package analyze

import (
	"bytes"
	"context"
	"fmt"
	"os/exec"
	"strings"

	"github.com/ytshih/stonks/internal/config"
)

func init() {
	Register("subscription", newSubscriptionAnalyzer)
}

// subscriptionAnalyzer shells out to the `claude` CLI in headless/print mode
// (`claude -p`), using whatever session `claude login` established on this
// host. Usage is billed against that Claude Pro/Max subscription's
// rate limits rather than a separate per-token API bill.
//
// The CLI has no separate "system prompt" flag documented for scripting, so
// the system and user prompts are concatenated and piped in over stdin —
// the most robust interface regardless of CLI version.
type subscriptionAnalyzer struct{}

func newSubscriptionAnalyzer(cfg config.AnalyzerConfig) (Analyzer, error) {
	if _, err := exec.LookPath("claude"); err != nil {
		return nil, fmt.Errorf("analyze (subscription mode): `claude` CLI not found on PATH — install Claude Code and run `claude login`: %w", err)
	}
	return &subscriptionAnalyzer{}, nil
}

func (a *subscriptionAnalyzer) Analyze(ctx context.Context, prompt string) (string, error) {
	fullPrompt := SystemPrompt + "\n\n---\n\n" + prompt

	cmd := exec.CommandContext(ctx, "claude", "-p")
	cmd.Stdin = strings.NewReader(fullPrompt)

	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	if err := cmd.Run(); err != nil {
		return "", fmt.Errorf("analyze (subscription mode): claude CLI failed: %w (stderr: %s)", err, strings.TrimSpace(stderr.String()))
	}

	out := strings.TrimSpace(stdout.String())
	if out == "" {
		return "", fmt.Errorf("analyze (subscription mode): claude CLI produced no output (stderr: %s)", strings.TrimSpace(stderr.String()))
	}
	return out, nil
}