#[cfg(not(feature = "metadata"))]
fn main() {
    // Update if needed
    println!("cargo:rerun-if-changed=src");
    println!("cargo:rerun-if-changed=build.rs");

    // Make empty file for documentation and tests
    std::fs::File::create(std::env::var("OUT_DIR").unwrap() + "/rhai-ml-docs.md").unwrap();
    std::fs::File::create(std::env::var("OUT_DIR").unwrap() + "/rhai-ml-tests.rs").unwrap();
}

#[cfg(feature = "metadata")]
fn main() {
    use rhai::{plugin::*, Engine};
    use serde::{Deserialize, Serialize};
    use std::collections::HashMap;
    use std::io::Write;

    #[derive(Serialize, Deserialize, Debug, Clone)]
    struct Metadata {
        #[serde(default)]
        pub functions: Vec<Function>,
    }

    #[allow(non_snake_case)]
    #[derive(Serialize, Deserialize, Debug, Clone)]
    struct Function {
        pub access: String,
        pub baseHash: u128,
        pub fullHash: u128,
        pub name: String,
        pub namespace: String,
        pub numParams: usize,
        pub params: Option<Vec<HashMap<String, String>>>,
        pub signature: String,
        pub returnType: Option<String>,
        pub docComments: Option<Vec<String>>,
    }

    // Update if needed
    println!("cargo:rerun-if-changed=src");
    println!("cargo:rerun-if-changed=build.rs");

    // Make a file for documentation
    let mut doc_file =
        std::fs::File::create(std::env::var("OUT_DIR").unwrap() + "/rhai-ml-docs.md").unwrap();

    // Make a file for tests
    let mut test_file =
        std::fs::File::create(std::env::var("OUT_DIR").unwrap() + "/rhai-ml-tests.rs").unwrap();

    // Build an engine for doctests
    let mut engine = Engine::new();

    // Add custom functions from Rust
    let mut lib = Module::new();
    combine_with_exported_module!(
        &mut lib,
        "rhai_ml_train_and_predict",
        train_and_predict_functions
    );
    engine.register_global_module(rhai::Shared::new(lib));

    // Extract metadata
    let json_fns = engine.gen_fn_metadata_to_json(false).unwrap();
    println!("{json_fns}");
    let v: Metadata = serde_json::from_str(&json_fns).unwrap();
    for function in &v.functions {
        println!("{:?}", function);
    }

    let function_list = v.functions;

    // Write functions
    write!(doc_file, "\n# API\n This package provides a large variety of functions to help with machine learning and artificial intelligence:\n").expect("Cannot write to {doc_file}");
    write!(test_file, "#[cfg(test)]\nmod rhai_tests {{\n").expect("Cannot write to {test_file}");

    let mut indented = false;
    for (idx, function) in function_list.iter().enumerate() {
        let function = function.clone();
        // Pull out basic info
        let name = function.name;
        if !name.starts_with("anon") && !name.starts_with("_") {
            let signature = function
                .signature
                .replace("Result<", "")
                .replace(", Box<EvalAltResult>>", "")
                .replace("&mut ", "")
                .replace("ImmutableString", "String");

            let id = signature
                .replace(": ", "-")
                .replace(", ", "-")
                .replace("(", "")
                .replace(")", "")
                .replace(" -> ", "---")
                .to_lowercase();

            // Check if there are multiple arities, and if so add a header and indent
            if idx < function_list.len() - 1 {
                if name == function_list[idx + 1].name && !indented {
                    write!(doc_file, "<a href=\"#{}\">{}</a>", name, name)
                        .expect("Cannot write to {doc_file}");
                    indented = true;
                    if idx != function_list.len() - 1 {
                        write!(doc_file, "&nbsp;&nbsp; ").expect("Cannot write to {doc_file}");
                    }
                }
            }

            if indented == false {
                write!(doc_file, "<a href=\"#{}\">{}</a>", id, name)
                    .expect("Cannot write to {doc_file}");

                if idx != function_list.len() - 1 {
                    write!(doc_file, "&nbsp;&nbsp; ").expect("Cannot write to {doc_file}");
                }
            }

            if idx == function_list.len() - 1 {
                write!(doc_file, "\n").expect("Cannot write to {doc_file}");
            }

            // End indentation when its time
            if idx != 0 && idx < function_list.len() - 1 {
                if name == function_list[idx - 1].name && name != function_list[idx + 1].name {
                    indented = false;
                }
            }
        }
    }
    let mut indented = false;
    for (idx, function) in function_list.iter().enumerate() {
        let function = function.clone();
        // Pull out basic info
        let name = function.name;
        if !name.starts_with("anon") {
            let comments = match function.docComments {
                None => "".to_owned(),
                Some(strings) => strings.join("\n"),
            }
            .replace("///", "")
            .replace("/**", "")
            .replace("**/", "");

            let signature = function
                .signature
                .replace("Result<", "")
                .replace(", Box<EvalAltResult>>", "")
                .replace("&mut ", "")
                .replace("ImmutableString", "String")
                .replace("$CONSTANTS$()", "physical constants");

            // Check if there are multiple arities, and if so add a header and indent
            if idx < function_list.len() - 1 {
                if name == function_list[idx + 1].name && !indented {
                    write!(doc_file, "## `{name}`\n").expect("Cannot write to {doc_file}");
                    indented = true;
                }
            }

            // Print definition with right level of indentation
            if indented {
                write!(doc_file, "### `{}`\n{}\n", signature, comments)
                    .expect("Cannot write to {doc_file}");
            } else {
                write!(doc_file, "## `{}`\n{}\n", signature, comments)
                    .expect("Cannot write to {doc_file}");
            }

            // End indentation when its time
            if idx != 0 && idx < function_list.len() - 1 {
                if name == function_list[idx - 1].name && name != function_list[idx + 1].name {
                    indented = false;
                }
            }

            // Run doc tests
            let code = comments.split("```").collect::<Vec<&str>>();
            for i in (1..code.len()).step_by(2) {
                let clean_code = code[i]
                    .replace("javascript", "")
                    .replace("typescript", "")
                    .replace("rhai", "");
                write!(
                    test_file,
                    "#[test]\nfn {}_{i}() {{ \n assert!(rhai_ml::eval::<bool>(\"{}\").unwrap()); }}\n",
                    signature
                        .replace("(", "_")
                        .replace(")", "_")
                        .replace(" ", "_")
                        .replace(":", "_")
                        .replace("->", "_")
                        .replace(",", "_").replace("____", "_").replace("___", "_").replace("__", "_").to_lowercase(),
                    clean_code.replace("\"", "\\\"")
                )
                .expect("Cannot write to {test_file}");
            }
        }
    }
    write!(test_file, "\n}}").expect("Cannot write to {test_file}");
}

#[cfg(feature = "metadata")]
#[allow(unused_imports)]
mod functions {
    include!("src/train_and_predict.rs");
}

#[cfg(feature = "metadata")]
pub use functions::*;