import {CompositeDisposable, Disposable} from 'event-kit';

import path from 'path';
import fs from 'fs-extra';

import React from 'react';
import ReactDom from 'react-dom';

import {fileExists, autobind} from './helpers';
import WorkdirCache from './models/workdir-cache';
import WorkdirContext from './models/workdir-context';
import WorkdirContextPool from './models/workdir-context-pool';
import Repository from './models/repository';
import StyleCalculator from './models/style-calculator';
import GithubLoginModel from './models/github-login-model';
import RootController from './controllers/root-controller';
import StubItem from './items/stub-item';
import Switchboard from './switchboard';
import yardstick from './yardstick';
import GitTimingsView from './views/git-timings-view';
import ContextMenuInterceptor from './context-menu-interceptor';
import AsyncQueue from './async-queue';
import WorkerManager from './worker-manager';
import getRepoPipelineManager from './get-repo-pipeline-manager';
import {reporterProxy} from './reporter-proxy';

const defaultState = {
  newProject: true,
  activeRepositoryPath: null,
  contextLocked: false,
};

export default class GithubPackage {
  constructor({
    workspace, project, commands, notificationManager, tooltips, styles, grammars,
    keymaps, config, deserializers,
    confirm, getLoadSettings, currentWindow,
    configDirPath,
    renderFn, loginModel,
  }) {
    autobind(
      this,
      'consumeStatusBar', 'createGitTimingsView', 'createIssueishPaneItemStub', 'createDockItemStub',
      'createFilePatchControllerStub', 'destroyGitTabItem', 'destroyGithubTabItem',
      'getRepositoryForWorkdir', 'scheduleActiveContextUpdate',
    );

    this.workspace = workspace;
    this.project = project;
    this.commands = commands;
    this.deserializers = deserializers;
    this.notificationManager = notificationManager;
    this.tooltips = tooltips;
    this.config = config;
    this.styles = styles;
    this.grammars = grammars;
    this.keymaps = keymaps;
    this.configPath = path.join(configDirPath, 'github.cson');
    this.currentWindow = currentWindow;

    this.styleCalculator = new StyleCalculator(this.styles, this.config);
    this.confirm = confirm;
    this.startOpen = false;
    this.activated = false;

    const criteria = {
      projectPathCount: this.project.getPaths().length,
      initPathCount: (getLoadSettings().initialPaths || []).length,
    };

    this.pipelineManager = getRepoPipelineManager({confirm, notificationManager, workspace});

    this.activeContextQueue = new AsyncQueue();
    this.guessedContext = WorkdirContext.guess(criteria, this.pipelineManager);
    this.activeContext = this.guessedContext;
    this.lockedContext = null;
    this.workdirCache = new WorkdirCache();
    this.contextPool = new WorkdirContextPool({
      window,
      workspace,
      promptCallback: query => this.controller.openCredentialsDialog(query),
      pipelineManager: this.pipelineManager,
    });

    this.switchboard = new Switchboard();

    this.loginModel = loginModel || new GithubLoginModel();
    this.renderFn = renderFn || ((component, node, callback) => {
      return ReactDom.render(component, node, callback);
    });

    // Handle events from all resident contexts.
    this.subscriptions = new CompositeDisposable(
      this.contextPool.onDidChangeWorkdirOrHead(context => {
        this.refreshAtomGitRepository(context.getWorkingDirectory());
      }),
      this.contextPool.onDidUpdateRepository(context => {
        this.switchboard.didUpdateRepository(context.getRepository());
      }),
      this.contextPool.onDidDestroyRepository(context => {
        if (context === this.activeContext) {
          this.setActiveContext(WorkdirContext.absent({pipelineManager: this.pipelineManager}));
        }
      }),
      ContextMenuInterceptor,
    );

    this.setupYardstick();
  }

  setupYardstick() {
    const stagingSeries = ['stageLine', 'stageHunk', 'unstageLine', 'unstageHunk'];

