//! 健康资讯 Service — 文章 CRUD + 审核工作流

use chrono::Utc;
use sea_orm::entity::prelude::*;
use sea_orm::{ActiveValue::Set, QueryOrder, QuerySelect};
use uuid::Uuid;

use erp_core::audit::AuditLog;
use erp_core::audit_service;
use erp_core::error::check_version;
use erp_core::events::DomainEvent;
use erp_core::types::PaginatedResponse;

use crate::dto::article_dto::{ArticleListItem, ArticleResp, CreateArticleReq, ReviewArticleReq, UpdateArticleReq};
use crate::entity::article;
use crate::entity::article_article_tag;
use crate::entity::article_tag;
use crate::error::{HealthError, HealthResult};
use crate::service::validation;
use crate::state::HealthState;

/// 文章列表（管理端，支持状态/分类/标签/关键词筛选）
pub async fn list_articles(
    state: &HealthState,
    tenant_id: Uuid,
    page: u64,
    page_size: u64,
    category: Option<String>,
    status: Option<String>,
    category_id: Option<Uuid>,
    tag_id: Option<Uuid>,
    keyword: Option<String>,
) -> HealthResult<PaginatedResponse<ArticleListItem>> {
    let limit = page_size.min(100);
    let offset = page.saturating_sub(1) * limit;

    let mut query = article::Entity::find()
        .filter(article::Column::TenantId.eq(tenant_id))
        .filter(article::Column::DeletedAt.is_null());

    if let Some(ref cat) = category {
        query = query.filter(article::Column::Category.eq(cat));
    }
    if let Some(ref s) = status {
        query = query.filter(article::Column::Status.eq(s));
    }
    if let Some(cid) = category_id {
        query = query.filter(article::Column::CategoryId.eq(cid));
    }
    if let Some(ref kw) = keyword {
        query = query.filter(article::Column::Title.contains(kw));
    }

    // 按标签筛选需要子查询
    if let Some(tid) = tag_id {
        let article_ids: Vec<Uuid> = article_article_tag::Entity::find()
            .filter(article_article_tag::Column::TagId.eq(tid))
            .all(&state.db)
            .await?
            .into_iter()
            .map(|r| r.article_id)
            .collect();
        if article_ids.is_empty() {
            return Ok(PaginatedResponse { data: vec![], total: 0, page, page_size: limit, total_pages: 0 });
        }
        query = query.filter(article::Column::Id.is_in(article_ids));
    }

    let total = query.clone().count(&state.db).await?;

    let models = query
        .order_by_desc(article::Column::SortOrder)
        .order_by_desc(article::Column::CreatedAt)
        .offset(offset)
        .limit(limit)
        .all(&state.db)
        .await?;

    let total_pages = total.div_ceil(limit.max(1));
    let mut data = Vec::with_capacity(models.len());
    for m in models {
        let tags = load_article_tags(state, m.id).await?;
        data.push(ArticleListItem {
            id: m.id,
            title: m.title,
            summary: m.summary,
            cover_image: m.cover_image,
            category: m.category,
            author: m.author,
            published_at: m.published_at,
            status: m.status,
            view_count: m.view_count,
            category_id: m.category_id,
            tags,
            version: m.version,
        });
    }

    Ok(PaginatedResponse { data, total, page, page_size: limit, total_pages })
}

/// 获取文章详情（管理端，不过滤发布状态）
pub async fn get_article(
    state: &HealthState,
    tenant_id: Uuid,
    id: Uuid,
) -> HealthResult<ArticleResp> {
    let model = article::Entity::find()
        .filter(article::Column::Id.eq(id))
        .filter(article::Column::TenantId.eq(tenant_id))
        .filter(article::Column::DeletedAt.is_null())
        .one(&state.db)
        .await?
        .ok_or(HealthError::ArticleNotFound)?;

    let tags = load_article_tags(state, model.id).await?;
    Ok(full_model_to_resp(model, tags))
}

// ---------------------------------------------------------------------------
// 审核工作流
// ---------------------------------------------------------------------------

