use actix_web::web::{self, Data};
use actix_web::{HttpRequest, HttpResponse};
use deserr::actix_web::{AwebJson, AwebQueryParameter};
use index_scheduler::IndexScheduler;
use meilisearch_types::deserr::query_params::Param;
use meilisearch_types::deserr::{DeserrJsonError, DeserrQueryParamError};
use meilisearch_types::error::deserr_codes::*;
use meilisearch_types::error::ResponseError;
use meilisearch_types::index_uid::IndexUid;
use meilisearch_types::keys::actions;
use meilisearch_types::milli::progress::Progress;
use meilisearch_types::milli::TotalProcessingTimeStep;
use meilisearch_types::serde_cs::vec::CS;
use serde_json::Value;
use tracing::debug;
use utoipa::IntoParams;

use super::ActionPolicy;
use crate::analytics::Analytics;
use crate::extractors::authentication::GuardedData;
use crate::routes::indexes::similar_analytics::{SimilarAggregator, SimilarGET, SimilarPOST};
use crate::search::{
    add_search_rules, perform_similar, RankingScoreThresholdSimilar, SimilarQuery, SimilarResult,
    DEFAULT_SEARCH_LIMIT, DEFAULT_SEARCH_OFFSET,
};

#[routes::routes(
    routes(""=>[get(similar_get), post(similar_post)]),
    tag = "Similar documents",
    tags(
        (
            name = "Similar documents",
            description = "The /similar route uses AI-powered search to return a number of documents similar to a target document.

Meilisearch exposes two routes for retrieving similar documents: POST and GET. In the majority of cases, POST will offer better performance and ease of use.",
        ),
    ),
)]
pub struct SimilarApi;

/// Get similar documents with GET
///
/// Retrieve documents similar to a reference document identified by its id.
///
/// > Useful for “more like this” or recommendations.
#[routes::path(
    security(("Bearer" = ["search", "*"])),
    params(
        ("index_uid" = String, Path, example = "movies", description = "Unique identifier of the index.", nullable = false),
        SimilarQueryGet
    ),
    responses(
        (status = 200, description = "The documents are returned.", body = SimilarResult, content_type = "application/json", example = json!(
            {
              "hits": [
                {
                  "id": 2770,
                  "title": "American Pie 2",
                  "poster": "https://image.tmdb.org/t/p/w1280/q4LNgUnRfltxzp3gf1MAGiK5LhV.jpg",
                  "overview": "The whole gang are back and as close as ever. They decide to get even closer by spending the summer together at a beach house. They decide to hold the biggest…",
                  "release_date": 997405200
                },
                {
                  "id": 190859,
                  "title": "American Sniper",
                  "poster": "https://image.tmdb.org/t/p/w1280/svPHnYE7N5NAGO49dBmRhq0vDQ3.jpg",
                  "overview": "U.S. Navy SEAL Chris Kyle takes his sole mission—protect his comrades—to heart and becomes one of the most lethal snipers in American history. His pinpoint accuracy not only saves countless lives but also makes him a prime…",
                  "release_date": 1418256000
                }
              ],
              "id": "143",
              "offset": 0,
              "limit": 2,
              "estimatedTotalHits": 976,
              "processingTimeMs": 35
            }
        )),
        (status = 404, description = "Index not found.", body = ResponseError, content_type = "application/json", example = json!(
            {
                "message": "Index `movies` not found.",
                "code": "index_not_found",
                "type": "invalid_request",
                "link": "https://docs.meilisearch.com/errors#index_not_found"
            }
        )),
        (status = 401, description = "The authorization header is missing.", body = ResponseError, content_type = "application/json", example = json!(
            {
                "message": "The Authorization header is missing. It must use the bearer authorization method.",
                "code": "missing_authorization_header",
                "type": "auth",
                "link": "https://docs.meilisearch.com/errors#missing_authorization_header"
            }
        )),
    )
)]
pub async fn similar_get(
    index_scheduler: GuardedData<ActionPolicy<{ actions::SEARCH }>, Data<IndexScheduler>>,
    index_uid: web::Path<String>,
    params: AwebQueryParameter<SimilarQueryGet, DeserrQueryParamError>,
    req: HttpRequest,
    analytics: web::Data<Analytics>,
) -> Result<HttpResponse, ResponseError> {
    let index_uid = IndexUid::try_from(index_uid.into_inner())?;

