//! `/api/v1/admin/groups/{id}/{kv,docs,files}*` — read-only operator inspection
//! of a group's §11.6 SHARED collections (M4). Mirrors the per-app `kv_api` /
//! `files_api` admin surface for groups so `pic {kv,docs,files} ls --group` (and
//! a future dashboard tab) can browse shared data without a script.
//!
//! **Read-only by design** — shared writes go through the SDK
//! (`kv::shared_collection(...)` etc.), which run the reads-open / writes-authed
//! authz + fire `shared = true` triggers; an admin write would bypass both. The
//! deferral (operator write/delete on shared blobs) stands.
//!
//! Capabilities: `GroupKvRead` / `GroupDocsRead` / `GroupFilesRead`, resolved
//! against the group loaded from the path (the same tier the SDK read path uses).

use std::sync::Arc;

use axum::extract::{Path, Query, State};
use axum::http::header::{CONTENT_LENGTH, CONTENT_TYPE};
use axum::response::{IntoResponse, Json, Response};
use axum::routing::get;
use axum::{Extension, Router};
use picloud_shared::{GroupId, Principal};
use serde::{Deserialize, Serialize};
use serde_json::json;
use uuid::Uuid;

use crate::authz::{require, AuthzDenied, AuthzRepo, Capability};
use crate::group_docs_repo::GroupDocsRepo;
use crate::group_files_repo::GroupFilesRepo;
use crate::group_kv_repo::GroupKvRepo;
use crate::group_repo::GroupRepository;

#[derive(Clone)]
pub struct GroupBlobsState {
    pub kv: Arc<dyn GroupKvRepo>,
    pub docs: Arc<dyn GroupDocsRepo>,
    pub files: Arc<dyn GroupFilesRepo>,
    pub groups: Arc<dyn GroupRepository>,
    pub authz: Arc<dyn AuthzRepo>,
}

pub fn group_blobs_router(state: GroupBlobsState) -> Router {
    Router::new()
        .route("/groups/{id}/kv", get(list_kv))
        .route("/groups/{id}/kv/{collection}/{key}", get(get_kv))
        .route("/groups/{id}/docs", get(list_docs))
        .route("/groups/{id}/docs/{collection}/{doc_id}", get(get_doc))
        .route("/groups/{id}/files", get(list_files))
        .route("/groups/{id}/files/{collection}/{file_id}", get(get_file))
        .with_state(state)
}

#[derive(Debug, Deserialize)]
pub struct ListQuery {
    pub collection: String,
    #[serde(default)]
    pub cursor: Option<String>,
    #[serde(default)]
    pub limit: Option<u32>,
}

#[derive(Debug, Serialize)]
struct ListKeysResponse {
    keys: Vec<String>,
    next_cursor: Option<String>,
}

async fn list_kv(
    State(s): State<GroupBlobsState>,
    Extension(principal): Extension<Principal>,
    Path(ident): Path<String>,
    Query(q): Query<ListQuery>,
) -> Result<Json<ListKeysResponse>, GroupBlobsError> {
    let group_id = resolve_group(&*s.groups, &ident).await?;
    require(
        s.authz.as_ref(),
        &principal,
        Capability::GroupKvRead(group_id),
    )
    .await?;
    let page =
        s.kv.list(
            group_id,
            &q.collection,
            q.cursor.as_deref(),
            q.limit.unwrap_or(0),
        )
        .await
        .map_err(|e| GroupBlobsError::Backend(e.to_string()))?;
    Ok(Json(ListKeysResponse {
        keys: page.keys,
        next_cursor: page.next_cursor,
    }))
}

async fn get_kv(
    State(s): State<GroupBlobsState>,
    Extension(principal): Extension<Principal>,
    Path((ident, collection, key)): Path<(String, String, String)>,
) -> Result<Json<serde_json::Value>, GroupBlobsError> {
    let group_id = resolve_group(&*s.groups, &ident).await?;
    require(
        s.authz.as_ref(),
        &principal,
        Capability::GroupKvRead(group_id),
    )
    .await?;
    let value =
        s.kv.get(group_id, &collection, &key)
            .await
            .map_err(|e| GroupBlobsError::Backend(e.to_string()))?
            .ok_or(GroupBlobsError::NotFound)?;
    Ok(Json(json!({ "value": value })))
}

#[derive(Debug, Serialize)]
struct DocEntry {
    id: String,
    data: serde_json::Value,
}

#[derive(Debug, Serialize)]
struct ListDocsResponse {
    docs: Vec<DocEntry>,
    next_cursor: Option<String>,
}

async fn list_docs(
    State(s): State<GroupBlobsState>,
    Extension(principal): Extension<Principal>,
    Path(ident): Path<String>,
    Query(q): Query<ListQuery>,
) -> Result<Json<ListDocsResponse>, GroupBlobsError> {
    let group_id = resolve_group(&*s.groups, &ident).await?;
    require(
        s.authz.as_ref(),
        &principal,
        Capability::GroupDocsRead(group_id),
    )
    .await?;
    let page = s
        .docs
        .list(
            group_id,
            &q.collection,
            q.cursor.as_deref(),
            q.limit.unwrap_or(0),
        )
        .await
        .map_err(|e| GroupBlobsError::Backend(e.to_string()))?;
    Ok(Json(ListDocsResponse {
        docs: page
            .docs
            .into_iter()
            .map(|d| DocEntry {
                id: d.id.to_string(),
                data: d.data,
            })
            .collect(),
        next_cursor: page.next_cursor,
    }))
}

