package repository

import (
	"database/sql"
	"errors"
	"fmt"

	"cmautobuy/admin/model"
	"github.com/go-sql-driver/mysql"
)

var ErrAIProviderNameExists = errors.New("AI 服务商名称已经存在")

func ListAIProviders(q Execer) ([]model.AIProviderConfig, error) {
	rows, err := q.Query(`SELECT provider_id,name,base_url,model,timeout_seconds,max_concurrency,
		confidence_threshold_bps,enabled,last_test_status,last_test_message,last_tested_at,
		last_test_fingerprint,created_by_user_id,updated_by_user_id,created_at,updated_at
		FROM ai_provider_configs ORDER BY enabled DESC,name,provider_id`)
	if err != nil {
		return nil, fmt.Errorf("查询 AI 服务商配置失败: %w", err)
	}
	defer rows.Close()
	var result []model.AIProviderConfig
	for rows.Next() {
		item, err := scanAIProvider(rows.Scan)
		if err != nil {
			return nil, err
		}
		result = append(result, item)
	}
	return result, rows.Err()
}

func GetAIProvider(q Execer, providerID string) (*model.AIProviderConfig, error) {
	item, err := scanAIProvider(func(dest ...any) error {
		return q.QueryRow(`SELECT provider_id,name,base_url,model,timeout_seconds,max_concurrency,
			confidence_threshold_bps,enabled,last_test_status,last_test_message,last_tested_at,
			last_test_fingerprint,created_by_user_id,updated_by_user_id,created_at,updated_at
			FROM ai_provider_configs WHERE provider_id=?`, providerID).Scan(dest...)
	})
	if errors.Is(err, sql.ErrNoRows) {
		return nil, nil
	}
	if err != nil {
		return nil, fmt.Errorf("查询 AI 服务商配置失败: %w", err)
	}
	return &item, nil
}

func GetEnabledAIProvider(q Execer) (*model.AIProviderConfig, error) {
	item, err := scanAIProvider(func(dest ...any) error {
		return q.QueryRow(`SELECT provider_id,name,base_url,model,timeout_seconds,max_concurrency,
			confidence_threshold_bps,enabled,last_test_status,last_test_message,last_tested_at,
			last_test_fingerprint,created_by_user_id,updated_by_user_id,created_at,updated_at
			FROM ai_provider_configs WHERE enabled=1`).Scan(dest...)
	})
	if errors.Is(err, sql.ErrNoRows) {
		return nil, nil
	}
	if err != nil {
		return nil, fmt.Errorf("查询当前 AI 服务商失败: %w", err)
	}
	return &item, nil
}

type scanValues func(dest ...any) error

func scanAIProvider(scan scanValues) (model.AIProviderConfig, error) {
	var item model.AIProviderConfig
	var enabled int
	var lastMessage, lastTestedAt, fingerprint sql.NullString
	err := scan(&item.ProviderID, &item.Name, &item.BaseURL, &item.Model, &item.TimeoutSeconds,
		&item.MaxConcurrency, &item.ConfidenceThresholdBPS, &enabled, &item.LastTestStatus,
		&lastMessage, &lastTestedAt, &fingerprint, &item.CreatedByUserID, &item.UpdatedByUserID,
		&item.CreatedAt, &item.UpdatedAt)
	item.Enabled = enabled == 1
	item.LastTestMessage = lastMessage.String
	item.LastTestedAt = lastTestedAt.String
	item.LastTestFingerprint = fingerprint.String
	return item, err
}

func InsertAIProvider(q Execer, item model.AIProviderConfig) error {
	_, err := q.Exec(`INSERT INTO ai_provider_configs
		(provider_id,name,base_url,model,timeout_seconds,max_concurrency,confidence_threshold_bps,
		enabled,last_test_status,created_by_user_id,updated_by_user_id,created_at,updated_at)
		VALUES(?,?,?,?,?,?,?,0,'pending',?,?,?,?)`, item.ProviderID, item.Name, item.BaseURL,
		item.Model, item.TimeoutSeconds, item.MaxConcurrency, item.ConfidenceThresholdBPS,
		item.CreatedByUserID, item.UpdatedByUserID, item.CreatedAt, item.UpdatedAt)
	return aiProviderWriteError("新增 AI 服务商配置", err)
}

