package store

import (
	"context"
	"database/sql"
	"encoding/json"
	"fmt"
	"time"
)

type AuditEntry struct {
	ID        int64          `json:"id"`
	Timestamp time.Time      `json:"timestamp"`
	Actor     string         `json:"actor"`
	Action    string         `json:"action"`
	Resource  string         `json:"resource"`
	Result    string         `json:"result"`
	Error     string         `json:"error,omitempty"`
	Metadata  map[string]any `json:"metadata,omitempty"`
}

type AuditRepo struct {
	db *sql.DB
}

func NewAuditRepo(db *sql.DB) *AuditRepo {
	return &AuditRepo{db: db}
}

func (r *AuditRepo) Append(ctx context.Context, e *AuditEntry) error {
	if e.Timestamp.IsZero() {
		e.Timestamp = time.Now().UTC()
	}
	if e.Actor == "" {
		e.Actor = "system"
	}
	metaJSON, _ := json.Marshal(e.Metadata)
	if e.Error == "" {
		_, err := r.db.ExecContext(ctx,
			`INSERT INTO audit_log (timestamp, actor, action, resource, result, metadata) VALUES (?, ?, ?, ?, ?, ?)`,
			e.Timestamp, e.Actor, e.Action, e.Resource, e.Result, string(metaJSON))
		if err != nil {
			return fmt.Errorf("insert audit: %w", err)
		}
		return nil
	}
	_, err := r.db.ExecContext(ctx,
		`INSERT INTO audit_log (timestamp, actor, action, resource, result, error, metadata) VALUES (?, ?, ?, ?, ?, ?, ?)`,
		e.Timestamp, e.Actor, e.Action, e.Resource, e.Result, e.Error, string(metaJSON))
	if err != nil {
		return fmt.Errorf("insert audit (with error): %w", err)
	}
	return nil
}

func (r *AuditRepo) List(ctx context.Context, limit int) ([]*AuditEntry, error) {
	if limit <= 0 {
		limit = 100
	}
	rows, err := r.db.QueryContext(ctx,
		`SELECT id, timestamp, actor, action, resource, result, COALESCE(error, ''), COALESCE(metadata, '') FROM audit_log ORDER BY id DESC LIMIT ?`, limit)
	if err != nil {
		return nil, fmt.Errorf("list audit: %w", err)
	}
	defer rows.Close()
	var entries []*AuditEntry
	for rows.Next() {
		var (
			e        AuditEntry
			metaJSON string
		)
		if err := rows.Scan(&e.ID, &e.Timestamp, &e.Actor, &e.Action, &e.Resource, &e.Result, &e.Error, &metaJSON); err != nil {
			return nil, fmt.Errorf("scan audit: %w", err)
		}
		if metaJSON != "" {
			_ = json.Unmarshal([]byte(metaJSON), &e.Metadata)
		}
		entries = append(entries, &e)
	}
	return entries, rows.Err()
}