use serde::{Deserialize, Serialize};

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SessionSummary {
    pub session_id: String,
    pub title: String,
    pub channel_name: String,
    pub chat_id: String,
    pub message_count: i64,
    pub last_active_at: i64,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub archived_at: Option<i64>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SlashCommandInfo {
    pub name: String,
    pub description: String,
    pub aliases: Vec<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct UploadDescriptor {
    pub upload_id: String,
    pub name: String,
    pub media_type: String,
    pub mime_type: String,
    pub size: u64,
    pub expires_at: i64,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct MessageAttachment {
    pub index: u32,
    pub name: String,
    pub media_type: String,
    pub mime_type: String,
}

impl MessageAttachment {
    pub fn from_media_ref(index: usize, media_ref: &crate::bus::MediaRef) -> Self {
        let name = std::path::Path::new(&media_ref.path)
            .file_name()
            .map(|name| name.to_string_lossy().into_owned())
            .filter(|name| !name.is_empty())
            .unwrap_or_else(|| "attachment".to_string());
        let mime_type = mime_guess::from_path(&name)
            .first_or_octet_stream()
            .to_string();
        Self {
            index: u32::try_from(index).unwrap_or(u32::MAX),
            name,
            media_type: media_ref.media_type.clone(),
            mime_type,
        }
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct HistoryMessage {
    pub id: String,
    pub seq: i64,
    pub role: String,
    pub content: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub reasoning_content: Option<String>,
    #[serde(default)]
    pub completion_status: crate::bus::CompletionStatus,
    pub created_at: i64,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub tool_call_id: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub tool_name: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub tool_calls: Option<Vec<crate::providers::ToolCall>>,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub attachments: Vec<MessageAttachment>,
}

impl From<crate::bus::CommittedMessage> for HistoryMessage {
    fn from(message: crate::bus::CommittedMessage) -> Self {
        let attachments = message
            .media_refs
            .iter()
            .enumerate()
            .map(|(index, media_ref)| MessageAttachment::from_media_ref(index, media_ref))
            .collect();
        Self {
            id: message.id,
            seq: message.seq,
            role: message.role,
            content: message.content,
            reasoning_content: message.reasoning_content,
            completion_status: message.completion_status,
            created_at: message.created_at,
            tool_call_id: message.tool_call_id,
            tool_name: message.tool_name,
            tool_calls: message.tool_calls,
            attachments,
        }
    }
}

