extern crate bindgen;

use std::env;
use std::path::{Path, PathBuf};

use std::fmt::Debug;

use std::fmt::{Display, Formatter};

fn find_static_lib(dir: &Path, base_name: &str, target_is_windows: bool) -> Option<PathBuf> {
    if !dir.is_dir() {
        return None;
    }
    let prefixes = ["", "lib"];
    let extensions = if target_is_windows {
        &[".lib", ".a"][..]
    } else {
        &[".a", ".lib"][..]
    };
    for prefix in prefixes {
        for ext in extensions {
            let name = format!("{}{}{}", prefix, base_name, ext);
            let path = dir.join(&name);
            if path.exists() {
                return Some(path);
            }
        }
    }
    None
}

fn lib_name_from_path(
    lib_path: &Path,
    target_is_windows: bool,
) -> Result<String, Box<dyn std::error::Error>> {
    let file_name = lib_path
        .file_stem()
        .ok_or(Error::msg("cannot get file stem"))?
        .to_str()
        .ok_or(Error::msg("cannot into string"))?;
    // On Unix, `cargo::rustc-link-lib=static=NAME` makes the linker search for libNAME.a,
    // so strip any leading "lib" prefix to avoid liblibNAME.a.
    // On MSVC, the linker searches for NAME.lib directly, so keep the full name
    // (e.g. libCZIAPIStatic.lib needs link-lib=static=libCZIAPIStatic).
    if target_is_windows {
        Ok(file_name.to_string())
    } else {
        Ok(file_name.strip_prefix("lib").unwrap_or(file_name).to_string())
    }
}

struct Error(String);

impl Debug for Error {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        f.write_str(&self.0)
    }
}

impl Display for Error {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        f.write_str(&self.0)
    }
}

impl std::error::Error for Error {}

impl Error {
    fn msg<S: ToString>(msg: S) -> Box<dyn std::error::Error> {
        Box::new(Error(msg.to_string()))
    }
}

fn restore_importexport(libcziapi_inc: &Path) -> Result<(), Box<dyn std::error::Error>> {
    let header = libcziapi_inc.join("importexport.h");
    let relative = header.strip_prefix("libczi").unwrap_or(&header);
    let status = std::process::Command::new("git")
        .args(["checkout", "HEAD", "--", relative.to_str().unwrap()])
        .current_dir("libczi")
        .status()?;
    if !status.success() {
        return Err(Error::msg("failed to restore importexport.h"));
    }
    Ok(())
}

struct ImportExportGuard<'a> {
    libcziapi_inc: &'a Path,
}

impl<'a> Drop for ImportExportGuard<'a> {
    fn drop(&mut self) {
        if let Err(e) = restore_importexport(self.libcziapi_inc) {
            eprintln!("warning: failed to restore importexport.h: {e}");
        }
    }
}

fn patch_importexport(
    libcziapi_inc: &Path,
) -> Result<ImportExportGuard<'_>, Box<dyn std::error::Error>> {
    let path = libcziapi_inc.join("importexport.h");
    let original = std::fs::read_to_string(&path)?;
    let patched = original.replace(
        "#define EXTERNALLIBCZIAPI_API(_returntype_) _returntype_",
        "#define EXTERNALLIBCZIAPI_API(_returntype_) extern \"C\" _returntype_",
    );
    if patched != original {
        std::fs::write(&path, &patched)?;
    }
    Ok(ImportExportGuard { libcziapi_inc })
}

fn fix_xwin_lib_case() -> Result<(), Box<dyn std::error::Error>> {
    let toolchain_key = format!(
        "CMAKE_TOOLCHAIN_FILE_{}",
        env::var("TARGET")?.replace('-', "_")
    );
    let toolchain_file = env::var(&toolchain_key)
        .or_else(|_| env::var("TARGET_CMAKE_TOOLCHAIN_FILE"))
        .or_else(|_| env::var("CMAKE_TOOLCHAIN_FILE"))?;

    let toolchain_path = PathBuf::from(&toolchain_file);
    let cargo_xwin_base = toolchain_path
        .parent()
        .and_then(|p| p.parent())
        .and_then(|p| p.parent())
        .ok_or(Error::msg("cannot determine cargo-xwin base dir"))?;

    let xwin_sdk_lib = cargo_xwin_base.join("xwin/sdk/lib/um/x86_64");
    if !xwin_sdk_lib.exists() {
        return Ok(());
    }

