// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

use crate::utils::is_mac;
use crate::X64;
use failure::{bail, Error, ResultExt};
use std::path::PathBuf;
use std::process::Command;
use std::{env, str};

/// The `TargetOptions` struct bundles together a number of parameters specific to
/// the Fuchsia target that need to be passed through various internal functions. For
/// the moment there is no way to set anything but the `release_os` field, but this
/// will change when fargo starts supporting ARM targets.
#[derive(Debug)]
pub struct TargetOptions<'a, 'b> {
    pub device_name: Option<&'b str>,
    pub config: &'a FuchsiaConfig,
}

impl<'a, 'b> TargetOptions<'a, 'b> {
    /// Constructs a new `TargetOptions`.
    ///
    /// # Examples
    ///
    /// ```
    /// use fargo::{FuchsiaConfig, TargetOptions};
    ///
    /// let target_options =
    ///     TargetOptions::new(&FuchsiaConfig::default(), Some("ivy-donut-grew-stoop"));
    /// ```

    pub fn new(config: &'a FuchsiaConfig, device_name: Option<&'b str>) -> TargetOptions<'a, 'b> {
        TargetOptions { device_name: device_name, config: config }
    }
}

fn get_path_from_env(env_name: &str, require_dir: bool) -> Result<Option<PathBuf>, Error> {
    if let Ok(file_value) = env::var(env_name) {
        let file_path = PathBuf::from(&file_value);
        if !file_path.exists() {
            bail!("{} is set to '{}' but nothing exists at that path.", env_name, &file_value);
        }
        if require_dir {
            if !file_path.is_dir() {
                bail!(
                    "{} is set to '{}' but that path does not point to a directory.",
                    env_name,
                    &file_value
                );
            }
        }
        return Ok(Some(file_path));
    }
    Ok(None)
}

fn looks_like_fuchsia_dir(path: &PathBuf) -> bool {
    for name in [".fx-build-dir", ".jiri_manifest"].iter() {
        let config_path = path.join(name);
        if !config_path.exists() {
            return false;
        }
    }
    true
}

pub fn fuchsia_dir() -> Result<PathBuf, Error> {
    let fuchsia_dir = if let Some(fuchsia_root) = get_path_from_env("FUCHSIA_ROOT", true)? {
        fuchsia_root
    } else if let Some(fuchsia_dir) = get_path_from_env("FUCHSIA_DIR", true)? {
        fuchsia_dir
    } else {
        let mut path = env::current_dir()?;
        loop {
            if looks_like_fuchsia_dir(&path) {
                return Ok(path);
            }
            path = if let Some(path) = path.parent() {
                path.to_path_buf()
            } else {
                bail!(
                    "FUCHSIA_DIR not set and current directory is not in a Fuchsia tree with a \
                     release-x64 build. You must set the environmental variable FUCHSIA_DIR to \
                     point to a Fuchsia tree with .config and .jiri_manifest files."
                )
            }
        }
    };

    Ok(fuchsia_dir)
}

pub fn target_out_dir(config: &FuchsiaConfig) -> Result<PathBuf, Error> {
    let fuchsia_dir = fuchsia_dir()?;
    Ok(fuchsia_dir.join(&config.fuchsia_build_dir))
}

pub fn host_out_dir(config: &FuchsiaConfig) -> Result<PathBuf, Error> {
    Ok(target_out_dir(config)?.join("host_x64"))
}

pub fn package_manager_path(config: &FuchsiaConfig) -> Result<PathBuf, Error> {
    Ok(host_out_dir(config)?.join("pm"))
}

pub fn cmc_path(config: &FuchsiaConfig) -> Result<PathBuf, Error> {
    Ok(host_out_dir(config)?.join("cmc"))
}

pub fn amber_path(config: &FuchsiaConfig) -> Result<PathBuf, Error> {
    Ok(target_out_dir(config)?.join("amber-files"))
}

pub fn strip_tool_path() -> Result<PathBuf, Error> {
    Ok(clang_base_path()?.join("bin/llvm-objcopy"))
}

pub fn sysroot_path(options: &TargetOptions<'_, '_>) -> Result<PathBuf, Error> {
    Ok(target_out_dir(&options.config)?
        .join("x64-shared")
        .join("gen")
        .join("build")
        .join("config")
        .join("fuchsia"))
}

pub fn zircon_build_path(config: &FuchsiaConfig) -> Result<PathBuf, Error> {
    Ok(PathBuf::from(&config.zircon_build_dir))
}

