// Copyright 2020-2023 The Jujutsu Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use clap_complete::ArgValueCandidates;
use jj_lib::object_id::ObjectId as _;

use super::DEFAULT_REVERT_WHAT;
use super::RevertWhatToRestore;
use super::view_with_desired_portions_restored;
use crate::cli_util::CommandHelper;
use crate::command_error::CommandError;
use crate::complete;
use crate::ui::Ui;

/// Create a new operation that restores the repo to an earlier state
///
/// This restores the repo to the state at the specified operation, effectively
/// undoing all later operations. It does so by creating a new operation.
#[derive(clap::Args, Clone, Debug)]
pub struct OperationRestoreArgs {
    /// The operation to restore to
    ///
    /// Use `jj op log` to find an operation to restore to. Use e.g. `jj
    /// --at-op=<operation ID> log` before restoring to an operation to see the
    /// state of the repo at that operation.
    #[arg(add = ArgValueCandidates::new(complete::operations))]
    operation: String,

    /// What portions of the local state to restore (can be repeated)
    ///
    /// This option is EXPERIMENTAL.
    #[arg(long, value_enum, default_values_t = DEFAULT_REVERT_WHAT)]
    what: Vec<RevertWhatToRestore>,
}

pub async fn cmd_op_restore(
    ui: &mut Ui,
    command: &CommandHelper,
    args: &OperationRestoreArgs,
) -> Result<(), CommandError> {
    let mut workspace_command = command.workspace_helper(ui)?;
    let target_op = workspace_command.resolve_single_op(&args.operation)?;
    let mut tx = workspace_command.start_transaction();
    let new_view = view_with_desired_portions_restored(
        target_op.view().await?.store_view(),
        tx.base_repo().view().store_view(),
        &args.what,
    );
    tx.repo_mut().set_view(new_view);
    if let Some(mut formatter) = ui.status_formatter() {
        write!(formatter, "Restored to operation: ")?;
        let template = tx.base_workspace_helper().operation_summary_template();
        template.format(&target_op, formatter.as_mut())?;
        writeln!(formatter)?;
    }
    tx.finish(ui, format!("restore to operation {}", target_op.id().hex()))
        .await?;

    Ok(())
}