    #[cfg(unix)]
    {
        use std::os::unix::fs::symlink;
        let fixes = [
            ("Windowscodecs.lib", "WINDOWSCODECS.lib"),
            ("Windowscodecs.lib", "windowscodecs.lib"),
        ];
        for (link_name, target_name) in &fixes {
            let target = xwin_sdk_lib.join(target_name);
            let link = xwin_sdk_lib.join(link_name);
            if target.exists() && !link.exists() {
                let _ = symlink(&target, &link);
            }
        }
    }

    Ok(())
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    if env::var("DOCS_RS").is_err() {
        let host = env::var("HOST")?;
        let target = env::var("TARGET")?;
        let is_cross = host != target
            || env::var(format!(
                "CMAKE_TOOLCHAIN_FILE_{}",
                target.replace('-', "_")
            ))
            .is_ok()
            || env::var("TARGET_CMAKE_TOOLCHAIN_FILE").is_ok()
            || env::var("CMAKE_TOOLCHAIN_FILE").is_ok();
        let is_windows = target.contains("windows");
        let _is_macos = target.contains("apple");

        let libczi_dir = PathBuf::from("libczi");
        let libczi_src = libczi_dir.join("Src/libCZI");
        let libcziapi_inc = libczi_dir.join("Src/libCZIAPI/inc");
        let libcziapi_src = libczi_dir.join("Src/libCZIAPI/src");
        let libcziapi_h = libcziapi_inc.join("libCZIApi.h");

        let mut cmake_config = cmake::Config::new(&libczi_dir);
        cmake_config
            .cxxflag("-fms-extensions")
            .define(
                "ADDITIONAL_LIBS_REQUIRED_FOR_ATOMIC",
                "",
            )
            .define("LIBCZI_BUILD_UNITTESTS", "OFF")
            .define("LIBCZI_BUILD_CZICMD", "OFF")
            .define("LIBCZI_BUILD_DYNLIB", "OFF")
            .define("LIBCZI_BUILD_PREFER_EXTERNALPACKAGE_EIGEN3", "OFF")
            .define("LIBCZI_BUILD_PREFER_EXTERNALPACKAGE_ZSTD", "OFF")
            .define("LIBCZI_BUILD_CURL_BASED_STREAM", "OFF")
            .define("LIBCZI_BUILD_PREFER_EXTERNALPACKAGE_LIBCURL", "OFF")
            .define("LIBCZI_BUILD_AZURESDK_BASED_STREAM", "OFF")
            .define("LIBCZI_BUILD_PREFER_EXTERNALPACKAGE_RAPIDJSON", "OFF")
            .define("LIBCZI_BUILD_LIBCZIAPI", "ON");

        if is_cross {
            if is_windows {
                cmake_config
                    .define("CMAKE_SYSTEM_NAME", "Windows")
                    .define("CRASH_ON_UNALIGNED_ACCESS", "FALSE");

                let has_toolchain_file = env::var("TARGET_CMAKE_TOOLCHAIN_FILE").is_ok()
                    || env::var(format!(
                        "CMAKE_TOOLCHAIN_FILE_{}",
                        target.replace('-', "_")
                    ))
                    .is_ok()
                    || env::var("CMAKE_TOOLCHAIN_FILE").is_ok();

                if !has_toolchain_file {
                    cmake_config
                        .define("CMAKE_C_COMPILER", "clang")
                        .define("CMAKE_CXX_COMPILER", "clang++")
                        .define("CMAKE_RC_COMPILER", "llvm-rc");
                }

                fix_xwin_lib_case()?;
            } else if target.contains("apple") {
                cmake_config
                    .define("CMAKE_SYSTEM_NAME", "Darwin")
                    .define("CRASH_ON_UNALIGNED_ACCESS", "OFF");
                if target.contains("aarch64") {
                    cmake_config.define("NEON_INTRINSICS_CAN_BE_USED", "ON");
                }
            } else {
                cmake_config
                    .define("CRASH_ON_UNALIGNED_ACCESS", "OFF")
                    .define("_UNALIGNED_ACCESS_RESULT_EXITCODE", "0");
                if target.contains("aarch64") {
                    cmake_config.define("_NEON_INTRINSICS_RESULT_EXITCODE", "0");
                }
            }
        }

        if is_cross && is_windows {
            cmake_config.build_target("libCZIAPIStatic");
        }

        let _importexport_guard = patch_importexport(&libcziapi_inc)?;
        let dst = cmake_config.build();

        #[cfg(not(feature = "dynamic"))]
        let bindings = bindgen::Builder::default();

