use crate::error::AppError;
use crate::models::common::MergeStrategyKind;
use crate::models::prs::PrMergeStrategy;
use crate::service::PrService;
use crate::session::Session;

use super::util::parse_enum;

#[derive(serde::Deserialize, serde::Serialize, Clone, Debug, utoipa::ToSchema)]
pub struct UpdateMergeStrategyParams {
    pub strategy: Option<String>,
    pub auto_merge: Option<bool>,
    pub squash_title: Option<String>,
    pub squash_message: Option<String>,
    pub delete_source_branch: Option<bool>,
    pub merge_when_checks_pass: Option<bool>,
}

impl PrService {
    pub async fn pr_merge_strategy(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        number: i64,
    ) -> Result<PrMergeStrategy, 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?;
        sqlx::query_as::<_, PrMergeStrategy>(
            "SELECT pull_request_id, strategy, auto_merge, squash_title, squash_message, \
             delete_source_branch, merge_when_checks_pass, selected_by, created_at, updated_at \
             FROM pr_merge_strategy WHERE pull_request_id = $1",
        )
        .bind(pr.id)
        .fetch_optional(self.ctx.db.reader())
        .await
        .map_err(AppError::Database)?
        .ok_or(AppError::NotFound("PR merge strategy not found".into()))
    }

    pub async fn pr_update_merge_strategy(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        number: i64,
        params: UpdateMergeStrategyParams,
    ) -> Result<PrMergeStrategy, 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 current = sqlx::query_as::<_, PrMergeStrategy>(
            "SELECT pull_request_id, strategy, auto_merge, squash_title, squash_message, \
             delete_source_branch, merge_when_checks_pass, selected_by, created_at, updated_at \
             FROM pr_merge_strategy WHERE pull_request_id = $1",
        )
        .bind(pr.id)
        .fetch_optional(self.ctx.db.reader())
        .await
        .map_err(AppError::Database)?;

        let strategy = match params.strategy {
            Some(ref v) => parse_enum(
                Some(v.clone()),
                current
                    .as_ref()
                    .map(|c| c.strategy)
                    .unwrap_or(MergeStrategyKind::Merge),
                MergeStrategyKind::Unknown,
                "strategy",
            )?,
            None => current
                .as_ref()
                .map(|c| c.strategy)
                .unwrap_or(MergeStrategyKind::Merge),
        };
        let auto_merge = params
            .auto_merge
            .or(current.as_ref().map(|c| c.auto_merge))
            .unwrap_or(false);
        let squash_title = params
            .squash_title
            .or_else(|| current.as_ref().and_then(|c| c.squash_title.clone()));
        let squash_message = params
            .squash_message
            .or_else(|| current.as_ref().and_then(|c| c.squash_message.clone()));
        let delete_source_branch = params
            .delete_source_branch
            .or(current.as_ref().map(|c| c.delete_source_branch))
            .unwrap_or(false);
        let merge_when_checks_pass = params
            .merge_when_checks_pass
            .or(current.as_ref().map(|c| c.merge_when_checks_pass))
            .unwrap_or(false);
        let now = chrono::Utc::now();

        if current.is_some() {
            sqlx::query_as::<_, PrMergeStrategy>(
                "UPDATE pr_merge_strategy SET strategy = $1, auto_merge = $2, squash_title = $3, \
                 squash_message = $4, delete_source_branch = $5, merge_when_checks_pass = $6, \
                 selected_by = $7, updated_at = $8 WHERE pull_request_id = $9 \
                 RETURNING pull_request_id, strategy, auto_merge, squash_title, squash_message, \
                 delete_source_branch, merge_when_checks_pass, selected_by, created_at, updated_at",
            )
            .bind(strategy)
            .bind(auto_merge)
            .bind(squash_title.as_deref())
            .bind(squash_message.as_deref())
            .bind(delete_source_branch)
            .bind(merge_when_checks_pass)
            .bind(user_uid)
            .bind(now)
            .bind(pr.id)
            .fetch_one(self.ctx.db.writer())
            .await
            .map_err(AppError::Database)
        } else {
            sqlx::query_as::<_, PrMergeStrategy>(
                "INSERT INTO pr_merge_strategy (pull_request_id, strategy, auto_merge, squash_title, \
                 squash_message, delete_source_branch, merge_when_checks_pass, selected_by, created_at, updated_at) \
                 VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $9) \
                 RETURNING pull_request_id, strategy, auto_merge, squash_title, squash_message, \
                 delete_source_branch, merge_when_checks_pass, selected_by, created_at, updated_at",
            )
            .bind(pr.id).bind(strategy).bind(auto_merge).bind(squash_title.as_deref()).bind(squash_message.as_deref())
            .bind(delete_source_branch).bind(merge_when_checks_pass).bind(user_uid).bind(now)
            .fetch_one(self.ctx.db.writer()).await.map_err(AppError::Database)
        }
    }
}