/// 提交审核: draft/rejected → pending_review
pub async fn submit_article(
    state: &HealthState,
    tenant_id: Uuid,
    id: Uuid,
    operator_id: Option<Uuid>,
    expected_version: i32,
) -> HealthResult<ArticleResp> {
    let model = find_article(state, tenant_id, id).await?;
    let next_ver = check_version(expected_version, model.version)
        .map_err(|_| HealthError::VersionMismatch)?;

    validation::validate_article_status_transition(&model.status, "pending_review")?;

    let mut active: article::ActiveModel = model.into();
    active.status = Set("pending_review".into());
    active.updated_at = Set(Utc::now());
    active.updated_by = Set(operator_id);
    active.version = Set(next_ver);
    let m = active.update(&state.db).await?;

    audit_service::record(
        AuditLog::new(tenant_id, operator_id, "article.submitted", "article")
            .with_resource_id(m.id),
        &state.db,
    ).await;

    let tags = load_article_tags(state, m.id).await?;
    Ok(full_model_to_resp(m, tags))
}

/// 审核通过并发布: pending_review → published
pub async fn approve_article(
    state: &HealthState,
    tenant_id: Uuid,
    id: Uuid,
    operator_id: Option<Uuid>,
    req: ReviewArticleReq,
    expected_version: i32,
) -> HealthResult<ArticleResp> {
    let model = find_article(state, tenant_id, id).await?;
    let next_ver = check_version(expected_version, model.version)
        .map_err(|_| HealthError::VersionMismatch)?;

    validation::validate_article_status_transition(&model.status, "published")?;

    let now = Utc::now();
    let mut active: article::ActiveModel = model.into();
    active.status = Set("published".into());
    active.published_at = Set(Some(now));
    active.reviewed_by = Set(operator_id);
    active.reviewed_at = Set(Some(now));
    active.review_note = Set(req.note);
    active.updated_at = Set(now);
    active.updated_by = Set(operator_id);
    active.version = Set(next_ver);
    let m = active.update(&state.db).await?;

    audit_service::record(
        AuditLog::new(tenant_id, operator_id, "article.published", "article")
            .with_resource_id(m.id),
        &state.db,
    ).await;

    state.event_bus.publish(
        DomainEvent::new(crate::event::ARTICLE_PUBLISHED, tenant_id, erp_core::events::build_event_payload(serde_json::json!({
            "article_id": m.id, "title": m.title, "category": m.category,
        }))),
        &state.db,
    ).await;

    let tags = load_article_tags(state, m.id).await?;
    Ok(full_model_to_resp(m, tags))
}

/// 审核拒绝: pending_review → rejected
pub async fn reject_article(
    state: &HealthState,
    tenant_id: Uuid,
    id: Uuid,
    operator_id: Option<Uuid>,
    req: ReviewArticleReq,
    expected_version: i32,
) -> HealthResult<ArticleResp> {
    let model = find_article(state, tenant_id, id).await?;
    let next_ver = check_version(expected_version, model.version)
        .map_err(|_| HealthError::VersionMismatch)?;

    validation::validate_article_status_transition(&model.status, "rejected")?;

    let now = Utc::now();
    let mut active: article::ActiveModel = model.into();
    active.status = Set("rejected".into());
    active.reviewed_by = Set(operator_id);
    active.reviewed_at = Set(Some(now));
    active.review_note = Set(req.note);
    active.updated_at = Set(now);
    active.updated_by = Set(operator_id);
    active.version = Set(next_ver);
    let m = active.update(&state.db).await?;

    audit_service::record(
        AuditLog::new(tenant_id, operator_id, "article.rejected", "article")
            .with_resource_id(m.id),
        &state.db,
    ).await;

    state.event_bus.publish(
        DomainEvent::new(crate::event::ARTICLE_REJECTED, tenant_id, erp_core::events::build_event_payload(serde_json::json!({
            "article_id": m.id, "title": m.title,
        }))),
        &state.db,
    ).await;

    let tags = load_article_tags(state, m.id).await?;
    Ok(full_model_to_resp(m, tags))
}

/// 撤回发布: published → draft
pub async fn unpublish_article(
    state: &HealthState,
    tenant_id: Uuid,
    id: Uuid,
    operator_id: Option<Uuid>,
    expected_version: i32,
) -> HealthResult<ArticleResp> {
    let model = find_article(state, tenant_id, id).await?;
    let next_ver = check_version(expected_version, model.version)
        .map_err(|_| HealthError::VersionMismatch)?;

    validation::validate_article_status_transition(&model.status, "draft")?;

    let mut active: article::ActiveModel = model.into();
    active.status = Set("draft".into());
    active.published_at = Set(None);
    active.updated_at = Set(Utc::now());
    active.updated_by = Set(operator_id);
    active.version = Set(next_ver);
    let m = active.update(&state.db).await?;

    audit_service::record(
        AuditLog::new(tenant_id, operator_id, "article.unpublished", "article")
            .with_resource_id(m.id),
        &state.db,
    ).await;

    let tags = load_article_tags(state, m.id).await?;
    Ok(full_model_to_resp(m, tags))
}

