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

use nu_engine::{current_dir, CallExt};
use nu_path::expand_path_with;
use nu_protocol::{engine::Command, Example, Signature, Span, SyntaxShape, Value};

use super::PathSubcommandArguments;

struct Arguments {
    columns: Option<Vec<String>>,
    pwd: PathBuf,
}

impl PathSubcommandArguments for Arguments {
    fn get_columns(&self) -> Option<Vec<String>> {
        self.columns.clone()
    }
}

#[derive(Clone)]
pub struct SubCommand;

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

    fn signature(&self) -> Signature {
        Signature::build("path exists").named(
            "columns",
            SyntaxShape::Table,
            "Optionally operate by column path",
            Some('c'),
        )
    }

    fn usage(&self) -> &str {
        "Check whether a path exists"
    }

    fn extra_usage(&self) -> &str {
        r#"This only checks if it is possible to either `open` or `cd` to the given path.
If you need to distinguish dirs and files, please use `path type`."#
    }

    fn run(
        &self,
        engine_state: &nu_protocol::engine::EngineState,
        stack: &mut nu_protocol::engine::Stack,
        call: &nu_protocol::ast::Call,
        input: nu_protocol::PipelineData,
    ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
        let head = call.head;
        let args = Arguments {
            columns: call.get_flag(engine_state, stack, "columns")?,
            pwd: current_dir(engine_state, stack)?,
        };
        input.map(
            move |value| super::operate(&exists, &args, value, head),
            engine_state.ctrlc.clone(),
        )
    }

    #[cfg(windows)]
    fn examples(&self) -> Vec<Example> {
        vec![
            Example {
                description: "Check if a file exists",
                example: "'C:\\Users\\joe\\todo.txt' | path exists",
                result: Some(Value::Bool {
                    val: false,
                    span: Span::test_data(),
                }),
            },
            Example {
                description: "Check if a file exists in a column",
                example: "ls | path exists -c [ name ]",
                result: None,
            },
        ]
    }

    #[cfg(not(windows))]
    fn examples(&self) -> Vec<Example> {
        vec![
            Example {
                description: "Check if a file exists",
                example: "'/home/joe/todo.txt' | path exists",
                result: Some(Value::Bool {
                    val: false,
                    span: Span::test_data(),
                }),
            },
            Example {
                description: "Check if a file exists in a column",
                example: "ls | path exists -c [ name ]",
                result: None,
            },
        ]
    }
}

fn exists(path: &Path, span: Span, args: &Arguments) -> Value {
    let path = expand_path_with(path, &args.pwd);
    Value::Bool {
        val: path.exists(),
        span,
    }
}

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

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

        test_examples(SubCommand {})
    }
}