use std::collections::{BTreeMap, HashMap};

use axum::{
  extract::{Path, Query, State},
  http::StatusCode,
  routing::{get, post, put},
  Json, Router,
};
use chrono::{DateTime, Utc};
use cozo::{DataValue, MultiTransaction, ScriptMutability};
use itertools::Itertools;
use panorama_core::state::node::ExtraData;
use serde_json::Value;
use utoipa::{OpenApi, ToSchema};
use uuid::Uuid;

use crate::{error::AppResult, AppState};

/// Node API
#[derive(OpenApi)]
#[openapi(
  paths(get_node, update_node, create_node),
  components(schemas(GetNodeResult))
)]
pub(super) struct NodeApi;

pub(super) fn router() -> Router<AppState> {
  Router::new()
    .route("/:id", get(get_node))
    .route("/:id", post(update_node))
    .route("/", put(create_node))
}

#[derive(Serialize, Deserialize, ToSchema, Clone)]
struct GetNodeResult {
  node_id: String,
  fields: HashMap<String, Value>,
  created_at: DateTime<Utc>,
  updated_at: DateTime<Utc>,
}

/// Get node info
///
/// This endpoint retrieves all the fields for a particular node
#[utoipa::path(
  get,
  path = "/{id}",
  responses(
    (status = 200, body = [GetNodeResult]),
    (status = 404, description = "the node ID provided was not found")
  ),
  params(
    ("id" = String, Path, description = "Node ID"),
  ),
)]
pub async fn get_node(
  State(state): State<AppState>,
  Path(node_id): Path<String>,
) -> AppResult<(StatusCode, Json<Value>)> {
  let node_info = state.get_node(&node_id).await?;

  Ok((
    StatusCode::OK,
    Json(json!({
      "node_id": node_id,
      "fields": node_info.fields,
      "created_at": node_info.created_at,
      "updated_at": node_info.updated_at,
    })),
  ))
}

#[derive(Deserialize, Debug)]
pub struct UpdateData {
  title: Option<String>,
  extra_data: Option<ExtraData>,
}

/// Update node info
#[utoipa::path(
  post,
  path = "/{id}",
  responses(
    (status = 200)
  ),
  params(
    ("id" = String, Path, description = "Node ID"),
  )
)]
pub async fn update_node(
  State(state): State<AppState>,
  Path(node_id): Path<String>,
  Json(update_data): Json<UpdateData>,
) -> AppResult<Json<Value>> {
  let node_id_data = DataValue::from(node_id.clone());

  // TODO: Combine these into the same script

  let tx = state.db.multi_transaction(true);

  if let Some(title) = update_data.title {
    let title = DataValue::from(title);

    tx.run_script(
      "
    # Always update the time
    ?[ id, title ] <- [[ $node_id, $title ]]
    :update node { id, title }
  ",
      btmap! {
        "node_id".to_owned() => node_id_data.clone(),
        "title".to_owned() => title,
      },
    )?;
  }

  if let Some(extra_data) = update_data.extra_data {
    let result = get_rows_for_extra_keys(&tx, &extra_data)?;

    for (key, (relation, field_name, ty)) in result.iter() {
      let new_value = extra_data.get(key).unwrap();

      // TODO: Make this more generic
      let new_value = DataValue::from(new_value.as_str().unwrap());

      let query = format!(
        "
          ?[ node_id, {field_name} ] <- [[$node_id, $input_data]]
          :update {relation} {{ node_id, {field_name} }}
        "
      );

      let result = tx.run_script(
        &query,
        btmap! {
          "node_id".to_owned() => node_id_data.clone(),
          "input_data".to_owned() => new_value,
        },
      )?;
    }
  }

  tx.run_script(
    "
    # Always update the time
    ?[ id, updated_at ] <- [[ $node_id, now() ]]
    :update node { id, updated_at }
  ",
    btmap! {
      "node_id".to_owned() => node_id_data,
    },
  )?;

  tx.commit()?;

  Ok(Json(json!({})))
}

#[derive(Debug, Deserialize)]
pub struct CreateNodeOpts {
  // TODO: Allow submitting a string
  // id: Option<String>,
  #[serde(rename = "type")]
  ty: String,
  extra_data: Option<ExtraData>,
}

