//!
//! Invoked by calling:
//! `goat-cli taxon/assembly lookup <args>`
//!
//! The state of the code here is not great, it's
//! quite fragmented. Functional, but lacks coherence.
//!
//! Probably should be refactored at some point.

use crate::IndexType;
use anyhow::{bail, Result};
use futures::StreamExt;
use reqwest;
use reqwest::header::ACCEPT;
use serde_json::Value;

/// The inner structs used in lookup.
pub mod lookup;
use lookup::{AssemblyCollector, Collector, Lookups, TaxonCollector};

/// Main entry point for `goat-cli lookup`.
pub async fn lookup(matches: &clap::ArgMatches, cli: bool, index_type: IndexType) -> Result<()> {
    let lookups = Lookups::new(matches, index_type)?;
    let url_vector_api = lookups.make_urls();
    let print_url = *matches.get_one::<bool>("url").expect("cli default false");
    let size = *matches.get_one::<u64>("size").expect("cli default = 10");

    if print_url {
        for (index, (url, _)) in url_vector_api.iter().enumerate() {
            println!("{}.\tGoaT lookup API URL: {}", index, url);
        }
        // don't exit here internally; we'll exit later
        if cli {
            std::process::exit(0);
        }
    }
    // so we can make as many concurrent requests
    let concurrent_requests = url_vector_api.len();

    let fetches = futures::stream::iter(url_vector_api.into_iter().map(|(path, search_query)| async move {
        // possibly make a again::RetryPolicy
        // to catch all the values in a *very* large request.
        let client = reqwest::Client::new();

        match again::retry(|| client.get(&path).header(ACCEPT, "application/json").send()).await {
            Ok(resp) => match resp.text().await {
                Ok(body) => {
                    let v: Value = serde_json::from_str(&body)?;
                    // print a warning if number of hits > size specified.
                    let request_size_op = &v["status"]["hits"].as_u64();
                    match request_size_op {
                        Some(s) => {
                            if size < *s {
                                eprintln!(
                                "For seach query {}, size specified ({}) was less than the number of results returned, ({}).",
                                search_query, size, s
                            )
                        }
                    },
                        None => (),
                    }

                    // get all the suggestions
                    let suggestions_text_op = &v["suggestions"].as_array();
                    // collect into a vec
                    let mut suggestions_vec = Vec::new();
                    let suggestions_text = match suggestions_text_op {
                        Some(suggestions) => {
                            for el in *suggestions {
                                let sug_str = el["suggestion"]["text"].as_str();
                                let sug_string_op = sug_str.map(String::from);
                                suggestions_vec.push(sug_string_op);
                            }
                            Some(suggestions_vec.clone())
                        }
                        None => None,
                    };
                    // we have all the information to process the results
                    match index_type {
                        IndexType::Taxon => Ok(Collector::Taxon(process_taxon_results(v, search_query, suggestions_text))),
                        IndexType::Assembly => Ok(Collector::Assembly(process_assembly_results(v, search_query, suggestions_text))),
                    }
                }
                Err(e) => bail!("Error reading {}: {}", path, e),
            },
            Err(e) => bail!("Error downloading {}: {}", path, e),
        }
    }))
    .buffer_unordered(concurrent_requests)
    .collect::<Vec<_>>();

    let awaited_fetches = fetches.await;

    for (index, el) in awaited_fetches.into_iter().enumerate() {
        match el {
            Ok(e) => {
                if cli {
                    match e {
                        Collector::Taxon(e) => e?.print_result(index)?,
                        Collector::Assembly(e) => e?.print_result(index)?,
                    }
                } else {
                    // this avenue is for internal use
                    // where the user could get info about
                    // bad spelling etc...
                    bail!("This is not yet implemented.")
                }
            }
            Err(_) => bail!("No results found."),
        }
    }

    Ok(())
}

/// As the taxon and assembly return JSON's are in
/// different structures, they have to be parsed differently.
///
/// Each must return [`Result<Collector, anyhow::Error>`].
fn process_taxon_results(
    v: Value,
    search_query: String,
    suggestions_text: Option<Vec<Option<String>>>,
) -> Result<TaxonCollector> {
    // and the taxon ID
    // we need to iterate over the array of results.
    // potentially look at the scores, and keep those over a certain amount
    // or keep everything. Currently I'm missing synonymous genera.

    let mut taxon_id_vec = Vec::new();
    let mut taxon_rank_vec = Vec::new();
    let mut taxon_names_array_vec = Vec::new();

    let results_array = v["results"].as_array();
    // unwrap safely here
    if let Some(arr) = results_array {
        for el in arr {
            let taxon_id = el["result"]["taxon_id"].as_str();
            let taxon_rank = el["result"]["taxon_rank"].as_str();
            let taxon_names_array_op = el["result"]["taxon_names"].as_array();

            let taxon_names_array = match taxon_names_array_op {
                Some(vec) => {
                    let mut collect_names = Vec::new();
                    for el in vec.iter() {
                        let key = el["name"].as_str().unwrap_or("-");
                        let value = el["class"].as_str().unwrap_or("-");
                        // let source = el["source"].as_str().unwrap_or("-");
                        collect_names.push((key.to_string(), value.to_string()));
                    }
                    Some(collect_names)
                }
                None => None,
            };

            // gather results into the vecs
            taxon_id_vec.push(taxon_id);
            taxon_rank_vec.push(taxon_rank);
            taxon_names_array_vec.push(taxon_names_array);
        }
    }

    // Vec<Option<&str>> -> Vec<Option<String>>
    let taxon_id = taxon_id_vec.iter().map(|e| e.map(String::from)).collect();
    let taxon_rank = taxon_rank_vec.iter().map(|e| e.map(String::from)).collect();

    Ok(TaxonCollector {
        search: Some(search_query),
        suggestions: suggestions_text,
        taxon_id,
        taxon_names: taxon_names_array_vec,
        taxon_rank,
    })
}

/// The assembly counterpart to the above function.
fn process_assembly_results(
    v: Value,
    search_query: String,
    suggestions_text: Option<Vec<Option<String>>>,
) -> Result<AssemblyCollector> {
    // taxon ID stays the same
    let mut taxon_id_vec = Vec::new();
    // there is no taxon rank
    let mut identifiers_array_vec = Vec::new();

    let results_array = v["results"].as_array();
    // unwrap safely here
    if let Some(arr) = results_array {
        for el in arr {
            let taxon_id = el["result"]["taxon_id"].as_str();
            let identifiers_array_op = el["result"]["identifiers"].as_array();

            let identifiers_array = match identifiers_array_op {
                Some(vec) => {
                    let mut collect_names = Vec::new();
                    for el in vec.iter() {
                        let key = el["identifier"].as_str().unwrap_or("-");
                        let value = el["class"].as_str().unwrap_or("-");
                        // let source = el["source"].as_str().unwrap_or("-");
                        collect_names.push((key.to_string(), value.to_string()));
                    }
                    Some(collect_names)
                }
                None => None,
            };

            // gather results into the vecs
            taxon_id_vec.push(taxon_id);
            identifiers_array_vec.push(identifiers_array);
        }
    }

    // Vec<Option<&str>> -> Vec<Option<String>>
    let taxon_id = taxon_id_vec.iter().map(|e| e.map(String::from)).collect();

    Ok(AssemblyCollector {
        search: Some(search_query),
        suggestions: suggestions_text,
        taxon_id,
        identifiers: identifiers_array_vec,
    })
}