use crate::host_bridge::clipboard::{
    clipboard_write_unavailable_response, write_desktop_clipboard_text,
};
use crate::host_bridge::protocol::{failed, ok, HostBridgeRequest, HostBridgeResponse};
use crate::shell::webview::WEB_APP_ORIGIN;
use serde_json::json;
use serde_json::Value;
use std::sync::Mutex;
use tauri::Manager;
use tauri::Url;

#[derive(Debug, Default)]
pub(crate) struct DesktopShareState {
    pub(crate) target: Mutex<Option<Value>>,
}

enum DesktopSharePayload {
    Empty,
    Invalid,
    Valid(String),
}

fn payload_string<'a>(value: &'a Value, field: &str) -> Option<&'a str> {
    value
        .get(field)
        .and_then(Value::as_str)
        .map(str::trim)
        .filter(|text| !text.is_empty())
}

fn log_desktop_share_failure(label: &str) -> bool {
    eprintln!("desktop share failed for {label}");
    false
}

fn share_unavailable_response(request: &HostBridgeRequest) -> HostBridgeResponse {
    failed(request.id.clone(), "host_error", "share unavailable")
}

fn share_target_payload(value: &Value) -> &Value {
    value.get("target").unwrap_or(value)
}

fn work_detail_url(work: &str) -> String {
    let mut url = Url::parse(WEB_APP_ORIGIN).expect("desktop web origin");
    url.set_path("/works/detail");
    url.set_query(None);
    url.query_pairs_mut().append_pair("work", work);
    url.to_string()
}

fn normalize_public_share_url(raw_url: &str) -> Option<String> {
    if raw_url.starts_with("//") {
        return None;
    }

    let base_url = Url::parse(WEB_APP_ORIGIN).ok()?;
    let url = base_url.join(raw_url).ok()?;
    if url.origin() != base_url.origin() {
        return None;
    }

    Some(url.to_string())
}

fn share_text_from_value(value: &Value) -> DesktopSharePayload {
    let target = share_target_payload(value);
    let payload = target.get("payload").unwrap_or(target);
    let title = payload_string(payload, "title");
    let message = payload_string(payload, "message");
    let raw_direct_url = payload_string(payload, "url").or_else(|| payload_string(payload, "href"));
    let direct_url = match raw_direct_url {
        Some(url) => match normalize_public_share_url(url) {
            Some(url) => Some(url),
            None => return DesktopSharePayload::Invalid,
        },
        None => None,
    };
    let work_url = payload_string(payload, "work").map(work_detail_url);
    let raw_path =
        payload_string(payload, "path").or_else(|| payload_string(payload, "targetPath"));
    let path_url = match raw_path {
        Some(path) => match normalize_public_share_url(path) {
            Some(url) => Some(url),
            None => return DesktopSharePayload::Invalid,
        },
        None => None,
    };
    let resolved_url = direct_url.or(work_url).or(path_url);
    let parts = [title, message, resolved_url.as_deref()]
        .into_iter()
        .flatten()
        .collect::<Vec<_>>();

    if parts.is_empty() {
        DesktopSharePayload::Empty
    } else {
        DesktopSharePayload::Valid(parts.join("\n"))
    }
}

pub(crate) fn share_text_from_request(
    request: &HostBridgeRequest,
    share_state: &DesktopShareState,
) -> Result<String, HostBridgeResponse> {
    if let Some(payload) = request.payload.as_ref() {
        match share_text_from_value(payload) {
            DesktopSharePayload::Valid(text) => return Ok(text),
            DesktopSharePayload::Invalid => {
                return Err(failed(
                    request.id.clone(),
                    "invalid_request",
                    "share target is invalid",
                ))
            }
            DesktopSharePayload::Empty => {}
        }
    }

    let stored_target = share_state
        .target
        .lock()
        .map_err(|_| {
            log_desktop_share_failure("target.lock");
            share_unavailable_response(request)
        })?
        .clone();

    match stored_target.as_ref().map(share_text_from_value) {
        Some(DesktopSharePayload::Valid(text)) => Ok(text),
        Some(DesktopSharePayload::Invalid) => Err(failed(
            request.id.clone(),
            "invalid_request",
            "share target is invalid",
        )),
        Some(DesktopSharePayload::Empty) | None => Err(failed(
            request.id.clone(),
            "invalid_request",
            "share target is required",
        )),
    }
}

pub(crate) fn set_desktop_host_bridge_share_target(
    app: &tauri::AppHandle,
    request: &HostBridgeRequest,
) -> HostBridgeResponse {
    let target = request
        .payload
        .as_ref()
        .and_then(|payload| payload.get("target"));
    let Some(target) = target else {
        return failed(request.id.clone(), "invalid_request", "target is required");
    };
    match share_text_from_value(target) {
        DesktopSharePayload::Valid(_) => {}
        DesktopSharePayload::Invalid => {
            return failed(
                request.id.clone(),
                "invalid_request",
                "share target is invalid",
            )
        }
        DesktopSharePayload::Empty => {
            return failed(
                request.id.clone(),
                "invalid_request",
                "share target is required",
            )
        }
    }
    let share_state = app.state::<DesktopShareState>();

    let response = match share_state.target.lock() {
        Ok(mut current_target) => {
            *current_target = Some(target.clone());
            ok(request.id.clone(), json!(true))
        }
        Err(_) => {
            log_desktop_share_failure("target.store");
            share_unavailable_response(request)
        }
    };
    response
}

pub(crate) fn open_desktop_host_bridge_share(
    app: &tauri::AppHandle,
    request: &HostBridgeRequest,
) -> HostBridgeResponse {
    let share_state = app.state::<DesktopShareState>();
    let share_text = match share_text_from_request(request, &share_state) {
        Ok(text) => text,
        Err(response) => return response,
    };

    match write_desktop_clipboard_text(app, &share_text) {
        Ok(()) => ok(
            request.id.clone(),
            json!({
                "action": "copied_to_clipboard"
            }),
        ),
        Err(_) => clipboard_write_unavailable_response(request),
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::host_bridge::protocol::request;
    use serde_json::json;

