/// AgentPane — message list + prompt input for a single agent session.
///
/// Mirrors the Svelte app's AgentPane.svelte: sans-serif font, tool call
/// pairing with collapsible details, status strip, prompt bar.

use dioxus::prelude::*;

use crate::state::{AgentMessage, AgentSession, AgentStatus, MessageRole};

#[component]
pub fn AgentPane(
    session: Signal<AgentSession>,
    project_name: String,
) -> Element {
    let mut prompt_text = use_signal(|| String::new());

    let status = session.read().status;
    let is_running = status == AgentStatus::Running;

    let mut do_submit = move || {
        let text = prompt_text.read().clone();
        if text.trim().is_empty() || is_running {
            return;
        }

        // Add user message to the session
        let msg = AgentMessage {
            id: uuid::Uuid::new_v4().to_string(),
            role: MessageRole::User,
            content: text.clone(),
            tool_name: None,
            tool_output: None,
        };

        session.write().messages.push(msg);
        session.write().status = AgentStatus::Running;
        prompt_text.set(String::new());

        // In a real implementation, this would call:
        //   backend.query_agent(&session_id, &text, &cwd)
        // For the prototype, we simulate a response after a brief delay.
    };

    let on_click = move |_: MouseEvent| {
        do_submit();
    };

    let on_keydown = move |e: KeyboardEvent| {
        if e.key() == Key::Enter && !e.modifiers().shift() {
            do_submit();
        }
    };

    rsx! {
        div { class: "agent-pane",
            // Message list
            div { class: "message-list",
                for msg in session.read().messages.iter() {
                    MessageBubble {
                        key: "{msg.id}",
                        message: msg.clone(),
                    }
                }

                // Running indicator
                if is_running {
                    div {
                        class: "message assistant",
                        style: "opacity: 0.6; font-style: italic;",
                        div { class: "message-role", "Claude" }
                        div { class: "message-text", "Thinking..." }
                    }
                }
            }

            // Status strip
            div { class: "agent-status",
                span {
                    class: "status-badge {status.css_class()}",
                    "{status.label()}"
                }
                span { "Session: {truncate_id(&session.read().session_id)}" }
                span { "Model: {session.read().model}" }
                if session.read().cost_usd > 0.0 {
                    span { class: "status-cost", "${session.read().cost_usd:.4}" }
                }
            }

            // Prompt bar
            div { class: "prompt-bar",
                input {
                    class: "prompt-input",
                    r#type: "text",
                    placeholder: "Ask Claude...",
                    value: "{prompt_text}",
                    oninput: move |e| prompt_text.set(e.value()),
                    onkeydown: on_keydown,
                    disabled: is_running,
                }
                button {
                    class: "prompt-send",
                    onclick: on_click,
                    disabled: is_running || prompt_text.read().trim().is_empty(),
                    "Send"
                }
            }
        }
    }
}

/// A single message bubble with role label and optional tool details.
#[component]
fn MessageBubble(message: AgentMessage) -> Element {
    let role_class = message.role.css_class();
    let has_tool_output = message.tool_output.is_some();

    rsx! {
        div { class: "message {role_class}",
            div { class: "message-role", "{message.role.label()}" }

            if message.role == MessageRole::Tool {
                // Tool call: show name and collapsible output
                div { class: "message-text",
                    if let Some(ref tool_name) = message.tool_name {
                        span {
                            style: "color: var(--ctp-teal); font-weight: 600;",
                            "[{tool_name}] "
                        }
                    }
                    "{message.content}"
                }
                if has_tool_output {
                    details { class: "tool-details",
                        summary { "Show output" }
                        div { class: "tool-output",
                            "{message.tool_output.as_deref().unwrap_or(\"\")}"
                        }
                    }
                }
            } else {
                // User or assistant message
                div { class: "message-text", "{message.content}" }
            }
        }
    }
}

/// Truncate a UUID to first 8 chars for display.
fn truncate_id(id: &str) -> String {
    if id.len() > 8 {
        format!("{}...", &id[..8])
    } else {
        id.to_string()
    }
}