package neovim

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

	"github.com/MDietermann/ArduinoArchSetup/internal/config"
	"github.com/MDietermann/ArduinoArchSetup/internal/module"
	"github.com/MDietermann/ArduinoArchSetup/internal/platform"
)

type fakeRunner struct {
	runCalls, outCalls [][]string
	installed          map[string]bool
}

func (f *fakeRunner) Run(_ context.Context, name string, args ...string) error {
	f.runCalls = append(f.runCalls, append([]string{name}, args...))
	if name == "git" && len(args) >= 1 && args[0] == "clone" {
		dest := args[len(args)-1]
		os.MkdirAll(filepath.Join(dest, "lua", "plugins"), 0o755)
		os.WriteFile(filepath.Join(dest, "lua", "plugins", "init.lua"),
			[]byte("return {\n  \"neovim/nvim-lspconfig\",\n  opts = {},\n},\n{\n  \"other\",\n},\n"),
			0o644)
		os.MkdirAll(filepath.Join(dest, "lua", "configs"), 0o755)
		os.WriteFile(filepath.Join(dest, "lua", "configs", "lspconfig.lua"), []byte("stub"), 0o644)
	}
	return nil
}

func (f *fakeRunner) Output(_ context.Context, name string, args ...string) ([]byte, error) {
	f.outCalls = append(f.outCalls, append([]string{name}, args...))
	if name == "pacman" && len(args) == 2 && args[0] == "-Q" {
		if f.installed[args[1]] {
			return []byte("ok"), nil
		}
		return nil, errExit1
	}
	return nil, nil
}

type exitOne struct{}

func (exitOne) Error() string { return "exit 1" }

var errExit1 = exitOne{}

type nopReporter struct{}

func (nopReporter) Progress(string, int, int, string) {}
func (nopReporter) Log(string, string)                {}

func TestDetectFreshSystem(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	r := &fakeRunner{installed: map[string]bool{}}
	m := New(config.NeovimConfig{NvChadStarterRepo: "https://x/starter"}, "gruvbox", platform.NewPacman(r), platform.GitClient{Runner: r})
	st, err := m.Detect(context.Background())
	if err != nil {
		t.Fatal(err)
	}
	s := st.(state)
	if s.NvimInstalled {
		t.Error("nvim should be absent")
	}
	if s.ChadrcPresent {
		t.Error("chadrc should be absent")
	}
	if s.BackupNeeded {
		t.Error("no backup on empty system")
	}
}

func TestDetectNonNvChadTriggersBackup(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	os.MkdirAll(filepath.Join(home, ".config", "nvim", "lua"), 0o755)
	os.WriteFile(filepath.Join(home, ".config", "nvim", "lua", "plugins.lua"), []byte("-- lazyvim"), 0o644)
	r := &fakeRunner{installed: map[string]bool{}}
	m := New(config.NeovimConfig{NvChadStarterRepo: "https://x/starter"}, "gruvbox", platform.NewPacman(r), platform.GitClient{Runner: r})
	st, _ := m.Detect(context.Background())
	if !st.(state).BackupNeeded {
		t.Fatal("expected BackupNeeded=true")
	}
}

func TestPlanApplyInstallsEverything(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	r := &fakeRunner{installed: map[string]bool{}}
	m := New(config.NeovimConfig{NvChadStarterRepo: "https://x/starter"}, "dracula", platform.NewPacman(r), platform.GitClient{Runner: r})
	st, _ := m.Detect(context.Background())
	p, _ := m.Plan(context.Background(), st)
	if len(p.Actions) == 0 {
		t.Fatal("empty plan")
	}
	if err := m.Apply(context.Background(), p, nopReporter{}); err != nil {
		t.Fatal(err)
	}

	sawPacman, sawClone := false, false
	for _, c := range r.runCalls {
		if len(c) >= 3 && c[0] == "sudo" && c[1] == "pacman" {
			sawPacman = true
		}
		if c[0] == "git" && len(c) >= 2 && c[1] == "clone" {
			sawClone = true
		}
	}
	if !sawPacman || !sawClone {
		t.Fatalf("missing steps; calls=%v", r.runCalls)
	}