    this.subscriptions.add(
      // Staging and unstaging operations
      this.switchboard.onDidBeginStageOperation(payload => {
        if (payload.stage && payload.line) {
          yardstick.begin('stageLine');
        } else if (payload.stage && payload.hunk) {
          yardstick.begin('stageHunk');
        } else if (payload.stage && payload.file) {
          yardstick.begin('stageFile');
        } else if (payload.stage && payload.mode) {
          yardstick.begin('stageMode');
        } else if (payload.stage && payload.symlink) {
          yardstick.begin('stageSymlink');
        } else if (payload.unstage && payload.line) {
          yardstick.begin('unstageLine');
        } else if (payload.unstage && payload.hunk) {
          yardstick.begin('unstageHunk');
        } else if (payload.unstage && payload.file) {
          yardstick.begin('unstageFile');
        } else if (payload.unstage && payload.mode) {
          yardstick.begin('unstageMode');
        } else if (payload.unstage && payload.symlink) {
          yardstick.begin('unstageSymlink');
        }
      }),
      this.switchboard.onDidUpdateRepository(() => {
        yardstick.mark(stagingSeries, 'update-repository');
      }),
      this.switchboard.onDidFinishRender(context => {
        if (context === 'RootController.showFilePatchForPath') {
          yardstick.finish(stagingSeries);
        }
      }),

      // Active context changes
      this.switchboard.onDidScheduleActiveContextUpdate(() => {
        yardstick.begin('activeContextChange');
      }),
      this.switchboard.onDidBeginActiveContextUpdate(() => {
        yardstick.mark('activeContextChange', 'queue-wait');
      }),
      this.switchboard.onDidFinishContextChangeRender(() => {
        yardstick.mark('activeContextChange', 'render');
      }),
      this.switchboard.onDidFinishActiveContextUpdate(() => {
        yardstick.finish('activeContextChange');
      }),
    );
  }

  async activate(state = {}) {
    const savedState = {...defaultState, ...state};

    const firstRun = !await fileExists(this.configPath);
    const newProject = savedState.firstRun !== undefined ? savedState.firstRun : savedState.newProject;

    this.startOpen = firstRun || newProject;
    this.startRevealed = firstRun && !this.config.get('welcome.showOnStartup');

    if (firstRun) {
      await fs.writeFile(this.configPath, '# Store non-visible GitHub package state.\n', {encoding: 'utf8'});
    }

    const hasSelectedFiles = event => {
      return !!event.target.closest('.github-FilePatchListView').querySelector('.is-selected');
    };

    this.subscriptions.add(
      this.workspace.getCenter().onDidChangeActivePaneItem(this.handleActivePaneItemChange),
      this.project.onDidChangePaths(this.handleProjectPathsChange),
      this.styleCalculator.startWatching(
        'github-package-styles',
        ['editor.fontSize', 'editor.fontFamily', 'editor.lineHeight', 'editor.tabLength'],
        config => `
          .github-HunkView-line {
            font-family: ${config.get('editor.fontFamily')};
            line-height: ${config.get('editor.lineHeight')};
            tab-size: ${config.get('editor.tabLength')}
          }
        `,
      ),
      atom.contextMenu.add({
        '.github-UnstagedChanges .github-FilePatchListView': [
          {
            label: 'Stage',
            command: 'core:confirm',
            shouldDisplay: hasSelectedFiles,
          },
          {
            type: 'separator',
            shouldDisplay: hasSelectedFiles,
          },
          {
            label: 'Discard Changes',
            command: 'github:discard-changes-in-selected-files',
            shouldDisplay: hasSelectedFiles,
          },
        ],
        '.github-StagedChanges .github-FilePatchListView': [
          {
            label: 'Unstage',
            command: 'core:confirm',
            shouldDisplay: hasSelectedFiles,
          },
        ],
        '.github-MergeConflictPaths .github-FilePatchListView': [
          {
            label: 'Stage',
            command: 'core:confirm',
            shouldDisplay: hasSelectedFiles,
          },
          {
            type: 'separator',
            shouldDisplay: hasSelectedFiles,
          },
          {
            label: 'Resolve File As Ours',
            command: 'github:resolve-file-as-ours',
            shouldDisplay: hasSelectedFiles,
          },
          {
            label: 'Resolve File As Theirs',
            command: 'github:resolve-file-as-theirs',
            shouldDisplay: hasSelectedFiles,
          },
        ],
      }),
    );

