// Copyright 2019-2024 Tauri Programme within The Commons Conservancy
// SPDX-License-Identifier: Apache-2.0
// SPDX-License-Identifier: MIT

use super::{ensure_init, env, get_app, get_config, read_options, MobileTarget};
use crate::{
  error::{Context, ErrorExt},
  helpers::config::{get_config as get_tauri_config, reload_config as reload_tauri_config},
  interface::{AppInterface, Options as InterfaceOptions},
  mobile::ios::LIB_OUTPUT_FILE_NAME,
  Error, Result,
};

use cargo_mobile2::{apple::target::Target, opts::Profile, target::TargetTrait};
use clap::{ArgAction, Parser};
use object::{Object, ObjectSymbol};

use std::{
  collections::HashMap,
  env::{current_dir, set_current_dir, var, var_os},
  ffi::OsStr,
  fs::read_to_string,
  io::Read,
  path::{Path, PathBuf},
};

#[derive(Debug, Parser)]
pub struct Options {
  /// Value of `PLATFORM_DISPLAY_NAME` env var
  #[clap(long)]
  platform: String,
  /// Value of `SDKROOT` env var
  #[clap(long)]
  sdk_root: PathBuf,
  /// Value of `FRAMEWORK_SEARCH_PATHS` env var
  #[clap(long, action = ArgAction::Append, num_args(0..))]
  framework_search_paths: Vec<String>,
  /// Value of `GCC_PREPROCESSOR_DEFINITIONS` env var
  #[clap(long, action = ArgAction::Append, num_args(0..))]
  gcc_preprocessor_definitions: Vec<String>,
  /// Value of `HEADER_SEARCH_PATHS` env var
  #[clap(long, action = ArgAction::Append, num_args(0..))]
  header_search_paths: Vec<String>,
  /// Value of `CONFIGURATION` env var
  #[clap(long)]
  configuration: String,
  /// Value of `FORCE_COLOR` env var
  #[clap(long)]
  force_color: bool,
  /// Value of `ARCHS` env var
  #[clap(index = 1, required = true)]
  arches: Vec<String>,
}

pub fn command(options: Options) -> Result<()> {
  fn macos_from_platform(platform: &str) -> bool {
    platform == "macOS"
  }

  fn profile_from_configuration(configuration: &str) -> Profile {
    if configuration == "release" {
      Profile::Release
    } else {
      Profile::Debug
    }
  }

  let process_path = std::env::current_exe().unwrap_or_default();

  // `xcode-script` is ran from the `gen/apple` folder when not using NPM/yarn/pnpm/deno.
  // so we must change working directory to the src-tauri folder to resolve the tauri dir
  // additionally, bun@<1.2 does not modify the current working directory, so it is also runs this script from `gen/apple`
  // bun@>1.2 now actually moves the CWD to the package root so we shouldn't modify CWD in that case
  // see https://bun.sh/blog/bun-v1.2#bun-run-uses-the-correct-directory
  if (var_os("npm_lifecycle_event").is_none()
    && var_os("PNPM_PACKAGE_NAME").is_none()
    && process_path.file_stem().unwrap_or_default() != "deno")
    || var("npm_config_user_agent")
      .is_ok_and(|agent| agent.starts_with("bun/1.0") || agent.starts_with("bun/1.1"))
  {
    set_current_dir(
      current_dir()
        .context("failed to resolve current directory")?
        .parent()
        .unwrap()
        .parent()
        .unwrap(),
    )
    .unwrap();
  }

  let dirs = crate::helpers::app_paths::resolve_dirs();

  let profile = profile_from_configuration(&options.configuration);
  let macos = macos_from_platform(&options.platform);

  let mut tauri_config = get_tauri_config(tauri_utils::platform::Target::Ios, &[], dirs.tauri)?;
  let cli_options = read_options(&tauri_config);
  if !cli_options.config.is_empty() {
    // reload config with merges from the ios dev|build script
    reload_tauri_config(
      &mut tauri_config,
      &cli_options
        .config
        .iter()
        .map(|conf| &conf.0)
        .collect::<Vec<_>>(),
      dirs.tauri,
    )?
  };

