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

use crate::error::AppError;
use crate::models::common::Role;
use crate::models::repos::RepoBranch;
use crate::service::RepoService;
use crate::session::Session;

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

#[derive(Deserialize, Serialize, Clone, Debug, utoipa::ToSchema)]
pub struct CreateBranchParams {
    pub name: String,
    pub commit_sha: String,
}

impl RepoService {
    pub async fn repo_branches(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        limit: i64,
        offset: i64,
    ) -> Result<Vec<RepoBranch>, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo = self.resolve_repo(wk_name, repo_name).await?;
        let repo_id = repo.id;
        self.ensure_repo_readable(user_uid, &repo).await?;
        let (limit, offset) = clamp_limit_offset(limit, offset);
        sqlx::query_as::<_, RepoBranch>(
            "SELECT id, repo_id, name, commit_sha, protected, default_branch, created_by, last_push_id, last_push_at, created_at, updated_at FROM repo_branch WHERE repo_id = $1 ORDER BY default_branch DESC, 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 repo_create_branch(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        params: CreateBranchParams,
    ) -> Result<RepoBranch, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo = self.resolve_repo(wk_name, repo_name).await?;
        let repo_id = repo.id;
        self.ensure_repo_role_at_least(user_uid, &repo, Role::Member)
            .await?;
        let name = required_text(params.name, "name")?;

        let existing = sqlx::query_scalar::<_, bool>(
            "SELECT EXISTS(SELECT 1 FROM repo_branch WHERE repo_id = $1 AND name = $2)",
        )
        .bind(repo_id)
        .bind(&name)
        .fetch_one(self.ctx.db.reader())
        .await
        .map_err(AppError::Database)?;

        if existing {
            return Err(AppError::Conflict("branch already exists".into()));
        }

        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 branch = sqlx::query_as::<_, RepoBranch>(
            "INSERT INTO repo_branch (id, repo_id, name, commit_sha, protected, default_branch, created_by, created_at, updated_at) \
             VALUES ($1, $2, $3, $4, false, false, $5, $6, $6) RETURNING id, repo_id, name, commit_sha, protected, default_branch, created_by, last_push_id, last_push_at, created_at, updated_at",
        )
        .bind(Uuid::now_v7())
        .bind(repo_id)
        .bind(&name)
        .bind(&params.commit_sha)
        .bind(user_uid)
        .bind(now)
        .fetch_one(&mut *txn)
        .await
        .map_err(AppError::Database)?;

        sqlx::query(
            "UPDATE repo_stats SET branches_count = branches_count + 1, updated_at = $1 WHERE repo_id = $2",
        )
        .bind(now)
        .bind(repo_id)
        .execute(&mut *txn)
        .await
        .map_err(AppError::Database)?;

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

    pub async fn repo_set_default_branch(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        branch_id: Uuid,
    ) -> Result<(), AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo = self.resolve_repo(wk_name, repo_name).await?;
        let repo_id = repo.id;
        self.ensure_repo_role_at_least(user_uid, &repo, Role::Admin)
            .await?;

        let branch = sqlx::query_as::<_, RepoBranch>(
            "SELECT id, repo_id, name, commit_sha, protected, default_branch, created_by, last_push_id, last_push_at, created_at, updated_at FROM repo_branch WHERE id = $1 AND repo_id = $2",
        )
        .bind(branch_id)
        .bind(repo_id)
        .fetch_optional(self.ctx.db.reader())
        .await
        .map_err(AppError::Database)?
        .ok_or(AppError::NotFound("branch not found".into()))?;

        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)?;

        sqlx::query("UPDATE repo_branch SET default_branch = false, updated_at = $1 WHERE repo_id = $2 AND default_branch = true")
            .bind(now)
            .bind(repo_id)
            .execute(&mut *txn)
            .await
            .map_err(AppError::Database)?;

        sqlx::query("UPDATE repo_branch SET default_branch = true, updated_at = $1 WHERE id = $2")
            .bind(now)
            .bind(branch_id)
            .execute(&mut *txn)
            .await
            .map_err(AppError::Database)?;

        sqlx::query("UPDATE repo SET default_branch = $1, updated_at = $2 WHERE id = $3 AND deleted_at IS NULL")
            .bind(&branch.name)
            .bind(now)
            .bind(repo_id)
            .execute(&mut *txn)
            .await
            .map_err(AppError::Database)?;

