// Copyright 2020 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 std::io::Write as _;

use clap_complete::ArgValueCompleter;
use jj_lib::object_id::ObjectId as _;
use tracing::instrument;

use crate::cli_util::CommandHelper;
use crate::cli_util::RevisionArg;
use crate::command_error::CommandError;
use crate::complete;
use crate::ui::Ui;

/// Sets the specified revision as the working-copy revision
///
/// Note: it is [generally recommended] to instead use `jj new` and `jj
/// squash`.
///
/// [generally recommended]:
///     https://docs.jj-vcs.dev/latest/FAQ#how-do-i-resume-working-on-an-existing-change
#[derive(clap::Args, Clone, Debug)]
#[command(group(clap::ArgGroup::new("revision").required(true)))]
pub(crate) struct EditArgs {
    /// The commit to edit [aliases: -r]
    #[arg(group = "revision", value_name = "REVSET")]
    #[arg(add = ArgValueCompleter::new(complete::revset_expression_mutable))]
    revision_pos: Option<RevisionArg>,

    #[arg(short = 'r', group = "revision", hide = true, value_name = "REVSET")]
    #[arg(add = ArgValueCompleter::new(complete::revset_expression_mutable))]
    revision_opt: Option<RevisionArg>,
}

#[instrument(skip_all)]
pub(crate) async fn cmd_edit(
    ui: &mut Ui,
    command: &CommandHelper,
    args: &EditArgs,
) -> Result<(), CommandError> {
    let mut workspace_command = command.workspace_helper(ui)?;
    let revision_arg = args
        .revision_pos
        .as_ref()
        .or(args.revision_opt.as_ref())
        .expect("either positional or -r arg should be provided");
    let new_commit = workspace_command
        .resolve_single_rev(ui, revision_arg)
        .await?;
    workspace_command
        .check_rewritable([new_commit.id()])
        .await?;
    if workspace_command.get_wc_commit_id() == Some(new_commit.id()) {
        writeln!(ui.status(), "Already editing that commit")?;
    } else {
        let mut tx = workspace_command.start_transaction();
        tx.edit(&new_commit)?;
        tx.finish(ui, format!("edit commit {}", new_commit.id().hex()))
            .await?;
    }
    Ok(())
}
