// ingestion/internal/extract/extract.go
package extract

import (
	"fmt"
	"os"
	"strings"
)

// Text reads the file at path and returns its plain-text content.
// Supported extensions: .md, .txt (passthrough), .pdf (via pdftotext).
func Text(path string) (string, error) {
	ext := strings.ToLower(fileExt(path))
	switch ext {
	case ".md", ".txt":
		b, err := os.ReadFile(path)
		if err != nil {
			return "", fmt.Errorf("read %s: %w", path, err)
		}
		return string(b), nil
	case ".pdf":
		return extractPDF(path)
	default:
		return "", fmt.Errorf("unsupported file extension: %s", ext)
	}
}

// fileExt returns the file extension including the dot, lowercased.
func fileExt(path string) string {
	for i := len(path) - 1; i >= 0; i-- {
		if path[i] == '.' {
			return path[i:]
		}
		if path[i] == '/' || path[i] == '\\' {
			break
		}
	}
	return ""
}