/// 增加浏览计数
pub async fn increment_view_count(
    state: &HealthState,
    tenant_id: Uuid,
    id: Uuid,
) -> HealthResult<()> {
    let model = find_article(state, tenant_id, id).await?;
    let mut active: article::ActiveModel = model.into();
    active.view_count = Set(active.view_count.unwrap() + 1);
    active.updated_at = Set(Utc::now());
    active.update(&state.db).await?;
    Ok(())
}

// ---------------------------------------------------------------------------
// 文章管理（写入）
// ---------------------------------------------------------------------------

pub async fn create_article(
    state: &HealthState,
    tenant_id: Uuid,
    operator_id: Option<Uuid>,
    req: CreateArticleReq,
) -> HealthResult<ArticleResp> {
    let now = Utc::now();

    let active = article::ActiveModel {
        id: Set(Uuid::now_v7()),
        tenant_id: Set(tenant_id),
        title: Set(req.title),
        summary: Set(req.summary),
        content: Set(req.content.unwrap_or_default()),
        cover_image: Set(req.cover_image),
        category: Set(req.category),
        category_id: Set(req.category_id),
        author: Set(req.author),
        published_at: Set(req.published_at),
        status: Set("draft".into()),
        slug: Set(req.slug),
        content_type: Set(req.content_type.unwrap_or_else(|| "rich_text".into())),
        reviewed_by: Set(None),
        reviewed_at: Set(None),
        review_note: Set(None),
        view_count: Set(0),
        sort_order: Set(0),
        created_at: Set(now),
        updated_at: Set(now),
        created_by: Set(operator_id),
        updated_by: Set(operator_id),
        deleted_at: Set(None),
        version: Set(1),
    };
    let m = active.insert(&state.db).await?;

    // 保存标签关联
    save_article_tags(state, m.id, &req.tag_ids).await?;

    audit_service::record(
        AuditLog::new(tenant_id, operator_id, "article.created", "article")
            .with_resource_id(m.id),
        &state.db,
    ).await;

    let tags = load_article_tags(state, m.id).await?;
    Ok(full_model_to_resp(m, tags))
}

pub async fn update_article(
    state: &HealthState,
    tenant_id: Uuid,
    id: Uuid,
    operator_id: Option<Uuid>,
    req: UpdateArticleReq,
) -> HealthResult<ArticleResp> {
    let model = find_article(state, tenant_id, id).await?;

    let next_ver = check_version(req.version, model.version)
        .map_err(|_| HealthError::VersionMismatch)?;

    // 保存版本历史
    save_revision(state, tenant_id, &model, operator_id).await?;

    let mut active: article::ActiveModel = model.into();
    if let Some(v) = req.title { active.title = Set(v); }
    if let Some(v) = req.summary { active.summary = Set(Some(v)); }
    if let Some(v) = req.content { active.content = Set(v); }
    if let Some(v) = req.cover_image { active.cover_image = Set(Some(v)); }
    if let Some(v) = req.category { active.category = Set(Some(v)); }
    if let Some(v) = req.category_id { active.category_id = Set(Some(v)); }
    if let Some(v) = req.author { active.author = Set(Some(v)); }
    if let Some(v) = req.published_at { active.published_at = Set(Some(v)); }
    if let Some(v) = req.slug { active.slug = Set(Some(v)); }
    if let Some(v) = req.content_type { active.content_type = Set(v); }
    if let Some(v) = req.sort_order { active.sort_order = Set(v); }
    active.updated_at = Set(Utc::now());
    active.updated_by = Set(operator_id);
    active.version = Set(next_ver);

    let m = active.update(&state.db).await?;

