package model

import (
	"database/sql"
	"errors"
	"fmt"
	"html/template"
	"net/url"
	"time"

	"git.aiterp.net/AiteRP/aitestory/formparser"
	"git.aiterp.net/AiteRP/aitestory/server"
	"git.aiterp.net/gisle/wrouter/generate"
	"github.com/microcosm-cc/bluemonday"
	"github.com/russross/blackfriday"
)

// PageTypes describes how the source is rendered. For now it's only markdown,
// but who knows what the future holds.
var PageTypes = []string{
	"Markdown",
}

// PageMinDate is the earliest date possible. Stories from Matriarch Eriana's childhood
// are thus not going to happen.
var PageMinDate, _ = time.Parse(time.RFC3339, "1753-01-01T00:00:00Z")

// Page is the model describing the individual articles posted
// by users.
type Page 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"`
	Dated         bool      `json:"dated"`
	Published     bool      `json:"published"`
	Unlisted      bool      `json:"unlisted"`
	Specific      bool      `json:"specific"`
	Indexed       bool      `json:"indexed"`
	BackgroundURL string    `json:"backgroundUrl"`
	Type          string    `json:"type"`
	Source        string    `json:"source"`
	Tags          []Tag     `json:"tags"`

	prevTags     []Tag
	cachedOutput string
	primaryTag   *Tag
}

// Defaults fills in the default details for a page, suited for populating a form
func (page *Page) Defaults() {
	page.Category = PageCategories[0].Key

	page.Dated = true
	page.Published = true
	page.Unlisted = false
	page.Specific = false
	page.Indexed = true

	page.BackgroundURL = ""
	page.Type = PageTypes[0]
	page.Source = ""
}

// Insert adds the page to the database
func (page *Page) Insert() error {
	const insertPage = `
	INSERT INTO page (
		id, name, author, category, fictional_date, 
		publish_date, edit_date, dated, published, 
		unlisted, page.specific, indexed, type, source
	) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);
	`
	const insertTag = `INSERT INTO page_tag (page_id,tag_id,page_tag.primary) VALUES (?, ?, ?)`

	db := server.Main.DB

	if page.ID == "" {
		page.generateID()
	}

	// Do the thing
	_, err := db.Exec(insertPage,
		page.ID, page.Name, page.Author, page.Category, page.FictionalDate, page.PublishDate,
		page.EditDate, page.Dated, page.Published, page.Unlisted, page.Specific, page.Indexed,
		page.Type, page.Source,
	)
	if err != nil {
		return err
	}

	// Insert tags
	for i, tag := range page.Tags {
		_, err := db.Exec(insertTag, page.ID, tag.ID, i == 0)
		if err != nil {
			page.Delete()
			return err
		}
	}

	if len(page.Tags) > 0 {
		page.primaryTag = &page.Tags[0]
	}

	return nil
}

// Update saves the page to the database
func (page *Page) Update() error {
	const updatePage = `
	UPDATE page SET 
		name=?,category=?,fictional_date=?,publish_date=?,
		edit_date=?,dated=?,published=?,unlisted=?,page.specific=?,
		indexed=?,type=?,source=?
	WHERE id=?
	`
	const clearTags = `DELETE FROM page_tag WHERE page_id=?`
	const insertTag = `INSERT INTO page_tag (page_id,tag_id,page_tag.primary) VALUES (?, ?, ?)`

	db := server.Main.DB

	if page.ID == "" {
		return errors.New("no id")
	}

	// Do the thing
	_, err := db.Exec(updatePage,
		page.Name, page.Category, page.FictionalDate, page.PublishDate,
		page.EditDate, page.Dated, page.Published, page.Unlisted, page.Specific, page.Indexed,
		page.Type, page.Source, page.ID,
	)
	if err != nil {
		return err
	}

	// Stop now if the tages haven't changed
	if len(page.prevTags) == len(page.Tags) {
		change := false

		for i, tag := range page.prevTags {
			if tag.ID != page.prevTags[i].ID {
				change = true
				break
			}
		}

		if !change {
			return nil
		}
	}

	// Re-tag (can be optimized if need arise)
	_, err = db.Exec(clearTags, page.ID)
	if err != nil {
		return err
	}
	for i, tag := range page.Tags {
		_, err := db.Exec(insertTag, page.ID, tag.ID, i == 0)
		if err != nil {
			return err
		}
	}
	if len(page.Tags) > 0 {
		page.primaryTag = &page.Tags[0]
	}

	return nil
}

// Delete removes the page from the database
func (page *Page) Delete() error {
	db := server.Main.DB

	// Do the thing
	results, err := db.Exec("DELETE FROM `page` WHERE id=? LIMIT 1", page.ID)
	if err != nil {
		return err
	}

