use std::sync::atomic::AtomicBool;
use std::sync::Arc;

use nu_engine::CallExt;
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
    Category, Example, PipelineData, ShellError, Signature, Spanned, SyntaxShape, Type, Value,
};

use crate::network::http::client::{
    check_response_redirection, http_client, http_parse_redirect_mode, http_parse_url,
    request_add_authorization_header, request_add_custom_headers, request_handle_response_headers,
    request_set_timeout, send_request,
};

#[derive(Clone)]
pub struct SubCommand;

impl Command for SubCommand {
    fn name(&self) -> &str {
        "http head"
    }

    fn signature(&self) -> Signature {
        Signature::build("http head")
            .input_output_types(vec![(Type::Nothing, Type::Any)])
            .allow_variants_without_examples(true)
            .required(
                "URL",
                SyntaxShape::String,
                "The URL to fetch the contents from.",
            )
            .named(
                "user",
                SyntaxShape::Any,
                "the username when authenticating",
                Some('u'),
            )
            .named(
                "password",
                SyntaxShape::Any,
                "the password when authenticating",
                Some('p'),
            )
            .named(
                "max-time",
                SyntaxShape::Int,
                "timeout period in seconds",
                Some('m'),
            )
            .named(
                "headers",
                SyntaxShape::Any,
                "custom headers you want to add ",
                Some('H'),
            )
            .switch(
                "insecure",
                "allow insecure server connections when using SSL",
                Some('k'),
            ).named(
                "redirect-mode",
                SyntaxShape::String,
                "What to do when encountering redirects. Default: 'follow'. Valid options: 'follow' ('f'), 'manual' ('m'), 'error' ('e').",
                Some('R')
            )
            .filter()
            .category(Category::Network)
    }

    fn usage(&self) -> &str {
        "Get the headers from a URL."
    }

    fn extra_usage(&self) -> &str {
        "Performs HTTP HEAD operation."
    }

    fn search_terms(&self) -> Vec<&str> {
        vec!["network", "request", "curl", "wget", "headers", "header"]
    }

    fn run(
        &self,
        engine_state: &EngineState,
        stack: &mut Stack,
        call: &Call,
        input: PipelineData,
    ) -> Result<PipelineData, ShellError> {
        run_head(engine_state, stack, call, input)
    }

    fn examples(&self) -> Vec<Example> {
        vec![
            Example {
                description: "Get headers from example.com",
                example: "http head https://www.example.com",
                result: None,
            },
            Example {
                description: "Get headers from example.com, with username and password",
                example: "http head --user myuser --password mypass https://www.example.com",
                result: None,
            },
            Example {
                description: "Get headers from example.com, with custom header",
                example:
                    "http head --headers [my-header-key my-header-value] https://www.example.com",
                result: None,
            },
        ]
    }
}

struct Arguments {
    url: Value,
    headers: Option<Value>,
    insecure: bool,
    user: Option<String>,
    password: Option<String>,
    timeout: Option<Value>,
    redirect: Option<Spanned<String>>,
}

fn run_head(
    engine_state: &EngineState,
    stack: &mut Stack,
    call: &Call,
    _input: PipelineData,
) -> Result<PipelineData, ShellError> {
    let args = Arguments {
        url: call.req(engine_state, stack, 0)?,
        headers: call.get_flag(engine_state, stack, "headers")?,
        insecure: call.has_flag(engine_state, stack, "insecure")?,
        user: call.get_flag(engine_state, stack, "user")?,
        password: call.get_flag(engine_state, stack, "password")?,
        timeout: call.get_flag(engine_state, stack, "max-time")?,
        redirect: call.get_flag(engine_state, stack, "redirect-mode")?,
    };
    let ctrl_c = engine_state.ctrlc.clone();

    helper(engine_state, stack, call, args, ctrl_c)
}

// Helper function that actually goes to retrieve the resource from the url given
// The Option<String> return a possible file extension which can be used in AutoConvert commands
fn helper(
    engine_state: &EngineState,
    stack: &mut Stack,
    call: &Call,
    args: Arguments,
    ctrlc: Option<Arc<AtomicBool>>,
) -> Result<PipelineData, ShellError> {
    let span = args.url.span();
    let (requested_url, _) = http_parse_url(call, span, args.url)?;
    let redirect_mode = http_parse_redirect_mode(args.redirect)?;

    let client = http_client(args.insecure, redirect_mode, engine_state, stack)?;
    let mut request = client.head(&requested_url);

    request = request_set_timeout(args.timeout, request)?;
    request = request_add_authorization_header(args.user, args.password, request);
    request = request_add_custom_headers(args.headers, request)?;

    let response = send_request(request, None, None, ctrlc);
    check_response_redirection(redirect_mode, span, &response)?;
    request_handle_response_headers(span, response)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_examples() {
        use crate::test_examples;

        test_examples(SubCommand {})
    }
}