    this.activated = true;
    this.scheduleActiveContextUpdate({
      usePath: savedState.activeRepositoryPath,
      lock: savedState.contextLocked,
    });
    this.rerender();
  }

  handleActivePaneItemChange = () => {
    if (this.lockedContext) {
      return;
    }

    const itemPath = pathForPaneItem(this.workspace.getCenter().getActivePaneItem());
    this.scheduleActiveContextUpdate({
      usePath: itemPath,
      lock: false,
    });
  }

  handleProjectPathsChange = () => {
    this.scheduleActiveContextUpdate();
  }

  serialize() {
    return {
      activeRepositoryPath: this.getActiveWorkdir(),
      contextLocked: Boolean(this.lockedContext),
      newProject: false,
    };
  }

  rerender(callback) {
    if (this.workspace.isDestroyed()) {
      return;
    }

    if (!this.activated) {
      return;
    }

    if (!this.element) {
      this.element = document.createElement('div');
      this.subscriptions.add(new Disposable(() => {
        ReactDom.unmountComponentAtNode(this.element);
        delete this.element;
      }));
    }

    const changeWorkingDirectory = workingDirectory => {
      return this.scheduleActiveContextUpdate({usePath: workingDirectory});
    };

    const setContextLock = (workingDirectory, lock) => {
      return this.scheduleActiveContextUpdate({usePath: workingDirectory, lock});
    };

    this.renderFn(
      <RootController
        ref={c => { this.controller = c; }}
        workspace={this.workspace}
        deserializers={this.deserializers}
        commands={this.commands}
        notificationManager={this.notificationManager}
        tooltips={this.tooltips}
        grammars={this.grammars}
        keymaps={this.keymaps}
        config={this.config}
        project={this.project}
        confirm={this.confirm}
        currentWindow={this.currentWindow}
        workdirContextPool={this.contextPool}
        loginModel={this.loginModel}
        repository={this.getActiveRepository()}
        resolutionProgress={this.getActiveResolutionProgress()}
        statusBar={this.statusBar}
        initialize={this.initialize}
        clone={this.clone}
        switchboard={this.switchboard}
        startOpen={this.startOpen}
        startRevealed={this.startRevealed}
        removeFilePatchItem={this.removeFilePatchItem}
        currentWorkDir={this.getActiveWorkdir()}
        contextLocked={this.lockedContext !== null}
        changeWorkingDirectory={changeWorkingDirectory}
        setContextLock={setContextLock}
      />, this.element, callback,
    );
  }

  async deactivate() {
    this.subscriptions.dispose();
    this.contextPool.clear();
    WorkerManager.reset(false);
    if (this.guessedContext) {
      this.guessedContext.destroy();
      this.guessedContext = null;
    }
    await yardstick.flush();
  }

  consumeStatusBar(statusBar) {
    this.statusBar = statusBar;
    this.rerender();
  }

  consumeReporter(reporter) {
    reporterProxy.setReporter(reporter);
  }

  createGitTimingsView() {
    return StubItem.create('git-timings-view', {
      title: 'GitHub Package Timings View',
    }, GitTimingsView.buildURI());
  }

  createIssueishPaneItemStub({uri, selectedTab}) {
    return StubItem.create('issueish-detail-item', {
      title: 'Issueish',
      initSelectedTab: selectedTab,
    }, uri);
  }

