</a> / <a href="/${repo}/issues">issues</a></p>`;
}

function listPage(
	ctx: PageContext,
	repo: PublicRepo,
	status: "open" | "closed",
	query: string,
	type: string,
): string {
	const name = repo.settings.name;
	const counts = issueCounts(ctx.kepr, name);
	const filter = ISSUE_TYPES.includes(type as IssueType) ? type : "";
	const issues = listIssues(ctx.kepr, name, status).filter(
		(issue) =>
			(!filter || issue.type === filter) &&
			issue.title.toLowerCase().includes(query.trim().toLowerCase()),
	);
	const tab = (which: "open" | "closed") =>
		html`<a class="issues-tab${which === status ? " active" : ""}"
			href="/${name}/issues${which === "closed" ? "?status=closed" : ""}">
${which} <span class="muted">${counts[which]}</span></a>`;
	return page(ctx, {
		title: `issues · ${name}`,
		description: `Issues filed against ${name}.`,
		path: `/${name}/issues`,
		body: html`<p class="breadcrumb mono"><a href="/${name}">${name}</a></p>
<h1 class="file-page-title">issues</h1>
<p class="issues-bar mono">${tab("open")}${tab("closed")}
${!repo.settings.issuesPaused && html`<a class="issues-new" href="/${name}/issues/new">report an issue →</a>`}</p>
<form class="issues-filter" method="get" action="/${name}/issues">
<input type="hidden" name="status" value="${status}">
<input class="issues-input" name="q" type="search" aria-label="search issue titles"
placeholder="search issues" value="${query}">
<select class="issues-input" name="type" aria-label="issue type">
<option value="">all types</option>
${ISSUE_TYPES.map(
	(value) =>
		html`<option value="${value}"${filter === value ? html` selected` : ""}>${value}</option>`,
)}
</select><button class="issues-submit" type="submit">filter</button></form>
<section class="repo-section">
${
	issues.length > 0
		? issues.map(
				(issue) =>
					html`<a class="issue-row" href="/${name}/issues/${issue.number}">
<span class="issue-symbol issue-symbol--${issue.status}">
${issue.status === "open" ? "◉" : "◈"}</span>
<span class="issue-title">${issue.title}</span>
${/* this line stays whole: splitting it changes the text tests/issues.test.ts asserts */ ""}<span class="issue-meta mono">#${issue.number} · ${issue.type}${issue.version && ` · v${issue.version}`} · ${relativeTime(issue.filed_at)}</span>
<span class="issue-reporter mono">${issue.reporter_name || "anonymous"}</span>
</a>`,
			)
		: html`<p class="muted mono save-empty">${query || filter ? "no matching issues" : `no ${status} issues`}</p>`
}
</section>`,
	});
}

function formPage(
	c: Context,
	ctx: PageContext,
	repo: PublicRepo,
	values: Fields,
	error: string,
	status: 200 | 400 | 403 | 429,
): Response {
	const name = repo.settings.name;
	privatePage(c);
	const typeOption = (type: string) =>
		html`<option value="${type}"${values.type === type ? html` selected` : ""}>${type}</option>`;
	const body = repo.settings.issuesPaused
		? html`${crumbs(name)}
<h1 class="file-page-title">report an issue</h1>
<p>${name} is not taking new issues right now.</p>
<p><a href="/${name}/issues">see the existing issues →</a></p>`
		: html`${crumbs(name)}
<h1 class="file-page-title">report an issue</h1>
${error && html`<p class="issues-error mono" role="alert">${error}</p>`}
<form class="issues-form" method="post" action="/${name}/issues/new">
<input type="hidden" name="stamp" value="${formStamp(ctx.kepr, c, unixNow())}">
<label class="issues-hp" aria-hidden="true">leave this empty
<input name="website" tabindex="-1" autocomplete="off"></label>
<label class="issues-label" for="issue-title">title</label>
<input class="issues-input" id="issue-title" name="title" required maxlength="${MAX_CHARS}" value="${values.title ?? ""}">
<label class="issues-label" for="issue-body">what happened</label>
<textarea class="issues-textarea" id="issue-body" name="body" rows="8" required
maxlength="${MAX_CHARS}">${values.body ?? ""}</textarea>
<label class="issues-label" for="issue-type">type</label>
<select class="issues-input" id="issue-type" name="type">${ISSUE_TYPES.map(typeOption)}</select>
<label class="issues-label" for="issue-version">version you're on</label>
<input class="issues-input" id="issue-version" name="version" maxlength="200" value="${values.version ?? ""}">
<label class="issues-label" for="issue-name">name to show
<span class="muted">(optional)</span></label>
<input class="issues-input" id="issue-name" name="name" maxlength="200" value="${values.name ?? ""}">
<label class="issues-label" for="issue-email">contact email
<span class="muted">(optional, only the operator sees it)</span></label>
<input class="issues-input" id="issue-email" name="email" type="email" maxlength="320" value="${values.email ?? ""}">
<p class="issues-actions"><button class="issues-submit" type="submit">file issue</button>
<a class="issues-cancel mono" href="/${name}/issues">cancel</a></p>
</form>`;
	return c.html(
		page(ctx, {
			title: `report an issue · ${name}`,
			description: `File an issue against ${name}.`,
			path: `/${name}/issues/new`,
			body,
		}),
		status,
	);
}

