use crate::commands::WholeStreamCommand;
use crate::context::CommandRegistry;
use crate::prelude::*;
use futures::stream::StreamExt;
use nu_errors::ShellError;
use nu_protocol::{ReturnValue, Signature, Value};

use clipboard::{ClipboardContext, ClipboardProvider};

pub struct Clip;

#[async_trait]
impl WholeStreamCommand for Clip {
    fn name(&self) -> &str {
        "clip"
    }

    fn signature(&self) -> Signature {
        Signature::build("clip")
    }

    fn usage(&self) -> &str {
        "Copy the contents of the pipeline to the copy/paste buffer"
    }

    async fn run(
        &self,
        args: CommandArgs,
        registry: &CommandRegistry,
    ) -> Result<OutputStream, ShellError> {
        clip(args, registry)
    }

    fn examples(&self) -> Vec<Example> {
        vec![Example {
            description: "Save text to the clipboard",
            example: "echo 'secret value' | clip",
            result: None,
        }]
    }
}

pub fn clip(args: CommandArgs, _registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
    let stream = async_stream! {
        let mut input = args.input;
        let name = args.call_info.name_tag.clone();
        let values: Vec<Value> = input.collect().await;

        let mut clip_stream = inner_clip(values, name).await;
        while let Some(value) = clip_stream.next().await {
            yield value;
        }
    };

    let stream: BoxStream<'static, ReturnValue> = stream.boxed();

    Ok(OutputStream::from(stream))
}

async fn inner_clip(input: Vec<Value>, name: Tag) -> OutputStream {
    if let Ok(clip_context) = ClipboardProvider::new() {
        let mut clip_context: ClipboardContext = clip_context;
        let mut new_copy_data = String::new();

        if !input.is_empty() {
            let mut first = true;
            for i in input.iter() {
                if !first {
                    new_copy_data.push_str("\n");
                } else {
                    first = false;
                }

                let string: String = match i.as_string() {
                    Ok(string) => string.to_string(),
                    Err(_) => {
                        return OutputStream::one(Err(ShellError::labeled_error(
                            "Given non-string data",
                            "expected strings from pipeline",
                            name,
                        )))
                    }
                };

                new_copy_data.push_str(&string);
            }
        }

        match clip_context.set_contents(new_copy_data) {
            Ok(_) => {}
            Err(_) => {
                return OutputStream::one(Err(ShellError::labeled_error(
                    "Could not set contents of clipboard",
                    "could not set contents of clipboard",
                    name,
                )));
            }
        }

        OutputStream::empty()
    } else {
        OutputStream::one(Err(ShellError::labeled_error(
            "Could not open clipboard",
            "could not open clipboard",
            name,
        )))
    }
}

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

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

        test_examples(Clip {})
    }
}