package org.embulk.input;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonValue;
import com.google.common.base.Objects;
import com.google.common.base.Optional;

import java.util.ArrayList;
import java.util.List;

public class ParamsConfig {

    private final List<QueryConfig> queries;

    @JsonCreator
    public ParamsConfig(List<QueryConfig> queries) {
        this.queries = queries;
    }

    @JsonValue
    public List<QueryConfig> getQueries() {
        return queries;
    }

    public List<List<QueryConfig.Query>> generateQueries(Optional<PagerConfig> pagerConfig) {
        List<List<QueryConfig.Query>> base = new ArrayList<>(queries.size());
        for (QueryConfig p : queries) {
            base.add(p.expand());
        }

        int productSize = 1;
        int baseSize = base.size();
        for (int i = 0; i < baseSize; productSize *= base.get(i).size(), i++);

        List<List<QueryConfig.Query>> expands = new ArrayList<>(productSize);
        for (int i = 0; i < productSize; i++) {
            int j = 1;
            List<QueryConfig.Query> one = new ArrayList<>();
            for (List<QueryConfig.Query> list : base) {
                QueryConfig.Query pc = list.get((i / j) % list.size());
                one.add(pc);
                j *= list.size();
            }
            if (pagerConfig.isPresent()) {
                for (List<QueryConfig.Query> q : pagerConfig.get().expand()) {
                    expands.add(copyAndConcat(one, q));
                }
            } else {
                expands.add(one);
            }
        }

        return expands;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (!(obj instanceof ParamsConfig)) {
            return false;
        }
        ParamsConfig other = (ParamsConfig) obj;
        return Objects.equal(queries, other.queries);
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(queries);
    }

    private List<QueryConfig.Query> copyAndConcat(List<QueryConfig.Query>... srcs) {
        List<QueryConfig.Query> dest = new ArrayList<>();
        for (List<QueryConfig.Query> src : srcs) {
            for (QueryConfig.Query q : src) {
                dest.add(q.copy());
            }
        }
        return dest;
    }
}