    let query = params.0.into();

    let mut aggregate = SimilarAggregator::<SimilarGET>::from_query(&query);

    debug!(parameters = ?query, "Similar get");

    let similar = similar(index_scheduler, index_uid, query).await;

    if let Ok(similar) = &similar {
        aggregate.succeed(similar);
    }
    analytics.publish(aggregate, &req);

    let similar = similar?;

    debug!(returns = ?similar, "Similar get");
    Ok(HttpResponse::Ok().json(similar))
}

/// Get similar documents with POST
///
/// Retrieve documents similar to a reference document identified by its id.
///
/// > Useful for “more like this” or recommendations.
#[routes::path(
    security(("Bearer" = ["search", "*"])),
    params(("index_uid" = String, Path, example = "movies", description = "Unique identifier of the index.", nullable = false)),
    request_body = SimilarQuery,
    responses(
        (status = 200, description = "The documents are returned.", body = SimilarResult, content_type = "application/json", example = json!(
            {
              "hits": [
                {
                  "id": 2770,
                  "title": "American Pie 2",
                  "poster": "https://image.tmdb.org/t/p/w1280/q4LNgUnRfltxzp3gf1MAGiK5LhV.jpg",
                  "overview": "The whole gang are back and as close as ever. They decide to get even closer by spending the summer together at a beach house. They decide to hold the biggest…",
                  "release_date": 997405200
                },
                {
                  "id": 190859,
                  "title": "American Sniper",
                  "poster": "https://image.tmdb.org/t/p/w1280/svPHnYE7N5NAGO49dBmRhq0vDQ3.jpg",
                  "overview": "U.S. Navy SEAL Chris Kyle takes his sole mission—protect his comrades—to heart and becomes one of the most lethal snipers in American history. His pinpoint accuracy not only saves countless lives but also makes him a prime…",
                  "release_date": 1418256000
                }
              ],
              "id": "143",
              "offset": 0,
              "limit": 2,
              "estimatedTotalHits": 976,
              "processingTimeMs": 35
            }
        )),
        (status = 404, description = "Index not found.", body = ResponseError, content_type = "application/json", example = json!(
            {
                "message": "Index `movies` not found.",
                "code": "index_not_found",
                "type": "invalid_request",
                "link": "https://docs.meilisearch.com/errors#index_not_found"
            }
        )),
        (status = 401, description = "The authorization header is missing.", body = ResponseError, content_type = "application/json", example = json!(
            {
                "message": "The Authorization header is missing. It must use the bearer authorization method.",
                "code": "missing_authorization_header",
                "type": "auth",
                "link": "https://docs.meilisearch.com/errors#missing_authorization_header"
            }
        )),
    )
)]
pub async fn similar_post(
    index_scheduler: GuardedData<ActionPolicy<{ actions::SEARCH }>, Data<IndexScheduler>>,
    index_uid: web::Path<String>,
    params: AwebJson<SimilarQuery, DeserrJsonError>,
    req: HttpRequest,
    analytics: web::Data<Analytics>,
) -> Result<HttpResponse, ResponseError> {
    let index_uid = IndexUid::try_from(index_uid.into_inner())?;

    let query = params.into_inner();
    debug!(parameters = ?query, "Similar post");

    let mut aggregate = SimilarAggregator::<SimilarPOST>::from_query(&query);

    let similar = similar(index_scheduler, index_uid, query).await;

