use std::collections::HashSet;
use std::sync::Arc;

use anyhow::Result;
use axum::extract::{Extension, Path, Query};
use bili_sync_entity::*;
use bili_sync_migration::Expr;
use sea_orm::{
    ColumnTrait, DatabaseConnection, EntityTrait, PaginatorTrait, QueryFilter, QueryOrder, QuerySelect,
    TransactionTrait,
};
use utoipa::OpenApi;

use crate::api::auth::OpenAPIAuth;
use crate::api::error::InnerApiError;
use crate::api::helper::{update_page_download_status, update_video_download_status};
use crate::api::request::{ResetVideoStatusRequest, VideosRequest};
use crate::api::response::{
    PageInfo, ResetAllVideosResponse, ResetVideoResponse, ResetVideoStatusResponse, VideoInfo, VideoResponse,
    VideoSource, VideoSourcesResponse, VideosResponse,
};
use crate::api::wrapper::{ApiError, ApiResponse, ValidatedJson};
use crate::utils::status::{PageStatus, VideoStatus};

#[derive(OpenApi)]
#[openapi(
    paths(get_video_sources, get_videos, get_video, reset_video, reset_all_videos, reset_video_status),
    modifiers(&OpenAPIAuth),
    security(
        ("Token" = []),
    )
)]
pub struct ApiDoc;

/// 列出所有视频来源
#[utoipa::path(
    get,
    path = "/api/video-sources",
    responses(
        (status = 200, body = ApiResponse<VideoSourcesResponse>),
    )
)]
pub async fn get_video_sources(
    Extension(db): Extension<Arc<DatabaseConnection>>,
) -> Result<ApiResponse<VideoSourcesResponse>, ApiError> {
    let (collection, favorite, submission, watch_later) = tokio::try_join!(
        collection::Entity::find()
            .select_only()
            .columns([collection::Column::Id, collection::Column::Name])
            .into_model::<VideoSource>()
            .all(db.as_ref()),
        favorite::Entity::find()
            .select_only()
            .columns([favorite::Column::Id, favorite::Column::Name])
            .into_model::<VideoSource>()
            .all(db.as_ref()),
        submission::Entity::find()
            .select_only()
            .column(submission::Column::Id)
            .column_as(submission::Column::UpperName, "name")
            .into_model::<VideoSource>()
            .all(db.as_ref()),
        watch_later::Entity::find()
            .select_only()
            .column(watch_later::Column::Id)
            .column_as(Expr::value("稍后再看"), "name")
            .into_model::<VideoSource>()
            .all(db.as_ref())
    )?;
    Ok(ApiResponse::ok(VideoSourcesResponse {
        collection,
        favorite,
        submission,
        watch_later,
    }))
}

/// 列出视频的基本信息，支持根据视频来源筛选、名称查找和分页
#[utoipa::path(
    get,
    path = "/api/videos",
    params(
        VideosRequest,
    ),
    responses(
        (status = 200, body = ApiResponse<VideosResponse>),
    )
)]
pub async fn get_videos(
    Extension(db): Extension<Arc<DatabaseConnection>>,
    Query(params): Query<VideosRequest>,
) -> Result<ApiResponse<VideosResponse>, ApiError> {
    let mut query = video::Entity::find();
    for (field, column) in [
        (params.collection, video::Column::CollectionId),
        (params.favorite, video::Column::FavoriteId),
        (params.submission, video::Column::SubmissionId),
        (params.watch_later, video::Column::WatchLaterId),
    ] {
        if let Some(id) = field {
            query = query.filter(column.eq(id));
        }
    }
    if let Some(query_word) = params.query {
        query = query.filter(video::Column::Name.contains(query_word));
    }
    let total_count = query.clone().count(db.as_ref()).await?;
    let (page, page_size) = if let (Some(page), Some(page_size)) = (params.page, params.page_size) {
        (page, page_size)
    } else {
        (0, 10)
    };
    Ok(ApiResponse::ok(VideosResponse {
        videos: query
            .order_by_desc(video::Column::Id)
            .into_partial_model::<VideoInfo>()
            .paginate(db.as_ref(), page_size)
            .fetch_page(page)
            .await?,
        total_count,
    }))
}

