package tui

import "testing"

func TestTriggerCompletion(t *testing.T) {
    t.Run("slash_triggers_command", func(t *testing.T) {
        m := newTestModel(t)
        m.triggerCompletion("/")

        if !m.isCompletionActive() {
            t.Error("/ should activate completion")
        }
        if m.completionState.Kind != "command" {
            t.Errorf("expected kind 'command', got %q", m.completionState.Kind)
        }
        if m.overlay != OverlayCompletion {
            t.Errorf("expected OverlayCompletion, got %d", m.overlay)
        }
        if len(m.completionState.AllItems) == 0 {
            t.Error("should have completion items for /")
        }
    })

    t.Run("at_triggers_attachments_with_multiselect", func(t *testing.T) {
        m := newTestModel(t)
        m.triggerCompletion("@")

        // @ triggers agent/file completion.
        // It may or may not find matches depending on agents + cwd.
        // If agents exist, it should activate.
        if m.isCompletionActive() {
            if m.completionState.Kind != "attachments" {
                t.Errorf("expected kind 'attachments', got %q", m.completionState.Kind)
            }
            if m.completionState.Selected == nil {
                t.Error("attachments should initialize Selected map")
            }
        }
    })

    t.Run("hash_triggers_skills", func(t *testing.T) {
        m := newTestModel(t)
        m.triggerCompletion("#")

        if !m.isCompletionActive() {
            t.Error("# should activate completion for skills")
        }
        if m.completionState.Kind != "skills" {
            t.Errorf("expected kind 'skills', got %q", m.completionState.Kind)
        }
        if m.completionState.Selected == nil {
            t.Error("skills should initialize Selected map")
        }
    })

    t.Run("no_matches_stays_inactive", func(t *testing.T) {
        m := newTestModel(t)
        m.triggerCompletion("/zzzznonexistent")

        if m.isCompletionActive() {
            t.Error("should not activate with no matches")
        }
    })

    t.Run("plain_text_no_trigger", func(t *testing.T) {
        m := newTestModel(t)
        m.triggerCompletion("hello")

        if m.isCompletionActive() {
            t.Error("plain text should not trigger completion")
        }
    })
}

func TestAcceptCompletion(t *testing.T) {
    t.Run("single_select", func(t *testing.T) {
        m := newTestModel(t)
        items := []Completion{
            {Label: "/help", Insert: "/help "},
            {Label: "/clear", Insert: "/clear "},
        }
        m.completionState = newCompletionState("command", items, false)
        m.overlay = OverlayCompletion
        m.completionState.Index = 0

        m.acceptCompletion()

        if m.input.Value() != "/help " {
            t.Errorf("expected '/help ', got %q", m.input.Value())
        }
        if m.isCompletionActive() {
            t.Error("should be inactive after accept")
        }
        if m.overlay != OverlayNone {
            t.Error("overlay should be OverlayNone")
        }
    })

    t.Run("multi_select_with_selections", func(t *testing.T) {
        m := newTestModel(t)
        items := []Completion{
            {Label: "@a", Insert: "@a "},
            {Label: "@b", Insert: "@b "},
            {Label: "@c", Insert: "@c "},
        }
        m.completionState = newCompletionState("attachments", items, true)
        m.overlay = OverlayCompletion
        m.completionState.Index = 0
        m.completionState.Selected[1] = true

        m.acceptCompletion()

        if m.input.Value() != "@b " {
            t.Errorf("expected '@b ', got %q", m.input.Value())
        }
        if m.isCompletionActive() {
            t.Error("should be inactive after accept")
        }
    })

    t.Run("multi_select_empty_fallback", func(t *testing.T) {
        m := newTestModel(t)
        items := []Completion{
            {Label: "@x", Insert: "@x "},
            {Label: "@y", Insert: "@y "},
        }
        m.completionState = newCompletionState("attachments", items, true)
        m.overlay = OverlayCompletion
        m.completionState.Index = 1

        m.acceptCompletion()

        if m.input.Value() != "@y " {
            t.Errorf("expected '@y ' as fallback, got %q", m.input.Value())
        }
    })

    t.Run("inactive_noop", func(t *testing.T) {
        m := newTestModel(t)
        m.completionState = nil
        m.input.SetValue("original")

        m.acceptCompletion()

        if m.input.Value() != "original" {
            t.Errorf("inactive accept should be noop, got %q", m.input.Value())
        }
    })
}

func TestCloseCompletion(t *testing.T) {
    m := newTestModel(t)
    items := []Completion{{Label: "test"}}
    m.completionState = newCompletionState("command", items, true)
    m.completionState.Index = 5
    m.completionState.Selected[0] = true
    m.overlay = OverlayCompletion

    m.closeCompletion()

    if m.isCompletionActive() {
        t.Error("completionState should be nil")
    }
    if m.overlay != OverlayNone {
        t.Errorf("overlay should be OverlayNone, got %d", m.overlay)
    }
}

func TestFilterCompletions(t *testing.T) {
    items := []Completion{
        {Label: "/help"},
        {Label: "/clear"},
        {Label: "/model"},
    }

    t.Run("empty_query_returns_all", func(t *testing.T) {
        filtered := FilterCompletions(items, "")
        if len(filtered) != 3 {
            t.Errorf("expected 3, got %d", len(filtered))
        }
    })

    t.Run("filters_by_substring", func(t *testing.T) {
        filtered := FilterCompletions(items, "el")
        if len(filtered) != 2 {
            t.Errorf("expected 2 (help, model), got %d", len(filtered))
        }
    })

    t.Run("case_insensitive", func(t *testing.T) {
        filtered := FilterCompletions(items, "HELP")
        if len(filtered) != 1 {
            t.Errorf("expected 1, got %d", len(filtered))
        }
    })

    t.Run("no_match", func(t *testing.T) {
        filtered := FilterCompletions(items, "zzz")
        if len(filtered) != 0 {
            t.Errorf("expected 0, got %d", len(filtered))
        }
    })
}