/*
 * This file is part of espanso.
 *
 * Copyright (C) 2019-2021 Federico Terzi
 *
 * espanso is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * espanso is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with espanso.  If not, see <https://www.gnu.org/licenses/>.
 */

use log::{debug, info};
use std::{
  fs::create_dir_all,
  path::{Path, PathBuf},
};

#[derive(Debug, Clone)]
pub struct Paths {
  pub config: PathBuf,
  pub runtime: PathBuf,
  pub packages: PathBuf,
}

pub fn resolve_paths() -> Paths {
  let config_dir = if let Some(config_dir) = get_config_dir() {
    config_dir
  } else {
    // Create the config directory if not already present
    let config_dir = get_default_config_path();
    info!("creating config directory in {:?}", config_dir);
    create_dir_all(&config_dir).expect("unable to create config directory");
    config_dir
  };

  let runtime_dir = if let Some(runtime_dir) = get_runtime_dir() {
    runtime_dir
  } else {
    // Create the runtime directory if not already present
    let runtime_dir = if !is_portable_mode() {
      get_default_runtime_path()
    } else {
      get_portable_runtime_path().expect("unable to obtain runtime directory path")
    };
    info!("creating runtime directory in {:?}", runtime_dir);
    create_dir_all(&runtime_dir).expect("unable to create runtime directory");
    runtime_dir
  };

  let packages_dir = if let Some(package_dir) = get_packages_dir(&config_dir, &runtime_dir) {
    package_dir
  } else {
    // Create the packages directory if not already present
    let packages_dir = get_default_packages_path(&config_dir);
    info!("creating packages directory in {:?}", packages_dir);
    create_dir_all(&packages_dir).expect("unable to create packages directory");
    packages_dir
  };

  Paths {
    config: config_dir,
    runtime: runtime_dir, 
    packages: packages_dir, 
  }
}

fn get_config_dir() -> Option<PathBuf> {
  if let Some(portable_dir) = get_portable_config_dir() {
    // Portable mode
    debug!("detected portable config directory in {:?}", portable_dir);
    Some(portable_dir)
  } else if let Some(config_dir) = get_home_espanso_dir() {
    // $HOME/.espanso
    debug!("detected config directory in $HOME/.espanso");
    Some(config_dir)
  } else if let Some(config_dir) = get_home_config_espanso_dir() {
    // $HOME/.config/espanso
    debug!("detected config directory in $HOME/.config/espanso");
    Some(config_dir)
  } else if let Some(legacy_mac_dir) = get_legacy_mac_dir() {
    // Legacy macOS location in ~/Library/Preferences/espanso
    debug!(
      "detected legacy config directory location at {:?}",
      legacy_mac_dir
    );
    Some(legacy_mac_dir)
  } else if let Some(config_dir) = get_default_config_dir() {
    debug!("detected default config directory at {:?}", config_dir);
    Some(config_dir)
  } else {
    None
  }
}

fn get_portable_config_dir() -> Option<PathBuf> {
  let espanso_exe_path = std::env::current_exe().expect("unable to obtain executable path");
  let exe_dir = espanso_exe_path.parent();
  if let Some(parent) = exe_dir {
    let config_dir = parent.join(".espanso");
    if config_dir.is_dir() {
      return Some(config_dir);
    }
  }
  None
}

fn get_home_espanso_dir() -> Option<PathBuf> {
  if let Some(home_dir) = dirs::home_dir() {
    let config_espanso_dir = home_dir.join(".espanso");
    if config_espanso_dir.is_dir() {
      return Some(config_espanso_dir);
    }
  }
  None
}

fn get_home_config_espanso_dir() -> Option<PathBuf> {
  if let Some(home_dir) = dirs::home_dir() {
    let home_espanso_dir = home_dir.join(".config").join("espanso");
    if home_espanso_dir.is_dir() {
      return Some(home_espanso_dir);
    }
  }
  None
}

fn get_default_config_dir() -> Option<PathBuf> {
  let config_path = get_default_config_path();
  if config_path.is_dir() {
    return Some(config_path);
  }
  None
}

fn get_default_config_path() -> PathBuf {
  let config_dir = dirs::config_dir().expect("unable to obtain dirs::config_dir()");
  config_dir.join("espanso")
}