/// 获取视频详细信息，包括关联的所有 page
#[utoipa::path(
    get,
    path = "/api/videos/{id}",
    responses(
        (status = 200, body = ApiResponse<VideoResponse>),
    )
)]
pub async fn get_video(
    Path(id): Path<i32>,
    Extension(db): Extension<Arc<DatabaseConnection>>,
) -> Result<ApiResponse<VideoResponse>, ApiError> {
    let (video_info, pages_info) = tokio::try_join!(
        video::Entity::find_by_id(id)
            .into_partial_model::<VideoInfo>()
            .one(db.as_ref()),
        page::Entity::find()
            .filter(page::Column::VideoId.eq(id))
            .order_by_asc(page::Column::Cid)
            .into_partial_model::<PageInfo>()
            .all(db.as_ref())
    )?;
    let Some(video_info) = video_info else {
        return Err(InnerApiError::NotFound(id).into());
    };
    Ok(ApiResponse::ok(VideoResponse {
        video: video_info,
        pages: pages_info,
    }))
}

/// 将某个视频与其所有分页的失败状态清空为未下载状态，这样在下次下载任务中会触发重试
#[utoipa::path(
    post,
    path = "/api/videos/{id}/reset",
    responses(
        (status = 200, body = ApiResponse<ResetVideoResponse>),
    )
)]
pub async fn reset_video(
    Path(id): Path<i32>,
    Extension(db): Extension<Arc<DatabaseConnection>>,
) -> Result<ApiResponse<ResetVideoResponse>, ApiError> {
    let (video_info, pages_info) = tokio::try_join!(
        video::Entity::find_by_id(id)
            .into_partial_model::<VideoInfo>()
            .one(db.as_ref()),
        page::Entity::find()
            .filter(page::Column::VideoId.eq(id))
            .order_by_asc(page::Column::Cid)
            .into_partial_model::<PageInfo>()
            .all(db.as_ref())
    )?;
    let Some(mut video_info) = video_info else {
        return Err(InnerApiError::NotFound(id).into());
    };
    let resetted_pages_info = pages_info
        .into_iter()
        .filter_map(|mut page_info| {
            let mut page_status = PageStatus::from(page_info.download_status);
            if page_status.reset_failed() {
                page_info.download_status = page_status.into();
                Some(page_info)
            } else {
                None
            }
        })
        .collect::<Vec<_>>();
    let mut video_status = VideoStatus::from(video_info.download_status);
    let mut video_resetted = video_status.reset_failed();
    if !resetted_pages_info.is_empty() {
        video_status.set(4, 0); //  将“分P下载”重置为 0
        video_resetted = true;
    }
    let resetted_videos_info = if video_resetted {
        video_info.download_status = video_status.into();
        vec![&video_info]
    } else {
        vec![]
    };
    let resetted = !resetted_videos_info.is_empty() || !resetted_pages_info.is_empty();
    if resetted {
        let txn = db.begin().await?;
        if !resetted_videos_info.is_empty() {
            // 只可能有 1 个元素，所以不用 batch
            update_video_download_status(&txn, &resetted_videos_info, None).await?;
        }
        if !resetted_pages_info.is_empty() {
            update_page_download_status(&txn, &resetted_pages_info, Some(500)).await?;
        }
        txn.commit().await?;
    }
    Ok(ApiResponse::ok(ResetVideoResponse {
        resetted,
        video: video_info,
        pages: resetted_pages_info,
    }))
}

