package news

import (
	"dk/internal/database"
	"dk/internal/helpers/scanner"
	"fmt"
	"strings"
	"time"

	"zombiezen.com/go/sqlite"
)

// News represents a news post in the database
type News struct {
	ID      int    `db:"id" json:"id"`
	Author  int    `db:"author" json:"author"`
	Posted  int64  `db:"posted" json:"posted"`
	Content string `db:"content" json:"content"`
}

// New creates a new News with sensible defaults
func New() *News {
	return &News{
		Author:  0,                    // No author by default
		Posted:  time.Now().Unix(),   // Current time
		Content: "",                  // Empty content
	}
}

var newsScanner = scanner.New[News]()

// newsColumns returns the column list for news queries
func newsColumns() string {
	return newsScanner.Columns()
}

// scanNews populates a News struct using the fast scanner
func scanNews(stmt *sqlite.Stmt) *News {
	news := &News{}
	newsScanner.Scan(stmt, news)
	return news
}

// Find retrieves a news post by ID
func Find(id int) (*News, error) {
	var news *News

	query := `SELECT ` + newsColumns() + ` FROM news WHERE id = ?`

	err := database.Query(query, func(stmt *sqlite.Stmt) error {
		news = scanNews(stmt)
		return nil
	}, id)

	if err != nil {
		return nil, fmt.Errorf("failed to find news: %w", err)
	}

	if news == nil {
		return nil, fmt.Errorf("news with ID %d not found", id)
	}

	return news, nil
}

// All retrieves all news posts ordered by posted date (newest first)
func All() ([]*News, error) {
	var newsPosts []*News

	query := `SELECT ` + newsColumns() + ` FROM news ORDER BY posted DESC, id DESC`

	err := database.Query(query, func(stmt *sqlite.Stmt) error {
		news := scanNews(stmt)
		newsPosts = append(newsPosts, news)
		return nil
	})

	if err != nil {
		return nil, fmt.Errorf("failed to retrieve all news: %w", err)
	}

	return newsPosts, nil
}

// ByAuthor retrieves news posts by a specific author
func ByAuthor(authorID int) ([]*News, error) {
	var newsPosts []*News

	query := `SELECT ` + newsColumns() + ` FROM news WHERE author = ? ORDER BY posted DESC, id DESC`

	err := database.Query(query, func(stmt *sqlite.Stmt) error {
		news := scanNews(stmt)
		newsPosts = append(newsPosts, news)
		return nil
	}, authorID)

	if err != nil {
		return nil, fmt.Errorf("failed to retrieve news by author: %w", err)
	}

	return newsPosts, nil
}

// Recent retrieves the most recent news posts (limited by count)
func Recent(limit int) ([]*News, error) {
	var newsPosts []*News

	query := `SELECT ` + newsColumns() + ` FROM news ORDER BY posted DESC, id DESC LIMIT ?`

	err := database.Query(query, func(stmt *sqlite.Stmt) error {
		news := scanNews(stmt)
		newsPosts = append(newsPosts, news)
		return nil
	}, limit)

	if err != nil {
		return nil, fmt.Errorf("failed to retrieve recent news: %w", err)
	}

	return newsPosts, nil
}

// Since retrieves news posts since a specific timestamp
func Since(since int64) ([]*News, error) {
	var newsPosts []*News

	query := `SELECT ` + newsColumns() + ` FROM news WHERE posted >= ? ORDER BY posted DESC, id DESC`

	err := database.Query(query, func(stmt *sqlite.Stmt) error {
		news := scanNews(stmt)
		newsPosts = append(newsPosts, news)
		return nil
	}, since)

	if err != nil {
		return nil, fmt.Errorf("failed to retrieve news since timestamp: %w", err)
	}

	return newsPosts, nil
}

// Between retrieves news posts between two timestamps (inclusive)
func Between(start, end int64) ([]*News, error) {
	var newsPosts []*News

	query := `SELECT ` + newsColumns() + ` FROM news WHERE posted >= ? AND posted <= ? ORDER BY posted DESC, id DESC`

	err := database.Query(query, func(stmt *sqlite.Stmt) error {
		news := scanNews(stmt)
		newsPosts = append(newsPosts, news)
		return nil
	}, start, end)

	if err != nil {
		return nil, fmt.Errorf("failed to retrieve news between timestamps: %w", err)
	}

	return newsPosts, nil
}

// Save updates an existing news post in the database
func (n *News) Save() error {
	if n.ID == 0 {
		return fmt.Errorf("cannot save news without ID")
	}

	query := `UPDATE news SET author = ?, posted = ?, content = ? WHERE id = ?`
	return database.Exec(query, n.Author, n.Posted, n.Content, n.ID)
}