impl HistoryMessage {
    pub fn from_message_meta(message: crate::storage::message::MessageMeta) -> Self {
        let attachments = message
            .media_refs
            .as_deref()
            .and_then(|refs| serde_json::from_str::<Vec<crate::bus::MediaRef>>(refs).ok())
            .unwrap_or_default()
            .iter()
            .enumerate()
            .map(|(index, media_ref)| MessageAttachment::from_media_ref(index, media_ref))
            .collect();
        Self {
            id: message.id,
            seq: message.seq,
            role: message.role,
            content: message.content,
            reasoning_content: message.reasoning_content,
            completion_status: message.completion_status,
            created_at: message.created_at,
            tool_call_id: message.tool_call_id,
            tool_name: message.tool_name,
            tool_calls: message
                .tool_calls
                .and_then(|calls| serde_json::from_str(&calls).ok()),
            attachments,
        }
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type")]
pub enum WsInbound {
    #[serde(rename = "user_input")]
    UserInput {
        content: String,
        #[serde(default, skip_serializing_if = "Vec::is_empty")]
        upload_ids: Vec<String>,
        /// Stable id generated by the client for optimistic-message
        /// reconciliation.  It is optional for older clients and channels.
        #[serde(default, skip_serializing_if = "Option::is_none")]
        client_message_id: Option<String>,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        channel: Option<String>,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        chat_id: Option<String>,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        sender_id: Option<String>,
    },
    #[serde(rename = "clear_history")]
    ClearHistory {
        #[serde(default, skip_serializing_if = "Option::is_none")]
        chat_id: Option<String>,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        session_id: Option<String>,
    },
    #[serde(rename = "create_session")]
    CreateSession {
        #[serde(default, skip_serializing_if = "Option::is_none")]
        title: Option<String>,
    },
    #[serde(rename = "list_sessions")]
    ListSessions {
        #[serde(default)]
        include_archived: bool,
    },
    #[serde(rename = "load_session")]
    LoadSession { session_id: String },
    #[serde(rename = "get_session_history")]
    GetSessionHistory {
        session_id: String,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        limit: Option<u32>,
    },
    #[serde(rename = "get_session_plan")]
    GetSessionPlan { session_id: String },
    #[serde(rename = "get_session_stats")]
    GetSessionStats { session_id: String },
    #[serde(rename = "rename_session")]
    RenameSession {
        #[serde(default, skip_serializing_if = "Option::is_none")]
        session_id: Option<String>,
        title: String,
    },
    #[serde(rename = "archive_session")]
    ArchiveSession {
        #[serde(default, skip_serializing_if = "Option::is_none")]
        session_id: Option<String>,
    },
    #[serde(rename = "delete_session")]
    DeleteSession {
        #[serde(default, skip_serializing_if = "Option::is_none")]
        session_id: Option<String>,
    },
    #[serde(rename = "get_slash_commands")]
    GetSlashCommands,
    #[serde(rename = "ping")]
    Ping,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type")]
pub enum WsOutbound {
    #[serde(rename = "turn_updated")]
    TurnUpdated {
        snapshot: crate::session::TurnSnapshot,
    },
    #[serde(rename = "turn_committed")]
    TurnCommitted {
        session_id: String,
        history_revision: i64,
        messages: Vec<HistoryMessage>,
    },
    #[serde(rename = "assistant_response")]
    AssistantResponse {
        id: String,
        content: String,
        role: String,
        #[serde(default, skip_serializing_if = "Vec::is_empty")]
        attachments: Vec<MessageAttachment>,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        session_id: Option<String>,
    },
    #[serde(rename = "error")]
    Error { code: String, message: String },
    #[serde(rename = "session_established")]
    SessionEstablished {
        session_id: String,
        #[serde(default, skip_serializing_if = "Vec::is_empty")]
        capabilities: Vec<String>,
    },
    #[serde(rename = "session_created")]
    SessionCreated { session_id: String, title: String },
    #[serde(rename = "session_list")]
    SessionList {
        sessions: Vec<SessionSummary>,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        current_session_id: Option<String>,
    },
    #[serde(rename = "session_loaded")]
    SessionLoaded {
        session_id: String,
        title: String,
        message_count: i64,
    },
    #[serde(rename = "session_history")]
    SessionHistory {
        session_id: String,
        messages: Vec<HistoryMessage>,
    },
    #[serde(rename = "session_plan")]
    SessionPlan {
        session_id: String,
        plan: Option<crate::work::TaskPlan>,
    },
    #[serde(rename = "session_stats")]
    SessionStats { stats: crate::session::SessionStats },
    #[serde(rename = "plan_updated")]
    PlanUpdated {
        session_id: String,
        reason: String,
        changed_item_ids: Vec<String>,
        plan: Option<crate::work::TaskPlan>,
    },
    #[serde(rename = "session_renamed")]
    SessionRenamed { session_id: String, title: String },
    #[serde(rename = "session_archived")]
    SessionArchived { session_id: String },
    #[serde(rename = "session_deleted")]
    SessionDeleted { session_id: String },
    #[serde(rename = "history_cleared")]
    HistoryCleared { session_id: String },
    #[serde(rename = "slash_commands_list")]
    SlashCommandsList { commands: Vec<SlashCommandInfo> },
    #[serde(rename = "pong")]
    Pong,
    #[serde(rename = "command_executed")]
    CommandExecuted { message: String },
    #[serde(rename = "system_notification")]
    SystemNotification {
        content: String,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        session_id: Option<String>,
    },
}

pub fn parse_inbound(raw: &str) -> Result<WsInbound, serde_json::Error> {
    serde_json::from_str(raw)
}

pub fn serialize_inbound(msg: &WsInbound) -> Result<String, serde_json::Error> {
    serde_json::to_string(msg)
}

pub fn serialize_outbound(msg: &WsOutbound) -> Result<String, serde_json::Error> {
    serde_json::to_string(msg)
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::session::{TurnId, TurnPhase, TurnState, TurnStatus};

