package db

import (
	"database/sql"
	"fmt"
	"strings"
)

type SyncResult struct {
	Direction  string         `json:"direction"`
	Tables     map[string]int `json:"tables"`
	FinishedAt string         `json:"finishedAt"`
}

type tableSpec struct {
	Name     string
	Columns  []string
	Conflict []string
}

var syncTables = []tableSpec{
	{"feedbacks", []string{"code", "received_at", "title", "type", "severity", "category", "priority", "contact", "body", "status", "status_detail", "note", "public_reply", "handled_by", "assignee", "due_at", "resolved_at", "archived_at", "sla_level", "source_channel", "risk_score", "resolution", "package_path", "encrypted_package_path", "package_sha256", "plain_package_sha256", "remote_addr", "summary_text", "included_files", "mail_sent", "updated_at", "last_activity_at"}, []string{"code"}},
	{"mail_records", []string{"id", "feedback_code", "kind", "status", "to_address", "subject", "plain_body", "html_body", "attachment_path", "attachment_name", "error_message", "created_at", "sent_at"}, []string{"id"}},
	{"feedback_events", []string{"id", "feedback_code", "event_type", "actor", "from_value", "to_value", "message", "created_at"}, []string{"id"}},
	{"feedback_comments", []string{"id", "feedback_code", "author", "body", "internal", "created_at"}, []string{"id"}},
	{"feedback_tags", []string{"feedback_code", "tag", "created_at"}, []string{"feedback_code", "tag"}},
	{"audit_logs", []string{"id", "actor", "type", "target", "message", "ip", "user_agent", "created_at"}, []string{"id"}},
	{"webhook_deliveries", []string{"id", "webhook_name", "event", "status", "attempts", "response_code", "error_message", "payload_sha256", "created_at", "finished_at"}, []string{"id"}},
}

func (s *Store) ImportSQLiteToRemote() (SyncResult, error) {
	s.mu.RLock()
	remote := s.remoteDB
	remoteDialect := s.remoteDialect
	local := s.localDB
	localDialect := s.localDialect
	s.mu.RUnlock()
	if remote == nil {
		return SyncResult{}, fmt.Errorf("remote database is not configured")
	}
	result, err := copyAllTables(local, localDialect, remote, remoteDialect, "sqlite_to_remote")
	s.setSyncStatus(result, err)
	return result, err
}

func (s *Store) SyncNow() (SyncResult, error) {
	return s.syncRemoteToSQLite()
}

func (s *Store) syncRemoteToSQLite() (SyncResult, error) {
	s.mu.RLock()
	remote := s.remoteDB
	remoteDialect := s.remoteDialect
	local := s.localDB
	localDialect := s.localDialect
	s.mu.RUnlock()
	if remote == nil {
		return SyncResult{}, nil
	}
	result, err := copyAllTables(remote, remoteDialect, local, localDialect, "remote_to_sqlite")
	s.setSyncStatus(result, err)
	return result, err
}

func (s *Store) setSyncStatus(result SyncResult, err error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	if err != nil {
		s.status.LastSyncError = err.Error()
		return
	}
	if result.FinishedAt != "" {
		s.status.LastSyncAt = result.FinishedAt
	}
	s.status.LastSyncError = ""
}

func copyAllTables(src *sql.DB, srcDialect dialect, dst *sql.DB, dstDialect dialect, direction string) (SyncResult, error) {
	result := SyncResult{Direction: direction, Tables: map[string]int{}, FinishedAt: Now()}
	for _, table := range syncTables {
		copied, err := copyTable(src, srcDialect, dst, dstDialect, table)
		if err != nil {
			return result, err
		}
		result.Tables[table.Name] = copied
	}
	return result, nil
}

func copyTable(src *sql.DB, srcDialect dialect, dst *sql.DB, dstDialect dialect, spec tableSpec) (int, error) {
	selectSQL := "SELECT " + strings.Join(spec.Columns, ", ") + " FROM " + spec.Name
	rows, err := src.Query(srcDialect.rebind(selectSQL))
	if err != nil {
		return 0, err
	}
	defer rows.Close()

	insertSQL := dstDialect.rebind(dstDialect.upsert(spec.Name, spec.Columns, spec.Conflict))
	count := 0
	for rows.Next() {
		values := make([]any, len(spec.Columns))
		ptrs := make([]any, len(spec.Columns))
		for index := range values {
			ptrs[index] = &values[index]
		}
		if err := rows.Scan(ptrs...); err != nil {
			return count, err
		}
		for index, value := range values {
			if bytes, ok := value.([]byte); ok {
				values[index] = string(bytes)
			}
		}
		if _, err := dst.Exec(insertSQL, values...); err != nil {
			return count, err
		}
		count++
	}
	return count, rows.Err()
}