use serde::{Deserialize, Serialize};
use uuid::Uuid;

use crate::error::AppError;
use crate::models::common::Role;
use crate::models::prs::PrTemplate;
use crate::service::PrService;
use crate::session::Session;

use super::util::{clamp_limit_offset, merge_optional_text, required_text};

#[derive(Deserialize, Serialize, Clone, Debug, utoipa::ToSchema)]
pub struct CreatePrTemplateParams {
    pub name: String,
    pub description: Option<String>,
    pub title_template: Option<String>,
    pub body_template: String,
    pub labels: Vec<String>,
}

#[derive(Deserialize, Serialize, Clone, Debug, utoipa::ToSchema)]
pub struct UpdatePrTemplateParams {
    pub name: Option<String>,
    pub description: Option<String>,
    pub title_template: Option<String>,
    pub body_template: Option<String>,
    pub labels: Option<Vec<String>>,
    pub active: Option<bool>,
}

impl PrService {
    pub async fn pr_templates(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        limit: i64,
        offset: i64,
    ) -> Result<Vec<PrTemplate>, 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?;
        let (limit, offset) = clamp_limit_offset(limit, offset);
        sqlx::query_as::<_, PrTemplate>(
            "SELECT * FROM pr_template WHERE repo_id = $1 AND active = true ORDER BY name ASC LIMIT $2 OFFSET $3",
        )
        .bind(repo.id)
        .bind(limit)
        .bind(offset)
        .fetch_all(self.ctx.db.reader())
        .await
        .map_err(AppError::Database)
    }

    pub async fn pr_create_template(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        params: CreatePrTemplateParams,
    ) -> Result<PrTemplate, 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")?;
        sqlx::query_as::<_, PrTemplate>(
            "INSERT INTO pr_template (id, repo_id, name, description, title_template, body_template, labels, created_by, created_at, updated_at) \
             VALUES ($1, $2, $3, $4, $5, $6, $7, $8, NOW(), NOW()) RETURNING *",
        )
        .bind(Uuid::now_v7())
        .bind(repo.id)
        .bind(&name)
        .bind(params.description.as_deref())
        .bind(params.title_template.as_deref())
        .bind(&params.body_template)
        .bind(&params.labels)
        .bind(user_uid)
        .fetch_one(self.ctx.db.writer())
        .await
        .map_err(AppError::Database)
    }

    pub async fn pr_update_template(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        template_id: Uuid,
        params: UpdatePrTemplateParams,
    ) -> Result<PrTemplate, 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: PrTemplate =
            sqlx::query_as("SELECT * FROM pr_template WHERE id = $1 AND repo_id = $2")
                .bind(template_id)
                .bind(repo.id)
                .fetch_optional(self.ctx.db.reader())
                .await
                .map_err(AppError::Database)?
                .ok_or(AppError::NotFound("template not found".into()))?;

        let name =
            merge_optional_text(params.name, Some(current.name.clone())).unwrap_or(current.name);
        let description = merge_optional_text(params.description, current.description);
        let title_template = merge_optional_text(params.title_template, current.title_template);
        let body_template = merge_optional_text(params.body_template, Some(current.body_template))
            .unwrap_or_default();
        let labels = params.labels.unwrap_or(current.labels);
        let active = params.active.unwrap_or(current.active);

        sqlx::query_as::<_, PrTemplate>(
            "UPDATE pr_template SET name = $1, description = $2, title_template = $3, body_template = $4, \
             labels = $5, active = $6, updated_at = NOW() WHERE id = $7 AND repo_id = $8 RETURNING *",
        )
        .bind(&name)
        .bind(&description)
        .bind(&title_template)
        .bind(&body_template)
        .bind(&labels)
        .bind(active)
        .bind(template_id)
        .bind(repo.id)
        .fetch_one(self.ctx.db.writer())
        .await
        .map_err(AppError::Database)
    }

    pub async fn pr_delete_template(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        template_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?;
        sqlx::query("DELETE FROM pr_template WHERE id = $1 AND repo_id = $2")
            .bind(template_id)
            .bind(repo.id)
            .execute(self.ctx.db.writer())
            .await
            .map_err(AppError::Database)?;
        Ok(())
    }
}