package command

import "testing"

func TestRegistry_Register(t *testing.T) {
    r := NewRegistry()
    cmd := &Command{
        Name:        "test",
        Description: "A test command",
        Handler: func(_ *Context, _ []string) Result {
            return Result{Text: "ok"}
        },
    }
    r.Register(cmd)

    all := r.All()
    if len(all) != 1 {
        t.Fatalf("expected 1 command, got %d", len(all))
    }
    if all[0].Name != "test" {
        t.Errorf("command name = %q, want %q", all[0].Name, "test")
    }

    // Execute to verify it was registered correctly
    result := r.Execute(&Context{}, "test", nil)
    if result.Text != "ok" {
        t.Errorf("result text = %q, want %q", result.Text, "ok")
    }
}

func TestRegistry_Execute(t *testing.T) {
    r := NewRegistry()
    called := false
    r.Register(&Command{
        Name: "run",
        Handler: func(_ *Context, _ []string) Result {
            called = true
            return Result{Text: "executed"}
        },
    })

    t.Run("found command executes handler", func(t *testing.T) {
        result := r.Execute(&Context{}, "run", nil)
        if !called {
            t.Error("handler was not called")
        }
        if result.Text != "executed" {
            t.Errorf("result text = %q, want %q", result.Text, "executed")
        }
    })

    t.Run("not found returns error", func(t *testing.T) {
        result := r.Execute(&Context{}, "nonexistent", nil)
        if result.Error == "" {
            t.Error("expected error for unknown command")
        }
    })
}

func TestRegistry_ExecuteByAlias(t *testing.T) {
    r := NewRegistry()
    r.Register(&Command{
        Name:    "mycommand",
        Aliases: []string{"mc", "m"},
        Handler: func(_ *Context, _ []string) Result {
            return Result{Text: "alias works"}
        },
    })

    tests := []struct {
        name    string
        cmdName string
        wantOk  bool
    }{
        {name: "by name", cmdName: "mycommand", wantOk: true},
        {name: "by alias mc", cmdName: "mc", wantOk: true},
        {name: "by alias m", cmdName: "m", wantOk: true},
    }

    for _, tt := range tests {
        t.Run(tt.name, func(t *testing.T) {
            result := r.Execute(&Context{}, tt.cmdName, nil)
            if tt.wantOk && result.Error != "" {
                t.Errorf("unexpected error: %s", result.Error)
            }
            if tt.wantOk && result.Text != "alias works" {
                t.Errorf("result text = %q, want %q", result.Text, "alias works")
            }
        })
    }
}

func TestRegistry_All(t *testing.T) {
    r := NewRegistry()
    names := []string{"alpha", "beta", "gamma"}
    for _, name := range names {
        n := name // capture
        r.Register(&Command{
            Name:    n,
            Handler: func(_ *Context, _ []string) Result { return Result{} },
        })
    }

    all := r.All()
    if len(all) != len(names) {
        t.Fatalf("expected %d commands, got %d", len(names), len(all))
    }
    for i, cmd := range all {
        if cmd.Name != names[i] {
            t.Errorf("All()[%d].Name = %q, want %q", i, cmd.Name, names[i])
        }
    }
}

func TestRegistry_Match(t *testing.T) {
    r := NewRegistry()
    r.Register(&Command{
        Name:    "model",
        Aliases: []string{"m"},
        Handler: func(_ *Context, _ []string) Result { return Result{} },
    })
    r.Register(&Command{
        Name:    "models",
        Aliases: []string{"ml"},
        Handler: func(_ *Context, _ []string) Result { return Result{} },
    })
    r.Register(&Command{
        Name:    "help",
        Handler: func(_ *Context, _ []string) Result { return Result{} },
    })

    tests := []struct {
        name   string
        prefix string
        want   int
    }{
        {name: "prefix mo matches model and models", prefix: "mo", want: 2},
        {name: "prefix model matches model and models", prefix: "model", want: 2},
        {name: "prefix models matches only models", prefix: "models", want: 1},
        {name: "prefix h matches help", prefix: "h", want: 1},
        {name: "no match", prefix: "z", want: 0},
    }

    for _, tt := range tests {
        t.Run(tt.name, func(t *testing.T) {
            matches := r.Match(tt.prefix)
            if len(matches) != tt.want {
                t.Errorf("Match(%q) returned %d results, want %d", tt.prefix, len(matches), tt.want)
            }
        })
    }

    // Verify no duplicates from aliases
    t.Run("aliases dont create dupes", func(t *testing.T) {
        matches := r.Match("model")
        seen := make(map[string]bool)
        for _, m := range matches {
            if seen[m.Name] {
                t.Errorf("duplicate match for %q", m.Name)
            }
            seen[m.Name] = true
        }
    })
}