package common

import (
	"database/sql"
	"errors"
	"strconv"

	qgen "git.tuxpa.in/a/gosora/query_gen"
)

var RepliesSearch Searcher

type Searcher interface {
    Query(q string, zones []int) ([]int, error)
}

// TODO: Implement this
// Note: This is slow compared to something like ElasticSearch and very limited
type SQLSearcher struct {
    queryReplies *sql.Stmt
    queryTopics  *sql.Stmt
    queryRepliesZone *sql.Stmt
    queryTopicsZone *sql.Stmt
    //queryZone    *sql.Stmt
    fuzzyZone *sql.Stmt
}

// TODO: Support things other than MySQL
// TODO: Use LIMIT?
func NewSQLSearcher(acc *qgen.Accumulator) (*SQLSearcher, error) {
    if acc.GetAdapter().GetName() != "mysql" {
        return nil, errors.New("SQLSearcher only supports MySQL at this time")
    }
    return &SQLSearcher{
        queryReplies: acc.RawPrepare("SELECT tid FROM replies WHERE MATCH(content) AGAINST (? IN BOOLEAN MODE)"),
        queryTopics:  acc.RawPrepare("SELECT tid FROM topics WHERE MATCH(title) AGAINST (? IN BOOLEAN MODE) OR MATCH(content) AGAINST (? IN BOOLEAN MODE)"),
        queryRepliesZone: acc.RawPrepare("SELECT tid FROM replies WHERE MATCH(content) AGAINST (? IN BOOLEAN MODE) AND tid=?"),
        queryTopicsZone:  acc.RawPrepare("SELECT tid FROM topics WHERE (MATCH(title) AGAINST (? IN BOOLEAN MODE) OR MATCH(content) AGAINST (? IN BOOLEAN MODE)) AND parentID=?"),
        //queryZone:    acc.RawPrepare("SELECT topics.tid FROM topics INNER JOIN replies ON topics.tid = replies.tid WHERE (topics.title=? OR (MATCH(topics.title) AGAINST (? IN BOOLEAN MODE) OR MATCH(topics.content) AGAINST (? IN BOOLEAN MODE) OR MATCH(replies.content) AGAINST (? IN BOOLEAN MODE)) OR topics.content=? OR replies.content=?) AND topics.parentID=?"),
        fuzzyZone:    acc.RawPrepare("SELECT topics.tid FROM topics INNER JOIN replies ON topics.tid = replies.tid WHERE (topics.title LIKE ? OR topics.content LIKE ? OR replies.content LIKE ?) AND topics.parentID=?"),
    }, acc.FirstError()
}

func (s *SQLSearcher) queryAll(q string) ([]int, error) {
    var ids []int
    run := func(stmt *sql.Stmt, q ...interface{}) error {
        rows, e := stmt.Query(q...)
        if e == sql.ErrNoRows {
            return nil
        } else if e != nil {
            return e
        }
        defer rows.Close()

        for rows.Next() {
            var id int
            if e := rows.Scan(&id); e != nil {
                return e
            }
            ids = append(ids, id)
        }
        return rows.Err()
    }

    err := run(s.queryReplies, q)
    if err != nil {
        return nil, err
    }
    err = run(s.queryTopics, q, q)
    if err != nil {
        return nil, err
    }
    if len(ids) == 0 {
        err = sql.ErrNoRows
    }
    return ids, err
}

func (s *SQLSearcher) Query(q string, zones []int) (ids []int, err error) {
    if len(zones) == 0 {
        return nil, nil
    }
    run := func(rows *sql.Rows, e error) error {
        /*if e == sql.ErrNoRows {
            return nil
        } else */if e != nil {
            return e
        }
        defer rows.Close()

        for rows.Next() {
            var id int
            if e := rows.Scan(&id); e != nil {
                return e
            }
            ids = append(ids, id)
        }
        return rows.Err()
    }

    if len(zones) == 1 {
        //err = run(s.queryZone.Query(q, q, q, q, q,q, zones[0]))
        err = run(s.queryRepliesZone.Query(q, zones[0]))
        if err != nil {
            return nil, err
        }
        err = run(s.queryTopicsZone.Query(q, q,zones[0]))
    } else {
        var zList string
        for _, zone := range zones {
            zList += strconv.Itoa(zone) + ","
        }
        zList = zList[:len(zList)-1]

        acc := qgen.NewAcc()
        /*stmt := acc.RawPrepare("SELECT topics.tid FROM topics INNER JOIN replies ON topics.tid = replies.tid WHERE (MATCH(topics.title) AGAINST (? IN BOOLEAN MODE) OR MATCH(topics.content) AGAINST (? IN BOOLEAN MODE) OR MATCH(replies.content) AGAINST (? IN BOOLEAN MODE) OR topics.title=? OR topics.content=? OR replies.content=?) AND topics.parentID IN(" + zList + ")")
        if err = acc.FirstError(); err != nil {
            return nil, err
        }*/
        // TODO: Cache common IN counts
        stmt := acc.RawPrepare("SELECT tid FROM topics WHERE (MATCH(topics.title) AGAINST (? IN BOOLEAN MODE) OR MATCH(topics.content) AGAINST (? IN BOOLEAN MODE)) AND parentID IN(" + zList + ")")
        if err = acc.FirstError(); err != nil {
            return nil, err
        }
        err = run(stmt.Query(q, q))
        if err != nil {
            return nil, err
        }
        stmt = acc.RawPrepare("SELECT tid FROM replies WHERE MATCH(replies.content) AGAINST (? IN BOOLEAN MODE) AND tid IN(" + zList + ")")
        if err = acc.FirstError(); err != nil {
            return nil, err
        }
        err = run(stmt.Query(q))
        //err = run(stmt.Query(q, q, q, q, q, q))
    }
    if err != nil {
        return nil, err
    }
    if len(ids) == 0 {
        err = sql.ErrNoRows
    }
    return ids, err
}

// TODO: Implement this
type ElasticSearchSearcher struct {
}

func NewElasticSearchSearcher() (*ElasticSearchSearcher, error) {
    return &ElasticSearchSearcher{}, nil
}

func (s *ElasticSearchSearcher) Query(q string, zones []int) ([]int, error) {
    return nil, nil
}