use serde::{Deserialize, Serialize};
use uuid::Uuid;

/// Information about a single window on the client machine
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct WindowInfo {
    pub id: u64,
    pub title: String,
    pub visible: bool,
}

/// Messages sent from the relay server to a connected client
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum ServerMessage {
    /// Request a screenshot from the client
    ScreenshotRequest { request_id: Uuid },
    /// Capture a specific window by its HWND (works even if behind other windows)
    WindowScreenshotRequest { request_id: Uuid, window_id: u64 },
    /// Show a MessageBox on the client asking the user to do something.
    /// Blocks until the user clicks OK — use this when you need the user
    /// to perform a manual action before continuing.
    PromptRequest {
        request_id: Uuid,
        message: String,
        title: Option<String>,
    },
    /// Execute a shell command on the client
    ExecRequest {
        request_id: Uuid,
        command: String,
        /// Timeout in milliseconds. None = use client default (30s)
        timeout_ms: Option<u64>,
    },
    /// Simulate a mouse click
    ClickRequest {
        request_id: Uuid,
        x: i32,
        y: i32,
        button: MouseButton,
    },
    /// Type text on the client
    TypeRequest {
        request_id: Uuid,
        text: String,
    },
    /// Acknowledge a client message
    Ack { request_id: Uuid },
    /// Server-side error response
    Error {
        request_id: Option<Uuid>,
        message: String,
    },
    /// List all visible windows on the client
    ListWindowsRequest { request_id: Uuid },
    /// Minimize all windows (like Win+D)
    MinimizeAllRequest { request_id: Uuid },
    /// Bring a window to the foreground
    FocusWindowRequest { request_id: Uuid, window_id: u64 },
    /// Maximize a window and bring it to the foreground
    MaximizeAndFocusRequest { request_id: Uuid, window_id: u64 },
    /// Request client version info
    VersionRequest { request_id: Uuid },
    /// Upload a file to the client
    UploadRequest {
        request_id: Uuid,
        path: String,
        content_base64: String,
    },
    /// Download a file from the client
    DownloadRequest {
        request_id: Uuid,
        path: String,
    },
    /// Launch a program on the client (fire-and-forget)
    RunRequest {
        request_id: Uuid,
        program: String,
        args: Vec<String>,
    },
    /// Get the contents of the client's clipboard
    ClipboardGetRequest { request_id: Uuid },
    /// Set the contents of the client's clipboard
    ClipboardSetRequest { request_id: Uuid, text: String },
}

/// Messages sent from the client to the relay server
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum ClientMessage {
    /// Client registers itself with optional display name
    Hello { label: Option<String> },
    /// Response to a screenshot request — base64-encoded PNG
    ScreenshotResponse {
        request_id: Uuid,
        image_base64: String,
        width: u32,
        height: u32,
    },
    /// Response to an exec request
    ExecResponse {
        request_id: Uuid,
        stdout: String,
        stderr: String,
        exit_code: i32,
    },
    /// Generic acknowledgement for click/type/minimize-all/focus/maximize
    Ack { request_id: Uuid },
    /// Client error response
    Error {
        request_id: Uuid,
        message: String,
    },
    /// Response to a list-windows request
    ListWindowsResponse {
        request_id: Uuid,
        windows: Vec<WindowInfo>,
    },
    /// Response to a version request
    VersionResponse {
        request_id: Uuid,
        version: String,
        commit: String,
    },
    /// Response to a download request
    DownloadResponse {
        request_id: Uuid,
        content_base64: String,
        size: u64,
    },
    /// Response to a clipboard-get request
    ClipboardGetResponse { request_id: Uuid, text: String },
}

/// Mouse button variants
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum MouseButton {
    Left,
    Right,
    Middle,
}

impl Default for MouseButton {
    fn default() -> Self {
        MouseButton::Left
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_server_message_serialization() {
        let msg = ServerMessage::ExecRequest {
            request_id: Uuid::nil(),
            command: "echo hello".into(),
            timeout_ms: None,
        };
        let json = serde_json::to_string(&msg).unwrap();
        assert!(json.contains("exec_request"));
        assert!(json.contains("echo hello"));
    }

    #[test]
    fn test_client_message_serialization() {
        let msg = ClientMessage::Hello { label: Some("test-pc".into()) };
        let json = serde_json::to_string(&msg).unwrap();
        assert!(json.contains("hello"));
        assert!(json.contains("test-pc"));
    }

    #[test]
    fn test_roundtrip() {
        let msg = ClientMessage::ExecResponse {
            request_id: Uuid::nil(),
            stdout: "hello\n".into(),
            stderr: String::new(),
            exit_code: 0,
        };
        let json = serde_json::to_string(&msg).unwrap();
        let decoded: ClientMessage = serde_json::from_str(&json).unwrap();
        match decoded {
            ClientMessage::ExecResponse { exit_code, .. } => assert_eq!(exit_code, 0),
            _ => panic!("wrong variant"),
        }
    }
}