use std::env;
use std::fs::{File, OpenOptions};
use std::io::{Read, Write};
use std::path::{Path, PathBuf};

use const_gen::*;
use embuild::cmd;
use indoc::writedoc;
use json::JsonValue;
use slint_build::{CompilerConfiguration, EmbedResourcesKind};
use xz2::read::XzEncoder;

fn build_xkbcommon() {
    let manifest_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());
    let build_script = manifest_dir.join("../libxkbcommon-compile.sh");
    let build_dir_name = env::var("XKBCOMMON_BUILD_DIR_NAME").unwrap();
    cmd!(build_script, build_dir_name)
        .run()
        .expect("Failed to compile xkbcommon.");
}

fn build_sodium() {
    let manifest_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());
    let build_script = manifest_dir.join("../libsodium-compile.sh");
    let install_dir_name = env::var("SODIUM_INSTALL_DIR_NAME").unwrap();
    cmd!(build_script, install_dir_name)
        .run()
        .expect("Failed to compile sodium.");
}

fn build_spectre() {
    let manifest_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());
    let build_script = manifest_dir.join("../spectre-api-compile.sh");
    let build_dir_name = env::var("SPECTRE_API_BUILD_DIR_NAME").unwrap();
    let sodium_install_dir = env::var("SODIUM_INSTALL_DIR").unwrap();
    cmd!(build_script, build_dir_name, sodium_install_dir)
        .run()
        .expect("Failed to compile the Spectre API.");
}

fn main() {
    let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
    if let Ok(repo) = gix::discover(&manifest_dir) {
        let commit_hash = repo.head_commit().unwrap().short_id().unwrap();
        println!("cargo:rustc-env=GIT_COMMIT_HASH={}", commit_hash);
        println!(
            "cargo:rustc-env=GIT_COMMIT={}",
            repo.find_tag(repo.head_id().unwrap())
                .ok()
                .map(|tag| format!("{} ({})", tag.decode().unwrap().name, commit_hash))
                .unwrap_or_else(|| commit_hash.to_string())
        );
    }

    // Generate vial config at the root of project
    println!("cargo:rerun-if-changed=vial.json");
    generate_vial_config();

    println!("cargo:rustc-link-arg-bins=-Tlinkall.x");

    // Set the extra linker script from defmt
    // println!("cargo:rustc-link-arg=-Tdefmt.x");

    #[derive(Debug)]
    struct NotBuilt {
        #[allow(unused)]
        lib_build_dir: String,
    }

    fn link_static_lib(env_var: &str, library: &str) -> Result<(), NotBuilt> {
        let lib_build_dir_str = env::var(env_var)
            .unwrap_or_else(|error| panic!("The build directory of lib{library} must be specified using the `{env_var}` environment variable: {error}"));
        let lib_build_dir = PathBuf::from(&lib_build_dir_str)
            .canonicalize()
            .map_err(|_| NotBuilt {
                lib_build_dir: lib_build_dir_str.clone(),
            })?;
        let lib_library_path = lib_build_dir
            .join(format!("lib{library}.a"))
            .canonicalize()
            .map_err(|_| NotBuilt {
                lib_build_dir: lib_build_dir_str.clone(),
            })?;
        let lib_build_dir = lib_build_dir.display();

        if !lib_library_path.is_file() {
            return Err(NotBuilt {
                lib_build_dir: lib_build_dir_str,
            });
        }

        println!("cargo:rustc-link-search=native={lib_build_dir}");
        println!("cargo:rustc-link-lib=static={library}");
        println!("cargo:rerun-if-changed={lib_build_dir}/lib{library}.a");

        Ok(())
    }

    fn link_static_lib_or_build(env_var: &str, library: &str, build: impl FnOnce()) {
        if link_static_lib(env_var, library).is_err() {
            (build)();
            link_static_lib(env_var, library)
                .unwrap_or_else(|err| panic!("Failed to link library after building it: {err:?}"));
        }
    }

    link_static_lib_or_build("XKBCOMMON_BUILD_DIR", "xkbcommon", || {
        build_xkbcommon();
    });

    link_static_lib_or_build("SPECTRE_API_BUILD_DIR", "spectre", || {
        build_sodium();
        build_spectre();
    });

