package main

import (
	"context"
	"fmt"
	"time"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgxpool"
)

var dbConn *pgxpool.Pool

func DbInit(ctx context.Context) {
	var err error
	dbConn, err = pgxpool.New(ctx, "postgres://master:secret@localhost:5432") // TODO change to env in production
	if err != nil {
		panic(err)
	}

	_, err = dbConn.Exec(ctx, `CREATE EXTENSION IF NOT EXISTS "pgcrypto";`)
	if err != nil {
		panic(err)
	}

	_, err = dbConn.Exec(ctx, `
		CREATE TABLE IF NOT EXISTS users (
		    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
		    name TEXT UNIQUE NOT NULL,
		    pass_hash TEXT NOT NULL,
		    pronouns TEXT DEFAULT NULL,
		    color_red SMALLINT DEFAULT NULL,
		    color_green SMALLINT DEFAULT NULL,
		    color_blue SMALLINT DEFAULT NULL,
		    created_at TIMESTAMP NOT NULL DEFAULT NOW()
		)
	`)
	if err != nil {
		panic(err)
	}

	_, err = dbConn.Exec(ctx, `
		CREATE TABLE IF NOT EXISTS user_connections (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			requestor_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
			recipient_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
		    state SMALLINT NOT NULL DEFAULT 0,
			created_at TIMESTAMP NOT NULL DEFAULT NOW()
		)
	`)
	if err != nil {
		panic(err)
	}

	_, err = dbConn.Exec(ctx, `
		CREATE TABLE IF NOT EXISTS direct_messages (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			sender_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
			receiver_id UUID NOT NULL REFERENCES user_connections(id) ON DELETE CASCADE,
			created_at TIMESTAMP NOT NULL DEFAULT NOW(),
			content TEXT NOT NULL
		)
	`)
	if err != nil {
		panic(err)
	}

}

func DbUserSave(ctx context.Context, user *User) error {
	err := dbConn.QueryRow(ctx, `
        INSERT INTO users (name, pass_hash, pronouns, color_red, color_green, color_blue, created_at)
        VALUES ($1, $2, $3, $4, $5, $6, $7)
        RETURNING id
    `, user.Name, user.PasswordHash, user.Pronouns, user.Color[0], user.Color[1], user.Color[2], user.CreatedAt).
		Scan(&user.Id)
	return err
}

func DbUserDelete(ctx context.Context, id uuid.UUID) error {
	_, err := dbConn.Exec(ctx, `
		DELETE FROM users WHERE id = $1
	`, id)
	return err
}

func DbUserGetStandardInfoByName(ctx context.Context, user *User) error {
	err := dbConn.QueryRow(ctx, `
		SELECT id, name, pass_hash, COALESCE(pronouns, ''), color_red, color_green, color_blue, created_at FROM users WHERE name = $1
	`, user.Name).Scan(&user.Id, &user.Name, &user.PasswordHash, &user.Pronouns, &user.Color[0], &user.Color[1], &user.Color[2], &user.CreatedAt)
	return err
}

func DbUserGetById(ctx context.Context, user *User) error {
	err := dbConn.QueryRow(ctx, `
		SELECT name, pass_hash, COALESCE(pronouns, ''), color_red, color_green, color_blue, created_at FROM users WHERE id = $1
	`, user.Id).Scan(&user.Name, &user.PasswordHash, &user.Pronouns, &user.Color[0], &user.Color[1], &user.Color[2], &user.CreatedAt)
	return err
}

func DbUserSetColor(ctx context.Context, user *User) error {
	_, err := dbConn.Exec(ctx, `
		UPDATE users SET color_red = $1, color_green = $2, color_blue = $3 WHERE id = $4
	`, user.Color[0], user.Color[1], user.Color[2], user.Id)
	return err
}

func DbUserSetPronouns(ctx context.Context, user *User) error {
	_, err := dbConn.Exec(ctx, `
		UPDATE users SET pronouns = $1 WHERE id = $2
	`, user.Pronouns, user.Id)
	return err
}

func DbGetWholeUser(ctx context.Context, user *User) error {
	if err := DbUserGetById(ctx, user); err != nil {
		return err
	}
	if err := DbConnectionsGetBelongingToUser(ctx, user); err != nil {
		return err
	}

	CacheSaveUser(user)
	return nil
}

func DbConnectionSave(ctx context.Context, conn *Connection) error {
	return dbConn.QueryRow(ctx, `
		INSERT INTO user_connections (requestor_id, recipient_id, state, created_at) VALUES ($1, $2, $3, $4)
		RETURNING id
	`, conn.RequestorId, conn.RecipientId, conn.State, conn.CreatedAt).Scan(&conn.Id)
}

func DbConnectionDelete(ctx context.Context, conn *Connection) error {
	_, err := dbConn.Exec(ctx, `
		DELETE FROM user_connections WHERE id = $1
	`, conn.Id)
	return err
}

func DbConnectionsGetBelongingToUser(ctx context.Context, user *User) error {
	rows, err := dbConn.Query(ctx, `
		SELECT id, requestor_id, recipient_id, state, created_at
		FROM user_connections
		WHERE requestor_id = $1 OR recipient_id = $1
	`, user.Id)
	if err != nil {
		return err
	}
	defer rows.Close()

	if user.Connections == nil {
		user.Connections = make(map[uuid.UUID]*Connection)
	}

	for rows.Next() {
		conn := &Connection{}
		if err = rows.Scan(&conn.Id, &conn.RequestorId, &conn.RecipientId, &conn.State, &conn.CreatedAt); err != nil {
			return fmt.Errorf("scanning connection row: %w", err)
		}
		user.Connections[conn.Id] = conn
	}
	return rows.Err()
}

func DbConnectionUpdateState(ctx context.Context, conn *Connection) error {
	_, err := dbConn.Exec(ctx, `
		UPDATE user_connections SET state = $1 WHERE id = $2
	`, conn.State, conn.Id)
	return err
}

func DbConnectionMessageSave(ctx context.Context, message *Message) error {
	if message.Id != (uuid.UUID{}) {
		_, err := dbConn.Exec(ctx, `
			INSERT INTO direct_messages (id, sender_id, receiver_id, created_at, content) VALUES ($1, $2, $3, $4, $5)
		`, message.Id, message.Sender, message.Receiver, message.CreatedAt, message.Content)
		return err
	}
	return dbConn.QueryRow(ctx, `
		INSERT INTO direct_messages (sender_id, receiver_id, created_at, content) VALUES ($1, $2, $3, $4)
		RETURNING id
	`, message.Sender, message.Receiver, message.CreatedAt, message.Content).Scan(&message.Id)
}

func DbConnectionGetMessagesBefore(ctx context.Context, before time.Time, connection uuid.UUID, cap uint32) ([]*Message, error) {
	rows, err := dbConn.Query(ctx, `
		SELECT id, sender_id, receiver_id, created_at, content
		FROM (
			SELECT id, sender_id, receiver_id, created_at, content
			FROM direct_messages
			WHERE receiver_id = $1
			  AND created_at < $2
			ORDER BY created_at DESC
			LIMIT $3
		) sub
		ORDER BY created_at ASC
	`, connection, before, cap)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	messages := make([]*Message, 0, cap)
	for rows.Next() {
		msg := &Message{}
		if err = rows.Scan(&msg.Id, &msg.Sender, &msg.Receiver, &msg.CreatedAt, &msg.Content); err != nil {
			return nil, err
		}
		messages = append(messages, msg)
	}
	return messages, rows.Err()
}