async fn get_doc(
    State(s): State<GroupBlobsState>,
    Extension(principal): Extension<Principal>,
    Path((ident, collection, doc_id)): Path<(String, String, String)>,
) -> Result<Json<serde_json::Value>, GroupBlobsError> {
    let group_id = resolve_group(&*s.groups, &ident).await?;
    require(
        s.authz.as_ref(),
        &principal,
        Capability::GroupDocsRead(group_id),
    )
    .await?;
    let id = doc_id
        .parse::<Uuid>()
        .map_err(|_| GroupBlobsError::NotFound)?;
    let row = s
        .docs
        .get(group_id, &collection, id)
        .await
        .map_err(|e| GroupBlobsError::Backend(e.to_string()))?
        .ok_or(GroupBlobsError::NotFound)?;
    Ok(Json(json!({ "id": row.id.to_string(), "data": row.data })))
}

async fn list_files(
    State(s): State<GroupBlobsState>,
    Extension(principal): Extension<Principal>,
    Path(ident): Path<String>,
    Query(q): Query<ListQuery>,
) -> Result<Json<serde_json::Value>, GroupBlobsError> {
    let group_id = resolve_group(&*s.groups, &ident).await?;
    require(
        s.authz.as_ref(),
        &principal,
        Capability::GroupFilesRead(group_id),
    )
    .await?;
    let page = s
        .files
        .list(
            group_id,
            &q.collection,
            q.cursor.as_deref(),
            q.limit.unwrap_or(0),
        )
        .await
        .map_err(|e| GroupBlobsError::Backend(e.to_string()))?;
    // FileMeta is Serialize; return the metadata list + cursor.
    Ok(Json(json!({
        "files": page.files,
        "next_cursor": page.next_cursor,
    })))
}

async fn get_file(
    State(s): State<GroupBlobsState>,
    Extension(principal): Extension<Principal>,
    Path((ident, collection, file_id)): Path<(String, String, String)>,
) -> Result<Response, GroupBlobsError> {
    let group_id = resolve_group(&*s.groups, &ident).await?;
    require(
        s.authz.as_ref(),
        &principal,
        Capability::GroupFilesRead(group_id),
    )
    .await?;
    let id = file_id
        .parse::<Uuid>()
        .map_err(|_| GroupBlobsError::NotFound)?;
    let meta = s
        .files
        .head(group_id, &collection, id)
        .await
        .map_err(|e| GroupBlobsError::Backend(e.to_string()))?
        .ok_or(GroupBlobsError::NotFound)?;
    let bytes = s
        .files
        .get(group_id, &collection, id)
        .await
        .map_err(|e| GroupBlobsError::Backend(e.to_string()))?
        .ok_or(GroupBlobsError::NotFound)?;
    Ok((
        [
            (CONTENT_TYPE, meta.content_type),
            (CONTENT_LENGTH, bytes.len().to_string()),
        ],
        bytes,
    )
        .into_response())
}

async fn resolve_group(
    groups: &dyn GroupRepository,
    ident: &str,
) -> Result<GroupId, GroupBlobsError> {
    let found = if let Ok(uuid) = ident.parse::<Uuid>() {
        groups
            .get_by_id(uuid.into())
            .await
            .map_err(|e| GroupBlobsError::Backend(e.to_string()))?
    } else {
        groups
            .get_by_slug(ident)
            .await
            .map_err(|e| GroupBlobsError::Backend(e.to_string()))?
    };
    found.map(|g| g.id).ok_or(GroupBlobsError::GroupNotFound)
}

#[derive(Debug, thiserror::Error)]
pub enum GroupBlobsError {
    #[error("group not found")]
    GroupNotFound,
    #[error("not found")]
    NotFound,
    #[error("forbidden")]
    Forbidden,
    #[error("authorization repo error: {0}")]
    AuthzRepo(String),
    #[error("backend: {0}")]
    Backend(String),
}

impl From<AuthzDenied> for GroupBlobsError {
    fn from(d: AuthzDenied) -> Self {
        match d {
            AuthzDenied::Denied => Self::Forbidden,
            AuthzDenied::Repo(e) => Self::AuthzRepo(e.to_string()),
        }
    }
}

impl IntoResponse for GroupBlobsError {
    fn into_response(self) -> Response {
        use axum::http::StatusCode;
        let (status, body) = match &self {
            Self::GroupNotFound | Self::NotFound => {
                (StatusCode::NOT_FOUND, json!({ "error": self.to_string() }))
            }
            Self::Forbidden => (StatusCode::FORBIDDEN, json!({ "error": self.to_string() })),
            Self::AuthzRepo(e) | Self::Backend(e) => {
                tracing::error!(error = %e, "group blobs admin error");
                (
                    StatusCode::INTERNAL_SERVER_ERROR,
                    json!({ "error": "internal error" }),
                )
            }
        };
        (status, Json(body)).into_response()
    }
}