    // Slint config and compilation
    {
        // Don't think this does anything:
        // println!("cargo:rerun-if-env-changed=SLINT_FONT_SIZES");

        let slint_config = CompilerConfiguration::new()
            // .with_scale_factor(2.0)
            .with_style("cosmic-dark".to_string())
            .embed_resources(EmbedResourcesKind::EmbedForSoftwareRenderer);
        slint_build::compile_with_config("ui/main.slint", slint_config)
            .expect("Slint build failed");
        slint_build::print_rustc_flags().unwrap()
    }
}

fn generate_vial_config() {
    // Generated vial config file
    let path = Path::new(&env::var_os("OUT_DIR").unwrap()).join("config_generated.rs");
    let mut out_file = OpenOptions::new()
        .create(true)
        .write(true)
        .truncate(true)
        .open(path)
        .unwrap();

    let p = Path::new("vial.json");
    let mut content = String::new();
    match File::open(p) {
        Ok(mut file) => {
            file.read_to_string(&mut content)
                .expect("Cannot read vial.json");
        }
        Err(e) => println!("Cannot find vial.json {p:?}: {e}"),
    };

    let vial_cfg = json::parse(&content).unwrap();

    let keyboard_def_compressed: Vec<u8> = {
        let vial_cfg_string = json::stringify(vial_cfg.clone());
        let mut keyboard_def_compressed = Vec::new();
        XzEncoder::new(vial_cfg_string.as_bytes(), 6)
            .read_to_end(&mut keyboard_def_compressed)
            .unwrap();
        keyboard_def_compressed
    };
    // This is a firmware-unique randomly generated ID.
    // If you fork this repo to make your own firmware, you should change this.
    let keyboard_id: Vec<u8> = vec![0x9a, 0x8a, 0x08, 0xae, 0x87, 0xcd, 0xc7, 0xb9];
    let keyboard_name: &str = {
        let JsonValue::Object(vial_cfg) = &vial_cfg else {
            panic!("The root element in `vial.json` is not an object.");
        };
        vial_cfg
            .get("name")
            .expect("No `name` in `vial.json`.")
            .as_str()
            .expect("`name` in `vial.json` is not a string.")
    };
    let vendor_id: u16 = {
        let JsonValue::Object(vial_cfg) = &vial_cfg else {
            panic!("The root element in `vial.json` is not an object.");
        };
        let vendor_id_string = vial_cfg
            .get("vendorId")
            .expect("No `vendorId` in `vial.json`.")
            .as_str()
            .expect("`vendorId` in `vial.json` is not a string.");
        assert!(vendor_id_string.starts_with("0x"));
        u16::from_str_radix(&vendor_id_string[2..], 16).expect("Invalid vendor ID.")
    };
    let product_id: u16 = {
        let JsonValue::Object(vial_cfg) = &vial_cfg else {
            panic!("The root element in `vial.json` is not an object.");
        };
        let product_id_string = vial_cfg
            .get("productId")
            .expect("No `productId` in `vial.json`.")
            .as_str()
            .expect("`productId` in `vial.json` is not a string.");
        assert!(product_id_string.starts_with("0x"));
        u16::from_str_radix(&product_id_string[2..], 16).expect("Invalid product ID.")
    };
    let const_declarations = [
        const_declaration!(pub VIAL_KEYBOARD_DEF = keyboard_def_compressed),
        const_declaration!(pub VIAL_KEYBOARD_ID = keyboard_id),
        const_declaration!(pub VIAL_KEYBOARD_NAME = keyboard_name),
        const_declaration!(pub VIAL_VENDOR_ID = vendor_id),
        const_declaration!(pub VIAL_PRODUCT_ID = product_id),
    ]
    .map(|s| "#[allow(clippy::redundant_static_lifetimes)]\n".to_owned() + s.as_str())
    .join("\n");

    writeln!(out_file, "{}", const_declarations).unwrap();

    writedoc!(
        out_file,
        "
        #[allow(dead_code, non_camel_case_types, clippy::upper_case_acronyms)]
        #[repr(u8)]
        pub enum CustomKeycodes {{
        "
    )
    .unwrap();

    // const CUSTOM_KEYCODE_FIRST: u16 = 0x840;

    #[allow(clippy::collapsible_if)]
    if let JsonValue::Object(vial_cfg) = vial_cfg {
        if let Some(JsonValue::Array(custom_keycodes)) = vial_cfg.get("customKeycodes") {
            for (index, custom_keycode) in custom_keycodes.iter().enumerate() {
                if let JsonValue::Object(custom_keycode) = custom_keycode {
                    let name = custom_keycode
                        .get("name")
                        .expect("A custom keycode in vial.json is missing a name.")
                        .as_str()
                        .expect("A custom keycode's name must be a string.");
                    writeln!(
                        out_file,
                        "    {} = {},",
                        name,
                        // CUSTOM_KEYCODE_FIRST + index as u16
                        index as u8
                    )
                    .unwrap();
                }
            }
        }
    }

    writeln!(out_file, "}}").unwrap();
}