package role

import (
	"encoding/json"
	"errors"

	"github.com/google/uuid"
	"github.com/justamessenger/server/internal/database"
	"github.com/justamessenger/server/internal/models"
)

type Manager struct {
	db *database.DB
}

func NewManager(db *database.DB) *Manager {
	return &Manager{db: db}
}

var DefaultPermissions = []string{
	"view_channels",
	"send_messages",
	"add_reactions",
	"read_message_history",
	"connect_voice",
	"speak",
}

var AdminPermissions = []string{
	"administrator",
	"manage_guild",
	"manage_channels",
	"manage_roles",
	"manage_messages",
	"kick_members",
	"ban_members",
	"view_channels",
	"send_messages",
	"add_reactions",
	"read_message_history",
	"connect_voice",
	"speak",
	"mute_members",
	"deafen_members",
	"move_members",
	"stream",
}

func (m *Manager) CreateDefaultRoles(guildID string) error {
	_, err := m.db.Exec(
		`INSERT OR IGNORE INTO roles (id, guild_id, name, color, position, permissions, is_default)
		 VALUES (?, ?, 'everyone', 0, 0, ?, 1)`,
		uuid.New().String(), guildID, mustJSON(DefaultPermissions),
	)
	return err
}

func mustJSON(v interface{}) string {
	b, _ := json.Marshal(v)
	return string(b)
}

func (m *Manager) Create(guildID, name string, color, position int, permissions []string) (*models.Role, error) {
	id := uuid.New().String()
	permJSON, _ := json.Marshal(permissions)
	_, err := m.db.Exec(
		`INSERT INTO roles (id, guild_id, name, color, position, permissions)
		 VALUES (?, ?, ?, ?, ?, ?)`,
		id, guildID, name, color, position, string(permJSON),
	)
	if err != nil {
		return nil, err
	}
	return m.Get(id)
}

func (m *Manager) Get(id string) (*models.Role, error) {
	row := m.db.QueryRow(
		`SELECT id, guild_id, name, color, position, permissions, is_default
		 FROM roles WHERE id = ?`, id,
	)
	r := &models.Role{}
	var permJSON string
	err := row.Scan(&r.ID, &r.GuildID, &r.Name, &r.Color, &r.Position, &permJSON, &r.IsDefault)
	if err != nil {
		return nil, err
	}
	json.Unmarshal([]byte(permJSON), &r.Permissions)
	return r, nil
}

func (m *Manager) ListByGuild(guildID string) ([]*models.Role, error) {
	rows, err := m.db.Query(
		`SELECT id, guild_id, name, color, position, permissions, is_default
		 FROM roles WHERE guild_id = ? ORDER BY position DESC`, guildID,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var roles []*models.Role
	for rows.Next() {
		r := &models.Role{}
		var permJSON string
		if err := rows.Scan(&r.ID, &r.GuildID, &r.Name, &r.Color, &r.Position, &permJSON, &r.IsDefault); err != nil {
			return nil, err
		}
		json.Unmarshal([]byte(permJSON), &r.Permissions)
		roles = append(roles, r)
	}
	return roles, nil
}

func (m *Manager) AssignRole(roleID, userID string) error {
	_, err := m.db.Exec(
		`INSERT OR IGNORE INTO role_members (role_id, user_id) VALUES (?, ?)`,
		roleID, userID,
	)
	return err
}

func (m *Manager) RemoveRole(roleID, userID string) error {
	result, err := m.db.Exec(
		`DELETE FROM role_members WHERE role_id = ? AND user_id = ?`,
		roleID, userID,
	)
	if err != nil {
		return err
	}
	affected, _ := result.RowsAffected()
	if affected == 0 {
		return errors.New("role assignment not found")
	}
	return nil
}

func (m *Manager) GetUserRoles(guildID, userID string) ([]*models.Role, error) {
	rows, err := m.db.Query(
		`SELECT r.id, r.guild_id, r.name, r.color, r.position, r.permissions, r.is_default
		 FROM roles r
		 INNER JOIN role_members rm ON r.id = rm.role_id
		 WHERE r.guild_id = ? AND rm.user_id = ?
		 UNION
		 SELECT id, guild_id, name, color, position, permissions, is_default
		 FROM roles WHERE guild_id = ? AND is_default = 1
		 ORDER BY position DESC`, guildID, userID, guildID,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var roles []*models.Role
	for rows.Next() {
		r := &models.Role{}
		var permJSON string
		if err := rows.Scan(&r.ID, &r.GuildID, &r.Name, &r.Color, &r.Position, &permJSON, &r.IsDefault); err != nil {
			return nil, err
		}
		json.Unmarshal([]byte(permJSON), &r.Permissions)
		roles = append(roles, r)
	}
	return roles, nil
}

func (m *Manager) HasPermission(guildID, userID, permission string) (bool, error) {
	roles, err := m.GetUserRoles(guildID, userID)
	if err != nil {
		return false, err
	}
	for _, r := range roles {
		for _, p := range r.Permissions {
			if p == "administrator" || p == permission {
				return true, nil
			}
		}
	}
	return false, nil
}