	nvimCfg := filepath.Join(home, ".config", "nvim")
	chadrc, err := os.ReadFile(filepath.Join(nvimCfg, "lua", "chadrc.lua"))
	if err != nil {
		t.Fatalf("chadrc missing: %v", err)
	}
	if !strings.Contains(string(chadrc), `theme = "dracula"`) {
		t.Fatalf("chadrc theme not applied: %s", chadrc)
	}

	initLua, _ := os.ReadFile(filepath.Join(nvimCfg, "lua", "plugins", "init.lua"))
	if strings.Contains(string(initLua), "nvim-lspconfig") {
		t.Fatalf("nvim-lspconfig not stripped: %s", initLua)
	}

	if _, err := os.Stat(filepath.Join(nvimCfg, "lua", "configs", "lspconfig.lua")); !os.IsNotExist(err) {
		t.Fatal("starter lspconfig.lua should be removed")
	}

	for _, name := range []string{"arduino.lua", "dap.lua"} {
		if _, err := os.Stat(filepath.Join(nvimCfg, "lua", "plugins", name)); err != nil {
			t.Errorf("asset %s missing: %v", name, err)
		}
	}
	if _, err := os.Stat(filepath.Join(nvimCfg, "lua", "mappings.lua")); err != nil {
		t.Errorf("mappings.lua missing: %v", err)
	}
	if _, err := os.Stat(filepath.Join(nvimCfg, "lsp", "clangd.lua")); err != nil {
		t.Errorf("clangd.lua missing: %v", err)
	}
}

func TestPlanAfterApplyIsEmpty(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	r := &fakeRunner{installed: map[string]bool{"neovim": true}}
	m := New(config.NeovimConfig{NvChadStarterRepo: "https://x/starter"}, "gruvbox", platform.NewPacman(r), platform.GitClient{Runner: r})
	st, _ := m.Detect(context.Background())
	p, _ := m.Plan(context.Background(), st)
	_ = m.Apply(context.Background(), p, nopReporter{})
	st2, _ := m.Detect(context.Background())
	p2, _ := m.Plan(context.Background(), st2)
	if !p2.IsEmpty() {
		t.Fatalf("second plan not empty: %+v", p2.Actions)
	}
}

func TestUnknownThemeFallsBackToFirst(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	r := &fakeRunner{installed: map[string]bool{"neovim": true}}
	m := New(config.NeovimConfig{NvChadStarterRepo: "https://x/starter"}, "does-not-exist", platform.NewPacman(r), platform.GitClient{Runner: r})
	st, _ := m.Detect(context.Background())
	p, _ := m.Plan(context.Background(), st)
	if err := m.Apply(context.Background(), p, nopReporter{}); err != nil {
		t.Fatal(err)
	}
	chadrc, _ := os.ReadFile(filepath.Join(home, ".config", "nvim", "lua", "chadrc.lua"))
	// Unknown theme IDs fall back to the first entry of theming.List(),
	// which is sorted alphabetically by ID (currently "catppuccin").
	if !strings.Contains(string(chadrc), `theme = "catppuccin"`) {
		t.Fatalf("fallback theme not applied: %s", chadrc)
	}
}

func TestWriteChadrcWritesFile(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	cfg := filepath.Join(home, ".config", "nvim")
	if err := os.MkdirAll(cfg, 0o755); err != nil {
		t.Fatal(err)
	}
	if err := WriteChadrc("dracula"); err != nil {
		t.Fatal(err)
	}
	data, err := os.ReadFile(filepath.Join(cfg, "lua", "chadrc.lua"))
	if err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(string(data), `theme = "dracula"`) {
		t.Fatalf("theme not applied: %s", data)
	}
}

func TestWriteChadrcNoopWithoutConfigDir(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	if err := WriteChadrc("gruvbox"); err != nil {
		t.Fatal(err)
	}
	if _, err := os.Stat(filepath.Join(home, ".config", "nvim", "lua", "chadrc.lua")); !os.IsNotExist(err) {
		t.Fatal("chadrc should not be created on a bare system")
	}
}

var _ module.Module = Module{}