// Activation: find oxy, find repositories, wire the source control view,

// decorations, the content provider, and the commands (spec §3).

import * as vscode from "vscode";

import { basename } from "node:path";

import { Oxy, OxyError, findBinary } from "./oxy";

import { Repository, OxyResourceState } from "./repository";

import { OxyContentProvider, SCHEME, baseUri } from "./contentProvider";

import { OxyDecorationProvider } from "./decorations";

const MIN_VERSION = { format: 2, protocol: 1 };

let output: vscode.OutputChannel;

let oxy: Oxy;

let contentProvider: OxyContentProvider;

let decorations: OxyDecorationProvider;

const repositories = new Map<string, Repository>();

export async function activate(context: vscode.ExtensionContext): Promise<void> {

  output = vscode.window.createOutputChannel("Oxygen");

  context.subscriptions.push(output);

  oxy = new Oxy(findBinary(vscode.workspace.getConfiguration("oxygen").get<string>("path")), (line) => output.appendLine(line));

  try {

    const v = await oxy.version();

    output.appendLine(`oxy ${v.version} (format ${v.format}, protocol ${v.protocol}) at ${oxy.binary}`);

    if (v.format < MIN_VERSION.format || v.protocol < MIN_VERSION.protocol) {

      void vscode.window.showWarningMessage(`Oxygen: oxy ${v.version} is older than this extension supports.`);

    }

  } catch (e) {

    const pick = await vscode.window.showErrorMessage(`Oxygen: could not run oxy (${(e as Error).message}). Set "oxygen.path" or put oxy on your PATH.`, "Open Settings");

    if (pick === "Open Settings") {

      void vscode.commands.executeCommand("workbench.action.openSettings", "oxygen.path");

    }

    return;

  }

  contentProvider = new OxyContentProvider(oxy);

  context.subscriptions.push(vscode.workspace.registerTextDocumentContentProvider(SCHEME, contentProvider));

  decorations = new OxyDecorationProvider(() => [...repositories.values()]);

  context.subscriptions.push(decorations);

  context.subscriptions.push(

    vscode.commands.registerCommand("oxygen.refresh", async () => {

      await Promise.all([...repositories.values()].map((r) => r.refresh()));

    }),

    vscode.commands.registerCommand("oxygen.showOutput", () => output.show()),

    vscode.commands.registerCommand("oxygen.openFile", (state?: OxyResourceState) => state && vscode.commands.executeCommand("vscode.open", state.resourceUri)),

    vscode.commands.registerCommand("oxygen.openChanges", (state?: OxyResourceState) => state && openChanges(state)),

    vscode.commands.registerCommand("oxygen.openBaseVersion", (state?: OxyResourceState) => state && vscode.commands.executeCommand("vscode.open", baseUri(state.repository.root, state.path))),

    vscode.commands.registerCommand("oxygen.commit", (arg?: Repository | vscode.SourceControl) => commit(arg)),

    vscode.commands.registerCommand("oxygen.showLog", () => showLog()),

    vscode.workspace.onDidChangeWorkspaceFolders(() => void discover()),

    vscode.workspace.onDidChangeConfiguration((e) => {

      if (e.affectsConfiguration("oxygen.path")) {

        void vscode.window.showInformationMessage("Oxygen: reload the window to use the new oxy path.");

      }

      if (e.affectsConfiguration("oxygen")) {

        decorations.refresh();

        for (const r of repositories.values()) {

          r.scheduleRefresh();

        }

      }

    }),

  );

  context.subscriptions.push({ dispose: () => repositories.forEach((r) => r.dispose()) });

  await discover();

}

export function deactivate(): void {

  for (const r of repositories.values()) {

    r.dispose();

  }

  repositories.clear();

}

/** One Repository per distinct oxy root among the workspace folders. */

async function discover(): Promise<void> {

  const wanted = new Map<string, vscode.WorkspaceFolder>();

  for (const folder of vscode.workspace.workspaceFolders ?? []) {

    const info = await oxy.root(folder.uri.fsPath);

    if (info) {

      wanted.set(info.root, folder);

