package api

import (
	"strings"
	"testing"

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

func TestParseFrontmatterSplitsHeaderAndBody(t *testing.T) {
	src := "---\nwing: jepa-fx\nhall: facts\ncreated_at: 2026-01-01T00:00:00Z\n---\n# Title\n\nbody text\n"
	fm, body := parseFrontmatter(src)

	assert.Equal(t, "jepa-fx", fm.get("wing"))
	assert.Equal(t, "facts", fm.get("hall"))
	assert.Equal(t, "2026-01-01T00:00:00Z", fm.get("created_at"))
	assert.Equal(t, "# Title\n\nbody text\n", body)
}

func TestParseFrontmatterNoHeader(t *testing.T) {
	src := "# Just a body\n\nno frontmatter here\n"
	fm, body := parseFrontmatter(src)

	assert.Empty(t, fm.lines)
	assert.Equal(t, src, body)
}

func TestFrontmatterSetOverridesExistingKey(t *testing.T) {
	fm, _ := parseFrontmatter("---\nwing: a\nupdated_at: old\n---\nbody\n")
	fm.set("updated_at", "new")

	assert.Equal(t, "new", fm.get("updated_at"))
	// No duplicate key.
	assert.Equal(t, 1, strings.Count(fm.render(), "updated_at:"))
}

func TestFrontmatterSetAppendsNewKey(t *testing.T) {
	fm, _ := parseFrontmatter("---\nwing: a\n---\nbody\n")
	fm.set("supersedes", "abc123")

	out := fm.render()
	assert.Contains(t, out, "wing: a")
	assert.Contains(t, out, "supersedes: abc123")
}

func TestFrontmatterRenderPreservesCustomFields(t *testing.T) {
	src := "---\nwing: a\nhall: facts\ncustom_field: keep-me\ntags: [x, y]\n---\nbody\n"
	fm, _ := parseFrontmatter(src)
	fm.set("updated_at", "2026-06-22T00:00:00Z")

	out := fm.render()
	assert.Contains(t, out, "custom_field: keep-me")
	assert.Contains(t, out, "tags: [x, y]")
	assert.Contains(t, out, "updated_at: 2026-06-22T00:00:00Z")
}

func TestFrontmatterRenderRoundTrips(t *testing.T) {
	src := "---\nwing: a\nhall: facts\n---\n"
	fm, _ := parseFrontmatter(src)
	assert.Equal(t, src, fm.render())
}