    #[test]
    fn turn_updated_serializes_as_one_complete_snapshot_frame() {
        let frame = WsOutbound::TurnUpdated {
            snapshot: TurnState {
                id: TurnId("turn-1".into()),
                session_id: "cli_chat:client:dialog".into(),
                message_id: "message-1".into(),
                revision: 7,
                status: TurnStatus::Running,
                phase: TurnPhase::Responding,
                blocks: Vec::new(),
                usage: None,
                error: None,
            },
        };

        let json = serialize_outbound(&frame).unwrap();
        let value: serde_json::Value = serde_json::from_str(&json).unwrap();
        assert_eq!(value["type"], "turn_updated");
        assert_eq!(value["snapshot"]["revision"], 7);
        assert_eq!(value["snapshot"]["status"], "running");
    }

    #[test]
    fn turn_committed_serializes_revision_and_durable_delta() {
        let frame = WsOutbound::TurnCommitted {
            session_id: "session".to_string(),
            history_revision: 7,
            messages: vec![HistoryMessage {
                id: "message".to_string(),
                seq: 7,
                role: "assistant".to_string(),
                content: "done".to_string(),
                reasoning_content: None,
                completion_status: crate::bus::CompletionStatus::Completed,
                created_at: 1,
                tool_call_id: None,
                tool_name: None,
                tool_calls: None,
                attachments: Vec::new(),
            }],
        };
        let value = serde_json::to_value(frame).unwrap();

        assert_eq!(value["type"], "turn_committed");
        assert_eq!(value["history_revision"], 7);
        assert_eq!(value["messages"][0]["id"], "message");
    }

    #[test]
    fn user_input_preserves_optional_client_message_id() {
        let inbound = parse_inbound(
            r#"{"type":"user_input","content":"hello","client_message_id":"client-1"}"#,
        )
        .unwrap();
        match inbound {
            WsInbound::UserInput {
                client_message_id,
                upload_ids,
                ..
            } => {
                assert_eq!(client_message_id.as_deref(), Some("client-1"));
                assert!(upload_ids.is_empty());
            }
            other => panic!("unexpected frame: {other:?}"),
        }

        let serialized = serialize_inbound(&WsInbound::UserInput {
            content: "hello".to_string(),
            upload_ids: Vec::new(),
            client_message_id: Some("client-1".to_string()),
            channel: None,
            chat_id: None,
            sender_id: None,
        })
        .unwrap();
        assert!(serialized.contains(r#""client_message_id":"client-1""#));
    }

    #[test]
    fn history_defaults_new_reasoning_fields_for_old_frames() {
        let message: HistoryMessage = serde_json::from_value(serde_json::json!({
            "id": "message",
            "seq": 1,
            "role": "assistant",
            "content": "answer",
            "created_at": 1,
            "attachments": []
        }))
        .unwrap();

        assert_eq!(message.reasoning_content, None);
        assert_eq!(
            message.completion_status,
            crate::bus::CompletionStatus::Completed
        );
    }

    #[test]
    fn session_stats_request_and_response_use_structured_frames() {
        let inbound =
            parse_inbound(r#"{"type":"get_session_stats","session_id":"cli_chat:client:dialog"}"#)
                .unwrap();
        assert!(matches!(inbound, WsInbound::GetSessionStats { .. }));

        let stats = crate::session::SessionStats {
            session_id: "cli_chat:client:dialog".into(),
            title: "stats".into(),
            provider: "provider".into(),
            model: "model".into(),
            user_message_count: 1,
            history_message_count: 2,
            lifetime_usage: crate::session::LifetimeUsage {
                input_tokens: 100,
                output_tokens: 20,
                total_tokens: 120,
                cached_input_tokens: Some(40),
                request_count: 1,
                turn_count: 1,
                tracked_since: Some(1),
            },
            context: crate::session::ContextUsage {
                configured_window_tokens: 128_000,
                effective_window_tokens: 128_000,
                used_tokens: 100,
                remaining_tokens: 127_900,
                compression_threshold_tokens: 89_600,
                source: crate::session::ContextUsageSource::Hybrid,
                last_observed_prompt_tokens: Some(90),
                observed_at: Some(1),
            },
            created_at: 1,
            last_active_at: 2,
            updated_at: 3,
        };
        let value = serde_json::to_value(WsOutbound::SessionStats { stats }).unwrap();
        assert_eq!(value["type"], "session_stats");
        assert_eq!(value["stats"]["context"]["source"], "hybrid");
        assert_eq!(value["stats"]["lifetime_usage"]["input_tokens"], 100);
    }
}