package sub2api

import (
	"context"
	"encoding/json"
	"net/http"
	"strings"
)

type GatewayAccessCheckRequest struct {
	APIKey        string
	ExpectedModel string
}

type GatewayAccessResult struct {
	OK               bool     `json:"ok"`
	StatusCode       int      `json:"status_code"`
	Models           []string `json:"models"`
	HasExpectedModel bool     `json:"has_expected_model"`
	CompletionOK     bool     `json:"completion_ok"`
	CompletionStatus int      `json:"completion_status"`
	CompletionType   string   `json:"completion_content_type,omitempty"`
	CompletionBody   string   `json:"completion_body_preview,omitempty"`
}

func (c *Client) CheckGatewayAccess(ctx context.Context, req GatewayAccessCheckRequest) (GatewayAccessResult, error) {
	gatewayClient := *c
	gatewayClient.apiKey = ""
	gatewayClient.bearerToken = strings.TrimSpace(req.APIKey)

	statusCode, _, body, err := gatewayClient.perform(ctx, http.MethodGet, "/v1/models", nil)
	if err != nil {
		return GatewayAccessResult{}, err
	}

	result := GatewayAccessResult{StatusCode: statusCode, OK: statusCode >= http.StatusOK && statusCode < http.StatusMultipleChoices}
	if !result.OK {
		return result, nil
	}
	result.Models = decodeGatewayModelIDs(body)
	for _, modelID := range result.Models {
		if modelID == strings.TrimSpace(req.ExpectedModel) {
			result.HasExpectedModel = true
			break
		}
	}
	return result, nil
}

func (c *Client) CheckGatewayCompletion(ctx context.Context, req GatewayCompletionCheckRequest) (GatewayCompletionResult, error) {
	gatewayClient := *c
	gatewayClient.apiKey = ""
	gatewayClient.bearerToken = strings.TrimSpace(req.APIKey)

	model := strings.TrimSpace(req.Model)
	if model == "" {
		return GatewayCompletionResult{}, nil
	}
	prompt := strings.TrimSpace(req.Prompt)
	if prompt == "" {
		prompt = "ping"
	}
	maxTokens := req.MaxTokens
	if maxTokens <= 0 {
		maxTokens = 8
	}
	payload := map[string]any{
		"model": model,
		"messages": []map[string]string{
			{"role": "user", "content": prompt},
		},
		"max_tokens":  maxTokens,
		"temperature": 0,
	}

	statusCode, headers, body, err := gatewayClient.perform(ctx, http.MethodPost, "/v1/chat/completions", payload)
	if err != nil {
		return GatewayCompletionResult{}, err
	}
	return GatewayCompletionResult{
		OK:          statusCode >= http.StatusOK && statusCode < http.StatusMultipleChoices,
		StatusCode:  statusCode,
		ContentType: strings.TrimSpace(headers.Get("Content-Type")),
		BodyPreview: previewGatewayBody(body, 400),
	}, nil
}

func decodeGatewayModelIDs(body []byte) []string {
	var payload struct {
		Data []struct {
			ID string `json:"id"`
		} `json:"data"`
	}
	if err := json.Unmarshal(body, &payload); err == nil && len(payload.Data) > 0 {
		models := make([]string, 0, len(payload.Data))
		for _, item := range payload.Data {
			if id := strings.TrimSpace(item.ID); id != "" {
				models = append(models, id)
			}
		}
		return models
	}
	return nil
}

func previewGatewayBody(body []byte, limit int) string {
	trimmed := strings.TrimSpace(string(body))
	if limit <= 0 || len(trimmed) <= limit {
		return trimmed
	}
	return trimmed[:limit]
}