import { jsonGet } from "./_request";
import { splitMessage, type CommitSummary } from "./repo";
import type { Did } from "@atcute/lexicons/syntax";
import type { BobbinContext, XrpcRequestInit } from "./client";
import type { Revspec } from "./pullRoute";
import type * as ShTangledGitDefs from "./lexicons/types/sh/tangled/git/defs";
import type * as GetDiff from "./lexicons/types/sh/tangled/git/temp2/getDiff";
import type * as GetInterdiff from "./lexicons/types/sh/tangled/git/temp2/getInterdiff";
import type * as ListCommits from "./lexicons/types/sh/tangled/git/temp2/listCommits";
import type * as MergeCheck from "./lexicons/types/sh/tangled/git/temp2/mergeCheck";

// gitmirror's own xrpc surface, proxied through bobbin — its grpc service is
// internal and streaming, so the read paths the frontend needs live here
const LIST_COMMITS_NSID = "sh.tangled.git.temp2.listCommits";
const GET_DIFF_NSID = "sh.tangled.git.temp2.getDiff";
const GET_INTERDIFF_NSID = "sh.tangled.git.temp2.getInterdiff";
const MERGE_CHECK_NSID = "sh.tangled.git.temp2.mergeCheck";

export type MirrorCommit = ListCommits.Commit;

export const listCommits = (
	ctx: BobbinContext,
	params: ListCommits.$params,
	init?: XrpcRequestInit
) => jsonGet<ListCommits.$output>(ctx, LIST_COMMITS_NSID, params, init);

const LOG_LIMIT = 100;

// every commit a pull version brought, newest first
export const listLog = async (
	ctx: BobbinContext,
	repo: Did,
	range: Revspec,
	init?: XrpcRequestInit
): Promise<CommitSummary[]> => {
	const page = await listCommits(
		ctx,
		{ repo, ranges: [`${range.base}..${range.head}`], limit: LOG_LIMIT },
		init
	);
	return page.commits.map(toMirrorCommitSummary);
};

export type MirrorFileDiff = ShTangledGitDefs.FileDiff;

export const getDiff = (ctx: BobbinContext, params: GetDiff.$params, init?: XrpcRequestInit) =>
	jsonGet<GetDiff.$output>(ctx, GET_DIFF_NSID, params, init);

// `base*` is the older version's span, `head*` the newer one's: gitmirror
// rebases base1..base2 onto head1 and diffs the result against head2
export const getInterdiff = (
	ctx: BobbinContext,
	params: GetInterdiff.$params,
	init?: XrpcRequestInit
) => jsonGet<GetInterdiff.$output>(ctx, GET_INTERDIFF_NSID, params, init);

export type MirrorConflict = MergeCheck.Conflict;

export const mergeCheck = (
	ctx: BobbinContext,
	params: MergeCheck.$params,
	init?: XrpcRequestInit
) => jsonGet<MergeCheck.$output>(ctx, MERGE_CHECK_NSID, params, init);

export type MirrorFileKind = "new" | "deleted" | "renamed" | "changed";

// an add or delete carries the same path on both sides — gix names both resources
// after the change's location — so the side that doesn't exist is the one whose oid
// is null, not the one whose path is empty
export const diffSideExists = (src: ShTangledGitDefs.DiffSrc): boolean =>
	src.path !== "" && !/^0+$/.test(src.oid);

export const diffFileName = (file: MirrorFileDiff): string => file.rhsSrc.path || file.lhsSrc.path;

export const diffFileKind = (file: MirrorFileDiff): MirrorFileKind => {
	if (!diffSideExists(file.lhsSrc)) return "new";
	if (!diffSideExists(file.rhsSrc)) return "deleted";
	return file.lhsSrc.path === file.rhsSrc.path ? "changed" : "renamed";
};

// the payload has no line text, only aligned line numbers: a pair with one side
// missing is a pure insertion or deletion, a pair with both is a replaced line
export const diffFileStat = (file: MirrorFileDiff): { insertions: number; deletions: number } => {
	let insertions = 0;
	let deletions = 0;
	for (const hunk of file.hunks) {
		for (const line of hunk.lines) {
			if (line.rhs !== undefined) insertions++;
			if (line.lhs !== undefined) deletions++;
		}
	}
	return { insertions, deletions };
};

export const toMirrorCommitSummary = (commit: MirrorCommit): CommitSummary => {
	const [subject, body] = splitMessage(commit.message);
	return {
		hash: commit.oid,
		shortHash: commit.oid.slice(0, 8),
		subject,
		body,
		authorName: commit.author.name,
		authorEmail: commit.author.email,
		when: commit.committer.when ?? commit.author.when,
		// the pull page links a commit row as `firstParent..commit`
		parent: commit.parents[0],
		// jj stashes the change id in a commit header, same lookup the appview does
		changeId: commit.extraHeaders.find((header) => header.key === "change-id")?.value
	};
};