    if let Ok(similar) = &similar {
        aggregate.succeed(similar);
    }
    analytics.publish(aggregate, &req);

    let similar = similar?;

    debug!(returns = ?similar, "Similar post");
    Ok(HttpResponse::Ok().json(similar))
}

async fn similar(
    index_scheduler: GuardedData<ActionPolicy<{ actions::SEARCH }>, Data<IndexScheduler>>,
    index_uid: IndexUid,
    mut query: SimilarQuery,
) -> Result<SimilarResult, ResponseError> {
    let progress = Progress::default();
    // Tenant token search_rules.
    if let Some(search_rules) = index_scheduler.filters().get_index_search_rules(&index_uid) {
        add_search_rules(&mut query.filter, search_rules);
    }

    let progress_clone = progress.clone();
    let result = tokio::task::spawn_blocking(move || {
        let _step = progress_clone.update_progress_scoped(TotalProcessingTimeStep::Search);

        perform_similar(&index_scheduler, index_uid, query, &progress_clone)
    })
    .await;

    debug!(progress = ?progress.accumulated_durations(), "Similar");

    result?
}

#[derive(Debug, deserr::Deserr, IntoParams)]
#[deserr(error = DeserrQueryParamError, rename_all = camelCase, deny_unknown_fields)]
#[into_params(parameter_in = Query)]
pub struct SimilarQueryGet {
    /// The unique identifier ([primary key](https://www.meilisearch.com/docs/learn/getting_started/primary_key) value) of the target document.
    /// Meilisearch will find and return documents that are semantically
    /// similar to this document based on their vector embeddings. This is a
    /// required parameter.
    #[deserr(error = DeserrQueryParamError<InvalidSimilarId>)]
    #[param(required = true, value_type = String)]
    id: Param<String>,
    /// The name of the embedder to use for finding similar documents. This
    /// must match one of the embedders configured in your index settings. The
    /// embedder determines how document similarity is calculated based on
    /// vector embeddings.
    #[param(required = true)]
    #[deserr(error = DeserrQueryParamError<InvalidSimilarEmbedder>)]
    pub embedder: String,
    /// Number of similar documents to skip in the response. Use together with
    /// `limit` for pagination through large result sets. For example, to get
    /// similar documents 21-40, set `offset=20` and `limit=20`. Defaults to
    /// `0`.
    #[deserr(default = Param(DEFAULT_SEARCH_OFFSET()), error = DeserrQueryParamError<InvalidSimilarOffset>)]
    #[param(required = false, value_type = usize, default = DEFAULT_SEARCH_OFFSET)]
    offset: Param<usize>,
    /// Maximum number of similar documents to return in a single response. Use
    /// together with `offset` for pagination. Higher values return more
    /// results but may increase response time. Defaults to `20`.
    #[deserr(default = Param(DEFAULT_SEARCH_LIMIT()), error = DeserrQueryParamError<InvalidSimilarLimit>)]
    #[param(required = false, value_type = usize, default = DEFAULT_SEARCH_LIMIT)]
    limit: Param<usize>,
    /// Comma-separated list of document attributes to include in the response.
    /// Use `*` to retrieve all attributes. By default, all attributes listed
    /// in the `displayedAttributes` setting are returned. Example:
    /// `title,description,price`.
    #[deserr(default, error = DeserrQueryParamError<InvalidSimilarAttributesToRetrieve>)]
    #[param(required = false, value_type = Vec<String>)]
    attributes_to_retrieve: Option<CS<String>>,
    /// When `true`, includes the vector embeddings for each returned document.
    /// Useful for debugging or when you need to inspect the vector data. Note
    /// that this can significantly increase response size. Defaults to
    /// `false`.
    #[deserr(default, error = DeserrQueryParamError<InvalidSimilarRetrieveVectors>)]
    #[param(required = false, value_type = bool, default)]
    retrieve_vectors: Param<bool>,
    /// Filter expression to narrow down which documents can be returned as
    /// similar. Uses the same syntax as search filters. Only documents
    /// matching this filter will be considered when finding similar documents.
    /// Example: `genres = action AND year > 2000`.
    #[param(required = false)]
    #[deserr(default, error = DeserrQueryParamError<InvalidSimilarFilter>)]
    filter: Option<String>,
    /// When `true`, includes a global `_rankingScore` field in each document
    /// showing how similar it is to the target document. The score is a value
    /// between 0 and 1, where higher values indicate greater similarity.
    /// Defaults to `false`.
    #[deserr(default, error = DeserrQueryParamError<InvalidSimilarShowRankingScore>)]
    #[param(required = false, value_type = bool, default)]
    show_ranking_score: Param<bool>,
    /// When `true`, includes a detailed `_rankingScoreDetails` object in each
    /// document breaking down how the similarity score was calculated. Useful
    /// for debugging and understanding why certain documents are considered
    /// more similar. Defaults to `false`.
    #[deserr(default, error = DeserrQueryParamError<InvalidSimilarShowRankingScoreDetails>)]
    #[param(required = false, value_type = bool, default)]
    show_ranking_score_details: Param<bool>,
    /// When `true`, includes a `_performanceDetails` object showing the
    /// performance details of the search.
    #[deserr(default, error = DeserrQueryParamError<InvalidSimilarShowPerformanceDetails>)]
    #[param(required = false, value_type = bool, default)]
    show_performance_details: Param<bool>,
    /// Minimum ranking score threshold (between 0.0 and 1.0) that documents
    /// must meet to be included in results. Documents with a similarity score
    /// below this threshold will be excluded. Useful for ensuring only highly
    /// similar documents are returned.
    #[deserr(default, error = DeserrQueryParamError<InvalidSimilarRankingScoreThreshold>, default)]
    #[param(required = false, value_type = Option<f32>)]
    pub ranking_score_threshold: Option<RankingScoreThresholdGet>,
}

