use axum::{
  Json,
  Router,
  extract::{Extension, Path, Query, State},
  http::StatusCode,
  response::IntoResponse,
  routing::{get, put},
};
use pinakes_core::{
  error::PinakesError,
  model::{
    AuthorInfo,
    BookMetadata,
    MediaId,
    Pagination,
    ReadingProgress,
    ReadingStatus,
  },
};
use serde::{Deserialize, Serialize};
use uuid::Uuid;

use crate::{
  auth::resolve_user_id,
  dto::MediaResponse,
  error::ApiError,
  state::AppState,
};

/// Book metadata response DTO
#[derive(Debug, Serialize, Deserialize)]
pub struct BookMetadataResponse {
  pub media_id:         Uuid,
  pub isbn:             Option<String>,
  pub isbn13:           Option<String>,
  pub publisher:        Option<String>,
  pub language:         Option<String>,
  pub page_count:       Option<i32>,
  pub publication_date: Option<String>,
  pub series_name:      Option<String>,
  pub series_index:     Option<f64>,
  pub format:           Option<String>,
  pub authors:          Vec<AuthorResponse>,
  pub identifiers:      std::collections::HashMap<String, Vec<String>>,
}

impl From<BookMetadata> for BookMetadataResponse {
  fn from(meta: BookMetadata) -> Self {
    Self {
      media_id:         meta.media_id.0,
      isbn:             meta.isbn,
      isbn13:           meta.isbn13,
      publisher:        meta.publisher,
      language:         meta.language,
      page_count:       meta.page_count,
      publication_date: meta.publication_date.map(|d| d.to_string()),
      series_name:      meta.series_name,
      series_index:     meta.series_index,
      format:           meta.format,
      authors:          meta
        .authors
        .into_iter()
        .map(AuthorResponse::from)
        .collect(),
      identifiers:      meta.identifiers,
    }
  }
}

/// Author response DTO
#[derive(Debug, Serialize, Deserialize)]
pub struct AuthorResponse {
  pub name:     String,
  pub role:     String,
  pub file_as:  Option<String>,
  pub position: i32,
}

impl From<AuthorInfo> for AuthorResponse {
  fn from(author: AuthorInfo) -> Self {
    Self {
      name:     author.name,
      role:     author.role,
      file_as:  author.file_as,
      position: author.position,
    }
  }
}

/// Reading progress response DTO
#[derive(Debug, Serialize, Deserialize)]
pub struct ReadingProgressResponse {
  pub media_id:         Uuid,
  pub user_id:          Uuid,
  pub current_page:     i32,
  pub total_pages:      Option<i32>,
  pub progress_percent: f64,
  pub last_read_at:     String,
}

impl From<ReadingProgress> for ReadingProgressResponse {
  fn from(progress: ReadingProgress) -> Self {
    Self {
      media_id:         progress.media_id.0,
      user_id:          progress.user_id,
      current_page:     progress.current_page,
      total_pages:      progress.total_pages,
      progress_percent: progress.progress_percent,
      last_read_at:     progress.last_read_at.to_rfc3339(),
    }
  }
}

/// Update reading progress request
#[derive(Debug, Deserialize)]
pub struct UpdateProgressRequest {
  pub current_page: i32,
}

/// Search books query parameters
#[derive(Debug, Deserialize)]
pub struct SearchBooksQuery {
  pub isbn:      Option<String>,
  pub author:    Option<String>,
  pub series:    Option<String>,
  pub publisher: Option<String>,
  pub language:  Option<String>,
  #[serde(default = "default_offset")]
  pub offset:    u64,
  #[serde(default = "default_limit")]
  pub limit:     u64,
}

const fn default_offset() -> u64 {
  0
}

const fn default_limit() -> u64 {
  50
}

/// Series summary DTO
#[derive(Debug, Serialize)]
pub struct SeriesSummary {
  pub name:       String,
  pub book_count: u64,
}

/// Author summary DTO
#[derive(Debug, Serialize)]
pub struct AuthorSummary {
  pub name:       String,
  pub book_count: u64,
}

/// Get book metadata by media ID
pub async fn get_book_metadata(
  State(state): State<AppState>,
  Path(media_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiError> {
  let media_id = MediaId(media_id);
  let metadata =
    state
      .storage
      .get_book_metadata(media_id)
      .await?
      .ok_or(ApiError(PinakesError::NotFound(
        "Book metadata not found".to_string(),
      )))?;

  Ok(Json(BookMetadataResponse::from(metadata)))
}

/// List all books with optional search filters
pub async fn list_books(
  State(state): State<AppState>,
  Query(query): Query<SearchBooksQuery>,
) -> Result<impl IntoResponse, ApiError> {
  let pagination = Pagination {
    offset: query.offset,
    limit:  query.limit.min(1000),
    sort:   None,
  };

  let items = state
    .storage
    .search_books(
      query.isbn.as_deref(),
      query.author.as_deref(),
      query.series.as_deref(),
      query.publisher.as_deref(),
      query.language.as_deref(),
      &pagination,
    )
    .await?;

  let roots = state.config.read().await.directories.roots.clone();
  let response: Vec<MediaResponse> = items
    .into_iter()
    .map(|item| MediaResponse::new(item, &roots))
    .collect();
  Ok(Json(response))
}

