use async_trait::async_trait;

use domain::{
    Collection, ContentType, DomainError, DomainResult, IMediaProvider, MediaFilter, MediaItem,
    MediaItemId, ProviderCapabilities, SeriesSummary, StreamQuality, StreamingProtocol,
};

use super::config::JellyfinConfig;
use super::mapping::{map_jellyfin_item, TICKS_PER_SEC};
use super::models::{jellyfin_item_type, JellyfinItemsResponse, JellyfinPlaybackInfoResponse};

pub struct JellyfinMediaProvider {
    pub(super) client: reqwest::Client,
    pub(super) config: JellyfinConfig,
}

impl JellyfinMediaProvider {
    pub fn new(config: JellyfinConfig) -> Self {
        Self {
            client: reqwest::Client::new(),
            config: JellyfinConfig {
                base_url: config.base_url.trim_end_matches('/').to_string(),
                ..config
            },
        }
    }

    /// Inner fetch: applies all filter fields plus an optional series name override.
    async fn fetch_items_for_series(
        &self,
        filter: &MediaFilter,
        series_name: Option<&str>,
    ) -> DomainResult<Vec<MediaItem>> {
        let url = format!(
            "{}/Users/{}/Items",
            self.config.base_url, self.config.user_id
        );

        let mut params: Vec<(&str, String)> = vec![
            ("Recursive", "true".into()),
            ("Fields", "Genres,Tags,RunTimeTicks,ProductionYear,Overview".into()),
        ];

        if let Some(ct) = &filter.content_type {
            params.push(("IncludeItemTypes", jellyfin_item_type(ct).into()));
        }

        if !filter.genres.is_empty() {
            params.push(("Genres", filter.genres.join("|")));
        }

        if let Some(decade) = filter.decade {
            params.push(("MinYear", decade.to_string()));
            params.push(("MaxYear", (decade + 9).to_string()));
        }

        if !filter.tags.is_empty() {
            params.push(("Tags", filter.tags.join("|")));
        }

        if let Some(min) = filter.min_duration_secs {
            params.push(("MinRunTimeTicks", (min as i64 * TICKS_PER_SEC).to_string()));
        }
        if let Some(max) = filter.max_duration_secs {
            params.push(("MaxRunTimeTicks", (max as i64 * TICKS_PER_SEC).to_string()));
        }

        if let Some(name) = series_name {
            // Series-level targeting: skip ParentId so the show is found regardless
            // of which library it lives in. SeriesName is already precise enough.
            params.push(("SeriesName", name.to_string()));
            // Return episodes in chronological order when a specific series is
            // requested — season first, then episode within the season.
            params.push(("SortBy", "ParentIndexNumber,IndexNumber".into()));
            params.push(("SortOrder", "Ascending".into()));
        } else {
            // No series filter — scope to the collection (library) if one is set.
            if let Some(parent_id) = filter.collections.first() {
                params.push(("ParentId", parent_id.clone()));
            }
        }

        if let Some(q) = &filter.search_term {
            params.push(("SearchTerm", q.clone()));
        }

        let response = self
            .client
            .get(&url)
            .header("X-Emby-Token", &self.config.api_key)
            .query(&params)
            .send()
            .await
            .map_err(|e| {
                DomainError::InfrastructureError(format!("Jellyfin request failed: {}", e))
            })?;

        if !response.status().is_success() {
            return Err(DomainError::InfrastructureError(format!(
                "Jellyfin returned HTTP {}",
                response.status()
            )));
        }

        let body: JellyfinItemsResponse = response.json().await.map_err(|e| {
            DomainError::InfrastructureError(format!("Failed to parse Jellyfin response: {}", e))
        })?;

        // Jellyfin's SeriesName query param is not a strict filter — it can
        // bleed items from other shows. Post-filter in Rust to guarantee that
        // only the requested series is returned.
        let items = body.items.into_iter().filter_map(map_jellyfin_item);
        let items: Vec<MediaItem> = if let Some(name) = series_name {
            items
                .filter(|item| {
                    item.series_name
                        .as_deref()
                        .map(|s| s.eq_ignore_ascii_case(name))
                        .unwrap_or(false)
                })
                .collect()
        } else {
            items.collect()
        };

        Ok(items)
    }
}

#[async_trait]
impl IMediaProvider for JellyfinMediaProvider {
    fn capabilities(&self) -> ProviderCapabilities {
        ProviderCapabilities {
            collections: true,
            series: true,
            genres: true,
            tags: true,
            decade: true,
            search: true,
            streaming_protocol: StreamingProtocol::Hls,
            rescan: false,
        }
    }

