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

use ropey::RopeSlice;
use tower_lsp::lsp_types::{GotoDefinitionResponse, LocationLink, Position, Range, Url};

/// 跳转到定义
pub fn goto_include_definition(uri: &Url, line: &RopeSlice, pos: Position) -> Option<GotoDefinitionResponse> {
    let line_text = line.as_str().unwrap_or("");
    if line_text.trim().starts_with("`include") {
        let character = pos.character as usize;
        let first_quote_idx = line_text.find("\"");
        let last_quote_idx = line_text.rfind("\"");
        
        if first_quote_idx.is_none() || last_quote_idx.is_none() {
            return None;
        }

        let first_quote_idx = first_quote_idx.unwrap();
        let last_quote_idx = last_quote_idx.unwrap();
        if character >= first_quote_idx && character <= last_quote_idx {
            let mut path_string = &line_text[(first_quote_idx + 1) .. last_quote_idx];
            if path_string.starts_with("./") || path_string.starts_with(".\\") {
                path_string = &path_string[2 ..];
            }
            // 此处得到路径，根据是否为绝对路径进行判断
            let path = Path::new(path_string);
            let mut abs_path: PathBuf;
            if path.is_absolute() {
                abs_path = PathBuf::from(path);
            } else {
                let base = Path::new(uri.path()).parent()?;
                abs_path = base.join(path);
            }

            if abs_path.exists() {
                let target_uri = match Url::from_file_path(abs_path.as_path()) {
                    Ok(uri) => uri,
                    Err(_) => return None
                };

                let origin_selection_range = Range::new(
                    Position { line: pos.line, character: first_quote_idx as u32 },
                    Position { line: pos.line, character: last_quote_idx as u32 }
                );

                let target_position = Position { line: 0, character: 0 };
                let target_range = Range::new(target_position, target_position);

                let link = vec![LocationLink {
                    target_uri,
                    origin_selection_range: Some(origin_selection_range),
                    target_range,
                    target_selection_range: target_range
                }];
                let links = GotoDefinitionResponse::Link(link);
                return Some(links);
            }
        }
    }

    None
}