package db

import (
	"encoding/json"
	"fmt"

	"git.wntrmute.dev/kyle/mcr/internal/policy"
)

// ruleBody is the JSON structure stored in the rule_json column.
type ruleBody struct {
	Effect       string   `json:"effect"`
	Roles        []string `json:"roles,omitempty"`
	AccountTypes []string `json:"account_types,omitempty"`
	SubjectUUID  string   `json:"subject_uuid,omitempty"`
	Actions      []string `json:"actions"`
	Repositories []string `json:"repositories,omitempty"`
}

// LoadEnabledPolicyRules returns all enabled policy rules from the database,
// ordered by priority ascending. It implements policy.RuleStore.
func (d *DB) LoadEnabledPolicyRules() ([]policy.Rule, error) {
	rows, err := d.Query(
		`SELECT id, priority, description, rule_json
		 FROM policy_rules
		 WHERE enabled = 1
		 ORDER BY priority ASC`,
	)
	if err != nil {
		return nil, fmt.Errorf("db: load policy rules: %w", err)
	}
	defer func() { _ = rows.Close() }()

	var rules []policy.Rule
	for rows.Next() {
		var id int64
		var priority int
		var description, ruleJSON string
		if err := rows.Scan(&id, &priority, &description, &ruleJSON); err != nil {
			return nil, fmt.Errorf("db: scan policy rule: %w", err)
		}

		var body ruleBody
		if err := json.Unmarshal([]byte(ruleJSON), &body); err != nil {
			return nil, fmt.Errorf("db: parse rule_json for rule %d: %w", id, err)
		}

		rule := policy.Rule{
			ID:           id,
			Priority:     priority,
			Description:  description,
			Effect:       policy.Effect(body.Effect),
			Roles:        body.Roles,
			AccountTypes: body.AccountTypes,
			SubjectUUID:  body.SubjectUUID,
			Repositories: body.Repositories,
		}
		for _, a := range body.Actions {
			rule.Actions = append(rule.Actions, policy.Action(a))
		}
		rules = append(rules, rule)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("db: iterate policy rules: %w", err)
	}

	return rules, nil
}