package sqlite

import (
	"crowsnest/internal/model"
	"database/sql"
)

// TODO docstring
type ArticleModel struct {
    DB *sql.DB
}

// TODO docstring
func (m *ArticleModel) All() ([]model.Article, error) {
    stmt := `
        SELECT id, title, sourceUrl, author, content, publishDate, fetchDate 
        FROM articles 
        ORDER BY publishDate DESC
    `
    rows, err := m.DB.Query(stmt)
    if err != nil { return nil, err }

    articles := []model.Article{}
    for rows.Next() {
        a := model.Article{}
        err := rows.Scan(&a.Identifier, &a.Title, &a.SourceUrl, &a.Author, &a.Content, &a.PublishDate, &a.FetchDate)
        if err != nil { return nil, err }

        articles = append(articles, a)
    }
    
    if err = rows.Err(); err != nil { return nil,  err }

    return articles, nil
}

// TODO docstring
func (m *ArticleModel) Search(query string) ([]model.Article, error) {
    stmt := `
        SELECT id, title, sourceUrl, author, content, publishDate, fetchDate
        FROM articles JOIN ( 
            SELECT id as id2, rank FROM fts_articles WHERE content MATCH ?
        ) ON id = id2 
        ORDER BY rank ASC, publishDate DESC
        LIMIT 10
    `
    rows, err := m.DB.Query(stmt, query)
    if err != nil { return nil, err }

    articles := []model.Article{}
    for rows.Next() {
        a := model.Article{}
        err := rows.Scan(&a.Identifier, &a.Title, &a.SourceUrl, &a.Author, &a.Content, &a.PublishDate, &a.FetchDate)
        if err != nil { return nil, err }

        articles = append(articles, a)
    }
    
    if err = rows.Err(); err != nil { return nil,  err }

    return articles, nil
}

// Inserts a new article into the database. The id attribute of the given
// article will be ignored. May throw an error if the execution of the database
// query fails.
func (m *ArticleModel) Insert(a *model.Article) error {
    // begin transaction 
    _, err := m.DB.Begin()
    if err != nil { return err }

    // insert article
    stmt := `INSERT INTO articles (title, sourceUrl, author, content, publishDate, fetchDate)
             VALUES (?, ?, ?, ?, ?, ?)
    `
    result, err := m.DB.Exec(stmt, a.Title, a.SourceUrl, a.Author, a.Content, a.PublishDate, a.FetchDate)
    if err != nil { return err }
    lastId, err := result.LastInsertId()
    if err != nil { return err }

    // insert into fts_articles for full-text search
    stmt = `INSERT INTO fts_articles (id, content)
             VALUES (?, ? || '\n' || ? || '\n' || ?)
    `
    _, err = m.DB.Exec(stmt, lastId, a.Title, a.Author, a.Content)
    return err
}

// TODO docstring
func (m *ArticleModel) Update(a *model.Article) error {
    // begin transaction 
    _, err := m.DB.Begin()
    if err != nil { return err }

    // insert article
    stmt := `UPDATE articles 
             SET title = ?, sourceUrl = ?, author = ?, content = ?, publishDate = ?, fetchDate = ?
             WHERE id = ?
    `
    _, err = m.DB.Exec(stmt, a.Title, a.SourceUrl, a.Author, a.Content, a.PublishDate, a.FetchDate, a.Identifier)
    if err != nil { return err }

    // insert into fts_articles for full-text search
    stmt = `INSERT INTO fts_articles (id, content)
             VALUES (?, ? || '\n' || ? || '\n' || ?)
    `
    _, err = m.DB.Exec(stmt, a.Identifier, a.Title, a.Author, a.Content)
    return err
}