  let (config, metadata) = get_config(
    &get_app(
      MobileTarget::Ios,
      &tauri_config,
      &AppInterface::new(&tauri_config, None, dirs.tauri)?,
      dirs.tauri,
    ),
    &tauri_config,
    &[],
    &cli_options,
    dirs.tauri,
  )?;

  ensure_init(
    &tauri_config,
    config.app(),
    config.project_dir(),
    MobileTarget::Ios,
    std::env::var("CI").is_ok(),
  )?;

  if !cli_options.config.is_empty() {
    crate::helpers::config::merge_config_with(
      &mut tauri_config,
      &cli_options
        .config
        .iter()
        .map(|conf| &conf.0)
        .collect::<Vec<_>>(),
    )?;
  }

  let env = env()
    .context("failed to load iOS environment")?
    .explicit_env_vars(cli_options.vars);

  if !options.sdk_root.is_dir() {
    crate::error::bail!(
      "SDK root provided by Xcode was invalid. {} doesn't exist or isn't a directory",
      options.sdk_root.display(),
    );
  }
  let include_dir = options.sdk_root.join("usr/include");
  if !include_dir.is_dir() {
    crate::error::bail!(
      "Include dir was invalid. {} doesn't exist or isn't a directory",
      include_dir.display()
    );
  }

  // Host flags that are used by build scripts
  let macos_isysroot = {
    let macos_sdk_root = options
      .sdk_root
      .join("../../../../MacOSX.platform/Developer/SDKs/MacOSX.sdk");
    if !macos_sdk_root.is_dir() {
      crate::error::bail!("Invalid SDK root {}", macos_sdk_root.display());
    }
    format!("-isysroot {}", macos_sdk_root.display())
  };

  let mut host_env = HashMap::<&str, &OsStr>::new();

  host_env.insert("RUST_BACKTRACE", "1".as_ref());

  host_env.insert("CFLAGS_x86_64_apple_darwin", macos_isysroot.as_ref());
  host_env.insert("CXXFLAGS_x86_64_apple_darwin", macos_isysroot.as_ref());

  host_env.insert(
    "OBJC_INCLUDE_PATH_x86_64_apple_darwin",
    include_dir.as_os_str(),
  );

  let framework_search_paths = options.framework_search_paths.join(" ");
  host_env.insert("FRAMEWORK_SEARCH_PATHS", framework_search_paths.as_ref());

  let gcc_preprocessor_definitions = options.gcc_preprocessor_definitions.join(" ");
  host_env.insert(
    "GCC_PREPROCESSOR_DEFINITIONS",
    gcc_preprocessor_definitions.as_ref(),
  );

  let header_search_paths = options.header_search_paths.join(" ");
  host_env.insert("HEADER_SEARCH_PATHS", header_search_paths.as_ref());

  let macos_target = Target::macos();

  let isysroot = format!("-isysroot {}", options.sdk_root.display());

  let simulator =
    options.platform == "iOS Simulator" || options.arches.contains(&"Simulator".to_string());
  let arches = if simulator {
    // when compiling for the simulator, we don't need to build other targets
    vec![if cfg!(target_arch = "aarch64") {
      "arm64"
    } else {
      "x86_64"
    }
    .to_string()]
  } else {
    options.arches
  };

  let installed_targets =
    crate::interface::rust::installation::installed_targets().unwrap_or_default();

  for arch in arches {
    // Set target-specific flags
    let (env_triple, rust_triple) = match arch.as_str() {
      "arm64" if !simulator => ("aarch64_apple_ios", "aarch64-apple-ios"),
      "arm64" if simulator => ("aarch64_apple_ios_sim", "aarch64-apple-ios-sim"),
      "x86_64" => ("x86_64_apple_ios", "x86_64-apple-ios"),
      _ => {
        crate::error::bail!("Arch specified by Xcode was invalid. {arch} isn't a known arch")
      }
    };

    let interface = AppInterface::new(&tauri_config, Some(rust_triple.into()), dirs.tauri)?;

