package main

import (
	"bytes"
	"context"
	"encoding/json"
	"io"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

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

func brainQueryServer(t *testing.T, body string) *httptest.Server {
	t.Helper()
	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(body))
	}))
}

func TestRunBrainQuery_Human(t *testing.T) {
	srv := brainQueryServer(t, `{"results":[{"path":"knowledge/a.md","title":"A","excerpt":"...","score":9},{"path":"knowledge/b.md","title":"B","excerpt":"...","score":3}]}`)
	defer srv.Close()
	t.Setenv("BRAIN_URL", srv.URL)

	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{"query", "topic"}, strings.NewReader(""), &out, &errBuf)
	require.NoError(t, err)
	got := out.String()
	assert.Contains(t, got, "knowledge/a.md")
	assert.Contains(t, got, "score=9")
	assert.Contains(t, got, "knowledge/b.md")
}

func TestRunBrainQuery_JSON(t *testing.T) {
	srv := brainQueryServer(t, `{"results":[{"path":"x.md","title":"X","excerpt":"e","score":5}]}`)
	defer srv.Close()
	t.Setenv("BRAIN_URL", srv.URL)

	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{"query", "--json", "topic"}, strings.NewReader(""), &out, &errBuf)
	require.NoError(t, err)
	assert.Contains(t, out.String(), `"path": "x.md"`)
	assert.Contains(t, out.String(), `"score": 5`)
}

func TestRunBrainQuery_Limit(t *testing.T) {
	gotLimit := -1
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		body, _ := io.ReadAll(r.Body)
		var p struct {
			Query string `json:"query"`
			Limit int    `json:"limit"`
		}
		_ = json.Unmarshal(body, &p)
		gotLimit = p.Limit
		_, _ = w.Write([]byte(`{"results":[]}`))
	}))
	defer srv.Close()
	t.Setenv("BRAIN_URL", srv.URL)

	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{"query", "--limit", "12", "topic"}, strings.NewReader(""), &out, &errBuf)
	require.NoError(t, err)
	assert.Equal(t, 12, gotLimit)
}

func TestRunBrainQuery_MissingTopic(t *testing.T) {
	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{"query"}, strings.NewReader(""), &out, &errBuf)
	assert.Error(t, err)
}

func TestRunBrain_NoSubsubcommand(t *testing.T) {
	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{}, strings.NewReader(""), &out, &errBuf)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "subcommand required")
}

func TestRunBrain_UnknownSubsubcommand(t *testing.T) {
	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{"bogus"}, strings.NewReader(""), &out, &errBuf)
	assert.Error(t, err)
}

func TestRunBrainWrite_Success(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		assert.Equal(t, http.MethodPost, r.Method)
		assert.Equal(t, "/write", r.URL.Path)
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"path":"knowledge/test-slug.md"}`))
	}))
	defer srv.Close()
	t.Setenv("BRAIN_URL", srv.URL)

	var out, errBuf bytes.Buffer
	err := runBrain(
		context.Background(),
		[]string{"write", "knowledge", "test-slug"},
		strings.NewReader("# Test\n\nSome body content.\n"),
		&out, &errBuf,
	)
	require.NoError(t, err)
	assert.Contains(t, out.String(), "knowledge/test-slug.md")
}

func TestRunBrainWrite_MissingArgs(t *testing.T) {
	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{"write", "knowledge"}, strings.NewReader("x"), &out, &errBuf)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "type and slug required")
}

func TestRunBrainWrite_BackendError(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusBadRequest)
		_, _ = w.Write([]byte("invalid slug"))
	}))
	defer srv.Close()
	t.Setenv("BRAIN_URL", srv.URL)

	var out, errBuf bytes.Buffer
	err := runBrain(
		context.Background(),
		[]string{"write", "knowledge", "bad slug"},
		strings.NewReader("body"),
		&out, &errBuf,
	)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "400")
}

func TestRunBrainWrite_EmptyStdin(t *testing.T) {
	gotLen := -1
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		body, _ := io.ReadAll(r.Body)
		var p struct {
			Content string `json:"content"`
		}
		_ = json.Unmarshal(body, &p)
		gotLen = len(p.Content)
		_, _ = w.Write([]byte(`{"path":"x.md"}`))
	}))
	defer srv.Close()
	t.Setenv("BRAIN_URL", srv.URL)

	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{"write", "knowledge", "empty"}, strings.NewReader(""), &out, &errBuf)
	require.NoError(t, err)
	assert.Equal(t, 0, gotLen, "empty stdin should produce empty content payload")
}

func TestRunBrainPassRate_Human(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = w.Write([]byte(`{"skill":"tdd","window":"7d","pass":47,"fail":3,"skip":0,"total":50,"pass_rate":0.94}`))
	}))
	defer srv.Close()
	t.Setenv("BRAIN_URL", srv.URL)

	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{"pass-rate", "tdd"}, strings.NewReader(""), &out, &errBuf)
	require.NoError(t, err)
	got := out.String()
	assert.Contains(t, got, "tdd")
	assert.Contains(t, got, "47 / 50")
	assert.Contains(t, got, "94%")
}

func TestRunBrainPassRate_NoData(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = w.Write([]byte(`{"skill":"tdd","window":"7d","pass":0,"fail":0,"skip":0,"total":0,"pass_rate":null}`))
	}))
	defer srv.Close()
	t.Setenv("BRAIN_URL", srv.URL)

	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{"pass-rate", "tdd"}, strings.NewReader(""), &out, &errBuf)
	require.NoError(t, err)
	assert.Contains(t, out.String(), "no data")
}

func TestRunBrainPassRate_JSON(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = w.Write([]byte(`{"skill":"tdd","window":"7d","pass":47,"fail":3,"skip":0,"total":50,"pass_rate":0.94}`))
	}))
	defer srv.Close()
	t.Setenv("BRAIN_URL", srv.URL)

	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{"pass-rate", "--json", "tdd"}, strings.NewReader(""), &out, &errBuf)
	require.NoError(t, err)
	assert.Contains(t, out.String(), `"pass_rate": 0.94`)
}

func TestRunBrainPassRate_MissingSkill(t *testing.T) {
	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{"pass-rate"}, strings.NewReader(""), &out, &errBuf)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "skill required")
}

func TestRunBrainPassRate_WindowFlag(t *testing.T) {
	gotWindow := ""
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		gotWindow = r.URL.Query().Get("window")
		_, _ = w.Write([]byte(`{"skill":"tdd","window":"30d","pass":0,"fail":0,"skip":0,"total":0,"pass_rate":null}`))
	}))
	defer srv.Close()
	t.Setenv("BRAIN_URL", srv.URL)

	var out, errBuf bytes.Buffer
	err := runBrain(context.Background(), []string{"pass-rate", "--window", "30d", "tdd"}, strings.NewReader(""), &out, &errBuf)
	require.NoError(t, err)
	assert.Equal(t, "30d", gotWindow)
}