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

    pub async fn repo_set_default_branch_by_name(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        branch_name: &str,
    ) -> Result<(), AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo = self.resolve_repo(wk_name, repo_name).await?;
        let repo_id = repo.id;
        self.ensure_repo_role_at_least(user_uid, &repo, Role::Admin)
            .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)?;

        sqlx::query("UPDATE repo_branch SET default_branch = false, updated_at = $1 WHERE repo_id = $2 AND default_branch = true")
            .bind(now).bind(repo_id).execute(&mut *txn).await.map_err(AppError::Database)?;

        sqlx::query("UPDATE repo_branch SET default_branch = true, updated_at = $1 WHERE repo_id = $2 AND name = $3")
            .bind(now).bind(repo_id).bind(branch_name).execute(&mut *txn).await.map_err(AppError::Database)?;

        sqlx::query("UPDATE repo SET default_branch = $1, updated_at = $2 WHERE id = $3 AND deleted_at IS NULL")
            .bind(branch_name).bind(now).bind(repo_id).execute(&mut *txn).await.map_err(AppError::Database)?;

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

    pub async fn repo_set_branch_protection(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        branch_id: Uuid,
        protected: bool,
    ) -> Result<(), AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo = self.resolve_repo(wk_name, repo_name).await?;
        let repo_id = repo.id;
        self.ensure_repo_role_at_least(user_uid, &repo, Role::Admin)
            .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 result = sqlx::query(
            "UPDATE repo_branch SET protected = $1, updated_at = $2 WHERE id = $3 AND repo_id = $4",
        )
        .bind(protected)
        .bind(now)
        .bind(branch_id)
        .bind(repo_id)
        .execute(&mut *txn)
        .await
        .map_err(AppError::Database)?;
        ensure_affected(result.rows_affected(), "branch not found")?;

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

    pub async fn repo_set_branch_protection_by_name(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        branch_name: &str,
        protected: bool,
    ) -> Result<(), AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo = self.resolve_repo(wk_name, repo_name).await?;
        let repo_id = repo.id;
        self.ensure_repo_role_at_least(user_uid, &repo, Role::Admin)
            .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 result = sqlx::query(
            "UPDATE repo_branch SET protected = $1, updated_at = $2 WHERE name = $3 AND repo_id = $4",
        )
        .bind(protected).bind(now).bind(branch_name).bind(repo_id)
        .execute(&mut *txn).await.map_err(AppError::Database)?;
        ensure_affected(result.rows_affected(), "branch not found")?;

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

    pub async fn repo_delete_branch(
        &self,
        ctx: &Session,
        wk_name: &str,
        repo_name: &str,
        branch_id: Uuid,
    ) -> Result<(), AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo = self.resolve_repo(wk_name, repo_name).await?;
        let repo_id = repo.id;
        self.ensure_repo_role_at_least(user_uid, &repo, Role::Admin)
            .await?;

        let is_default = sqlx::query_scalar::<_, bool>(
            "SELECT default_branch FROM repo_branch WHERE id = $1 AND repo_id = $2",
        )
        .bind(branch_id)
        .bind(repo_id)
        .fetch_optional(self.ctx.db.reader())
        .await
        .map_err(AppError::Database)?
        .ok_or(AppError::NotFound("branch not found".into()))?;

        if is_default {
            return Err(AppError::BadRequest("cannot delete default branch".into()));
        }

        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 repo_branch WHERE id = $1 AND repo_id = $2")
            .bind(branch_id)
            .bind(repo_id)
            .execute(&mut *txn)
            .await
            .map_err(AppError::Database)?;
        ensure_affected(result.rows_affected(), "branch not found")?;

        sqlx::query(
            "UPDATE repo_stats SET branches_count = GREATEST(branches_count - 1, 0), updated_at = $1 WHERE repo_id = $2",
        )
        .bind(chrono::Utc::now())
        .bind(repo_id)
        .execute(&mut *txn)
        .await
        .map_err(AppError::Database)?;

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