package main

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
	"sync"
)

const validProposal = `{"corrections":[{"id":1,"original_text":"hello world","corrected_text":"Hello, world.","confidence":0.95}]}`
const validAssessment = `{"validations":[{"correction_index":0,"approved":true,"confidence":0.95,"reason":"Punctuation and capitalization only"}]}`

// roundTripFunc exercises PromptKit's built-in HTTP path without any network.
type roundTripFunc func(*http.Request) (*http.Response, error)

func (f roundTripFunc) RoundTrip(r *http.Request) (*http.Response, error) { return f(r) }

func providerResponse(status int, content string, usage any) *http.Response {
	body := map[string]any{"choices": []any{map[string]any{"message": map[string]any{"role": "assistant", "content": content}, "finish_reason": "stop"}}}
	if status != http.StatusOK {
		body = map[string]any{"error": map[string]any{"message": "synthetic temporary failure"}}
	}
	if usage != nil {
		body["usage"] = usage
	}
	data, _ := json.Marshal(body)
	return &http.Response{StatusCode: status, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(string(data)))}
}

func demonstrationClient() *http.Client {
	var mu sync.Mutex
	calls := map[string]int{}
	return &http.Client{Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
		if req.URL.Host != "offline.invalid" {
			return nil, fmt.Errorf("unexpected offline target")
		}
		var body struct {
			Model string `json:"model"`
		}
		if err := json.NewDecoder(req.Body).Decode(&body); err != nil {
			return nil, err
		}
		mu.Lock()
		calls[body.Model]++
		n := calls[body.Model]
		mu.Unlock()
		if n == 1 {
			return providerResponse(200, "not JSON", nil), nil
		}
		switch body.Model {
		case "synthetic-grammar", "synthetic-grammar-testing":
			return providerResponse(200, validProposal, nil), nil
		case "synthetic-review", "synthetic-review-testing":
			return providerResponse(200, validAssessment, nil), nil
		default:
			return nil, fmt.Errorf("unexpected synthetic model")
		}
	})}
}