  createDockItemStub({uri}) {
    let item;
    switch (uri) {
    // always return an empty stub
    // but only set it as the active item for a tab type
    // if it doesn't already exist
    case 'atom-github://dock-item/git':
      item = this.createGitStub(uri);
      this.gitTabStubItem = this.gitTabStubItem || item;
      break;
    case 'atom-github://dock-item/github':
      item = this.createGitHubStub(uri);
      this.githubTabStubItem = this.githubTabStubItem || item;
      break;
    default:
      throw new Error(`Invalid DockItem stub URI: ${uri}`);
    }

    if (this.controller) {
      this.rerender();
    }
    return item;
  }

  createGitStub(uri) {
    return StubItem.create('git', {
      title: 'Git',
    }, uri);
  }

  createGitHubStub(uri) {
    return StubItem.create('github', {
      title: 'GitHub',
    }, uri);
  }

  createFilePatchControllerStub({uri} = {}) {
    const item = StubItem.create('git-file-patch-controller', {
      title: 'Diff',
    }, uri);
    if (this.controller) {
      this.rerender();
    }
    return item;
  }

  createCommitPreviewStub({uri}) {
    const item = StubItem.create('git-commit-preview', {
      title: 'Commit preview',
    }, uri);
    if (this.controller) {
      this.rerender();
    }
    return item;
  }

  createCommitDetailStub({uri}) {
    const item = StubItem.create('git-commit-detail', {
      title: 'Commit',
    }, uri);
    if (this.controller) {
      this.rerender();
    }
    return item;
  }

  createReviewsStub({uri}) {
    const item = StubItem.create('github-reviews', {
      title: 'Reviews',
    }, uri);
    if (this.controller) {
      this.rerender();
    }
    return item;
  }

  destroyGitTabItem() {
    if (this.gitTabStubItem) {
      this.gitTabStubItem.destroy();
      this.gitTabStubItem = null;
      if (this.controller) {
        this.rerender();
      }
    }
  }

  destroyGithubTabItem() {
    if (this.githubTabStubItem) {
      this.githubTabStubItem.destroy();
      this.githubTabStubItem = null;
      if (this.controller) {
        this.rerender();
      }
    }
  }

  initialize = async projectPath => {
    await fs.mkdirs(projectPath);

    const repository = this.contextPool.add(projectPath).getRepository();
    await repository.init();
    this.workdirCache.invalidate();

    if (!this.project.contains(projectPath)) {
      this.project.addPath(projectPath);
    }

    await this.refreshAtomGitRepository(projectPath);
    await this.scheduleActiveContextUpdate();
  }

  clone = async (remoteUrl, projectPath, sourceRemoteName = 'origin') => {
    const context = this.contextPool.getContext(projectPath);
    let repository;
    if (context.isPresent()) {
      repository = context.getRepository();
      await repository.clone(remoteUrl, sourceRemoteName);
      repository.destroy();
    } else {
      repository = new Repository(projectPath, null, {pipelineManager: this.pipelineManager});
      await repository.clone(remoteUrl, sourceRemoteName);
    }

    this.workdirCache.invalidate();
    this.project.addPath(projectPath);
    await this.scheduleActiveContextUpdate();

    reporterProxy.addEvent('clone-repository', {project: 'github'});
  }

  getRepositoryForWorkdir(projectPath) {
    const loadingGuessRepo = Repository.loadingGuess({pipelineManager: this.pipelineManager});
    return this.guessedContext ? loadingGuessRepo : this.contextPool.getContext(projectPath).getRepository();
  }

  getActiveWorkdir() {
    return this.activeContext.getWorkingDirectory();
  }

  getActiveRepository() {
    return this.activeContext.getRepository();
  }

  getActiveResolutionProgress() {
    return this.activeContext.getResolutionProgress();
  }

  getContextPool() {
    return this.contextPool;
  }

  getSwitchboard() {
    return this.switchboard;
  }

  /**
   * Enqueue a request to modify the active context.
   *
   * options:
   *   usePath - Path of the context to use as the next context, if it is present in the pool.
   *   lock - True or false to lock the ultimately chosen context. Omit to preserve the current lock state.
   *
   * This method returns a Promise that resolves when the requested context update has completed. Note that it's
   * *possible* for the active context after resolution to differ from a requested `usePath`, if the workdir
   * containing `usePath` is no longer a viable option, such as if it belongs to a project that is no longer present.
   */
  async scheduleActiveContextUpdate(options = {}) {
    this.switchboard.didScheduleActiveContextUpdate();
    await this.activeContextQueue.push(this.updateActiveContext.bind(this, options), {parallel: false});
  }