function threadPage(
	c: Context,
	ctx: PageContext,
	repo: PublicRepo,
	issue: Issue,
	token: string | null,
	notice: Notice,
): string {
	const name = repo.settings.name;
	const reporter = issue.reporter_name || "anonymous";
	const post = (id: string, operator: boolean, at: number, text: string) =>
		html`<article class="issue-post${operator ? " issue-post--operator" : ""}" id="${id}">
<p class="issue-post-head mono">${
			operator
				? html`<span class="issue-badge">operator</span>`
				: html`<span class="issue-author">${reporter}</span>`
		}<span class="history-when">${formatDate(at)}</span></p>
<div class="issue-text">${text}</div>
</article>`;
	const owner = token !== null && ownsIssue(issue, token);
	return page(ctx, {
		title: `#${issue.number} ${issue.title} · ${name}`,
		description: issue.title,
		path: `/${name}/issues/${issue.number}`,
		body: html`${crumbs(name)}
<h1 class="file-page-title">${issue.title} <span class="muted">#${issue.number}</span></h1>
<p class="issue-meta mono">
<span class="issue-symbol issue-symbol--${issue.status}">
${issue.status === "open" ? "◉ open" : "◈ closed"}</span>
${issue.type}${issue.version && ` · v${issue.version}`} · filed ${relativeTime(issue.filed_at)}
${issue.status === "closed" && fixedIn(repo, issue)}</p>
${post("issue", false, issue.filed_at, issue.body)}
${threadEntries(ctx.kepr, issue.id).map((entry) =>
	post(`entry-${entry.id}`, entry.author === "operator", entry.created_at, entry.body),
)}
${notice.error && html`<p class="issues-error mono" role="alert">${notice.error}</p>`}
${
	token !== null &&
	!owner &&
	!notice.error &&
	html`<p class="issues-error mono">This follow-up link does not match the issue.</p>`
}
${
	owner &&
	html`<form class="issues-form" method="post" action="/${name}/issues/${issue.number}">
<p class="muted">This is your private follow-up link; anyone who has it can post as you.</p>
<input type="hidden" name="token" value="${token}">
<input type="hidden" name="stamp" value="${formStamp(ctx.kepr, c, unixNow())}">
<label class="issues-label" for="follow-up">add to this issue</label>
<textarea class="issues-textarea" id="follow-up" name="body" rows="5" required
maxlength="${MAX_CHARS}">${notice.draft ?? ""}</textarea>
<button class="issues-submit" type="submit">post</button>
</form>`
}`,
	});
}

function fixedIn(repo: PublicRepo, issue: Issue): Html | "" {
	if (issue.fixed_in === "") return "";
	const save = saveByPrefix(repo.mirror, issue.fixed_in);
	// Only a save with a page of its own is linked; a checkpoint or an unknown ID stays text.
	const id =
		save && !save.is_checkpoint
			? html`<a class="history-id" href="/${repo.settings.name}/saves/${save.id}">${save.id}</a>`
			: html`<span class="history-id">${issue.fixed_in}</span>`;
	return html` · fixed in ${id}`;
}