use uuid::Uuid;

use crate::error::AppError;
use crate::models::common::RelationType;
use crate::models::issues::IssueRepoRelation;
use crate::service::IssueService;
use crate::session::Session;

use super::util::{clamp_limit_offset, ensure_affected, parse_enum, set_local_user_id};

#[derive(serde::Deserialize, serde::Serialize, Clone, Debug, utoipa::ToSchema)]
pub struct LinkRepoParams {
    pub repo_id: Uuid,
    pub relation_type: Option<String>,
}

impl IssueService {
    pub async fn issue_repo_relations(
        &self,
        ctx: &Session,
        wk_name: &str,
        number: i64,
        limit: i64,
        offset: i64,
    ) -> Result<Vec<IssueRepoRelation>, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let issue = self.resolve_issue(wk_name, number).await?;
        let issue_id = issue.id;
        self.ensure_issue_readable(user_uid, &issue).await?;
        let (limit, offset) = clamp_limit_offset(limit, offset);
        sqlx::query_as::<_, IssueRepoRelation>(
            "SELECT id, issue_id, repo_id, relation_type, created_by, created_at \
             FROM issue_repo_relation WHERE issue_id = $1 ORDER BY created_at ASC LIMIT $2 OFFSET $3",
        )
        .bind(issue_id).bind(limit).bind(offset)
        .fetch_all(self.ctx.db.reader()).await.map_err(AppError::Database)
    }

    pub async fn issue_link_repo(
        &self,
        ctx: &Session,
        wk_name: &str,
        number: i64,
        params: LinkRepoParams,
    ) -> Result<IssueRepoRelation, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let issue = self.resolve_issue(wk_name, number).await?;
        let issue_id = issue.id;
        self.ensure_issue_editable(user_uid, &issue).await?;
        let relation_type = match params.relation_type {
            Some(ref v) => parse_enum(
                Some(v.clone()),
                RelationType::References,
                RelationType::Unknown,
                "relation_type",
            )?,
            None => RelationType::References,
        };
        let now = chrono::Utc::now();
        let mut txn = self
            .ctx
            .db
            .writer()
            .begin()
            .await
            .map_err(|_| AppError::TxnError)?;
        sqlx::query(set_local_user_id(user_uid))
            .execute(&mut *txn)
            .await
            .map_err(AppError::Database)?;
        let rel = sqlx::query_as::<_, IssueRepoRelation>(
            "INSERT INTO issue_repo_relation (id, issue_id, repo_id, relation_type, created_by, created_at) \
             VALUES ($1, $2, $3, $4, $5, $6) ON CONFLICT (issue_id, repo_id) DO NOTHING \
             RETURNING id, issue_id, repo_id, relation_type, created_by, created_at",
        )
        .bind(Uuid::now_v7()).bind(issue_id).bind(params.repo_id)
        .bind(relation_type).bind(user_uid).bind(now)
        .fetch_optional(&mut *txn).await.map_err(AppError::Database)?
        .ok_or(AppError::Conflict("repo already linked".into()))?;
        txn.commit().await.map_err(|_| AppError::TxnError)?;
        Ok(rel)
    }

    pub async fn issue_unlink_repo(
        &self,
        ctx: &Session,
        wk_name: &str,
        number: i64,
        relation_id: Uuid,
    ) -> Result<(), AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let issue = self.resolve_issue(wk_name, number).await?;
        let issue_id = issue.id;
        self.ensure_issue_editable(user_uid, &issue).await?;
        let mut txn = self
            .ctx
            .db
            .writer()
            .begin()
            .await
            .map_err(|_| AppError::TxnError)?;
        sqlx::query(set_local_user_id(user_uid))
            .execute(&mut *txn)
            .await
            .map_err(AppError::Database)?;
        let result = sqlx::query("DELETE FROM issue_repo_relation WHERE id = $1 AND issue_id = $2")
            .bind(relation_id)
            .bind(issue_id)
            .execute(&mut *txn)
            .await
            .map_err(AppError::Database)?;
        ensure_affected(result.rows_affected(), "repo relation not found")?;
        txn.commit().await.map_err(|_| AppError::TxnError)?;
        Ok(())
    }
}