use export::pagination::{Page, PageQuery};
use models::pull_request::{pull_request_event_line, pull_requests};
use models::users::user;
use sea_orm::{
    ActiveModelTrait, ActiveValue::Set, ColumnTrait, ConnectionTrait, EntityTrait, PaginatorTrait,
    QueryFilter, QueryOrder, QuerySelect,
};
use serde::{Deserialize, Serialize};
use space::services::spaces::UserDto;
use std::collections::HashMap;
use time::OffsetDateTime;
use uuid::Uuid;

use crate::errors::PullError;
use crate::services::service::PullService;

pub const EVENT_CREATED: &str = "created";
pub const EVENT_UPDATED: &str = "updated";
pub const EVENT_CLOSED: &str = "closed";
pub const EVENT_REOPENED: &str = "reopened";
pub const EVENT_MERGED: &str = "merged";
pub const EVENT_COMMENTED: &str = "commented";
pub const EVENT_REVIEW_SUBMITTED: &str = "review_submitted";
pub const EVENT_REVIEW_DISMISSED: &str = "review_dismissed";
pub const EVENT_REVIEW_REQUESTED: &str = "review_requested";
pub const EVENT_REVIEW_REQUEST_CANCELLED: &str = "review_request_cancelled";
pub const EVENT_HEAD_UPDATED: &str = "head_updated";
pub const EVENT_LABELED: &str = "labeled";
pub const EVENT_UNLABELED: &str = "unlabeled";
pub const EVENT_ASSIGNED: &str = "assigned";
pub const EVENT_UNASSIGNED: &str = "unassigned";
pub const EVENT_LOCKED: &str = "locked";
pub const EVENT_UNLOCKED: &str = "unlocked";
pub const EVENT_AUTO_MERGE_ENABLED: &str = "auto_merge_enabled";
pub const EVENT_AUTO_MERGE_DISABLED: &str = "auto_merge_disabled";

#[derive(Debug, Clone, Serialize, Deserialize, utoipa::ToSchema)]
pub struct PullEventDto {
    pub id: Uuid,
    pub pull_request_id: Uuid,
    pub event_type: String,
    pub actor: Option<UserDto>,
    pub commit_sha: Option<String>,
    pub content: Option<String>,
    pub created_at: OffsetDateTime,
}

pub type EventPage = Page<PullEventDto>;

pub async fn write_event(
    db: &impl ConnectionTrait,
    pull: &pull_requests::Model,
    actor: Option<i64>,
    event_type: &str,
    commit_sha: Option<String>,
    content: Option<String>,
) -> Result<(), sea_orm::DbErr> {
    let actor = match actor {
        Some(actor) => actor,
        None => pull.author_id,
    };
    let payload = serde_json::json!({
        "pull_request_id": pull.id,
        "user_id": actor,
        "event_type": event_type,
        "commit_sha": &commit_sha,
        "content": &content,
    });
    let row = pull_request_event_line::ActiveModel {
        id: Set(Uuid::now_v7()),
        pull_request_id: Set(pull.id),
        user_id: Set(actor),
        event_type: Set(event_type.to_string()),
        commit_sha: Set(commit_sha),
        content: Set(content),
        created_at: Set(OffsetDateTime::now_utc()),
    };
    row.insert(db).await?;

    let Some(kind) = event_kind(event_type) else {
        return Ok(());
    };
    let mut labels = queue::Labels::new()
        .with("pull_id", pull.id)
        .with("user_id", actor);
    if let Some(request_id) = export::events::request_id() {
        labels.insert("request_id", request_id);
    }
    export::events::enqueue(db, kind, labels, payload, format!("pull:{}", pull.id)).await
}

fn event_kind(event_type: &str) -> Option<&'static str> {
    Some(match event_type {
        EVENT_CREATED => "pull.pull.create",
        EVENT_UPDATED => "pull.pull.update",
        EVENT_CLOSED => "pull.pull.close",
        EVENT_REOPENED => "pull.pull.reopen",
        EVENT_MERGED => "pull.pull.merge",
        EVENT_COMMENTED => "pull.comment.create",
        EVENT_REVIEW_SUBMITTED => "pull.review.create",
        EVENT_REVIEW_DISMISSED => "pull.review.delete",
        EVENT_REVIEW_REQUESTED => "pull.review-request.create",
        EVENT_REVIEW_REQUEST_CANCELLED => "pull.review-request.delete",
        EVENT_HEAD_UPDATED => "pull.head.update",
        EVENT_LABELED => "pull.label.create",
        EVENT_UNLABELED => "pull.label.delete",
        EVENT_ASSIGNED => "pull.assignee.create",
        EVENT_UNASSIGNED => "pull.assignee.delete",
        EVENT_LOCKED => "pull.lock.create",
        EVENT_UNLOCKED => "pull.lock.delete",
        EVENT_AUTO_MERGE_ENABLED => "pull.auto-merge.create",
        EVENT_AUTO_MERGE_DISABLED => "pull.auto-merge.delete",
        _ => return None,
    })
}

impl PullService {
    pub async fn record_event(
        &self,
        pull: &pull_requests::Model,
        actor: Option<i64>,
        event_type: &str,
        commit_sha: Option<String>,
        content: Option<String>,
    ) -> Result<(), PullError> {
        write_event(
            self.db_write(),
            pull,
            actor,
            event_type,
            commit_sha,
            content,
        )
        .await?;
        Ok(())
    }

    pub async fn list_events(
        &self,
        pull_id: Uuid,
        page: PageQuery,
    ) -> Result<EventPage, PullError> {
        let (limit, offset) = page.page();
        let total = pull_request_event_line::Entity::find()
            .filter(pull_request_event_line::Column::PullRequestId.eq(pull_id))
            .count(self.db_read())
            .await? as i64;
        let rows = pull_request_event_line::Entity::find()
            .filter(pull_request_event_line::Column::PullRequestId.eq(pull_id))
            .order_by_asc(pull_request_event_line::Column::CreatedAt)
            .limit(limit)
            .offset(offset)
            .all(self.db_read())
            .await?;
        let actors = self.user_briefs(&unique_users(&rows)).await?;
        let items = rows
            .into_iter()
            .map(|row| PullEventDto {
                id: row.id,
                pull_request_id: row.pull_request_id,
                event_type: row.event_type,
                commit_sha: row.commit_sha,
                content: row.content,
                created_at: row.created_at,
                actor: actors.get(&row.user_id).cloned(),
            })
            .collect();
        Ok(Page {
            items,
            total,
            limit,
            offset,
        })
    }

    pub(crate) async fn user_briefs(
        &self,
        ids: &[i64],
    ) -> Result<HashMap<i64, UserDto>, PullError> {
        if ids.is_empty() {
            return Ok(HashMap::new());
        }
        let users = export::users::load_public_users(&self.state, ids).await?;
        Ok(users
            .into_iter()
            .map(|(uid, user)| (uid, UserDto::from_public(&user)))
            .collect())
    }
}

fn unique_users(rows: &[pull_request_event_line::Model]) -> Vec<i64> {
    let mut ids: Vec<i64> = rows.iter().map(|row| row.user_id).collect();
    ids.sort();
    ids.dedup();
    ids
}