import { describe, expect, it, vi } from "vitest";
import { createBobbinClient } from "./client";
import { gitTarget } from "./gitclient";
import { loadPullDiff, loadPullInterdiff } from "./pullDiff";
import type { MirrorFileDiff } from "./gitmirror";

const src = (path: string, extra: Partial<MirrorFileDiff["lhsSrc"]> = {}) => ({
	path,
	oid: `oid-${path}`,
	size: 10,
	isBinary: false,
	isSubmodule: false,
	...extra
});

// gitmirror names both sides of an add or delete after the same path and marks the
// side that doesn't exist with a null oid
const absent = (path: string) => src(path, { oid: "0".repeat(40), size: 0 });

const json = (body: unknown) =>
	new Response(JSON.stringify(body), {
		status: 200,
		headers: { "content-type": "application/json" }
	});

const params = {
	baseRepo: "did:plc:repo" as never,
	baseCommit: "base",
	headRepo: "did:plc:repo" as never,
	headCommit: "head"
};

// contents keyed by `<ref>:<path>`, so each side can differ
const harness = (diffs: MirrorFileDiff[], contents: Record<string, string>) => {
	const calls: string[] = [];
	const fetchMock = vi.fn<typeof globalThis.fetch>().mockImplementation(async (input) => {
		const url = new URL(String(input));
		calls.push(url.pathname);
		if (url.pathname.endsWith("temp2.getDiff") || url.pathname.endsWith("temp2.getInterdiff")) {
			return json({ diffs });
		}
		const key = `${url.searchParams.get("ref")}:${url.searchParams.get("path")}`;
		const content = contents[key];
		if (content === undefined) return new Response("nope", { status: 404 });
		return json({ path: url.searchParams.get("path"), content, encoding: "utf-8", size: 1 });
	});

	const ctx = createBobbinClient({ serviceUrl: "https://bobbin.test", fetch: fetchMock });
	const git = gitTarget(
		{ bobbinUrl: "https://bobbin.test", knotMirrorUrl: "" } as never,
		{ uri: "at://did:plc:alice/sh.tangled.repo/core", repoDid: "did:plc:repo" },
		fetchMock
	);
	return { ctx, git, calls };
};

describe("loadPullDiff", () => {
	it("pairs each file's two sides and sums the stat", async () => {
		const { ctx, git, calls } = harness(
			[
				{
					lhsSrc: src("a.ts"),
					rhsSrc: src("a.ts"),
					hunks: [{ novelLhs: [0], novelRhs: [0, 1], lines: [{ lhs: 0, rhs: 0 }, { rhs: 1 }] }],
					hasSyntacticChanges: false
				},
				{
					lhsSrc: absent("new.ts"),
					rhsSrc: src("new.ts"),
					hunks: [{ novelLhs: [], novelRhs: [0], lines: [{ rhs: 0 }] }],
					hasSyntacticChanges: false
				},
				{
					lhsSrc: src("gone.ts"),
					rhsSrc: absent("gone.ts"),
					hunks: [{ novelLhs: [0], novelRhs: [], lines: [{ lhs: 0 }] }],
					hasSyntacticChanges: false
				}
			],
			{
				"base:a.ts": "one\n",
				"head:a.ts": "two\nthree\n",
				"head:new.ts": "hello\n",
				"base:gone.ts": "bye\n"
			}
		);

		const diff = await loadPullDiff(ctx, git, params, "unified");

		expect(diff.stat).toEqual({ insertions: 3, deletions: 2, files_changed: 3 });
		expect(diff.truncated).toBe(0);
		expect(diff.files[0]).toMatchObject({
			name: "a.ts",
			kind: "changed",
			oldFile: { name: "a.ts", contents: "one\n" },
			newFile: { name: "a.ts", contents: "two\nthree\n" }
		});
		// a file with no left side gets an empty left side, not a failed fetch
		expect(diff.files[1]).toMatchObject({
			name: "new.ts",
			kind: "new",
			oldFile: { contents: "" },
			newFile: { contents: "hello\n" }
		});
		expect(diff.files[2]).toMatchObject({
			name: "gone.ts",
			kind: "deleted",
			oldFile: { contents: "bye\n" },
			newFile: { contents: "" }
		});
		// two for the changed file, one each for the sides that exist: the absent side
		// is never fetched, it would 404
		expect(calls.filter((path) => path.endsWith("repo.blob"))).toHaveLength(4);
		// the server prerenders each pair so the first paint ships highlighted
		expect(diff.prerendered?.["a.ts→a.ts"]).toContain("three");
	});

	it("notes the files it cannot render instead of dropping them", async () => {
		const { ctx, git } = harness(
			[
				{
					lhsSrc: src("logo.png", { isBinary: true }),
					rhsSrc: src("logo.png", { isBinary: true }),
					hunks: [],
					hasSyntacticChanges: false
				},
				{
					lhsSrc: src("vendor", { isSubmodule: true }),
					rhsSrc: src("vendor", { isSubmodule: true }),
					hunks: [],
					hasSyntacticChanges: false
				},
				{
					lhsSrc: src("gone.ts"),
					rhsSrc: src("gone.ts"),
					hunks: [],
					hasSyntacticChanges: false
				}
			],
			{}
		);

		const diff = await loadPullDiff(ctx, git, params, "unified");

		expect(diff.files.map((file) => file.note)).toEqual([
			"This is a binary file and will not be displayed.",
			"Submodule pointer, not shown.",
			// both blob fetches 404
			"Contents could not be loaded."
		]);
		expect(diff.files.every((file) => file.oldFile === undefined)).toBe(true);
	});
});

describe("loadPullInterdiff", () => {
	const interdiffParams = {
		baseRepo: "did:plc:repo" as never,
		baseCommit1: "v1base",
		baseCommit2: "v1head",
		headRepo: "did:plc:repo" as never,
		headCommit1: "v2base",
		headCommit2: "v2head"
	};

	it("takes the left side inline and fetches only the right", async () => {
		const { ctx, git, calls } = harness(
			[
				{
					lhsSrc: src("a.ts", { content: "one\n" }),
					rhsSrc: src("a.ts"),
					hunks: [{ novelLhs: [0], novelRhs: [0], lines: [{ lhs: 0, rhs: 0 }] }],
					hasSyntacticChanges: false
				},
				// the rebased tree only exists inside one gitmirror request, so a left
				// side with no inline text can never be recovered
				{
					lhsSrc: src("b.ts"),
					rhsSrc: src("b.ts"),
					hunks: [],
					hasSyntacticChanges: false
				},
				// an added file has no left side to inline in the first place
				{
					lhsSrc: absent("c.ts"),
					rhsSrc: src("c.ts"),
					hunks: [{ novelLhs: [], novelRhs: [0], lines: [{ rhs: 0 }] }],
					hasSyntacticChanges: false
				}
			],
			{ "v2head:a.ts": "two\n", "v2head:b.ts": "two\n", "v2head:c.ts": "new\n" }
		);

		const diff = await loadPullInterdiff(ctx, git, interdiffParams, "unified");

		expect(diff.files[0]).toMatchObject({
			oldFile: { name: "a.ts", contents: "one\n" },
			newFile: { name: "a.ts", contents: "two\n" }
		});
		expect(diff.files[1].note).toBe("Contents could not be loaded.");
		expect(diff.files[2]).toMatchObject({
			kind: "new",
			oldFile: { contents: "" },
			newFile: { name: "c.ts", contents: "new\n" }
		});
		// one blob per file, the right side only
		expect(calls.filter((path) => path.endsWith("repo.blob"))).toHaveLength(3);
	});
});