func UpdateAIProvider(q Execer, item model.AIProviderConfig) (bool, error) {
	result, err := q.Exec(`UPDATE ai_provider_configs SET name=?,base_url=?,model=?,timeout_seconds=?,
		max_concurrency=?,confidence_threshold_bps=?,last_test_status='pending',last_test_message=NULL,
		last_tested_at=NULL,last_test_fingerprint=NULL,enabled=0,updated_by_user_id=?,updated_at=? WHERE provider_id=?`,
		item.Name, item.BaseURL, item.Model, item.TimeoutSeconds, item.MaxConcurrency,
		item.ConfidenceThresholdBPS, item.UpdatedByUserID, item.UpdatedAt, item.ProviderID)
	if err != nil {
		return false, aiProviderWriteError("更新 AI 服务商配置", err)
	}
	n, err := result.RowsAffected()
	return n == 1, err
}

func RecordAIProviderTest(q Execer, providerID, status, message, testedAt, fingerprint, actorID string) (bool, error) {
	result, err := q.Exec(`UPDATE ai_provider_configs SET last_test_status=?,last_test_message=?,
		last_tested_at=?,last_test_fingerprint=?,updated_by_user_id=?,updated_at=? WHERE provider_id=?`,
		status, nullableText(message), testedAt, nullableText(fingerprint), actorID, testedAt, providerID)
	if err != nil {
		return false, fmt.Errorf("记录 AI 连接测试失败: %w", err)
	}
	n, err := result.RowsAffected()
	return n == 1, err
}

func InvalidateAIProviderTest(q Execer, providerID, actorID, updatedAt string) (bool, error) {
	result, err := q.Exec(`UPDATE ai_provider_configs SET last_test_status='pending',last_test_message=NULL,
		last_tested_at=NULL,last_test_fingerprint=NULL,enabled=0,updated_by_user_id=?,updated_at=? WHERE provider_id=?`,
		actorID, updatedAt, providerID)
	if err != nil {
		return false, fmt.Errorf("重置 AI 连接测试状态失败: %w", err)
	}
	n, err := result.RowsAffected()
	return n == 1, err
}

func LockAIProviders(q Execer) error {
	rows, err := q.Query(`SELECT provider_id FROM ai_provider_configs FOR UPDATE`)
	if err != nil {
		return fmt.Errorf("锁定 AI 服务商配置失败: %w", err)
	}
	defer rows.Close()
	for rows.Next() {
		var providerID string
		if err := rows.Scan(&providerID); err != nil {
			return err
		}
	}
	return rows.Err()
}

func EnableAIProvider(q Execer, providerID, actorID, updatedAt string) (bool, error) {
	if _, err := q.Exec(`UPDATE ai_provider_configs SET enabled=0,updated_by_user_id=?,updated_at=? WHERE enabled=1`, actorID, updatedAt); err != nil {
		return false, fmt.Errorf("停用旧 AI 服务商失败: %w", err)
	}
	result, err := q.Exec(`UPDATE ai_provider_configs SET enabled=1,updated_by_user_id=?,updated_at=? WHERE provider_id=?`, actorID, updatedAt, providerID)
	if err != nil {
		return false, fmt.Errorf("启用 AI 服务商失败: %w", err)
	}
	n, err := result.RowsAffected()
	return n == 1, err
}

func DisableAIProvider(q Execer, providerID, actorID, updatedAt string) (bool, error) {
	result, err := q.Exec(`UPDATE ai_provider_configs SET enabled=0,updated_by_user_id=?,updated_at=? WHERE provider_id=?`, actorID, updatedAt, providerID)
	if err != nil {
		return false, fmt.Errorf("停用 AI 服务商失败: %w", err)
	}
	n, err := result.RowsAffected()
	return n == 1, err
}

func InsertAIProviderAudit(q Execer, audit model.AIProviderAudit) error {
	_, err := q.Exec(`INSERT INTO ai_provider_audits(provider_id,action,details_json,actor_user_id,created_at)
		VALUES(?,?,?,?,?)`, nullableText(audit.ProviderID), audit.Action, audit.DetailsJSON,
		audit.ActorUserID, audit.CreatedAt)
	if err != nil {
		return fmt.Errorf("写入 AI 配置审计失败: %w", err)
	}
	return nil
}

func aiProviderWriteError(action string, err error) error {
	if err == nil {
		return nil
	}
	var mysqlErr *mysql.MySQLError
	if errors.As(err, &mysqlErr) && mysqlErr.Number == 1062 {
		return ErrAIProviderNameExists
	}
	return fmt.Errorf("%s失败: %w", action, err)
}