package models

import (
	"database/sql"
	"time"
)

type ChatMessage struct {
	ID          int
	UserID      int
	Content     string
	ReplyTo     int // -1 if not a reply
	Timestamp   time.Time
	Username    string // For display, fetched from user
	PfpURL      string // For display, fetched from user
	Mentions    []string // List of mentioned usernames
}

func CreateChatMessage(db *sql.DB, msg ChatMessage) error {
	query := "INSERT INTO chat_messages (user_id, content, reply_to, timestamp) VALUES (?, ?, ?, NOW())"
	_, err := db.Exec(query, msg.UserID, msg.Content, msg.ReplyTo)
	return err
}

func GetRecentChatMessages(db *sql.DB, limit int) ([]ChatMessage, error) {
	query := `
		SELECT cm.id, cm.user_id, cm.content, cm.reply_to, cm.timestamp, u.username, u.pfp_url
		FROM chat_messages cm
		JOIN users u ON cm.user_id = u.id
		ORDER BY cm.timestamp DESC
		LIMIT ?`
	rows, err := db.Query(query, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var messages []ChatMessage
	for rows.Next() {
		var msg ChatMessage
		var timestampStr string
		var pfpURL sql.NullString
		err := rows.Scan(&msg.ID, &msg.UserID, &msg.Content, &msg.ReplyTo, &timestampStr, &msg.Username, &pfpURL)
		if err != nil {
			return nil, err
		}
		msg.Timestamp, err = time.Parse("2006-01-02 15:04:05", timestampStr)
		if err != nil {
			msg.Timestamp = time.Time{}
		}
		if pfpURL.Valid {
			msg.PfpURL = pfpURL.String
		}
		// Parse mentions from content (simple @username detection)
		msg.Mentions = extractMentions(msg.Content)
		messages = append(messages, msg)
	}
	return messages, nil
}

func GetChatMessageByID(db *sql.DB, id int) (*ChatMessage, error) {
	query := `
		SELECT cm.id, cm.user_id, cm.content, cm.reply_to, cm.timestamp, u.username, u.pfp_url
		FROM chat_messages cm
		JOIN users u ON cm.user_id = u.id
		WHERE cm.id = ?`
	row := db.QueryRow(query, id)
	var msg ChatMessage
	var timestampStr string
	var pfpURL sql.NullString
	err := row.Scan(&msg.ID, &msg.UserID, &msg.Content, &msg.ReplyTo, &timestampStr, &msg.Username, &pfpURL)
	if err == sql.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	msg.Timestamp, err = time.Parse("2006-01-02 15:04:05", timestampStr)
	if err != nil {
		msg.Timestamp = time.Time{}
	}
	if pfpURL.Valid {
		msg.PfpURL = pfpURL.String
	}
	msg.Mentions = extractMentions(msg.Content)
	return &msg, nil
}

func GetUsernamesMatching(db *sql.DB, prefix string) ([]string, error) {
	query := "SELECT username FROM users WHERE username LIKE ? LIMIT 10"
	rows, err := db.Query(query, prefix+"%")
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var usernames []string
	for rows.Next() {
		var username string
		if err := rows.Scan(&username); err != nil {
			return nil, err
		}
		usernames = append(usernames, username)
	}
	return usernames, nil
}

// Simple utility to extract mentions from content
func extractMentions(content string) []string {
	var mentions []string
	var currentMention string
	inMention := false

	for _, char := range content {
		if char == '@' {
			inMention = true
			currentMention = "@"
		} else if inMention && (char == ' ' || char == '\n' || char == '\t') {
			if len(currentMention) > 1 {
				mentions = append(mentions, currentMention)
			}
			inMention = false
			currentMention = ""
		} else if inMention {
			currentMention += string(char)
		}
	}
	if inMention && len(currentMention) > 1 {
		mentions = append(mentions, currentMention)
	}
	return mentions
}