/// List all series with book counts
pub async fn list_series(
  State(state): State<AppState>,
) -> Result<impl IntoResponse, ApiError> {
  let series = state.storage.list_series().await?;
  let response: Vec<SeriesSummary> = series
    .into_iter()
    .map(|(name, count)| {
      SeriesSummary {
        name,
        book_count: count,
      }
    })
    .collect();

  Ok(Json(response))
}

/// Get books in a specific series
pub async fn get_series_books(
  State(state): State<AppState>,
  Path(series_name): Path<String>,
) -> Result<impl IntoResponse, ApiError> {
  let items = state.storage.get_series_books(&series_name).await?;
  let roots = state.config.read().await.directories.roots.clone();
  let response: Vec<MediaResponse> = items
    .into_iter()
    .map(|item| MediaResponse::new(item, &roots))
    .collect();
  Ok(Json(response))
}

/// List all authors with book counts
pub async fn list_authors(
  State(state): State<AppState>,
  Query(pagination): Query<Pagination>,
) -> Result<impl IntoResponse, ApiError> {
  let authors = state.storage.list_all_authors(&pagination).await?;
  let response: Vec<AuthorSummary> = authors
    .into_iter()
    .map(|(name, count)| {
      AuthorSummary {
        name,
        book_count: count,
      }
    })
    .collect();

  Ok(Json(response))
}

/// Get books by a specific author
pub async fn get_author_books(
  State(state): State<AppState>,
  Path(author_name): Path<String>,
  Query(pagination): Query<Pagination>,
) -> Result<impl IntoResponse, ApiError> {
  let items = state
    .storage
    .search_books(None, Some(&author_name), None, None, None, &pagination)
    .await?;

  let roots = state.config.read().await.directories.roots.clone();
  let response: Vec<MediaResponse> = items
    .into_iter()
    .map(|item| MediaResponse::new(item, &roots))
    .collect();
  Ok(Json(response))
}

/// Get reading progress for a book
pub async fn get_reading_progress(
  State(state): State<AppState>,
  Extension(username): Extension<String>,
  Path(media_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiError> {
  let user_id = resolve_user_id(&state.storage, &username).await?;
  let media_id = MediaId(media_id);

  let progress = state
    .storage
    .get_reading_progress(user_id.0, media_id)
    .await?
    .ok_or(ApiError(PinakesError::NotFound(
      "Reading progress not found".to_string(),
    )))?;

  Ok(Json(ReadingProgressResponse::from(progress)))
}

/// Update reading progress for a book
pub async fn update_reading_progress(
  State(state): State<AppState>,
  Extension(username): Extension<String>,
  Path(media_id): Path<Uuid>,
  Json(req): Json<UpdateProgressRequest>,
) -> Result<impl IntoResponse, ApiError> {
  if req.current_page < 0 {
    return Err(ApiError::bad_request("current_page must be non-negative"));
  }
  let user_id = resolve_user_id(&state.storage, &username).await?;
  let media_id = MediaId(media_id);

  state
    .storage
    .update_reading_progress(user_id.0, media_id, req.current_page)
    .await?;

  Ok(StatusCode::NO_CONTENT)
}

/// Get user's reading list
pub async fn get_reading_list(
  State(state): State<AppState>,
  Extension(username): Extension<String>,
  Query(params): Query<ReadingListQuery>,
) -> Result<impl IntoResponse, ApiError> {
  let user_id = resolve_user_id(&state.storage, &username).await?;

  let items = state
    .storage
    .get_reading_list(user_id.0, params.status)
    .await?;

  let roots = state.config.read().await.directories.roots.clone();
  let response: Vec<MediaResponse> = items
    .into_iter()
    .map(|item| MediaResponse::new(item, &roots))
    .collect();
  Ok(Json(response))
}

#[derive(Debug, Deserialize)]
pub struct ReadingListQuery {
  pub status: Option<ReadingStatus>,
}

/// Build the books router
pub fn routes() -> Router<AppState> {
  Router::new()
        // Metadata routes
        .route("/{id}/metadata", get(get_book_metadata))
        // Browse routes
        .route("/", get(list_books))
        .route("/series", get(list_series))
        .route("/series/{name}", get(get_series_books))
        .route("/authors", get(list_authors))
        .route("/authors/{name}/books", get(get_author_books))
        // Reading progress routes
        .route("/{id}/progress", get(get_reading_progress))
        .route("/{id}/progress", put(update_reading_progress))
        .route("/reading-list", get(get_reading_list))
}