pub fn shared_libraries_path(options: &TargetOptions<'_, '_>) -> Result<PathBuf, Error> {
    let shared_name =
        if options.config.fuchsia_arch == X64 { "x64-shared" } else { "arm64-shared" };
    Ok(target_out_dir(&options.config)?.join(shared_name))
}

fn platform_name() -> &'static str {
    if is_mac() {
        "mac-x64"
    } else {
        "linux-x64"
    }
}

fn prebuilt_path() -> Result<PathBuf, Error> {
    Ok(fuchsia_dir()?.join("prebuilt"))
}

fn rust_path() -> Result<PathBuf, Error> {
    Ok(prebuilt_path()?.join("third_party/rust").join(platform_name()))
}

pub fn cargo_path() -> Result<PathBuf, Error> {
    if let Some(cargo_path) = get_path_from_env("FARGO_CARGO", false)? {
        Ok(cargo_path)
    } else {
        Ok(rust_path()?.join("bin/cargo"))
    }
}

pub fn rustc_path() -> Result<PathBuf, Error> {
    if let Some(rustc_path) = get_path_from_env("FARGO_RUSTC", false)? {
        Ok(rustc_path)
    } else {
        Ok(rust_path()?.join("bin/rustc"))
    }
}

pub fn rustdoc_path() -> Result<PathBuf, Error> {
    if let Some(rustdoc_path) = get_path_from_env("FARGO_RUSTDOC", false)? {
        Ok(rustdoc_path)
    } else {
        Ok(rust_path()?.join("bin/rustdoc"))
    }
}

pub fn clang_base_path() -> Result<PathBuf, Error> {
    Ok(prebuilt_path()?.join("third_party/clang").join(platform_name()))
}

pub fn clang_c_compiler_path() -> Result<PathBuf, Error> {
    Ok(clang_base_path()?.join("bin").join("clang"))
}

pub fn clang_cpp_compiler_path() -> Result<PathBuf, Error> {
    Ok(clang_base_path()?.join("bin").join("clang++"))
}

pub fn clang_archiver_path() -> Result<PathBuf, Error> {
    Ok(clang_base_path()?.join("bin").join("llvm-ar"))
}

pub fn clang_ranlib_path() -> Result<PathBuf, Error> {
    Ok(clang_base_path()?.join("bin").join("llvm-ranlib"))
}

pub fn clang_resource_dir(target: &str) -> Result<PathBuf, Error> {
    let clang = clang_c_compiler_path()?;

    let output = Command::new(clang)
        .arg(format!("--target={}", target))
        .arg("-print-resource-dir")
        .output()
        .context("Running `clang` to get resource dir")?;

    if !output.status.success() {
        bail!("Failed to get `clang` resource dir: {}", String::from_utf8_lossy(&output.stderr));
    }

    let path_string =
        String::from_utf8(output.stdout).context("Invalid UTF8 in `clang` resource dir")?;

    Ok(PathBuf::from(path_string.trim()))
}

pub fn fx_path() -> Result<PathBuf, Error> {
    let fuchsia_dir = fuchsia_dir()?;
    Ok(fuchsia_dir.join("scripts/fx"))
}

#[derive(Debug, Default)]
pub struct FuchsiaConfig {
    pub fuchsia_build_dir: String,
    pub zircon_build_dir: String,
    pub fuchsia_arch: String,
}

impl FuchsiaConfig {
    pub fn new_from_fx_exec() -> Result<FuchsiaConfig, Error> {
        let fuchsia_dir = fuchsia_dir()?;
        let fx_script = fx_path()?;
        if !fx_script.exists() {
            bail!("fx script not found at {:?}", fx_script);
        }
        let args = vec!["exec", "printenv"];
        let fx_exec_result =
            Command::new(fx_script).args(args).current_dir(&fuchsia_dir).output()?;
        let result = str::from_utf8(&fx_exec_result.stdout)?.trim().to_string();
        let mut config = FuchsiaConfig {
            fuchsia_build_dir: String::from(""),
            zircon_build_dir: String::from(""),
            fuchsia_arch: String::from(""),
        };
        for one_line in result.lines() {
            let parts: Vec<&str> = one_line.split("=").collect();
            const QUOTE: char = '\'';
            match parts[0] {
                "FUCHSIA_BUILD_DIR" => {
                    config.fuchsia_build_dir = String::from(parts[1].trim_matches(QUOTE))
                }
                "ZIRCON_BUILDROOT" => {
                    config.zircon_build_dir = String::from(parts[1].trim_matches(QUOTE))
                }
                "FUCHSIA_ARCH" => config.fuchsia_arch = String::from(parts[1].trim_matches(QUOTE)),
                _ => (),
            }
        }
        Ok(config)
    }
}