use crate::{Error, Result};
use js_int::UInt;
use ruma::{
    events::{
        pdu::EventHash, room::member::MemberEventContent, AnyRoomEvent, AnyStateEvent,
        AnyStrippedStateEvent, AnySyncRoomEvent, AnySyncStateEvent, EventType, StateEvent,
    },
    EventId, Raw, RoomId, ServerName, UserId,
};
use serde::{Deserialize, Serialize};
use serde_json::json;
use std::collections::HashMap;

#[derive(Deserialize, Serialize)]
pub struct PduEvent {
    pub event_id: EventId,
    pub room_id: RoomId,
    pub sender: UserId,
    pub origin: Box<ServerName>,
    pub origin_server_ts: UInt,
    #[serde(rename = "type")]
    pub kind: EventType,
    pub content: serde_json::Value,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub state_key: Option<String>,
    pub prev_events: Vec<EventId>,
    pub depth: UInt,
    pub auth_events: Vec<EventId>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub redacts: Option<EventId>,
    #[serde(default, skip_serializing_if = "serde_json::Map::is_empty")]
    pub unsigned: serde_json::Map<String, serde_json::Value>,
    pub hashes: EventHash,
    pub signatures: HashMap<String, HashMap<String, String>>,
}

impl PduEvent {
    pub fn redact(&mut self, reason: &PduEvent) -> Result<()> {
        self.unsigned.clear();

        let allowed: &[&str] = match self.kind {
            EventType::RoomMember => &["membership"],
            EventType::RoomCreate => &["creator"],
            EventType::RoomJoinRules => &["join_rule"],
            EventType::RoomPowerLevels => &[
                "ban",
                "events",
                "events_default",
                "kick",
                "redact",
                "state_default",
                "users",
                "users_default",
            ],
            EventType::RoomHistoryVisibility => &["history_visibility"],
            _ => &[],
        };

        let old_content = self
            .content
            .as_object_mut()
            .ok_or_else(|| Error::bad_database("PDU in db has invalid content."))?;

        let mut new_content = serde_json::Map::new();

        for key in allowed {
            if let Some(value) = old_content.remove(*key) {
                new_content.insert((*key).to_owned(), value);
            }
        }

        self.unsigned.insert(
            "redacted_because".to_owned(),
            serde_json::to_string(reason)
                .expect("PduEvent::to_string always works")
                .into(),
        );

        self.content = new_content.into();

        Ok(())
    }

    pub fn to_sync_room_event(&self) -> Raw<AnySyncRoomEvent> {
        let mut json = json!({
            "content": self.content,
            "type": self.kind,
            "event_id": self.event_id,
            "sender": self.sender,
            "origin_server_ts": self.origin_server_ts,
            "unsigned": self.unsigned,
        });

        if let Some(state_key) = &self.state_key {
            json["state_key"] = json!(state_key);
        }
        if let Some(redacts) = &self.redacts {
            json["redacts"] = json!(redacts);
        }

        serde_json::from_value(json).expect("Raw::from_value always works")
    }

    pub fn to_room_event(&self) -> Raw<AnyRoomEvent> {
        let mut json = json!({
            "content": self.content,
            "type": self.kind,
            "event_id": self.event_id,
            "sender": self.sender,
            "origin_server_ts": self.origin_server_ts,
            "unsigned": self.unsigned,
            "room_id": self.room_id,
        });

        if let Some(state_key) = &self.state_key {
            json["state_key"] = json!(state_key);
        }
        if let Some(redacts) = &self.redacts {
            json["redacts"] = json!(redacts);
        }

        serde_json::from_value(json).expect("Raw::from_value always works")
    }

    pub fn to_state_event(&self) -> Raw<AnyStateEvent> {
        let json = json!({
            "content": self.content,
            "type": self.kind,
            "event_id": self.event_id,
            "sender": self.sender,
            "origin_server_ts": self.origin_server_ts,
            "unsigned": self.unsigned,
            "room_id": self.room_id,
            "state_key": self.state_key,
        });

        serde_json::from_value(json).expect("Raw::from_value always works")
    }

    pub fn to_sync_state_event(&self) -> Raw<AnySyncStateEvent> {
        let json = json!({
            "content": self.content,
            "type": self.kind,
            "event_id": self.event_id,
            "sender": self.sender,
            "origin_server_ts": self.origin_server_ts,
            "unsigned": self.unsigned,
            "state_key": self.state_key,
        });

        serde_json::from_value(json).expect("Raw::from_value always works")
    }

    pub fn to_stripped_state_event(&self) -> Raw<AnyStrippedStateEvent> {
        let json = json!({
            "content": self.content,
            "type": self.kind,
            "sender": self.sender,
            "state_key": self.state_key,
        });

        serde_json::from_value(json).expect("Raw::from_value always works")
    }

    pub fn to_member_event(&self) -> Raw<StateEvent<MemberEventContent>> {
        let json = json!({
            "content": self.content,
            "type": self.kind,
            "event_id": self.event_id,
            "sender": self.sender,
            "origin_server_ts": self.origin_server_ts,
            "redacts": self.redacts,
            "unsigned": self.unsigned,
            "room_id": self.room_id,
            "state_key": self.state_key,
        });

        serde_json::from_value(json).expect("Raw::from_value always works")
    }
}

/// Build the start of a PDU in order to add it to the `Database`.
#[derive(Debug)]
pub struct PduBuilder {
    pub room_id: RoomId,
    pub sender: UserId,
    pub event_type: EventType,
    pub content: serde_json::Value,
    pub unsigned: Option<serde_json::Map<String, serde_json::Value>>,
    pub state_key: Option<String>,
    pub redacts: Option<EventId>,
}