#[utoipa::path(
  put,
  path = "/",
  responses(
    (status = 200)
  ),
  params(
    ("id" = String, Path, description = "Node ID"),
  )
)]
pub async fn create_node(
  State(state): State<AppState>,
  Json(opts): Json<CreateNodeOpts>,
) -> AppResult<Json<Value>> {
  let node_id = Uuid::now_v7();
  let node_id = node_id.to_string();

  let tx = state.db.multi_transaction(true);

  let result = tx.run_script(
    "
    ?[id, type] <- [[$node_id, $type]]
    :put node { id, type }
  ",
    btmap! {
      "node_id".to_owned() => DataValue::from(node_id.clone()),
      "type".to_owned() => DataValue::from(opts.ty),
    },
  );

  if let Some(extra_data) = opts.extra_data {
    let result = get_rows_for_extra_keys(&tx, &extra_data)?;

    let result_by_relation = result
      .iter()
      .into_group_map_by(|(key, (relation, field_name, ty))| relation);

    for (relation, fields) in result_by_relation.iter() {
      let fields_mapping = fields
        .into_iter()
        .map(|(key, (_, field_name, ty))| {
          let new_value = extra_data.get(*key).unwrap();
          // TODO: Make this more generic
          let new_value = match ty.as_str() {
            "int" => DataValue::from(new_value.as_i64().unwrap()),
            _ => DataValue::from(new_value.as_str().unwrap()),
          };
          (field_name.to_owned(), new_value)
        })
        .collect::<BTreeMap<_, _>>();

      let keys = fields_mapping.keys().collect::<Vec<_>>();
      let keys_joined = keys.iter().join(", ");

      let query = format!(
        "
          ?[ node_id, {keys_joined} ] <- [$input_data]
          :insert {relation} {{ node_id, {keys_joined} }}
        "
      );

      let mut params = vec![];
      params.push(DataValue::from(node_id.clone()));
      for key in keys {
        params.push(fields_mapping[key].clone());
      }

      let result = tx.run_script(
        &query,
        btmap! {
          "input_data".to_owned() => DataValue::List(params),
        },
      )?;
    }
  }

  tx.commit()?;

  Ok(Json(json!({
    "node_id": node_id,
  })))
}

#[derive(Deserialize)]
pub struct SearchQuery {
  query: String,
}

pub async fn search_nodes(
  State(state): State<AppState>,
  Query(query): Query<SearchQuery>,
) -> AppResult<Json<Value>> {
  // TODO: This is temporary, there may be more ways to search so tacking on *
  // at the end may destroy some queries
  let query = format!("{}*", query.query);

  let results = state.db.run_script(
    "
      results[node_id, content, score] := ~journal:text_index {node_id, content, |
        query: $q,
        k: 10,
        score_kind: 'tf_idf',
        bind_score: score
      }

      ?[node_id, content, title, score] :=
        results[node_id, content, score],
        *node{ id: node_id, title }

      :order -score
      ",
    btmap! {
      "q".to_owned() => DataValue::from(query),
    },
    ScriptMutability::Immutable,
  )?;

  let results = results
    .rows
    .into_iter()
    .map(|row| {
      json!({
        "node_id": row[0].get_str().unwrap(),
        "content": row[1].get_str().unwrap(),
        "title": row[2].get_str().unwrap(),
        "score": row[3].get_float().unwrap(),
      })
    })
    .collect::<Vec<_>>();

  Ok(Json(json!({
    "results": results
  })))
}

fn get_rows_for_extra_keys(
  tx: &MultiTransaction,
  extra_data: &ExtraData,
) -> AppResult<HashMap<String, (String, String, String)>> {
  let result = tx.run_script(
    "
      ?[key, relation, field_name, type] :=
        *fqkey_to_dbkey{key, relation, field_name, type},
        is_in(key, $keys)
    ",
    btmap! {
      "keys".to_owned() => DataValue::List(
        extra_data
          .keys()
          .map(|s| DataValue::from(s.as_str()))
          .collect::<Vec<_>>()
      ),
    },
  )?;

  let s = |s: &DataValue| s.get_str().unwrap().to_owned();

  Ok(
    result
      .rows
      .into_iter()
      .map(|row| (s(&row[0]), (s(&row[1]), s(&row[2]), s(&row[3]))))
      .collect::<HashMap<_, _>>(),
  )
}