  /**
   * Derive the git working directory context that should be used for the package's git operations based on the current
   * state of the Atom workspace. In priority, this prefers:
   *
   * - When activating: the working directory that was active when the package was last serialized, if it still a viable
   *   option. (usePath)
   * - The working directory chosen by the user from the context tile on the git or GitHub tabs. (usePath)
   * - The working directory containing the path of the active pane item.
   * - A git working directory corresponding to "first" project, if any projects are open.
   * - The current context, unchanged, which may be a `NullWorkdirContext`.
   *
   * First updates the pool of resident contexts to match all git working directories that correspond to open
   * projects and pane items.
   */
  async getNextContext(usePath = null) {
    // Internal utility function to normalize paths not contained within a git
    // working tree.
    const workdirForNonGitPath = async sourcePath => {
      const containingRoot = this.project.getDirectories().find(root => root.contains(sourcePath));
      if (containingRoot) {
        return containingRoot.getPath();
      /* istanbul ignore else */
      } else if (!(await fs.stat(sourcePath)).isDirectory()) {
        return path.dirname(sourcePath);
      } else {
        return sourcePath;
      }
    };

    // Internal utility function to identify the working directory to use for
    // an arbitrary (file or directory) path.
    const workdirForPath = async sourcePath => {
      return (await Promise.all([
        this.workdirCache.find(sourcePath),
        workdirForNonGitPath(sourcePath),
      ])).find(Boolean);
    };

    // Identify paths that *could* contribute a git working directory to the pool. This is drawn from
    // the roots of open projects, the currently locked context if one is present, and the path of the
    // open workspace item.
    const candidatePaths = new Set(this.project.getPaths());
    if (this.lockedContext) {
      const lockedRepo = this.lockedContext.getRepository();
      /* istanbul ignore else */
      if (lockedRepo) {
        candidatePaths.add(lockedRepo.getWorkingDirectoryPath());
      }
    }
    const activeItemPath = pathForPaneItem(this.workspace.getCenter().getActivePaneItem());
    if (activeItemPath) {
      candidatePaths.add(activeItemPath);
    }

    let activeItemWorkdir = null;
    let firstProjectWorkdir = null;

    // Convert the candidate paths into the set of viable git working directories, by means of a cached
    // `git rev-parse` call. Candidate paths that are not contained within a git working directory will
    // be preserved as-is within the pool, to allow users to initialize them.
    const workdirs = new Set(
      await Promise.all(
        Array.from(candidatePaths, async candidatePath => {
          const workdir = await workdirForPath(candidatePath);

          // Note the workdirs associated with the active pane item and the first open project so we can
          // prefer them later.
          if (candidatePath === activeItemPath) {
            activeItemWorkdir = workdir;
          } else if (candidatePath === this.project.getPaths()[0]) {
            firstProjectWorkdir = workdir;
          }

          return workdir;
        }),
      ),
    );

    // Update pool with the identified projects.
    this.contextPool.set(workdirs);

    // 1 - Explicitly requested workdir. This is either selected by the user from a context tile or
    //     deserialized from package state. Choose this context only if it still exists in the pool.
    if (usePath) {
      // Normalize usePath in a similar fashion to the way we do activeItemPath.
      let useWorkdir = usePath;
      if (usePath === activeItemPath) {
        useWorkdir = activeItemWorkdir;
      } else if (usePath === this.project.getPaths()[0]) {
        useWorkdir = firstProjectWorkdir;
      } else {
        useWorkdir = await workdirForPath(usePath);
      }

      const stateContext = this.contextPool.getContext(useWorkdir);
      if (stateContext.isPresent()) {
        return stateContext;
      }
    }

