// 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;

use clap_complete::ArgValueCandidates;
use jj_lib::commit::Commit;
use jj_lib::config::ConfigNamePathBuf;
use jj_lib::config::ConfigValue;
use jj_lib::repo::Repo as _;
use tracing::instrument;

use super::ConfigLevelArgs;
use crate::cli_util::CommandHelper;
use crate::cli_util::WorkspaceCommandHelper;
use crate::command_error::CommandError;
use crate::command_error::user_error_with_message;
use crate::complete;
use crate::config::parse_value_or_bare_string;
use crate::ui::Ui;

/// Update a config file to set the given option to a given value.
#[derive(clap::Args, Clone, Debug)]
pub struct ConfigSetArgs {
    #[arg(required = true, add = ArgValueCandidates::new(complete::leaf_config_keys))]
    name: ConfigNamePathBuf,
    /// New value to set
    ///
    /// The value should be specified as a TOML expression. If string value
    /// isn't enclosed by any TOML constructs (such as apostrophes or array
    /// notation), quotes can be omitted. Note that the value may also need
    /// shell quoting. TOML multi-line strings can be useful if the value
    /// contains apostrophes. For example, to set `foo.bar` to the string
    /// "{don't}" use `jj config set --user foo.bar "'''{don't}'''"`. This is
    /// valid in both Bash and Fish.
    ///
    /// Alternative, e.g. to avoid dealing with shell quoting, use `jj config
    /// edit` to edit the TOML file directly.
    #[arg(required = true, value_parser = parse_value_or_bare_string)]
    value: ConfigValue,
    #[command(flatten)]
    level: ConfigLevelArgs,
}

/// Denotes a type of author change
enum AuthorChange {
    Name,
    Email,
}

#[instrument(skip_all)]
pub fn cmd_config_set(
    ui: &mut Ui,
    command: &CommandHelper,
    args: &ConfigSetArgs,
) -> Result<(), CommandError> {
    let mut file = args.level.edit_config_file(ui, command)?;

    // If the user is trying to change the author config, we should warn them that
    // it won't affect the working copy author
    if args.name == ConfigNamePathBuf::from_iter(vec!["user", "name"]) {
        check_wc_author(ui, command, &args.value, AuthorChange::Name)?;
    } else if args.name == ConfigNamePathBuf::from_iter(vec!["user", "email"]) {
        check_wc_author(ui, command, &args.value, AuthorChange::Email)?;
    };

    file.set_value(&args.name, &args.value)
        .map_err(|err| user_error_with_message(format!("Failed to set {}", args.name), err))?;
    file.save()?;
    Ok(())
}

/// Returns the commit of the working copy if it exists.
fn maybe_wc_commit(helper: &WorkspaceCommandHelper) -> Option<Commit> {
    let repo = helper.repo();
    let id = helper.get_wc_commit_id()?;
    repo.store().get_commit(id).ok()
}

/// Check if the working copy author name matches the user's config value
/// If it doesn't, print a warning message
fn check_wc_author(
    ui: &mut Ui,
    command: &CommandHelper,
    new_value: &toml_edit::Value,
    author_change: AuthorChange,
) -> io::Result<()> {
    let helper = match command.workspace_helper(ui) {
        Ok(helper) => helper,
        Err(_) => return Ok(()), // config set should work even if cwd isn't a jj repo
    };
    if let Some(wc_commit) = maybe_wc_commit(&helper) {
        let author = wc_commit.author();
        let orig_value = match author_change {
            AuthorChange::Name => &author.name,
            AuthorChange::Email => &author.email,
        };
        if new_value.as_str() != Some(orig_value) {
            warn_wc_author(ui, &author.name, &author.email)?;
        }
    }
    Ok(())
}

/// Prints a warning message about the working copy to the user
fn warn_wc_author(ui: &Ui, user_name: &str, user_email: &str) -> io::Result<()> {
    Ok(writeln!(
        ui.warning_default(),
        "This setting will only impact future commits.\nThe author of the working copy will stay \
         \"{user_name} <{user_email}>\".\nTo change the working copy author, use \"jj metaedit \
         --update-author\""
    )?)
}