use uuid::Uuid;

use crate::error::AppError;
use crate::models::common::Role;
use crate::models::prs::{PrLabel, PrLabelRelation};
use crate::service::PrService;
use crate::session::Session;

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

#[derive(serde::Deserialize, serde::Serialize, Clone, Debug, utoipa::ToSchema)]
pub struct CreatePrLabelParams {
    pub name: String,
    pub color: String,
    pub description: Option<String>,
}

#[derive(serde::Deserialize, serde::Serialize, Clone, Debug, utoipa::ToSchema)]
pub struct UpdatePrLabelParams {
    pub name: Option<String>,
    pub color: Option<String>,
    pub description: Option<String>,
}

impl PrService {
    pub async fn pr_labels(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
    ) -> Result<Vec<PrLabel>, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo = self.resolve_repo(wk_name, repo_name).await?;
        self.ensure_repo_readable(user_uid, &repo).await?;
        sqlx::query_as::<_, PrLabel>(
            "SELECT id, repo_id, name, color, description, created_by, created_at, updated_at \
             FROM pr_label WHERE repo_id = $1 ORDER BY name ASC",
        )
        .bind(repo.id)
        .fetch_all(self.ctx.db.reader())
        .await
        .map_err(AppError::Database)
    }

    pub async fn pr_create_label(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        params: CreatePrLabelParams,
    ) -> Result<PrLabel, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo = self.resolve_repo(wk_name, repo_name).await?;
        self.ensure_repo_role_at_least(user_uid, &repo, Role::Member)
            .await?;
        let name = required_text(params.name, "name")?;
        let color = required_text(params.color, "color")?;
        let now = chrono::Utc::now();
        sqlx::query_as::<_, PrLabel>(
            "INSERT INTO pr_label (id, repo_id, name, color, description, created_by, created_at, updated_at) \
             VALUES ($1, $2, $3, $4, $5, $6, $7, $7) \
             RETURNING id, repo_id, name, color, description, created_by, created_at, updated_at",
        )
        .bind(Uuid::now_v7()).bind(repo.id).bind(&name).bind(&color)
        .bind(params.description.as_deref()).bind(user_uid).bind(now)
        .fetch_one(self.ctx.db.writer()).await.map_err(AppError::Database)
    }

    pub async fn pr_update_label(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        label_id: Uuid,
        params: UpdatePrLabelParams,
    ) -> Result<PrLabel, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo = self.resolve_repo(wk_name, repo_name).await?;
        self.ensure_repo_role_at_least(user_uid, &repo, Role::Admin)
            .await?;
        let current = sqlx::query_as::<_, PrLabel>(
            "SELECT id, repo_id, name, color, description, created_by, created_at, updated_at \
             FROM pr_label WHERE id = $1 AND repo_id = $2",
        )
        .bind(label_id)
        .bind(repo.id)
        .fetch_optional(self.ctx.db.reader())
        .await
        .map_err(AppError::Database)?
        .ok_or(AppError::NotFound("label not found".into()))?;

        let name = params.name.unwrap_or(current.name);
        let color = params.color.unwrap_or(current.color);
        let description = super::util::merge_optional_text(params.description, current.description);
        let now = chrono::Utc::now();
        sqlx::query_as::<_, PrLabel>(
            "UPDATE pr_label SET name = $1, color = $2, description = $3, updated_at = $4 \
             WHERE id = $5 RETURNING id, repo_id, name, color, description, created_by, created_at, updated_at",
        )
        .bind(&name).bind(&color).bind(&description).bind(now).bind(label_id)
        .fetch_one(self.ctx.db.writer()).await.map_err(AppError::Database)
    }

    pub async fn pr_delete_label(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        label_id: Uuid,
    ) -> Result<(), AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo = self.resolve_repo(wk_name, repo_name).await?;
        self.ensure_repo_role_at_least(user_uid, &repo, Role::Admin)
            .await?;
        let result = sqlx::query("DELETE FROM pr_label WHERE id = $1 AND repo_id = $2")
            .bind(label_id)
            .bind(repo.id)
            .execute(self.ctx.db.writer())
            .await
            .map_err(AppError::Database)?;
        ensure_affected(result.rows_affected(), "label not found")
    }

    pub async fn pr_assign_label(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        number: i64,
        label_id: Uuid,
    ) -> Result<PrLabelRelation, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let pr = self.resolve_pr(wk_name, repo_name, number).await?;
        self.ensure_pr_editable(user_uid, &pr).await?;
        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::<_, PrLabelRelation>(
            "INSERT INTO pr_label_relation (id, pull_request_id, label_id, created_by, created_at) \
             VALUES ($1, $2, $3, $4, $5) \
             RETURNING id, pull_request_id, label_id, created_by, created_at",
        )
        .bind(Uuid::now_v7())
        .bind(pr.id)
        .bind(label_id)
        .bind(user_uid)
        .bind(now)
        .fetch_one(&mut *txn)
        .await
        .map_err(AppError::Database)?;

        txn.commit().await.map_err(|_| AppError::TxnError)?;
        Ok(rel)
    }

    pub async fn pr_unassign_label(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        number: i64,
        label_id: Uuid,
    ) -> Result<(), AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let pr = self.resolve_pr(wk_name, repo_name, number).await?;
        self.ensure_pr_editable(user_uid, &pr).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 pr_label_relation WHERE pull_request_id = $1 AND label_id = $2",
        )
        .bind(pr.id)
        .bind(label_id)
        .execute(&mut *txn)
        .await
        .map_err(AppError::Database)?;
        ensure_affected(result.rows_affected(), "label not assigned")?;

        txn.commit().await.map_err(|_| AppError::TxnError)?;
        Ok(())
    }

    pub async fn pr_label_relations(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        number: i64,
        limit: i64,
        offset: i64,
    ) -> Result<Vec<PrLabelRelation>, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let pr = self.resolve_pr(wk_name, repo_name, number).await?;
        self.ensure_pr_readable(user_uid, &pr).await?;
        let (limit, offset) = clamp_limit_offset(limit, offset);
        sqlx::query_as::<_, PrLabelRelation>(
            "SELECT id, pull_request_id, label_id, created_by, created_at \
             FROM pr_label_relation WHERE pull_request_id = $1 ORDER BY created_at ASC LIMIT $2 OFFSET $3",
        )
        .bind(pr.id).bind(limit).bind(offset)
        .fetch_all(self.ctx.db.reader()).await.map_err(AppError::Database)
    }
}