use std::borrow::Cow;
use std::path::Path;

use organic::types::LinkType;
use organic::types::StandardProperties;
use url::Url;

use super::get_web_path;
use super::macros::intermediate;
use super::IntermediateContext;

use super::IObject;
use crate::context::RenderContext;
use crate::error::CustomError;

#[derive(Debug, Clone)]
pub(crate) struct IRegularLink {
    pub(crate) raw_link: String,
    pub(crate) children: Vec<IObject>,
    pub(crate) target: LinkTarget,
    pub(crate) post_blank: organic::types::PostBlank,
}

intermediate!(
    IRegularLink,
    &'orig organic::types::RegularLink<'parse>,
    original,
    intermediate_context,
    {
        let children = {
            let mut ret = Vec::new();
            for obj in original.children.iter() {
                ret.push(IObject::new(intermediate_context.clone(), obj).await?);
            }
            ret
        };
        let raw_link = original.get_raw_link();
        let target = LinkTarget::from_string(
            intermediate_context.clone(),
            raw_link.clone().into_owned(),
            &original.link_type,
        )?;
        Ok(IRegularLink {
            raw_link: raw_link.into_owned(),
            children,
            target,
            post_blank: original.get_post_blank(),
        })
    }
);

#[derive(Debug, Clone, PartialEq)]
pub(crate) enum LinkTarget {
    Raw(String),
    Post {
        post_id: Option<String>,
        subpath: String,
    },
    Target {
        target_id: String,
    },
    Image {
        src: String,
        alt: String,
    },
}

impl LinkTarget {
    pub(crate) fn from_string(
        intermediate_context: IntermediateContext<'_, '_>,
        input: String,
        link_type: &LinkType<'_>,
    ) -> Result<LinkTarget, CustomError> {
        // If link type is file and the path ends in .svg then make it an image target
        if let LinkType::File = link_type
            && input.to_ascii_lowercase().ends_with(".svg")
        {
            let src = Self::get_image_src(&input)?;
            let alt = Self::get_image_alt(&input)?;

            return Ok(LinkTarget::Image { src, alt });
        };

        let parsed = Url::parse(&input);
        if let Err(url::ParseError::RelativeUrlWithoutBase) = parsed {
            let target_id = {
                let mut registry = intermediate_context.registry.lock().unwrap();
                let target_id = registry.get_target(input).to_owned();
                target_id
            };
            return Ok(LinkTarget::Target { target_id });
        }
        let parsed = parsed?;
        match parsed.scheme() {
            "post" => {
                let post_id = parsed.host_str().map(str::to_owned);
                let subpath = {
                    let subpath = parsed.path();
                    if let Some(subpath) = subpath.strip_prefix('/') {
                        subpath
                    } else {
                        subpath
                    }
                };
                Ok(LinkTarget::Post {
                    post_id,
                    subpath: subpath.to_owned(),
                })
            }
            _ => Ok(LinkTarget::Raw(input.to_owned())),
        }
    }

    pub(crate) fn generate_final_target(
        &self,
        render_context: RenderContext<'_>,
    ) -> Result<Option<String>, CustomError> {
        match self {
            LinkTarget::Raw(raw_link) => Ok(Some(raw_link.clone())),
            LinkTarget::Post { post_id, subpath } => {
                let path = post_id
                    .as_ref()
                    .map(|post_id| {
                        let path_to_post = render_context
                            .config
                            .get_relative_path_to_post(post_id)
                            .join(subpath);
                        get_web_path(
                            render_context.config,
                            render_context.output_root_directory,
                            render_context.output_file,
                            path_to_post,
                        )
                    })
                    .map_or(Ok(None), |r| r.map(Some))?;
                Ok(path)
            }
            LinkTarget::Target { target_id } => Ok(Some(format!(
                "#{}{}",
                render_context
                    .id_addition
                    .map(|id_addition| format!("sec{}.", id_addition))
                    .unwrap_or_default(),
                target_id
            ))),
            LinkTarget::Image { src, .. } => {
                let path_to_file = render_context
                    .dependency_manager
                    .lock()
                    .unwrap()
                    .get_current_folder()?
                    .join(src)
                    .canonicalize()?;
                let input_root_directory = render_context.config.get_root_directory();
                let relative_path_to_file = path_to_file.strip_prefix(input_root_directory)?;
                dbg!(input_root_directory);
                dbg!(&path_to_file);
                dbg!(relative_path_to_file);
                let web_path = get_web_path(
                    render_context.config,
                    render_context.output_root_directory,
                    render_context.output_file,
                    relative_path_to_file,
                )?;
                dbg!(&web_path);
                // TODO: Record interest in copying the file to output.
                Ok(Some(web_path))
            }
        }
    }