    let cflags = format!("CFLAGS_{env_triple}");
    let cxxflags = format!("CFLAGS_{env_triple}");
    let objc_include_path = format!("OBJC_INCLUDE_PATH_{env_triple}");
    let mut target_env = host_env.clone();
    target_env.insert(cflags.as_ref(), isysroot.as_ref());
    target_env.insert(cxxflags.as_ref(), isysroot.as_ref());
    target_env.insert(objc_include_path.as_ref(), include_dir.as_ref());

    let target = if macos {
      &macos_target
    } else {
      Target::for_arch(if arch == "arm64" && simulator {
        "arm64-sim"
      } else {
        &arch
      })
      .with_context(|| format!("Arch specified by Xcode was invalid. {arch} isn't a known arch"))?
    };

    if !installed_targets.contains(&rust_triple.into()) {
      log::info!("Installing target {}", target.triple());
      target.install().map_err(|error| Error::CommandFailed {
        command: "rustup target add".to_string(),
        error,
      })?;
    }

    target
      .compile_lib(
        &config,
        &metadata,
        cli_options.noise_level,
        true,
        profile,
        &env,
        target_env,
      )
      .context("failed to compile iOS app")?;

    let out_dir = interface.app_settings().out_dir(
      &InterfaceOptions {
        debug: matches!(profile, Profile::Debug),
        target: Some(rust_triple.into()),
        ..Default::default()
      },
      dirs.tauri,
    )?;

    let lib_path = out_dir.join(format!("lib{}.a", config.app().lib_name()));
    if !lib_path.exists() {
      crate::error::bail!("Library not found at {}. Make sure your Cargo.toml file has a [lib] block with `crate-type = [\"staticlib\", \"cdylib\", \"lib\"]`", lib_path.display());
    }

    validate_lib(&lib_path)?;

    let project_dir = config.project_dir();
    let externals_lib_dir = project_dir.join(format!("Externals/{arch}/{}", profile.as_str()));
    std::fs::create_dir_all(&externals_lib_dir).fs_context(
      "failed to create externals lib directory",
      externals_lib_dir.clone(),
    )?;

    // backwards compatible lib output file name
    let uses_new_lib_output_file_name = {
      let pbxproj_path = project_dir
        .join(format!("{}.xcodeproj", config.app().name()))
        .join("project.pbxproj");
      let pbxproj_contents = read_to_string(&pbxproj_path)
        .fs_context("failed to read project.pbxproj file", pbxproj_path)?;

      pbxproj_contents.contains(LIB_OUTPUT_FILE_NAME)
    };

    let lib_output_file_name = if uses_new_lib_output_file_name {
      LIB_OUTPUT_FILE_NAME.to_string()
    } else {
      format!("lib{}.a", config.app().lib_name())
    };

    std::fs::copy(&lib_path, externals_lib_dir.join(lib_output_file_name)).fs_context(
      "failed to copy mobile lib file to Externals directory",
      lib_path.to_path_buf(),
    )?;
  }
  Ok(())
}

fn validate_lib(path: &Path) -> Result<()> {
  let mut archive = ar::Archive::new(
    std::fs::File::open(path).fs_context("failed to open mobile lib file", path.to_path_buf())?,
  );
  // Iterate over all entries in the archive:
  while let Some(entry) = archive.next_entry() {
    let Ok(mut entry) = entry else {
      continue;
    };
    let mut obj_bytes = Vec::new();
    entry
      .read_to_end(&mut obj_bytes)
      .fs_context("failed to read mobile lib entry", path.to_path_buf())?;

    let file = object::File::parse(&*obj_bytes)
      .map_err(std::io::Error::other)
      .fs_context("failed to parse mobile lib entry", path.to_path_buf())?;
    for symbol in file.symbols() {
      let Ok(name) = symbol.name() else {
        continue;
      };
      if name.contains("start_app") {
        return Ok(());
      }
    }
  }

  crate::error::bail!(
    "Library from {} does not include required runtime symbols. This means you are likely missing the tauri::mobile_entry_point macro usage, see the documentation for more information: https://v2.tauri.app/start/migrate/from-tauri-1",
    path.display()
  )
}