package analyze

import (
	"context"
	"fmt"
	"strings"

	"github.com/anthropics/anthropic-sdk-go"

	"gitea.konchin.com/service/stonks/internal/config"
)

func init() {
	Register("api", newAPIAnalyzer)
}

const defaultAPIModel = anthropic.ModelClaudeOpus5

// apiAnalyzer calls the Claude Messages API directly, billed per token.
// Reads credentials the standard way (ANTHROPIC_API_KEY / ANTHROPIC_AUTH_TOKEN
// / an `ant auth login` profile) via the zero-arg client constructor.
type apiAnalyzer struct {
	client anthropic.Client
	model  anthropic.Model
	effort anthropic.OutputConfigEffort
}

func newAPIAnalyzer(cfg config.AnalyzerConfig) (Analyzer, error) {
	model := anthropic.Model(cfg.Model)
	if cfg.Model == "" {
		model = defaultAPIModel
	}

	effort := anthropic.OutputConfigEffortMedium
	if cfg.Effort != "" {
		effort = anthropic.OutputConfigEffort(cfg.Effort)
	}

	return &apiAnalyzer{
		client: anthropic.NewClient(),
		model:  model,
		effort: effort,
	}, nil
}

func (a *apiAnalyzer) Analyze(ctx context.Context, prompt string) (string, error) {
	resp, err := a.client.Messages.New(ctx, anthropic.MessageNewParams{
		Model:     a.model,
		MaxTokens: 4096,
		System:    []anthropic.TextBlockParam{{Text: SystemPrompt}},
		OutputConfig: anthropic.OutputConfigParam{
			Effort: a.effort,
		},
		Messages: []anthropic.MessageParam{
			anthropic.NewUserMessage(anthropic.NewTextBlock(prompt)),
		},
	})
	if err != nil {
		return "", fmt.Errorf("analyze (api mode): %w", err)
	}

	if resp.StopReason == anthropic.StopReasonRefusal {
		return "", fmt.Errorf("analyze (api mode): request refused by safety classifiers")
	}

	var out strings.Builder
	for _, block := range resp.Content {
		if text, ok := block.AsAny().(anthropic.TextBlock); ok {
			out.WriteString(text.Text)
		}
	}
	if out.Len() == 0 {
		return "", fmt.Errorf("analyze (api mode): response contained no text content (stop_reason=%s)", resp.StopReason)
	}

	return out.String(), nil
}