// Due to the original behavior of the dirs crate, espanso placed the config
// directory in the Preferences folder on macOS, but this is not an optimal
// approach.
// For more context, see: https://github.com/federico-terzi/espanso/issues/611
fn get_legacy_mac_dir() -> Option<PathBuf> {
  if cfg!(target_os = "macos") {
    if let Some(preferences_dir) = dirs::preference_dir() {
      let espanso_dir = preferences_dir.join("espanso");
      if espanso_dir.is_dir() {
        return Some(espanso_dir);
      }
    }
  }
  None
}

fn get_runtime_dir() -> Option<PathBuf> {
  if let Some(runtime_dir) = get_portable_runtime_dir() {
    debug!("detected portable runtime dir: {:?}", runtime_dir);
    Some(runtime_dir)
  } else if let Some(legacy_dir) = get_legacy_runtime_dir() {
    debug!("detected legacy runtime dir: {:?}", legacy_dir);
    Some(legacy_dir)
  } else if let Some(default_dir) = get_default_runtime_dir() {
    debug!("detected default runtime dir: {:?}", default_dir);
    Some(default_dir)
  } else {
    None
  }
}

fn get_portable_runtime_dir() -> Option<PathBuf> {
  if let Some(runtime_dir) = get_portable_runtime_path() {
    if runtime_dir.is_dir() {
      return Some(runtime_dir);
    }
  }
  None
}

fn get_portable_runtime_path() -> Option<PathBuf> {
  let espanso_exe_path = std::env::current_exe().expect("unable to obtain executable path");
  let exe_dir = espanso_exe_path.parent();
  if let Some(parent) = exe_dir {
    let config_dir = parent.join(".espanso-runtime");
    return Some(config_dir);
  }
  None
}

fn get_legacy_runtime_dir() -> Option<PathBuf> {
  let data_dir = dirs::data_local_dir().expect("unable to obtain dirs::data_local_dir()");
  let espanso_dir = data_dir.join("espanso");
  if espanso_dir.is_dir() {
    Some(espanso_dir)
  } else {
    None
  }
}

fn get_default_runtime_dir() -> Option<PathBuf> {
  let default_dir = get_default_runtime_path();
  if default_dir.is_dir() {
    Some(default_dir)
  } else {
    None
  }
}

fn get_default_runtime_path() -> PathBuf {
  let runtime_dir = if cfg!(target_os = "linux") {
    dirs::runtime_dir().expect("unable to obtain dirs::runtime_dir()")
  } else {
    dirs::cache_dir().expect("unable to obtain dirs::cache_dir()")
  };
  runtime_dir.join("espanso")
}

fn get_packages_dir(config_dir: &Path, legacy_data_dir: &Path) -> Option<PathBuf> {
  if let Some(packages_dir) = get_legacy_embedded_packages_dir(config_dir) {
    debug!("detected legacy packages dir: {:?}", packages_dir);
    Some(packages_dir)
  } else if let Some(packages_dir) = get_legacy_packages_dir(legacy_data_dir) {
    debug!("detected legacy packages dir: {:?}", packages_dir);
    Some(packages_dir)
  } else if let Some(packages_dir) = get_default_packages_dir(config_dir) {
    debug!("detected default packages dir: {:?}", packages_dir);
    Some(packages_dir)
  } else {
    None
  }
}

fn get_legacy_packages_dir(legacy_data_dir: &Path) -> Option<PathBuf> {
  let legacy_dir = legacy_data_dir.join("packages");
  if legacy_dir.is_dir() {
    Some(legacy_dir)
  } else {
    None
  }
}

fn get_legacy_embedded_packages_dir(config_dir: &Path) -> Option<PathBuf> {
  let legacy_dir = config_dir.join("packages");
  if legacy_dir.is_dir() {
    Some(legacy_dir)
  } else {
    None
  }
}

fn get_default_packages_dir(config_dir: &Path) -> Option<PathBuf> {
  let packages_dir = get_default_packages_path(config_dir);
  if packages_dir.is_dir() {
    Some(packages_dir)
  } else {
    None
  }
}

fn get_default_packages_path(config_dir: &Path) -> PathBuf {
  config_dir.join("match").join("packages")
}

fn is_portable_mode() -> bool {
  let espanso_exe_path = std::env::current_exe().expect("unable to obtain executable path");
  let exe_dir = espanso_exe_path.parent();
  if let Some(parent) = exe_dir {
    let config_dir = parent.join(".espanso");
    if config_dir.is_dir() {
      return true;
    }
  }
  false
}