// Copyright 2020 Google LLC
//
// 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::cell::RefCell;
use std::collections::HashMap;
use std::path::{Path, PathBuf};

use tempfile::TempDir;

pub struct TestEnvironment {
    _temp_dir: TempDir,
    env_root: PathBuf,
    home_dir: PathBuf,
    config_dir: PathBuf,
    env_vars: HashMap<String, String>,
    config_file_number: RefCell<i64>,
    command_number: RefCell<i64>,
}

impl Default for TestEnvironment {
    fn default() -> Self {
        let tmp_dir = TempDir::new().unwrap();
        let env_root = tmp_dir.path().canonicalize().unwrap();
        let home_dir = env_root.join("home");
        std::fs::create_dir(&home_dir).unwrap();
        let config_dir = env_root.join("config");
        std::fs::create_dir(&config_dir).unwrap();
        let env_vars = HashMap::new();
        Self {
            _temp_dir: tmp_dir,
            env_root,
            home_dir,
            config_dir,
            env_vars,
            config_file_number: RefCell::new(0),
            command_number: RefCell::new(0),
        }
    }
}

impl TestEnvironment {
    pub fn jj_cmd(&self, current_dir: &Path, args: &[&str]) -> assert_cmd::Command {
        let mut cmd = assert_cmd::Command::cargo_bin("jj").unwrap();
        cmd.current_dir(current_dir);
        cmd.args(args);
        cmd.env_clear();
        for (key, value) in &self.env_vars {
            cmd.env(key, value);
        }
        cmd.env("RUST_BACKTRACE", "1");
        cmd.env("HOME", self.home_dir.to_str().unwrap());
        let timestamp = chrono::DateTime::parse_from_rfc3339("2001-02-03T04:05:06+07:00").unwrap();
        let mut command_number = self.command_number.borrow_mut();
        *command_number += 1;
        cmd.env("JJ_CONFIG", self.config_dir.to_str().unwrap());
        let timestamp = timestamp + chrono::Duration::seconds(*command_number);
        cmd.env("JJ_TIMESTAMP", timestamp.to_rfc3339());
        cmd.env("JJ_USER", "Test User");
        cmd.env("JJ_EMAIL", "test.user@example.com");
        cmd
    }

    /// Run a `jj` command, check that it was successful, and return its stdout
    pub fn jj_cmd_success(&self, current_dir: &Path, args: &[&str]) -> String {
        let assert = self.jj_cmd(current_dir, args).assert().success().stderr("");
        get_stdout_string(&assert)
    }

    /// Run a `jj` command, check that it was successful, and return its stdout
    pub fn jj_cmd_failure(&self, current_dir: &Path, args: &[&str]) -> String {
        let assert = self.jj_cmd(current_dir, args).assert().failure().stdout("");
        get_stderr_string(&assert)
    }

    pub fn env_root(&self) -> &Path {
        &self.env_root
    }

    pub fn home_dir(&self) -> &Path {
        &self.home_dir
    }

    pub fn add_config(&self, content: &[u8]) {
        // Concatenating two valid TOML files does not (generally) result in a valid
        // TOML file, so we use create a new file every time instead.
        let mut config_file_number = self.config_file_number.borrow_mut();
        *config_file_number += 1;
        let config_file_number = *config_file_number;
        std::fs::write(
            self.config_dir
                .join(format!("config{config_file_number:04}.toml")),
            content,
        )
        .unwrap();
    }

    pub fn add_env_var(&mut self, key: &str, val: &str) {
        self.env_vars.insert(key.to_string(), val.to_string());
    }

    /// Sets up the fake diff-editor to read an edit script from the returned
    /// path
    pub fn set_up_fake_diff_editor(&mut self) -> PathBuf {
        let diff_editor_path = assert_cmd::cargo::cargo_bin("fake-diff-editor");
        assert!(diff_editor_path.is_file());
        // Simplified TOML escaping, hoping that there are no '"' or control characters
        // in it
        let escaped_diff_editor_path = diff_editor_path.to_str().unwrap().replace('\\', r"\\");
        self.add_config(
            format!(
                r###"
        [ui]
        diff-editor = "{}"
        "###,
                escaped_diff_editor_path
            )
            .as_bytes(),
        );
        let edit_script = self.env_root().join("edit_script");
        self.add_env_var("EDIT_SCRIPT", edit_script.to_str().unwrap());
        edit_script
    }
}

pub fn get_stdout_string(assert: &assert_cmd::assert::Assert) -> String {
    String::from_utf8(assert.get_output().stdout.clone()).unwrap()
}

pub fn get_stderr_string(assert: &assert_cmd::assert::Assert) -> String {
    String::from_utf8(assert.get_output().stderr.clone()).unwrap()
}