package api

import (
	"fmt"
	"path/filepath"

	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
	"github.com/mathiasbq/hyperguild/ingestion/internal/provenance"
)

// StampProvenance applies server-owned provenance (hyperguild#145) to note
// content. See package provenance for the rule; an error means the stamped
// note would not read back as stamped, and the write must be refused.
func StampProvenance(content, origin, writtenBy string) (string, error) {
	return provenance.Apply(content, provenance.Stamp{Origin: origin, WrittenBy: writtenBy})
}

// StampProvenanceFile applies StampProvenance to a brain-relative note path,
// read and rewritten through the brain root (hyperguild#158).
func StampProvenanceFile(brainDir, relPath, origin, writtenBy string) error {
	rel, _, err := resolveWithin(brainDir, relPath)
	if err != nil {
		return err
	}
	bfs, err := brainfs.Open(brainDir)
	if err != nil {
		return fmt.Errorf("open brain: %w", err)
	}
	defer func() { _ = bfs.Close() }()
	b, err := bfs.ReadRegular(rel)
	if err != nil {
		return fmt.Errorf("read for provenance: %w", err)
	}
	out, err := provenance.Apply(string(b), provenance.Stamp{Origin: origin, WrittenBy: writtenBy})
	if err != nil {
		return err
	}
	if out == string(b) {
		return nil
	}
	if err := bfs.WriteRegular(rel, []byte(out)); err != nil {
		return fmt.Errorf("write provenance: %w", err)
	}
	return nil
}

// createBrainFile creates the file at abs (inside brainDir) through the
// brain root and fails if anything is already there.
func createBrainFile(brainDir, abs string, data []byte) error {
	rel, err := filepath.Rel(brainDir, abs)
	if err != nil {
		return err
	}
	bfs, err := brainfs.Open(brainDir)
	if err != nil {
		return fmt.Errorf("open brain: %w", err)
	}
	defer func() { _ = bfs.Close() }()
	return bfs.CreateRegular(filepath.ToSlash(rel), data)
}

// removeBrainFile removes the file at abs (inside brainDir) through the
// brain root.
func removeBrainFile(brainDir, abs string) error {
	rel, err := filepath.Rel(brainDir, abs)
	if err != nil {
		return err
	}
	bfs, err := brainfs.Open(brainDir)
	if err != nil {
		return fmt.Errorf("open brain: %w", err)
	}
	defer func() { _ = bfs.Close() }()
	return bfs.Remove(filepath.ToSlash(rel))
}