    }

  }

  for (const [root, repo] of repositories) {

    if (!wanted.has(root)) {

      repo.dispose();

      repositories.delete(root);

    }

  }

  for (const [root, folder] of wanted) {

    if (!repositories.has(root)) {

      const repo = new Repository(oxy, root, folder);

      repo.onDidChangeStatus(() => {

        decorations.refresh();

        contentProvider.invalidate(root);

      });

      repositories.set(root, repo);

      output.appendLine(`repository ${root}`);

      await repo.refresh();

    }

  }

  void vscode.commands.executeCommand("setContext", "oxygen.hasRepository", repositories.size > 0);

}

function repositoryFor(arg: Repository | vscode.SourceControl | undefined): Repository | undefined {

  if (arg instanceof Repository) {

    return arg;

  }

  if (arg && "rootUri" in arg && arg.rootUri) {

    return repositories.get(arg.rootUri.fsPath);

  }

  const active = vscode.window.activeTextEditor?.document.uri;

  for (const repo of repositories.values()) {

    if (active && repo.relativePath(active) !== undefined) {

      return repo;

    }

  }

  return repositories.size === 1 ? [...repositories.values()][0] : undefined;

}

async function openChanges(state: OxyResourceState): Promise<void> {

  const repo = state.repository;

  const title = `${basename(state.path)} (base ↔ working copy)`;

  if (state.status === "Added") {

    await vscode.commands.executeCommand("vscode.open", state.resourceUri);

    return;

  }

  if (state.status === "Removed") {

    await vscode.commands.executeCommand("vscode.open", baseUri(repo.root, state.path));

    return;

  }

  await vscode.commands.executeCommand("vscode.diff", baseUri(repo.root, state.path), state.resourceUri, title);

}

async function commit(arg: Repository | vscode.SourceControl | undefined): Promise<void> {

  const repo = repositoryFor(arg);

  if (!repo) {

    void vscode.window.showErrorMessage("Oxygen: no repository for the active file.");

    return;

  }

  let message = repo.sourceControl.inputBox.value.trim();

  if (!message) {

    message = (await vscode.window.showInputBox({ prompt: "Commit message", placeHolder: "What did you change?" }))?.trim() ?? "";

  }

  if (!message) {

    return;

  }

  try {

    await vscode.window.withProgress({ location: vscode.ProgressLocation.SourceControl, title: "Committing" }, () => repo.oxy.commit(repo.root, message));

    repo.sourceControl.inputBox.value = "";

    await repo.refresh();

  } catch (e) {

    showError(e);

  }

}

async function showLog(): Promise<void> {

  const repo = repositoryFor(undefined);

  if (!repo) {

    return;

  }

  try {

    const log = await repo.oxy.log(repo.root, 50);

    const items = log.changes

      .filter((c) => !c.working_copy)

      .map((c) => ({

        label: `${c.head ? "$(circle-filled)" : "$(circle-outline)"} ${c.message.split("\n")[0]}`,

        description: `${c.change_id.slice(0, 8)} · ${c.author}`,

        detail: `${new Date(c.when_ms).toLocaleString()} · ${c.signature?.status ?? "unsigned"}${c.signature?.revoked ? " (key revoked)" : ""}`,

        change: c,

      }));

    const pick = await vscode.window.showQuickPick(items, { placeHolder: `${log.bookmark}: ${log.total - 1} changes`, matchOnDescription: true, matchOnDetail: true });

    if (pick) {

      const doc = await vscode.workspace.openTextDocument({ content: pick.change.message, language: "markdown" });

      await vscode.window.showTextDocument(doc, { preview: true });

    }

  } catch (e) {

    showError(e);

  }

}

function showError(e: unknown): void {

  const message = e instanceof OxyError ? e.message : String(e);

  void vscode.window.showErrorMessage(`Oxygen: ${message}`, "Show Output").then((pick) => pick && output.show());

}