use std::env::current_dir;
use std::path::PathBuf;

use nu_engine::CallExt;
use nu_path::canonicalize_with;
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EvaluationContext};
use nu_protocol::{ShellError, Signature, SyntaxShape, Value};

use crate::filesystem::util::FileStructure;

pub struct Cp;

impl Command for Cp {
    fn name(&self) -> &str {
        "cp"
    }

    fn usage(&self) -> &str {
        "Copy files."
    }

    fn signature(&self) -> Signature {
        Signature::build("cp")
            .required("source", SyntaxShape::GlobPattern, "the place to copy from")
            .required("destination", SyntaxShape::Filepath, "the place to copy to")
            .switch(
                "recursive",
                "copy recursively through subdirectories",
                Some('r'),
            )
            .switch("interactive", "ask user to confirm action", Some('i'))
    }

    fn run(
        &self,
        context: &EvaluationContext,
        call: &Call,
        _input: Value,
    ) -> Result<Value, ShellError> {
        let source: String = call.req(context, 0)?;
        let destination: String = call.req(context, 1)?;
        let interactive = call.has_flag("interactive");

        if interactive {
            println!(
                "Are you shure that you want to move {} to {}?",
                source, destination
            );
        }

        let path: PathBuf = current_dir().unwrap();
        let source = path.join(source.as_str());
        let destination = path.join(destination.as_str());

        let sources =
            glob::glob(&source.to_string_lossy()).map_or_else(|_| Vec::new(), Iterator::collect);
        if sources.is_empty() {
            return Err(ShellError::FileNotFound(call.positional[0].span));
        }

        if sources.len() > 1 && !destination.is_dir() {
            return Err(ShellError::MoveNotPossible {
                source_message: "Can't move many files".to_string(),
                source_span: call.positional[0].span,
                destination_message: "into single file".to_string(),
                destination_span: call.positional[1].span,
            });
        }

        let any_source_is_dir = sources.iter().any(|f| matches!(f, Ok(f) if f.is_dir()));
        let recursive: bool = call.has_flag("recursive");
        if any_source_is_dir && !recursive {
            return Err(ShellError::MoveNotPossibleSingle(
                "Directories must be copied using \"--recursive\"".to_string(),
                call.positional[0].span,
            ));
        }

        for entry in sources.into_iter().flatten() {
            let mut sources = FileStructure::new();
            sources.walk_decorate(&entry)?;

            if entry.is_file() {
                let sources = sources.paths_applying_with(|(source_file, _depth_level)| {
                    if destination.is_dir() {
                        let mut dest = canonicalize_with(&destination, &path)?;
                        if let Some(name) = entry.file_name() {
                            dest.push(name);
                        }
                        Ok((source_file, dest))
                    } else {
                        Ok((source_file, destination.clone()))
                    }
                })?;

                for (src, dst) in sources {
                    if src.is_file() {
                        std::fs::copy(&src, dst).map_err(|e| {
                            ShellError::MoveNotPossibleSingle(
                                format!(
                                    "failed to move containing file \"{}\": {}",
                                    src.to_string_lossy(),
                                    e
                                ),
                                call.positional[0].span,
                            )
                        })?;
                    }
                }
            } else if entry.is_dir() {
                let destination = if !destination.exists() {
                    destination.clone()
                } else {
                    match entry.file_name() {
                        Some(name) => destination.join(name),
                        None => {
                            return Err(ShellError::FileNotFoundCustom(
                                format!("containing \"{:?}\" is not a valid path", entry),
                                call.positional[0].span,
                            ))
                        }
                    }
                };

                std::fs::create_dir_all(&destination).map_err(|e| {
                    ShellError::MoveNotPossibleSingle(
                        format!("failed to recursively fill destination: {}", e),
                        call.positional[1].span,
                    )
                })?;

                let sources = sources.paths_applying_with(|(source_file, depth_level)| {
                    let mut dest = destination.clone();
                    let path = canonicalize_with(&source_file, &path)?;
                    let components = path
                        .components()
                        .map(|fragment| fragment.as_os_str())
                        .rev()
                        .take(1 + depth_level);

                    components.for_each(|fragment| dest.push(fragment));
                    Ok((PathBuf::from(&source_file), dest))
                })?;

                for (src, dst) in sources {
                    if src.is_dir() && !dst.exists() {
                        std::fs::create_dir_all(&dst).map_err(|e| {
                            ShellError::MoveNotPossibleSingle(
                                format!(
                                    "failed to create containing directory \"{}\": {}",
                                    dst.to_string_lossy(),
                                    e
                                ),
                                call.positional[1].span,
                            )
                        })?;
                    }

                    if src.is_file() {
                        std::fs::copy(&src, &dst).map_err(|e| {
                            ShellError::MoveNotPossibleSingle(
                                format!(
                                    "failed to move containing file \"{}\": {}",
                                    src.to_string_lossy(),
                                    e
                                ),
                                call.positional[0].span,
                            )
                        })?;
                    }
                }
            }
        }

        Ok(Value::Nothing { span: call.head })
    }
}