    // 替换标签关联
    if let Some(tag_ids) = req.tag_ids {
        replace_article_tags(state, m.id, &tag_ids).await?;
    }

    audit_service::record(
        AuditLog::new(tenant_id, operator_id, "article.updated", "article")
            .with_resource_id(m.id),
        &state.db,
    ).await;

    let tags = load_article_tags(state, m.id).await?;
    Ok(full_model_to_resp(m, tags))
}

pub async fn delete_article(
    state: &HealthState,
    tenant_id: Uuid,
    id: Uuid,
    operator_id: Option<Uuid>,
    expected_version: i32,
) -> HealthResult<()> {
    let model = find_article(state, tenant_id, id).await?;

    let next_ver = check_version(expected_version, model.version)
        .map_err(|_| HealthError::VersionMismatch)?;

    let mut active: article::ActiveModel = model.into();
    active.deleted_at = Set(Some(Utc::now()));
    active.updated_at = Set(Utc::now());
    active.updated_by = Set(operator_id);
    active.version = Set(next_ver);
    active.update(&state.db).await?;

    audit_service::record(
        AuditLog::new(tenant_id, operator_id, "article.deleted", "article")
            .with_resource_id(id),
        &state.db,
    ).await;

    Ok(())
}

// ---------------------------------------------------------------------------
// 内部辅助
// ---------------------------------------------------------------------------

async fn find_article(state: &HealthState, tenant_id: Uuid, id: Uuid) -> HealthResult<article::Model> {
    article::Entity::find()
        .filter(article::Column::Id.eq(id))
        .filter(article::Column::TenantId.eq(tenant_id))
        .filter(article::Column::DeletedAt.is_null())
        .one(&state.db)
        .await?
        .ok_or(HealthError::ArticleNotFound)
}

fn full_model_to_resp(m: article::Model, tags: Vec<String>) -> ArticleResp {
    ArticleResp {
        id: m.id,
        title: m.title,
        summary: m.summary,
        content: Some(m.content),
        cover_image: m.cover_image,
        category: m.category,
        author: m.author,
        published_at: m.published_at,
        status: m.status,
        slug: m.slug,
        content_type: m.content_type,
        reviewed_by: m.reviewed_by,
        reviewed_at: m.reviewed_at,
        review_note: m.review_note,
        view_count: m.view_count,
        sort_order: m.sort_order,
        category_id: m.category_id,
        tags,
        created_at: m.created_at,
        updated_at: m.updated_at,
        version: m.version,
    }
}

async fn load_article_tags(state: &HealthState, article_id: Uuid) -> HealthResult<Vec<String>> {
    let relations = article_article_tag::Entity::find()
        .filter(article_article_tag::Column::ArticleId.eq(article_id))
        .all(&state.db)
        .await?;

    let tag_ids: Vec<Uuid> = relations.into_iter().map(|r| r.tag_id).collect();
    if tag_ids.is_empty() {
        return Ok(vec![]);
    }

    let tags = article_tag::Entity::find()
        .filter(article_tag::Column::Id.is_in(tag_ids))
        .filter(article_tag::Column::DeletedAt.is_null())
        .all(&state.db)
        .await?;

    Ok(tags.into_iter().map(|t| t.name).collect())
}

async fn save_article_tags(state: &HealthState, article_id: Uuid, tag_ids: &[Uuid]) -> HealthResult<()> {
    for tid in tag_ids {
        let active = article_article_tag::ActiveModel {
            article_id: Set(article_id),
            tag_id: Set(*tid),
        };
        active.insert(&state.db).await?;
    }
    Ok(())
}

async fn replace_article_tags(state: &HealthState, article_id: Uuid, tag_ids: &[Uuid]) -> HealthResult<()> {
    article_article_tag::Entity::delete_many()
        .filter(article_article_tag::Column::ArticleId.eq(article_id))
        .exec(&state.db)
        .await?;

    save_article_tags(state, article_id, tag_ids).await
}

async fn save_revision(
    state: &HealthState,
    tenant_id: Uuid,
    model: &article::Model,
    operator_id: Option<Uuid>,
) -> HealthResult<()> {
    use crate::entity::article_revision;

    // 获取当前最大版本号
    let max_rev = article_revision::Entity::find()
        .filter(article_revision::Column::ArticleId.eq(model.id))
        .order_by_desc(article_revision::Column::RevisionNumber)
        .one(&state.db)
        .await?;

    let next_rev = max_rev.map(|r| r.revision_number + 1).unwrap_or(1);

    let active = article_revision::ActiveModel {
        id: Set(Uuid::now_v7()),
        tenant_id: Set(tenant_id),
        article_id: Set(model.id),
        revision_number: Set(next_rev),
        title: Set(model.title.clone()),
        content: Set(model.content.clone()),
        summary: Set(model.summary.clone()),
        created_by: Set(operator_id),
        created_at: Set(Utc::now()),
    };
    active.insert(&state.db).await?;
    Ok(())
}