package llm

import (
	"context"
	"strings"
)

// RewriteMaxRunes caps how much selected text a single rewrite will accept. A
// rewrite is a focused "fix this sentence/paragraph" action, not a whole-doc
// pass — bounding it keeps latency sane and the model on-task. The handler
// rejects longer selections before calling the model.
const RewriteMaxRunes = 2000

// RunRewrite rewrites a selected passage in the requested style (e.g. "natural",
// "academic"). It is a one-shot Complete — the result is shown as a preview the
// writer accepts or discards, so we want the whole rewrite before rendering.
func RunRewrite(ctx context.Context, client LLMClient, text, style string) (string, error) {
	out, err := client.Complete(ctx, CompletionRequest{
		Messages:          RewriteMessages(text, style),
		MaxTokens:         1024,
		Temperature:       0.7,
		TopP:              0.9,
		RepetitionPenalty: 1.1,
	})
	if err != nil {
		return "", err
	}
	return cleanRewrite(out), nil
}

// cleanRewrite trims the model's output down to just the rewritten passage. The
// prompt asks for no quotes or preamble, but small instruct models occasionally
// wrap the answer in matching quotes — strip a single surrounding pair so the
// text drops cleanly into the editor.
func cleanRewrite(s string) string {
	s = strings.TrimSpace(s)
	if len(s) >= 2 {
		first, last := s[0], s[len(s)-1]
		if (first == '"' && last == '"') ||
			(first == '\'' && last == '\'') ||
			(strings.HasPrefix(s, "“") && strings.HasSuffix(s, "”")) {
			s = strings.TrimSpace(strings.Trim(s, "\"'“”"))
		}
	}
	return s
}