    // 2 - Use the currently locked context, if one is present.
    if (this.lockedContext) {
      return this.lockedContext;
    }

    // 3 - Follow the active workspace pane item.
    if (activeItemWorkdir) {
      return this.contextPool.getContext(activeItemWorkdir);
    }

    // 4 - The first open project.
    if (firstProjectWorkdir) {
      return this.contextPool.getContext(firstProjectWorkdir);
    }

    // No projects. Revert to the absent context unless we've guessed that more projects are on the way.
    if (this.project.getPaths().length === 0 && !this.activeContext.getRepository().isUndetermined()) {
      return WorkdirContext.absent({pipelineManager: this.pipelineManager});
    }

    // It is only possible to reach here if there there was no preferred directory, there are no project paths, and the
    // the active context's repository is not undetermined. Preserve the existing active context.
    return this.activeContext;
  }

  /**
   * Modify the active context and re-render the React tree. This should only be done as part of the
   * context update queue; use scheduleActiveContextUpdate() to do this.
   *
   * nextActiveContext - The WorkdirContext to make active next, as derived from the current workspace
   *   state by getNextContext(). This may be absent or undetermined.
   * lock - If true, also set this context as the "locked" one and engage the context lock if it isn't
   *   already. If false, clear any existing context lock. If null or undefined, leave the lock in its
   *   existing state.
   */
  setActiveContext(nextActiveContext, lock) {
    if (nextActiveContext !== this.activeContext) {
      if (this.activeContext === this.guessedContext) {
        this.guessedContext.destroy();
        this.guessedContext = null;
      }
      this.activeContext = nextActiveContext;
      if (lock === true) {
        this.lockedContext = this.activeContext;
      } else if (lock === false) {
        this.lockedContext = null;
      }

      this.rerender(() => {
        this.switchboard.didFinishContextChangeRender();
        this.switchboard.didFinishActiveContextUpdate();
      });
    } else if ((lock === true || lock === false) && lock !== (this.lockedContext !== null)) {
      if (lock) {
        this.lockedContext = this.activeContext;
      } else {
        this.lockedContext = null;
      }

      this.rerender(() => {
        this.switchboard.didFinishContextChangeRender();
        this.switchboard.didFinishActiveContextUpdate();
      });
    } else {
      this.switchboard.didFinishActiveContextUpdate();
    }
  }

  /**
   * Derive the next active context with getNextContext(), then enact the context change with setActiveContext().
   *
   * options:
   *   usePath - Path of the context to use as the next context, if it is present in the pool.
   *   lock - True or false to lock the ultimately chosen context. Omit to preserve the current lock state.
   */
  async updateActiveContext(options) {
    if (this.workspace.isDestroyed()) {
      return;
    }

    this.switchboard.didBeginActiveContextUpdate();

    const nextActiveContext = await this.getNextContext(options.usePath);
    this.setActiveContext(nextActiveContext, options.lock);
  }

  async refreshAtomGitRepository(workdir) {
    const directory = this.project.getDirectoryForProjectPath(workdir);
    if (!directory) {
      return;
    }

    const atomGitRepo = await this.project.repositoryForDirectory(directory);
    if (atomGitRepo) {
      await atomGitRepo.refreshStatus();
    }
  }
}

function pathForPaneItem(paneItem) {
  if (!paneItem) {
    return null;
  }

  // Likely GitHub package provided pane item
  if (typeof paneItem.getWorkingDirectory === 'function') {
    return paneItem.getWorkingDirectory();
  }

  // TextEditor-like
  if (typeof paneItem.getPath === 'function') {
    return paneItem.getPath();
  }

  // Oh well
  return null;
}