    /// Fetch items matching `filter` from the Jellyfin library.
    ///
    /// When `series_names` has more than one entry the results from each series
    /// are fetched sequentially and concatenated (Jellyfin only supports one
    /// `SeriesName` param per request).
    async fn fetch_items(&self, filter: &MediaFilter) -> DomainResult<Vec<MediaItem>> {
        match filter.series_names.len() {
            0 | 1 => {
                let series = filter.series_names.first().map(String::as_str);
                self.fetch_items_for_series(filter, series).await
            }
            _ => {
                // Fetch each series independently, then interleave round-robin.
                // Round-robin ensures every show gets fair representation when a
                // downstream limit is applied (preview, block fill) even if one
                // series has far more episodes than another.
                let mut per_series: Vec<Vec<MediaItem>> = Vec::new();
                for series_name in &filter.series_names {
                    let items = self
                        .fetch_items_for_series(filter, Some(series_name.as_str()))
                        .await?;
                    if !items.is_empty() {
                        per_series.push(items);
                    }
                }
                let max_len = per_series.iter().map(|s| s.len()).max().unwrap_or(0);
                let mut all = Vec::with_capacity(per_series.iter().map(|s| s.len()).sum());
                for i in 0..max_len {
                    for s in &per_series {
                        if let Some(item) = s.get(i) {
                            all.push(item.clone());
                        }
                    }
                }
                Ok(all)
            }
        }
    }

    /// Fetch a single item by its opaque ID.
    ///
    /// Returns `None` if the item is not found or cannot be mapped.
    async fn fetch_by_id(&self, item_id: &MediaItemId) -> DomainResult<Option<MediaItem>> {
        let url = format!(
            "{}/Users/{}/Items",
            self.config.base_url, self.config.user_id
        );

        let response = self
            .client
            .get(&url)
            .header("X-Emby-Token", &self.config.api_key)
            .query(&[
                ("Ids", item_id.as_ref()),
                ("Fields", "Genres,Tags,RunTimeTicks,ProductionYear"),
            ])
            .send()
            .await
            .map_err(|e| {
                DomainError::InfrastructureError(format!("Jellyfin request failed: {}", e))
            })?;

        if !response.status().is_success() {
            return Ok(None);
        }

        let body: JellyfinItemsResponse = response.json().await.map_err(|e| {
            DomainError::InfrastructureError(format!("Failed to parse Jellyfin response: {}", e))
        })?;

        Ok(body.items.into_iter().next().and_then(map_jellyfin_item))
    }

    /// List top-level virtual libraries available to the configured user.
    ///
    /// Uses the `/Users/{userId}/Views` endpoint which returns exactly the
    /// top-level nodes the user has access to (Movies, TV Shows, etc.).
    async fn list_collections(&self) -> DomainResult<Vec<Collection>> {
        let url = format!(
            "{}/Users/{}/Views",
            self.config.base_url, self.config.user_id
        );

        let response = self
            .client
            .get(&url)
            .header("X-Emby-Token", &self.config.api_key)
            .send()
            .await
            .map_err(|e| {
                DomainError::InfrastructureError(format!("Jellyfin request failed: {}", e))
            })?;

        if !response.status().is_success() {
            return Err(DomainError::InfrastructureError(format!(
                "Jellyfin returned HTTP {}",
                response.status()
            )));
        }

        let body: JellyfinItemsResponse = response.json().await.map_err(|e| {
            DomainError::InfrastructureError(format!("Failed to parse Jellyfin response: {}", e))
        })?;

        Ok(body
            .items
            .into_iter()
            .map(|item| Collection {
                id: item.id,
                name: item.name,
                collection_type: item.collection_type,
            })
            .collect())
    }