        #[cfg(feature = "dynamic")]
        let bindings = bindgen::Builder::default();

        let bindings = bindings
            .merge_extern_blocks(true)
            .clang_args([
                "-fms-extensions",
                "-x",
                "c++",
                "-std=c++14",
                "-I",
                libcziapi_inc
                    .to_str()
                    .ok_or(Error::msg("cannot into string"))?,
                "-I",
                libcziapi_src
                    .to_str()
                    .ok_or(Error::msg("cannot into string"))?,
                "-I",
                libczi_src
                    .to_str()
                    .ok_or(Error::msg("cannot into string"))?,
            ])
            .header(
                libcziapi_h
                    .to_str()
                    .ok_or(Error::msg("cannot into string"))?,
            )
            .generate()?;

        bindings.write_to_file(dst.join("lib_czi_api.rs"))?;

        #[cfg(not(feature = "dynamic"))]
        {
            let libcziapi_dir = dst.join("build/Src/libCZIAPI");
            let libcziapi_dir2 = dst.join("Src/libCZIAPI");
            let libczi_dir = dst.join("build/Src/libCZI");
            let libczi_dir2 = dst.join("Src/libCZI");

            let libcziapi_lib = find_static_lib(&libcziapi_dir, "libCZIAPIStatic", is_windows)
                .or_else(|| find_static_lib(&libcziapi_dir2, "libCZIAPIStatic", is_windows))
                .ok_or(Error::msg("cannot find libCZIAPIStatic for linking"))?;
            let libcziapi_name = lib_name_from_path(&libcziapi_lib, is_windows)?;

            let profile = env::var("PROFILE")?;
            let libczi_base = match profile.as_str() {
                "debug" => "libCZIStaticd",
                "release" => "libCZIStatic",
                _ => return Err(Error::msg(format!("unsupported profile: {}", profile))),
            };
            let libczi_lib = find_static_lib(&libczi_dir, libczi_base, is_windows)
                .or_else(|| find_static_lib(&libczi_dir2, libczi_base, is_windows))
                .ok_or(Error::msg(format!(
                    "cannot find {} for linking",
                    libczi_base
                )))?;
            let libczi_name = lib_name_from_path(&libczi_lib, is_windows)?;

            if libcziapi_dir.exists() {
                println!(
                    "cargo::rustc-link-search=native={}",
                    libcziapi_dir.display()
                );
            }
            if libcziapi_dir2.exists() {
                println!(
                    "cargo::rustc-link-search=native={}",
                    libcziapi_dir2.display()
                );
            }
            println!("cargo::rustc-link-lib=static={}", libcziapi_name);

            if libczi_dir.exists() {
                println!(
                    "cargo::rustc-link-search=native={}",
                    libczi_dir.display()
                );
            }
            if libczi_dir2.exists() {
                println!(
                    "cargo::rustc-link-search=native={}",
                    libczi_dir2.display()
                );
            }
            println!("cargo::rustc-link-lib=static={}", libczi_name);

            println!(
                "cargo::rustc-link-search=native={}",
                dst.join("lib").display()
            );
            println!(
                "cargo::rustc-link-search=native={}",
                dst.join("lib64").display()
            );
            if is_windows && is_cross {
                let zstd_dir = dst.join("build/_deps/zstd-build/lib");
                let zstd_dir2 = dst.join("_deps/zstd-build/lib");
                if zstd_dir.exists() {
                    println!(
                        "cargo::rustc-link-search=native={}",
                        zstd_dir.display()
                    );
                }
                if zstd_dir2.exists() {
                    println!(
                        "cargo::rustc-link-search=native={}",
                        zstd_dir2.display()
                    );
                }
                let zstd_name = find_static_lib(&zstd_dir, "zstd_static", is_windows)
                    .or_else(|| find_static_lib(&zstd_dir2, "zstd_static", is_windows))
                    .map(|p| lib_name_from_path(&p, is_windows).unwrap_or_else(|_| "zstd_static".to_string()))
                    .unwrap_or_else(|| "zstd_static".to_string());
                println!("cargo::rustc-link-lib=static={}", zstd_name);
            } else {
                println!("cargo::rustc-link-lib=static=zstd");
            }

            if is_windows {
                println!("cargo::rustc-link-lib=kernel32");
                println!("cargo::rustc-link-lib=advapi32");
                println!("cargo::rustc-link-lib=bcrypt");
                println!("cargo::rustc-link-lib=ntdll");
                println!("cargo::rustc-link-lib=user32");
                println!("cargo::rustc-link-lib=ole32");
                println!("cargo::rustc-link-lib=shell32");
                println!("cargo::rustc-link-lib=Windowscodecs");
            }
        }

        #[cfg(feature = "dynamic")]
        {
            println!(
                "cargo::rustc-link-search=native={}",
                dst.join("build/Src/libCZIAPI").display()
            );
            println!("cargo::rustc-link-lib=libCZIAPI");
        }
    }
    println!("cargo::rerun-if-changed=build.rs");
    Ok(())
}