// ingestion/internal/frontmatter/scan_test.go
package frontmatter

import (
	"os"
	"path/filepath"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func writeTree(t *testing.T, files map[string]string) string {
	t.Helper()
	root := t.TempDir()
	for name, content := range files {
		path := filepath.Join(root, name)
		require.NoError(t, os.MkdirAll(filepath.Dir(path), 0o755))
		require.NoError(t, os.WriteFile(path, []byte(content), 0o644))
	}
	return root
}

const (
	brokenDoc = "---\ntitle: Broken: title here\nwing: homelab\n---\n\nbody\n"
	validDoc  = "---\ntitle: 'Fine: quoted'\n---\n\nbody\n"
)

func TestScan_ReportsOnlyBrokenFiles(t *testing.T) {
	root := writeTree(t, map[string]string{
		"wiki/a/broken.md": brokenDoc,
		"wiki/a/valid.md":  validDoc,
		"wiki/b/plain.md":  "# no frontmatter\n\nbody: with colon\n",
		"wiki/a/notes.txt": brokenDoc, // not markdown — must be ignored
	})

	found, err := Scan(root, false)
	require.NoError(t, err)

	require.Len(t, found, 1)
	assert.Equal(t, "wiki/a/broken.md", found[0].Path)
	assert.False(t, found[0].Repaired)
	assert.Error(t, found[0].Err)

	// Dry run must not touch the file.
	got, err := os.ReadFile(filepath.Join(root, "wiki/a/broken.md"))
	require.NoError(t, err)
	assert.Equal(t, brokenDoc, string(got))
}

func TestScan_FixWritesRepairedFilesAndLeavesTheRestAlone(t *testing.T) {
	root := writeTree(t, map[string]string{
		"wiki/a/broken.md": brokenDoc,
		"wiki/a/valid.md":  validDoc,
	})

	found, err := Scan(root, true)
	require.NoError(t, err)
	require.Len(t, found, 1)
	assert.True(t, found[0].Repaired)
	assert.NoError(t, found[0].Err)

	repaired, err := os.ReadFile(filepath.Join(root, "wiki/a/broken.md"))
	require.NoError(t, err)
	require.NoError(t, Lint(repaired), "the repaired file must parse")
	assert.Contains(t, string(repaired), "title: 'Broken: title here'")
	assert.Contains(t, string(repaired), "wing: homelab", "untouched keys must survive")

	untouched, err := os.ReadFile(filepath.Join(root, "wiki/a/valid.md"))
	require.NoError(t, err)
	assert.Equal(t, validDoc, string(untouched))

	// Second pass finds nothing — the repair is idempotent and complete.
	again, err := Scan(root, true)
	require.NoError(t, err)
	assert.Empty(t, again)
}

func TestScan_ReportsUnfixableWithoutWriting(t *testing.T) {
	unfixable := "---\ntitle: fine\n\tbad: tab-indented\n  - stray\n---\n\nbody\n"
	root := writeTree(t, map[string]string{"wiki/x.md": unfixable})

	found, err := Scan(root, true)
	require.NoError(t, err)
	require.Len(t, found, 1)
	assert.False(t, found[0].Repaired)
	assert.Error(t, found[0].Err)

	got, err := os.ReadFile(filepath.Join(root, "wiki/x.md"))
	require.NoError(t, err)
	assert.Equal(t, unfixable, string(got), "an unfixable file must be left exactly as it was")
}

func TestScan_ReportsUndecodableFilesInsteadOfFailingTheRun(t *testing.T) {
	root := writeTree(t, map[string]string{"wiki/ok.md": validDoc})
	require.NoError(t, os.WriteFile(filepath.Join(root, "wiki/bad-bytes.md"),
		[]byte{'-', '-', '-', '\n', 0xff, 0xfe, '\n', '-', '-', '-', '\n'}, 0o644))

	found, err := Scan(root, false)
	require.NoError(t, err, "one unreadable file must not abort the whole scan")
	require.Len(t, found, 1)
	assert.Equal(t, "wiki/bad-bytes.md", found[0].Path)
}