    /// List all Series items, optionally scoped to a collection (ParentId).
    ///
    /// Results are sorted alphabetically. `RecursiveItemCount` gives the total
    /// episode count across all seasons without a second round-trip.
    async fn list_series(&self, collection_id: Option<&str>) -> DomainResult<Vec<SeriesSummary>> {
        let url = format!(
            "{}/Users/{}/Items",
            self.config.base_url, self.config.user_id
        );

        let mut params: Vec<(&str, String)> = vec![
            ("Recursive", "true".into()),
            ("IncludeItemTypes", "Series".into()),
            (
                "Fields",
                "Genres,ProductionYear,RecursiveItemCount".into(),
            ),
            ("SortBy", "SortName".into()),
            ("SortOrder", "Ascending".into()),
        ];

        if let Some(id) = collection_id {
            params.push(("ParentId", id.to_string()));
        }

        let response = self
            .client
            .get(&url)
            .header("X-Emby-Token", &self.config.api_key)
            .query(&params)
            .send()
            .await
            .map_err(|e| {
                DomainError::InfrastructureError(format!("Jellyfin request failed: {}", e))
            })?;

        if !response.status().is_success() {
            return Err(DomainError::InfrastructureError(format!(
                "Jellyfin returned HTTP {}",
                response.status()
            )));
        }

        let body: JellyfinItemsResponse = response.json().await.map_err(|e| {
            DomainError::InfrastructureError(format!("Failed to parse Jellyfin response: {}", e))
        })?;

        Ok(body
            .items
            .into_iter()
            .map(|item| SeriesSummary {
                id: item.id,
                name: item.name,
                episode_count: item.recursive_item_count.unwrap_or(0),
                genres: item.genres.unwrap_or_default(),
                year: item.production_year,
            })
            .collect())
    }

    /// List available genres from the Jellyfin `/Genres` endpoint.
    ///
    /// Optionally filtered to a specific content type (Movie or Episode).
    async fn list_genres(
        &self,
        content_type: Option<&ContentType>,
    ) -> DomainResult<Vec<String>> {
        let url = format!("{}/Genres", self.config.base_url);

        let mut params: Vec<(&str, String)> = vec![
            ("UserId", self.config.user_id.clone()),
            ("SortBy", "SortName".into()),
            ("SortOrder", "Ascending".into()),
        ];

        if let Some(ct) = content_type {
            params.push(("IncludeItemTypes", jellyfin_item_type(ct).into()));
        }

        let response = self
            .client
            .get(&url)
            .header("X-Emby-Token", &self.config.api_key)
            .query(&params)
            .send()
            .await
            .map_err(|e| {
                DomainError::InfrastructureError(format!("Jellyfin request failed: {}", e))
            })?;

        if !response.status().is_success() {
            return Err(DomainError::InfrastructureError(format!(
                "Jellyfin returned HTTP {}",
                response.status()
            )));
        }

        let body: JellyfinItemsResponse = response.json().await.map_err(|e| {
            DomainError::InfrastructureError(format!("Failed to parse Jellyfin response: {}", e))
        })?;

        Ok(body.items.into_iter().map(|item| item.name).collect())
    }

    async fn get_stream_url(&self, item_id: &MediaItemId, quality: &StreamQuality) -> DomainResult<String> {
        match quality {
            StreamQuality::Direct => {
                let url = format!("{}/Items/{}/PlaybackInfo", self.config.base_url, item_id.as_ref());
                let resp = self.client.post(&url)
                    .header("X-Emby-Token", &self.config.api_key)
                    .query(&[("userId", &self.config.user_id), ("mediaSourceId", &item_id.as_ref().to_string())])
                    .json(&serde_json::json!({}))
                    .send().await
                    .map_err(|e| DomainError::InfrastructureError(format!("PlaybackInfo failed: {e}")))?;

                if resp.status().is_success() {
                    let info: JellyfinPlaybackInfoResponse = resp.json().await
                        .map_err(|e| DomainError::InfrastructureError(format!("PlaybackInfo parse failed: {e}")))?;
                    if let Some(src) = info.media_sources.first() {
                        if src.supports_direct_stream {
                            if let Some(rel_url) = &src.direct_stream_url {
                                return Ok(format!("{}{}&api_key={}", self.config.base_url, rel_url, self.config.api_key));
                            }
                        }
                    }
                }
                // Fallback: HLS at 8 Mbps
                Ok(self.hls_url(item_id, 8_000_000))
            }
            StreamQuality::Transcode(bps) => Ok(self.hls_url(item_id, *bps)),
        }
    }
}

impl JellyfinMediaProvider {
    fn hls_url(&self, item_id: &MediaItemId, bitrate: u32) -> String {
        format!(
            "{}/Videos/{}/master.m3u8?videoCodec=h264&audioCodec=aac&VideoBitRate={}&mediaSourceId={}&api_key={}",
            self.config.base_url,
            item_id.as_ref(),
            bitrate,
            item_id.as_ref(),
            self.config.api_key,
        )
    }
}