/// 重置所有视频和页面的失败状态为未下载状态，这样在下次下载任务中会触发重试
#[utoipa::path(
    post,
    path = "/api/videos/reset-all",
    responses(
        (status = 200, body = ApiResponse<ResetAllVideosResponse>),
    )
)]
pub async fn reset_all_videos(
    Extension(db): Extension<Arc<DatabaseConnection>>,
) -> Result<ApiResponse<ResetAllVideosResponse>, ApiError> {
    // 先查询所有视频和页面数据
    let (all_videos, all_pages) = tokio::try_join!(
        video::Entity::find().into_partial_model::<VideoInfo>().all(db.as_ref()),
        page::Entity::find().into_partial_model::<PageInfo>().all(db.as_ref())
    )?;
    let resetted_pages_info = all_pages
        .into_iter()
        .filter_map(|mut page_info| {
            let mut page_status = PageStatus::from(page_info.download_status);
            if page_status.reset_failed() {
                page_info.download_status = page_status.into();
                Some(page_info)
            } else {
                None
            }
        })
        .collect::<Vec<_>>();
    let video_ids_with_resetted_pages: HashSet<i32> = resetted_pages_info.iter().map(|page| page.video_id).collect();
    let resetted_videos_info = all_videos
        .into_iter()
        .filter_map(|mut video_info| {
            let mut video_status = VideoStatus::from(video_info.download_status);
            let mut video_resetted = video_status.reset_failed();
            if video_ids_with_resetted_pages.contains(&video_info.id) {
                video_status.set(4, 0); // 将"分P下载"重置为 0
                video_resetted = true;
            }
            if video_resetted {
                video_info.download_status = video_status.into();
                Some(video_info)
            } else {
                None
            }
        })
        .collect::<Vec<_>>();
    let resetted = !(resetted_videos_info.is_empty() && resetted_pages_info.is_empty());
    if resetted {
        let txn = db.begin().await?;
        if !resetted_videos_info.is_empty() {
            update_video_download_status(&txn, &resetted_videos_info, Some(500)).await?;
        }
        if !resetted_pages_info.is_empty() {
            update_page_download_status(&txn, &resetted_pages_info, Some(500)).await?;
        }
        txn.commit().await?;
    }
    Ok(ApiResponse::ok(ResetAllVideosResponse {
        resetted,
        resetted_videos_count: resetted_videos_info.len(),
        resetted_pages_count: resetted_pages_info.len(),
    }))
}

/// 重置指定视频及其分页的指定状态位
#[utoipa::path(
    post,
    path = "/api/videos/{id}/reset-status",
    request_body = ResetVideoStatusRequest,
    responses(
        (status = 200, body = ApiResponse<ResetVideoStatusResponse>),
    )
)]
pub async fn reset_video_status(
    Path(id): Path<i32>,
    Extension(db): Extension<Arc<DatabaseConnection>>,
    ValidatedJson(request): ValidatedJson<ResetVideoStatusRequest>,
) -> Result<ApiResponse<ResetVideoStatusResponse>, ApiError> {
    let (video_info, mut pages_info) = tokio::try_join!(
        video::Entity::find_by_id(id)
            .into_partial_model::<VideoInfo>()
            .one(db.as_ref()),
        page::Entity::find()
            .filter(page::Column::VideoId.eq(id))
            .order_by_asc(page::Column::Cid)
            .into_partial_model::<PageInfo>()
            .all(db.as_ref())
    )?;
    let Some(mut video_info) = video_info else {
        return Err(InnerApiError::NotFound(id).into());
    };
    let mut video_status = VideoStatus::from(video_info.download_status);
    for update in &request.video_updates {
        video_status.set(update.status_index, update.status_value);
    }
    video_info.download_status = video_status.into();
    let mut updated_pages_info = Vec::new();
    let mut page_id_map = pages_info
        .iter_mut()
        .map(|page| (page.id, page))
        .collect::<std::collections::HashMap<_, _>>();
    for page_update in &request.page_updates {
        if let Some(page_info) = page_id_map.remove(&page_update.page_id) {
            let mut page_status = PageStatus::from(page_info.download_status);
            for update in &page_update.updates {
                page_status.set(update.status_index, update.status_value);
            }
            page_info.download_status = page_status.into();
            updated_pages_info.push(page_info);
        }
    }
    let has_video_updates = !request.video_updates.is_empty();
    let has_page_updates = !updated_pages_info.is_empty();
    if has_video_updates || has_page_updates {
        let txn = db.begin().await?;
        if has_video_updates {
            update_video_download_status(&txn, &[&video_info], None).await?;
        }
        if has_page_updates {
            update_page_download_status(&txn, &updated_pages_info, None).await?;
        }
        txn.commit().await?;
    }
    Ok(ApiResponse::ok(ResetVideoStatusResponse {
        success: has_video_updates || has_page_updates,
        video: video_info,
        pages: pages_info,
    }))
}