#[derive(Debug, Clone, Copy, PartialEq, deserr::Deserr)]
#[deserr(try_from(String) = TryFrom::try_from -> InvalidSimilarRankingScoreThreshold)]
pub struct RankingScoreThresholdGet(RankingScoreThresholdSimilar);

impl std::convert::TryFrom<String> for RankingScoreThresholdGet {
    type Error = InvalidSimilarRankingScoreThreshold;

    fn try_from(s: String) -> Result<Self, Self::Error> {
        let f: f64 = s.parse().map_err(|_| InvalidSimilarRankingScoreThreshold)?;
        Ok(RankingScoreThresholdGet(RankingScoreThresholdSimilar::try_from(f)?))
    }
}

impl From<SimilarQueryGet> for SimilarQuery {
    fn from(
        SimilarQueryGet {
            id,
            offset,
            limit,
            attributes_to_retrieve,
            retrieve_vectors,
            filter,
            show_ranking_score,
            show_ranking_score_details,
            show_performance_details,
            embedder,
            ranking_score_threshold,
        }: SimilarQueryGet,
    ) -> Self {
        let filter = match filter {
            Some(f) => match serde_json::from_str(&f) {
                Ok(v) => Some(v),
                _ => Some(Value::String(f)),
            },
            None => None,
        };

        SimilarQuery {
            id: serde_json::Value::String(id.0),
            offset: offset.0,
            limit: limit.0,
            filter,
            embedder,
            attributes_to_retrieve: attributes_to_retrieve.map(|o| o.into_iter().collect()),
            retrieve_vectors: retrieve_vectors.0,
            show_ranking_score: show_ranking_score.0,
            show_ranking_score_details: show_ranking_score_details.0,
            show_performance_details: show_performance_details.0,
            ranking_score_threshold: ranking_score_threshold.map(|x| x.0),
        }
    }
}