    /// Get the value for the src attribute of the image.
    fn get_image_src(input: &str) -> Result<String, CustomError> {
        let input = if input.to_ascii_lowercase().starts_with("file:") {
            Cow::Borrowed(&input[5..])
        } else {
            Cow::Borrowed(input)
        };
        let path = Path::new(input.as_ref());

        if input.to_ascii_lowercase().starts_with("/ssh:") {
            return Ok(format!("file:/{}", input));
        }

        if path.is_absolute() {
            return Ok(format!("file://{}", input));
        }
        return Ok(input.into_owned());
    }

    /// Get file name from the last segment of an image path.
    fn get_image_alt(input: &str) -> Result<String, CustomError> {
        let input = if input.to_ascii_lowercase().starts_with("file:") {
            Cow::Borrowed(&input[5..])
        } else {
            Cow::Borrowed(input)
        };
        let path = Path::new(input.as_ref());
        match path
            .components()
            .last()
            .ok_or("Images should have at least one component in their path.")?
        {
            std::path::Component::Prefix(_) => {
                // Prefix components only occur on windows
                panic!("Prefix components are not supporterd.")
            }
            std::path::Component::RootDir
            | std::path::Component::CurDir
            | std::path::Component::ParentDir => {
                return Err(
                    "Final component of an image path should be a normal component.".into(),
                );
            }
            std::path::Component::Normal(file_name) => Ok(file_name
                .to_str()
                .ok_or("Image link was not valid utf-8.")?
                .to_owned()),
        }
    }
}

#[cfg(test)]
mod tests {
    use std::borrow::Cow;
    use std::sync::Arc;
    use std::sync::Mutex;

    use crate::intermediate::Registry;

    use super::*;

    #[test]
    fn link_target_raw() -> Result<(), CustomError> {
        let registry = Registry::new();
        let registry = Arc::new(Mutex::new(registry));
        let intermediate_context = IntermediateContext::new(registry)?;
        for (inp, typ) in [(
            "https://test.example/foo",
            LinkType::Protocol(Cow::from("https")),
        )] {
            assert_eq!(
                LinkTarget::from_string(intermediate_context.clone(), inp.to_owned(), &typ)?,
                LinkTarget::Raw(inp.to_owned())
            );
        }
        Ok(())
    }

    #[test]
    fn link_target_image() -> Result<(), CustomError> {
        let registry = Registry::new();
        let registry = Arc::new(Mutex::new(registry));
        let intermediate_context = IntermediateContext::new(registry)?;
        for (inp, typ, expected_src, expected_alt) in [
            ("file:image.svg", LinkType::File, "image.svg", "image.svg"),
            (
                "file:/image.svg",
                LinkType::File,
                "file:///image.svg",
                "image.svg",
            ),
            (
                "file:./image.svg",
                LinkType::File,
                "./image.svg",
                "image.svg",
            ),
            (
                "/image.svg",
                LinkType::File,
                "file:///image.svg",
                "image.svg",
            ),
            ("./image.svg", LinkType::File, "./image.svg", "image.svg"),
            ("./image.SVG", LinkType::File, "./image.SVG", "image.SVG"),
            (
                "./image and stuff.SVG",
                LinkType::File,
                "./image and stuff.SVG",
                "image and stuff.SVG",
            ),
            (
                "/ssh:admin@test.example:important/file.svg",
                LinkType::File,
                "file://ssh:admin@test.example:important/file.svg",
                "file.svg",
            ),
            (
                "file:/ssh:admin@test.example:important/file.svg",
                LinkType::File,
                "file://ssh:admin@test.example:important/file.svg",
                "file.svg",
            ),
            (
                "file:/foo/bar/baz/image.svg",
                LinkType::File,
                "file:///foo/bar/baz/image.svg",
                "image.svg",
            ),
        ] {
            assert_eq!(
                LinkTarget::from_string(intermediate_context.clone(), inp.to_owned(), &typ)?,
                LinkTarget::Image {
                    src: expected_src.to_owned(),
                    alt: expected_alt.to_owned()
                }
            );
        }
        Ok(())
    }
}