use std::path::PathBuf;

use anyhow::anyhow;
use collections::HashMap;
use serde::Deserialize;
use util::ResultExt as _;

use crate::{
    AttachRequest, DebugRequest, DebugTaskDefinition, DebugTaskFile, DebugTaskTemplate,
    EnvVariableReplacer, LaunchRequest, TcpArgumentsTemplate, VariableName,
};

#[derive(Clone, Debug, Deserialize, PartialEq)]
#[serde(rename_all = "camelCase")]
enum Request {
    Launch,
    Attach,
}

// TODO support preLaunchTask linkage with other tasks
#[derive(Clone, Debug, Deserialize, PartialEq)]
#[serde(rename_all = "camelCase")]
struct VsCodeDebugTaskDefinition {
    r#type: String,
    name: String,
    request: Request,

    #[serde(default)]
    program: Option<String>,
    #[serde(default)]
    args: Vec<String>,
    #[serde(default)]
    env: HashMap<String, Option<String>>,
    // TODO envFile?
    #[serde(default)]
    cwd: Option<String>,
    #[serde(default)]
    port: Option<u16>,
    #[serde(default)]
    stop_on_entry: Option<bool>,
    #[serde(flatten)]
    other_attributes: HashMap<String, serde_json_lenient::Value>,
}

impl VsCodeDebugTaskDefinition {
    fn try_to_zed(self, replacer: &EnvVariableReplacer) -> anyhow::Result<DebugTaskTemplate> {
        let label = replacer.replace(&self.name);
        // TODO based on grep.app results it seems that vscode supports whitespace-splitting this field (ugh)
        let definition = DebugTaskDefinition {
            label,
            request: match self.request {
                Request::Launch => {
                    let cwd = self.cwd.map(|cwd| PathBuf::from(replacer.replace(&cwd)));
                    let program = self.program.ok_or_else(|| {
                        anyhow!("vscode debug launch configuration does not define a program")
                    })?;
                    let program = replacer.replace(&program);
                    let args = self
                        .args
                        .into_iter()
                        .map(|arg| replacer.replace(&arg))
                        .collect();
                    DebugRequest::Launch(LaunchRequest { program, cwd, args })
                }
                Request::Attach => DebugRequest::Attach(AttachRequest { process_id: None }),
            },
            adapter: task_type_to_adapter_name(self.r#type),
            // TODO host?
            tcp_connection: self.port.map(|port| TcpArgumentsTemplate {
                port: Some(port),
                host: None,
                timeout: None,
            }),
            stop_on_entry: self.stop_on_entry,
            // TODO
            initialize_args: None,
        };
        let template = DebugTaskTemplate {
            locator: None,
            definition,
        };
        Ok(template)
    }
}

#[derive(Clone, Debug, Deserialize, PartialEq)]
#[serde(rename_all = "camelCase")]
pub struct VsCodeDebugTaskFile {
    version: String,
    configurations: Vec<VsCodeDebugTaskDefinition>,
}

impl TryFrom<VsCodeDebugTaskFile> for DebugTaskFile {
    type Error = anyhow::Error;

    fn try_from(file: VsCodeDebugTaskFile) -> Result<Self, Self::Error> {
        let replacer = EnvVariableReplacer::new(HashMap::from_iter([
            (
                "workspaceFolder".to_owned(),
                VariableName::WorktreeRoot.to_string(),
            ),
            // TODO other interesting variables?
        ]));
        let templates = file
            .configurations
            .into_iter()
            .filter_map(|config| config.try_to_zed(&replacer).log_err())
            .collect::<Vec<_>>();
        Ok(DebugTaskFile(templates))
    }
}

// TODO figure out how to make JsDebugAdapter::ADAPTER_NAME et al available here
fn task_type_to_adapter_name(task_type: String) -> String {
    match task_type.as_str() {
        "node" => "JavaScript".to_owned(),
        "go" => "Delve".to_owned(),
        "php" => "PHP".to_owned(),
        "cppdbg" | "lldb" => "CodeLLDB".to_owned(),
        "debugpy" => "Debugpy".to_owned(),
        _ => task_type,
    }
}

#[cfg(test)]
mod tests {
    use crate::{
        DebugRequest, DebugTaskDefinition, DebugTaskFile, DebugTaskTemplate, LaunchRequest,
        TcpArgumentsTemplate,
    };

    use super::VsCodeDebugTaskFile;

    #[test]
    fn test_parsing_vscode_launch_json() {
        let raw = r#"
            {
                "version": "0.2.0",
                "configurations": [
                    {
                        "name": "Debug my JS app",
                        "request": "launch",
                        "type": "node",
                        "program": "${workspaceFolder}/xyz.js",
                        "showDevDebugOutput": false,
                        "stopOnEntry": true,
                        "args": ["--foo", "${workspaceFolder}/thing"],
                        "cwd": "${workspaceFolder}/${env:FOO}/sub",
                        "env": {
                            "X": "Y"
                        },
                        "port": 17
                    },
                ]
            }
        "#;
        let parsed: VsCodeDebugTaskFile =
            serde_json_lenient::from_str(&raw).expect("deserializing launch.json");
        let zed = DebugTaskFile::try_from(parsed).expect("converting to Zed debug templates");
        pretty_assertions::assert_eq!(
            zed,
            DebugTaskFile(vec![DebugTaskTemplate {
                locator: None,
                definition: DebugTaskDefinition {
                    label: "Debug my JS app".into(),
                    adapter: "JavaScript".into(),
                    stop_on_entry: Some(true),
                    initialize_args: None,
                    tcp_connection: Some(TcpArgumentsTemplate {
                        port: Some(17),
                        host: None,
                        timeout: None,
                    }),
                    request: DebugRequest::Launch(LaunchRequest {
                        program: "${ZED_WORKTREE_ROOT}/xyz.js".into(),
                        args: vec!["--foo".into(), "${ZED_WORKTREE_ROOT}/thing".into()],
                        cwd: Some("${ZED_WORKTREE_ROOT}/${FOO}/sub".into()),
                    }),
                }
            }])
        );
    }
}