package service

import (
	"context"
	"fmt"
	"strings"

	"model-gateway/dao"
	"model-gateway/model/dto"
	"model-gateway/model/entity"

	"github.com/gogf/gf/v2/util/gconv"
)

// ====================== 模型引用解析层 ======================
// 引用行(ref_system_model_id>0) 调用时实时取系统模型配置 + 本人 apiKey 合成可执行配置；
// 系统模型调整零同步。Id 被覆盖为系统模型 id → 计价/并发键按系统模型走（会话/任务落库仍用引用行 id）。

const apiKeyPlaceholder = "{apiKey}"

// replacePlaceholder 递归替换 map/slice/string 中的占位符（泛化自 task_end 的 replaceTaskPlaceholder，非破坏式）。
func replacePlaceholder(v any, from, to string) any {
	switch val := v.(type) {
	case string:
		return strings.ReplaceAll(val, from, to)
	case map[string]any:
		m := make(map[string]any, len(val))
		for k, x := range val {
			m[k] = replacePlaceholder(x, from, to)
		}
		return m
	case map[string]string:
		m := make(map[string]string, len(val))
		for k, x := range val {
			m[k] = strings.ReplaceAll(x, from, to)
		}
		return m
	case []any:
		arr := make([]any, len(val))
		for i, x := range val {
			arr[i] = replacePlaceholder(x, from, to)
		}
		return arr
	default:
		return v
	}
}

// copyAndReplaceStringMap 非破坏式替换 map[string]string 值（新建 map，不污染入参）
func copyAndReplaceStringMap(src map[string]string, from, to string) map[string]string {
	if src == nil {
		return nil
	}
	m := make(map[string]string, len(src))
	for k, v := range src {
		m[k] = strings.ReplaceAll(v, from, to)
	}
	return m
}

// substituteAPIPlaceholder 把输入侧配置中的 {apiKey} 替换为生效 key（非破坏式：新建 map/struct，不污染入参）。
// 覆盖 BaseURL / RequestHeadMapping / RequestBodyMapping / RequestBusinessFieldMapping /
// AsyncTaskMapping(Url/RequestHeadMapping/RequestBodyMapping)。
func substituteAPIPlaceholder(m *entity.ModelManage, key string) {
	m.BaseURL = strings.ReplaceAll(m.BaseURL, apiKeyPlaceholder, key)
	m.RequestHeadMapping = copyAndReplaceStringMap(m.RequestHeadMapping, apiKeyPlaceholder, key)
	m.RequestBusinessFieldMapping = copyAndReplaceStringMap(m.RequestBusinessFieldMapping, apiKeyPlaceholder, key)
	if v, ok := replacePlaceholder(m.RequestBodyMapping, apiKeyPlaceholder, key).(map[string]any); ok {
		m.RequestBodyMapping = v
	}
	if a := m.AsyncTaskMapping; a != nil {
		ac := *a
		ac.Url = strings.ReplaceAll(a.Url, apiKeyPlaceholder, key)
		ac.RequestHeadMapping = copyAndReplaceStringMap(a.RequestHeadMapping, apiKeyPlaceholder, key)
		if v, ok := replacePlaceholder(a.RequestBodyMapping, apiKeyPlaceholder, key).(map[string]any); ok {
			ac.RequestBodyMapping = v
		}
		m.AsyncTaskMapping = &ac
	}
}

// mergeReferenceConfig 引用行 + 系统行 → 有效配置（纯函数，便于单测）。
// 配置字段取系统行；个人字段(apiKey/enabled/chatModel)取引用行；enabled 取 AND（系统停用=引用失效）。
func mergeReferenceConfig(stub, sys *entity.ModelManage) *entity.ModelManage {
	out := *sys
	out.ApiKey = stub.ApiKey
	if stub.Enabled != nil {
		out.Enabled = stub.Enabled
	}
	if stub.ChatModel != nil {
		out.ChatModel = stub.ChatModel
	}
	if sys.Enabled != nil && !*sys.Enabled {
		out.Enabled = gconv.PtrBool(false)
	}
	return &out
}

// resolveModelConfig 把请求命中的模型行解析为可执行配置：
// 引用行 → 系统行配置 + 引用行 apiKey（Id 覆盖为系统模型 id）；非引用行 → 原配置 + 自身 apiKey 替换占位。
// 引用系统模型已删除 → 报错（调用方阻塞）。
func resolveModelConfig(ctx context.Context, m *entity.ModelManage) (*entity.ModelManage, error) {
	if m == nil {
		return nil, nil
	}
	if m.RefSystemModelId > 0 {
		sys, err := dao.ModelManage.GetNotTenantId(ctx, &dto.GetModelManageReq{Id: m.RefSystemModelId})
		if err != nil {
			return nil, err
		}
		if sys == nil {
			return nil, fmt.Errorf("引用的系统模型已删除")
		}
		out := mergeReferenceConfig(m, sys)
		substituteAPIPlaceholder(out, out.ApiKey)
		return out, nil
	}
	out := *m
	substituteAPIPlaceholder(&out, out.ApiKey)
	return &out, nil
}