package model

import (
	"database/sql"
	"errors"
	"time"

	"git.aiterp.net/AiteRP/aitestory/server"
)

// Header contains a subset of the page database
// table needed for the front page. It's a read-only
// model.
type Header struct {
	ID            string    `json:"id"`
	Name          string    `json:"name"`
	Author        string    `json:"author"`
	Category      string    `json:"category"`
	FictionalDate time.Time `json:"fictionalDate"`
	PublishDate   time.Time `json:"publishDate"`
	EditDate      time.Time `json:"editDate"`
	PrimaryTag    *Tag      `json:"primaryTag"`
}

func (header *Header) Dated() bool {
	return !header.FictionalDate.IsZero()
}

// CategoryInfo gets information about the category
func (header *Header) CategoryInfo() PageCategory {
	for _, category := range PageCategories {
		if category.Key == header.Category {
			return category
		}
	}

	return PageCategory{"Unknown", "Unknown", "?", ""}
}

// ListHeaders grabs all the general pages from
// the database to list them
func ListHeaders() ([]Header, error) {
	const query = `
	SELECT page.id,page.name,author,category,fictional_date,publish_date,edit_date,tag.id,tag.type,tag.name 
  FROM page
  LEFT JOIN page_tag ON (page.id = page_tag.page_id AND page_tag.primary = true)
  LEFT JOIN tag ON (tag.id = page_tag.tag_id)
 	WHERE page.specific=false AND page.published=true AND page.unlisted=false
	ORDER BY page.publish_date DESC
	`

	db := server.Main.DB

	rows, err := db.Query(query)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	results := make([]Header, 0, 64)
	header := Header{}
	for rows.Next() {
		err := parseHeader(&header, rows)
		if err != nil {
			return nil, err
		}

		results = append(results, header)
	}

	return results, nil
}

// ListHeadersByCategory grabs all the pages in the given category
func ListHeadersByCategory(category string) ([]Header, error) {
	const query = `
	SELECT page.id,page.name,author,category,fictional_date,publish_date,edit_date,tag.id,tag.type,tag.name 
  FROM page
  LEFT JOIN page_tag ON (page.id = page_tag.page_id AND page_tag.primary = true)
  LEFT JOIN tag ON (tag.id = page_tag.tag_id)
 	WHERE page.specific=false AND page.published=true AND page.unlisted=false AND page.category = ?
	ORDER BY page.publish_date DESC	
	`

	db := server.Main.DB

	rows, err := db.Query(query, category)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	results := make([]Header, 0, 64)
	header := Header{}
	for rows.Next() {
		err := parseHeader(&header, rows)
		if err != nil {
			return nil, err
		}

		results = append(results, header)
	}

	return results, nil
}

// ListHeadersByTag lists all headers that has the tag. Leave the category empty
// to not filter by it
func ListHeadersByTag(category string, tag *Tag) ([]Header, error) {
	const query1 = `
		SELECT page.id,page.name,page.author,page.category,page.fictional_date,page.publish_date,page.edit_date,tag.id,tag.type,tag.name 
		FROM page_tag
		RIGHT JOIN page ON page.id = page_tag.page_id
		LEFT JOIN (page_tag AS pt2) ON (page.id = pt2.page_id AND pt2.primary = true)
		LEFT JOIN (tag AS tag) ON (tag.id = pt2.tag_id)
		WHERE page_tag.tag_id=? AND page.unlisted=false AND page.published=true
		ORDER BY page.publish_date DESC
	`
	const query2 = `
		SELECT page.id,page.name,page.author,page.category,page.fictional_date,page.publish_date,page.edit_date,tag.id,tag.type,tag.name 
		FROM page_tag
		RIGHT JOIN page ON page.id = page_tag.page_id
		LEFT JOIN (page_tag AS pt2) ON (page.id = pt2.page_id AND pt2.primary = true)
		LEFT JOIN (tag AS tag) ON (tag.id = pt2.tag_id)
		WHERE page_tag.tag_id=? AND page.category=? AND page.unlisted=false AND page.published=true
		ORDER BY page.publish_date DESC		
	`

	if tag == nil {
		return nil, errors.New("no tag")
	}

	db := server.Main.DB

	query := query1
	if category != "" {
		query = query2
	}

	rows, err := db.Query(query, tag.ID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	results := make([]Header, 0, 64)
	header := Header{}
	for rows.Next() {
		err := parseHeader(&header, rows)
		if err != nil {
			return nil, err
		}

		results = append(results, header)
	}

	return results, nil
}

// ListHeadersByTags searches for the first tag, then filters the result based on the
// others. There is room for improvement in this function, but I'll have to judge whether
// there will be a need for that.
func ListHeadersByTags(category string, tags []Tag) ([]Header, error) {
	if len(tags) == 0 {
		return nil, errors.New("no tags")
	}

	headers, err := ListHeadersByTag(category, &tags[0])
	if err != nil {
		return nil, err
	}

	if len(headers) == 0 {
		return headers, nil
	}

	for _, tag := range tags[1:] {
		headers2, err := ListHeadersByTag(category, &tag)
		if err != nil {
			return nil, err
		}

		results := make([]Header, 0, len(headers))
		for _, header := range headers {
			found := false
			for _, header2 := range headers2 {
				if header.ID == header2.ID {
					found = true
					break
				}
			}

			if found {
				results = append(results, header)
			}
		}

		headers = results
	}

	return headers, nil
}

func parseHeader(header *Header, rows *sql.Rows) error {
	var tagID, tagName, tagType string
	var fictionalDate, publishDate, editDate string
	var err error

	rows.Scan(&header.ID, &header.Name, &header.Author, &header.Category, &fictionalDate, &publishDate, &editDate, &tagID, &tagType, &tagName)
	if tagID != "" {
		header.PrimaryTag = &Tag{tagID, tagType, tagName}
	} else {
		header.PrimaryTag = nil
	}

	header.FictionalDate, err = time.Parse("2006-01-02 15:04:05", fictionalDate)
	if err != nil {
		header.FictionalDate = time.Time{}
	}
	header.PublishDate, err = time.Parse("2006-01-02 15:04:05", publishDate)
	if err != nil {
		return err
	}
	header.EditDate, err = time.Parse("2006-01-02 15:04:05", editDate)
	if err != nil {
		return err
	}

	return nil
}