import { git, IGitExecutionOptions } from '../core/git';

/** The reset modes which are supported. */
export const enum GitResetMode {
    /**
     * Resets the index and working tree. Any changes to tracked files in the
     * working tree since <commit> are discarded.
     */
    Hard = 0,
    /**
     * Does not touch the index file or the working tree at all (but resets the
     * head to <commit>, just like all modes do). This leaves all your changed
     * files "Changes to be committed", as git status would put it.
     */
    Soft,

    /**
     * Resets the index but not the working tree (i.e., the changed files are
     * preserved but not marked for commit) and reports what has not been updated.
     * This is the default action for git reset.
     */
    Mixed,
}

function resetModeToFlag(mode: GitResetMode): string {
    switch (mode) {
        case GitResetMode.Hard:
            return '--hard';
        case GitResetMode.Mixed:
            return '--mixed';
        case GitResetMode.Soft:
            return '--soft';
        default:
            throw new Error(`Unknown reset mode: ${mode}`);
    }
}

/** Reset with the mode to the ref. */
export async function reset(repositoryPath: string, mode: GitResetMode, ref: string, options?: IGitExecutionOptions): Promise<void> {
    const modeFlag = resetModeToFlag(mode);
    await git(['reset', modeFlag, ref, '--'], repositoryPath, 'reset', options);
}

/**
 * Updates the index with information from a particular tree for a given
 * set of paths.
 *
 * @param repository The repository in which to reset the index.
 *
 * @param mode      Which mode to use when resetting, see the GitResetMode
 *                  enum for more information.
 *
 * @param ref       A string which resolves to a tree, for example 'HEAD' or a
 *                  commit sha.
 *
 * @param paths     The paths that should be updated in the index with information
 *                  from the given tree
 */
export async function resetPaths(repositoryPath: string, mode: GitResetMode, ref: string, paths: string[], options?: IGitExecutionOptions): Promise<void> {
    if (!paths.length) {
        return;
    }

    const modeFlag = resetModeToFlag(mode);
    await git(['reset', modeFlag, ref, '--', ...paths], repositoryPath, 'reset', options);
}

/** Unstage all paths. */
export async function unstageAll(repositoryPath: string, options?: IGitExecutionOptions): Promise<void> {
    await git(['reset', '--', '.'], repositoryPath, 'unstageAll', options);
}