	// Count the stuffs that were done things to
	affected, err := results.RowsAffected()
	if err != nil {
		return err
	}
	if affected == 0 {
		return errors.New("page not found")
	}

	return nil
}

// Content parses the content of the page
func (page *Page) Content() (template.HTML, error) {
	if page.Type == "Markdown" {
		// TODO: Convert [[Ehanis Tioran]] to [Ehanis Tioran](https://wiki.aiterp.net/index.php?title=Ehanis%20Tioran)

		unsafe := blackfriday.MarkdownCommon([]byte(page.Source))
		output := string(bluemonday.UGCPolicy().SanitizeBytes(unsafe))

		return template.HTML(output), nil
	}

	return "", fmt.Errorf("Page type '%s' is not supported", page.Type)
}

// PrimaryTag gets the page's primary tag
func (page *Page) PrimaryTag() Tag {
	if page.primaryTag == nil {
		return Tag{}
	}

	return *page.primaryTag
}

// ParseForm validates the values in a form and sets the page's values whenever possible regardless
// so that it can be pushed to the viewmodel to allow the user to correct their mistakes without fear
// of losing their hard work
func (page *Page) ParseForm(form url.Values) []error {
	errors := make([]error, 0, 4)

	err := formparser.String(form.Get("name"), &page.Name, 2, 192)
	if err != nil {
		errors = append(errors, fmt.Errorf("Name: %s", err))
	}

	err = formparser.Select(form.Get("category"), &page.Category, pageCategories, page.Category != "")
	if err != nil {
		errors = append(errors, fmt.Errorf("Category: %s", err))
	}

	err = formparser.Date(form.Get("fictionalDate"), &page.FictionalDate, !page.FictionalDate.IsZero())
	if err != nil {
		errors = append(errors, fmt.Errorf("Fictonal Date: %s", err))
	}

	page.Dated = form.Get("dated") != ""
	page.Published = form.Get("published") != ""
	page.Unlisted = form.Get("unlisted") != ""
	page.Specific = form.Get("specific") != ""
	page.Indexed = form.Get("indexed") != ""

	err = formparser.String(form.Get("backgroundUrl"), &page.BackgroundURL, 0, 255)
	if err != nil {
		errors = append(errors, fmt.Errorf("Background URL: %s", err))
	}

	err = formparser.Select(form.Get("type"), &page.Type, PageTypes, page.Type != "")
	if err != nil {
		errors = append(errors, fmt.Errorf("Type: %s", err))
	}

	err = formparser.String(form.Get("source"), &page.Source, 0, 102400)
	if err != nil {
		errors = append(errors, fmt.Errorf("Content is too long, max: 100 KB (~16k words)"))
	}

	if len(errors) == 0 {
		errors = nil
	}

	return errors
}

// Standardize page ID generation
func (page *Page) generateID() {
	page.ID = generate.FriendlyID(16)
}

// FindPage finds a page by ID. The Header model handles
// listning pages
func FindPage(id string) (*Page, error) {
	const selectPage = `
	SELECT id,name,author,category,fictional_date,publish_date,edit_date,dated,published,
				 unlisted,page.specific,indexed,type,source,background_url
  FROM page
	WHERE id=?
	`
	const selectPageTags = `
	SELECT tag.id,tag.type,tag.name,page_tag.primary
	FROM page_tag
	RIGHT JOIN tag ON (tag.id = page_tag.tag_id)
	WHERE page_tag.page_id = ?
	ORDER BY tag.type DESC, tag.name
	`

	db := server.Main.DB

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

	if !rows.Next() {
		return nil, errors.New("not found")
	}

	page := new(Page)
	err = parsePage(page, rows)
	if err != nil {
		return nil, err
	}

	rows, err = db.Query(selectPageTags, page.ID)
	if err != nil {
		return nil, err
	}

	page.Tags = make([]Tag, 0, 64)
	for rows.Next() {
		primary := false

		tag := Tag{}
		rows.Scan(&tag.ID, &tag.Type, &tag.Name, &primary)
		page.Tags = append(page.Tags, tag)

		if primary {
			page.primaryTag = &tag
		}
	}

	return page, nil
}

func parsePage(page *Page, rows *sql.Rows) error {
	var fictionalDate, publishDate, editDate string
	var bgURL *string

	err := rows.Scan(
		&page.ID, &page.Name, &page.Author, &page.Category, &fictionalDate,
		&publishDate, &editDate, &page.Dated, &page.Published, &page.Unlisted,
		&page.Specific, &page.Indexed, &page.Type, &page.Source, &bgURL,
	)
	if err != nil {
		return err
	}

	if bgURL != nil {
		page.BackgroundURL = *bgURL
	}

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

	return nil
}