    #[test]
    fn share_text_uses_direct_share_payload() {
        let state = DesktopShareState::default();
        let mut open = request("share.open");
        open.payload = Some(json!({
            "title": "测试作品",
            "message": "来玩这个作品",
            "url": "https://www.genarrative.world/works/detail?work=PZ-1"
        }));

        let text = share_text_from_request(&open, &state).expect("share text");

        assert_eq!(
            text,
            "测试作品\n来玩这个作品\nhttps://www.genarrative.world/works/detail?work=PZ-1"
        );
    }

    #[test]
    fn share_text_normalizes_public_urls_only() {
        let state = DesktopShareState::default();
        let mut direct_path = request("share.open");
        direct_path.payload = Some(json!({
            "title": "测试作品",
            "path": "/works/detail?work=PZ-1"
        }));

        let path_text = share_text_from_request(&direct_path, &state).expect("path share text");

        assert_eq!(
            path_text,
            "测试作品\nhttps://www.genarrative.world/works/detail?work=PZ-1"
        );

        let mut work = request("share.open");
        work.payload = Some(json!({
            "title": "测试作品",
            "work": "PZ 1/二"
        }));

        let work_text = share_text_from_request(&work, &state).expect("work share text");

        assert_eq!(
            work_text,
            "测试作品\nhttps://www.genarrative.world/works/detail?work=PZ+1%2F%E4%BA%8C"
        );
    }

    #[test]
    fn share_text_rejects_external_or_unsafe_urls_without_using_cached_target() {
        let state = DesktopShareState::default();
        *state.target.lock().expect("share target lock") = Some(json!({
            "payload": {
                "title": "缓存作品",
                "work": "PZ-1"
            }
        }));

        for field in ["url", "href", "path", "targetPath"] {
            let mut open = request("share.open");
            open.payload = Some(json!({
                "title": "危险作品",
                field: if field == "path" {
                    "//evil.example/works/detail?work=PZ-1"
                } else {
                    "https://evil.example/works/detail?work=PZ-1"
                }
            }));

            let response = share_text_from_request(&open, &state).expect_err("invalid share url");

            assert!(!response.ok);
            let error = response.error.expect("error");
            assert_eq!(error.code, "invalid_request");
            assert_eq!(error.message, "share target is invalid");
        }

        let mut javascript_url = request("share.open");
        javascript_url.payload = Some(json!({
            "title": "危险作品",
            "url": "javascript:alert(1)"
        }));

        assert!(
            !share_text_from_request(&javascript_url, &state)
                .expect_err("unsafe share url")
                .ok
        );
    }

    #[test]
    fn share_text_uses_stored_work_target() {
        let state = DesktopShareState::default();
        let mut set_target = request("share.setTarget");
        set_target.payload = Some(json!({
            "target": {
                "type": "genarrative:share-target",
                "payload": {
                    "work": "PZ-1",
                    "title": "测试作品"
                }
            }
        }));
        let target = set_target
            .payload
            .as_ref()
            .and_then(|payload| payload.get("target"))
            .expect("target");
        *state.target.lock().expect("share target lock") = Some(target.clone());

        let text = share_text_from_request(&request("share.open"), &state).expect("share text");

        assert_eq!(
            text,
            "测试作品\nhttps://www.genarrative.world/works/detail?work=PZ-1"
        );
    }

    #[test]
    fn share_target_payload_must_be_valid_before_cache() {
        assert!(matches!(
            share_text_from_value(&json!({})),
            DesktopSharePayload::Empty
        ));
        assert!(matches!(
            share_text_from_value(&json!({
                "title": "危险作品",
                "url": "https://example.com/works/detail?work=PZ-1"
            })),
            DesktopSharePayload::Invalid
        ));
        assert!(matches!(
            share_text_from_value(&json!({
                "title": "测试作品",
                "work": "PZ-1"
            })),
            DesktopSharePayload::Valid(_)
        ));
    }

    #[test]
    fn share_text_requires_payload_or_stored_target() {
        let state = DesktopShareState::default();
        let response =
            share_text_from_request(&request("share.open"), &state).expect_err("missing target");

        assert!(!response.ok);
        let error = response.error.expect("error");
        assert_eq!(error.code, "invalid_request");
        assert_eq!(error.message, "share target is required");
    }

    #[test]
    fn share_unavailable_response_is_stable() {
        let response = share_unavailable_response(&request("share.open"));

        assert!(!response.ok);
        let error = response.error.expect("share error");
        assert_eq!(error.code, "host_error");
        assert_eq!(error.message, "share unavailable");
    }

    #[test]
    fn share_failures_are_logged_without_exposing_native_detail() {
        assert!(!log_desktop_share_failure("target.lock"));
        assert!(!log_desktop_share_failure("target.store"));
    }

    #[test]
    fn share_failures_log_stable_label_only() {
        assert!(!log_desktop_share_failure("target.lock"));
    }
}