package main

import (
	"bytes"
	"context"
	"encoding/json"
	"os"
	"path/filepath"
	"strings"
	"testing"

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

func readJSON(t *testing.T, path string) map[string]any {
	t.Helper()
	b, err := os.ReadFile(path)
	require.NoError(t, err)
	var out map[string]any
	require.NoError(t, json.Unmarshal(b, &out))
	return out
}

func TestRunMode_Cloud_Default(t *testing.T) {
	dir := t.TempDir()
	outPath := filepath.Join(dir, ".mcp.json")
	t.Setenv("BRAIN_URL", "http://koala:30330")

	var stdout, stderr bytes.Buffer
	err := runMode(context.Background(), []string{"cloud", "--out", outPath}, strings.NewReader(""), &stdout, &stderr)
	require.NoError(t, err)

	got := readJSON(t, outPath)
	servers, ok := got["mcpServers"].(map[string]any)
	require.True(t, ok, "mcpServers must be a JSON object")
	assert.Contains(t, servers, "brain")
	assert.NotContains(t, servers, "routing")
	assert.NotContains(t, got, "_mode_note")
}

func TestRunMode_ClientLocal_HasRoutingEntry(t *testing.T) {
	dir := t.TempDir()
	outPath := filepath.Join(dir, ".mcp.json")
	t.Setenv("BRAIN_URL", "http://koala:30330")

	var stdout, stderr bytes.Buffer
	err := runMode(context.Background(), []string{"client-local", "--out", outPath}, strings.NewReader(""), &stdout, &stderr)
	require.NoError(t, err)

	got := readJSON(t, outPath)
	servers := got["mcpServers"].(map[string]any)
	require.Contains(t, servers, "brain")
	require.Contains(t, servers, "routing")

	routing := servers["routing"].(map[string]any)
	assert.NotContains(t, routing, "_routing_pending", "placeholder should be removed once Plan 6 ships")

	headers, ok := routing["headers"].(map[string]any)
	require.True(t, ok, "routing entry should have headers block")
	assert.Equal(t, "client-local", headers["X-Hyperguild-Mode"])
}

func TestModeClientLocalHasRoutingHeader(t *testing.T) {
	tmp := t.TempDir() + "/mcp.json"
	out := &bytes.Buffer{}
	stderr := &bytes.Buffer{}
	require.NoError(t, runMode(context.Background(), []string{"client-local", "--out", tmp}, nil, out, stderr))

	body, err := os.ReadFile(tmp)
	require.NoError(t, err)
	var doc map[string]any
	require.NoError(t, json.Unmarshal(body, &doc))

	servers := doc["mcpServers"].(map[string]any)
	routing := servers["routing"].(map[string]any)
	assert.Equal(t, "http://koala:30310/mcp", routing["url"])
	assert.NotContains(t, routing, "_routing_pending", "placeholder should be removed once Plan 6 ships")

	headers, ok := routing["headers"].(map[string]any)
	require.True(t, ok, "routing entry should have headers block")
	assert.Equal(t, "client-local", headers["X-Hyperguild-Mode"])
}

func TestRunMode_Sovereign_HasModeNote(t *testing.T) {
	dir := t.TempDir()
	outPath := filepath.Join(dir, ".mcp.json")

	var stdout, stderr bytes.Buffer
	err := runMode(context.Background(), []string{"sovereign", "--out", outPath}, strings.NewReader(""), &stdout, &stderr)
	require.NoError(t, err)

	got := readJSON(t, outPath)
	assert.Contains(t, got, "_mode_note")
	servers := got["mcpServers"].(map[string]any)
	assert.Contains(t, servers, "brain")
	assert.NotContains(t, servers, "routing")
}

func TestRunMode_DefaultsOutToCwd(t *testing.T) {
	dir := t.TempDir()
	t.Chdir(dir) // Go 1.24+ — replaces the older os.Chdir-with-cleanup pattern

	var stdout, stderr bytes.Buffer
	err := runMode(context.Background(), []string{"cloud"}, strings.NewReader(""), &stdout, &stderr)
	require.NoError(t, err)
	_, statErr := os.Stat(filepath.Join(dir, ".mcp.json"))
	assert.NoError(t, statErr, ".mcp.json should exist in cwd")
}

func TestRunMode_UnknownMode(t *testing.T) {
	dir := t.TempDir()
	outPath := filepath.Join(dir, ".mcp.json")
	var stdout, stderr bytes.Buffer
	err := runMode(context.Background(), []string{"bogus", "--out", outPath}, strings.NewReader(""), &stdout, &stderr)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "unknown mode")
}

func TestRunMode_NoArgs(t *testing.T) {
	var stdout, stderr bytes.Buffer
	err := runMode(context.Background(), []string{}, strings.NewReader(""), &stdout, &stderr)
	assert.Error(t, err)
}

func TestRunMode_RefusesToOverwrite(t *testing.T) {
	dir := t.TempDir()
	outPath := filepath.Join(dir, ".mcp.json")
	require.NoError(t, os.WriteFile(outPath, []byte(`{"existing":"file"}`), 0o644))

	var stdout, stderr bytes.Buffer
	err := runMode(context.Background(), []string{"cloud", "--out", outPath}, strings.NewReader(""), &stdout, &stderr)
	require.Error(t, err)
	assert.Contains(t, err.Error(), "exists")
}

func TestRunMode_Force(t *testing.T) {
	dir := t.TempDir()
	outPath := filepath.Join(dir, ".mcp.json")
	require.NoError(t, os.WriteFile(outPath, []byte(`{"existing":"file"}`), 0o644))

	var stdout, stderr bytes.Buffer
	err := runMode(context.Background(), []string{"cloud", "--out", outPath, "--force"}, strings.NewReader(""), &stdout, &stderr)
	require.NoError(t, err)
	got := readJSON(t, outPath)
	assert.Contains(t, got, "mcpServers")
	assert.NotContains(t, got, "existing")
}