// Insert saves a new news post to the database and sets the ID
func (n *News) Insert() error {
	if n.ID != 0 {
		return fmt.Errorf("news already has ID %d, use Save() to update", n.ID)
	}

	// Use a transaction to ensure we can get the ID
	err := database.Transaction(func(tx *database.Tx) error {
		query := `INSERT INTO news (author, posted, content) VALUES (?, ?, ?)`

		if err := tx.Exec(query, n.Author, n.Posted, n.Content); err != nil {
			return fmt.Errorf("failed to insert news: %w", err)
		}

		// Get the last insert ID
		var id int
		err := tx.Query("SELECT last_insert_rowid()", func(stmt *sqlite.Stmt) error {
			id = stmt.ColumnInt(0)
			return nil
		})
		if err != nil {
			return fmt.Errorf("failed to get insert ID: %w", err)
		}

		n.ID = id
		return nil
	})

	return err
}

// Delete removes the news post from the database
func (n *News) Delete() error {
	if n.ID == 0 {
		return fmt.Errorf("cannot delete news without ID")
	}

	query := "DELETE FROM news WHERE id = ?"
	return database.Exec(query, n.ID)
}

// PostedTime returns the posted timestamp as a time.Time
func (n *News) PostedTime() time.Time {
	return time.Unix(n.Posted, 0)
}

// SetPostedTime sets the posted timestamp from a time.Time
func (n *News) SetPostedTime(t time.Time) {
	n.Posted = t.Unix()
}

// IsRecent returns true if the news post was made within the last 24 hours
func (n *News) IsRecent() bool {
	return time.Since(n.PostedTime()) < 24*time.Hour
}

// Age returns how long ago the news post was made
func (n *News) Age() time.Duration {
	return time.Since(n.PostedTime())
}

// IsAuthor returns true if the given user ID is the author of this news post
func (n *News) IsAuthor(userID int) bool {
	return n.Author == userID
}

// Preview returns a truncated version of the content for previews
func (n *News) Preview(maxLength int) string {
	if len(n.Content) <= maxLength {
		return n.Content
	}

	if maxLength < 3 {
		return n.Content[:maxLength]
	}

	return n.Content[:maxLength-3] + "..."
}

// WordCount returns the number of words in the content
func (n *News) WordCount() int {
	if n.Content == "" {
		return 0
	}

	// Simple word count by splitting on spaces
	words := 0
	inWord := false

	for _, char := range n.Content {
		if char == ' ' || char == '\t' || char == '\n' || char == '\r' {
			if inWord {
				words++
				inWord = false
			}
		} else {
			inWord = true
		}
	}

	if inWord {
		words++
	}

	return words
}

// Length returns the character length of the content
func (n *News) Length() int {
	return len(n.Content)
}

// Contains returns true if the content contains the given term (case-insensitive)
func (n *News) Contains(term string) bool {
	return strings.Contains(strings.ToLower(n.Content), strings.ToLower(term))
}

// IsEmpty returns true if the content is empty or whitespace-only
func (n *News) IsEmpty() bool {
	return strings.TrimSpace(n.Content) == ""
}

// Search retrieves news posts containing the search term in content
func Search(term string) ([]*News, error) {
	var newsPosts []*News

	query := `SELECT ` + newsColumns() + ` FROM news WHERE LOWER(content) LIKE LOWER(?) ORDER BY posted DESC, id DESC`
	searchTerm := "%" + term + "%"

	err := database.Query(query, func(stmt *sqlite.Stmt) error {
		news := scanNews(stmt)
		newsPosts = append(newsPosts, news)
		return nil
	}, searchTerm)

	if err != nil {
		return nil, fmt.Errorf("failed to search news: %w", err)
	}

	return newsPosts, nil
}

// ToMap converts the news to a map for efficient template rendering
func (n *News) ToMap() map[string]any {
	return map[string]any{
		"ID":      n.ID,
		"Author":  n.Author,
		"Posted":  n.Posted,
		"Content": n.Content,
		
		// Computed values
		"PostedTime": n.PostedTime(),
		"IsRecent":   n.IsRecent(),
		"Age":        n.Age(),
		"WordCount":  n.WordCount(),
		"Length":     n.Length(),
		"IsEmpty":    n.IsEmpty(),
	}
}