package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"strings"
)

type ModelsResponse struct {
	Object string  `json:"object"`
	Data   []Model `json:"data"`
}

type Model struct {
	ID       string                 `json:"id"`
	Object   string                 `json:"object"`
	Created  int64                  `json:"created,omitempty"`
	OwnedBy  string                 `json:"owned_by,omitempty"`
	Metadata map[string]interface{} `json:"metadata,omitempty"`
}

type Limit struct {
	Context int `json:"context"`
	Output  int `json:"output"`
}

type OpencodeModel struct {
	Name  string `json:"name"`
	Limit Limit  `json:"limit"`
}

type DynamicProvider struct {
	Npm     string                   `json:"npm"`
	Name    string                   `json:"name"`
	Options map[string]string        `json:"options"`
	Models  map[string]OpencodeModel `json:"models"`
}

type OpencodeConfig struct {
	Schema   string                     `json:"$schema"`
	Provider map[string]DynamicProvider `json:"provider"`
}

func getIntFromMetadata(md map[string]interface{}, key string, defaultVal int) int {
	if md == nil {
		return defaultVal
	}
	if v, ok := md[key]; ok {
		if i, ok := v.(float64); ok {
			return int(i)
		}
	}
	return defaultVal
}

func main() {
	var providerName, baseURL, apiURL, outputFile string

	flag.StringVar(&providerName, "provider", "Myprovider", "Name of the provider (default: Myprovider)")
	flag.StringVar(&baseURL, "baseurl", "", "Base URL for the provider (required, e.g., http://localhost:8080/v1)")
	flag.StringVar(&apiURL, "apiurl", "", "API URL to fetch models from (default: <baseurl>/models)")
	flag.StringVar(&outputFile, "output", "opencode.jsonc", "Output file name (default: opencode.jsonc)")

	flag.Usage = func() {
		fmt.Fprintf(os.Stderr, "Usage: %s [options]\n\n", os.Args[0])
		fmt.Fprintf(os.Stderr, "Example:\n")
		fmt.Fprintf(os.Stderr, "  %s --provider Myprovider --baseurl http://localhost:8080/v1\n\n", os.Args[0])
		flag.PrintDefaults()
	}

	flag.Parse()

	if baseURL == "" {
		log.Fatal("--baseurl is required")
	}

	if apiURL == "" {
		apiURL = strings.TrimSuffix(baseURL, "/") + "/models"
	}

	if baseURL == "" || apiURL == "" {
		log.Fatal("Both --baseurl and --apiurl are required")
	}

	resp, err := http.Get(apiURL)
	if err != nil {
		log.Fatalf("Failed to fetch %s: %v", apiURL, err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		log.Fatalf("Unexpected status code: %d", resp.StatusCode)
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		log.Fatalf("Failed to read response: %v", err)
	}

	var modelsResp ModelsResponse
	if err := json.Unmarshal(body, &modelsResp); err != nil {
		log.Fatalf("Failed to parse models response: %v", err)
	}

	config := OpencodeConfig{
		Schema: "https://opencode.ai/config.json",
		Provider: map[string]DynamicProvider{
			providerName: {
				Npm:  "@ai-sdk/openai-compatible",
				Name: providerName,
				Options: map[string]string{
					"baseURL": baseURL,
					"apiKey":  "noneneeded",
				},
				Models: make(map[string]OpencodeModel),
			},
		},
	}

	for _, m := range modelsResp.Data {
		ctx := getIntFromMetadata(m.Metadata, "context_window", 131072)
		out := getIntFromMetadata(m.Metadata, "max_output_tokens", 8192)

		config.Provider[providerName].Models[m.ID] = OpencodeModel{
			Name: m.ID,
			Limit: Limit{
				Context: ctx,
				Output:  out,
			},
		}
	}

	out, err := json.MarshalIndent(config, "", "  ")
	if err != nil {
		log.Fatalf("Failed to marshal config: %v", err)
	}

	if err := os.WriteFile(outputFile, out, 0644); err != nil {
		log.Fatalf("Failed to write %s: %v", outputFile, err)
	}

	fmt.Printf("Successfully wrote %s with %d models for provider %s\n", outputFile, len(config.Provider[providerName].Models), providerName)
}