feat: add tab completion api

tab complete is better than it was before!
there is a new `complete` function which allows adding custom arguments
to complete specific functions.
hilbish will now also complete executables if it's the first input
argument (this also works with ./)
if no completion is added for a command, hilbish will just complete
files

go.mod

@@ -4,6 +4,7 @@ go 1.16
 
 require (
 	github.com/Rosettea/Hilbiline v0.0.0-20210603231612-80054dac3650
+	github.com/Rosettea/readline v0.0.0-20211122152601-6d95ce44b7ed
 	github.com/bobappleyard/readline v0.0.0-20150707195538-7e300e02d38e
 	github.com/chuckpreslar/emission v0.0.0-20170206194824-a7ddd980baf9
 	github.com/mattn/go-runewidth v0.0.13 // indirect

go.sum

@@ -1,5 +1,7 @@
 github.com/Rosettea/Hilbiline v0.0.0-20210603231612-80054dac3650 h1:nzFJUdJU8UJ1DA8mSQp4eoBtQyOJyecekVWusjfQsqE=
 github.com/Rosettea/Hilbiline v0.0.0-20210603231612-80054dac3650/go.mod h1:/FFZ4cgR6TXXYaskRUxyLIYdfG0PS4BPtWjWRQms754=
+github.com/Rosettea/readline v0.0.0-20211122152601-6d95ce44b7ed h1:sGsGPG+b5h9OR1GjM0PiM4iemB9hmi0o8cg2YRSRKko=
+github.com/Rosettea/readline v0.0.0-20211122152601-6d95ce44b7ed/go.mod h1:OH+WJSCks0t2ISvaCFUT4ZxNGr4Etq4ju9JE/UxH/5o=
 github.com/Rosettea/sh/v3 v3.3.0 h1:0/xmOfzpy46gB1I2oPj8QwdYvyJzpdF5STcgNPRQHcI=
 github.com/Rosettea/sh/v3 v3.3.0/go.mod h1:dh3avhLDhJJ/MJKzbak6FYn+DJKUWk7Fb6Dh5mGdv6Y=
 github.com/Rosettea/sh/v3 v3.4.0-0.dev.0.20211022004519-f67a49cb50f5 h1:ygwVRX8gf5MHA0VzSgOdscCEoAJLjM8joEotfQPgAd0=

lua.go

@@ -58,6 +58,8 @@ func LuaInit() {
 	hooks = bait.New()
 	l.PreloadModule("bait", hooks.Loader)
 
+	l.SetGlobal("complete", l.NewFunction(hshcomplete))
+
 	// Add more paths that Lua can require from
 	l.DoString("package.path = package.path .. " + requirePaths)
 
@@ -210,3 +212,17 @@ func hshinterval(L *lua.LState) int {
 	return 1
 }
 
+// complete(scope, cb)
+// Registers a completion handler for `scope`.
+// A `scope` is currently only expected to be `command.<cmd>`,
+// replacing <cmd> with the name of the command (for example `command.git`).
+// `cb` must be a function that returns a table of the entries to complete.
+// Nested tables will be used as sub-completions.
+func hshcomplete(L *lua.LState) int {
+	scope := L.CheckString(1)
+	cb := L.CheckFunction(2)
+
+	luaCompletions[scope] = cb
+
+	return 0
+}

main.go

@@ -26,6 +26,7 @@ var (
 
 	commands = map[string]*lua.LFunction{}
 	aliases = map[string]string{}
+	luaCompletions = map[string]*lua.LFunction{}
 
 	homedir string
 	confDir string

rl.go

@@ -7,15 +7,149 @@ package main
 // making them interchangable during build time
 // this is normal readline
 
-import "github.com/bobappleyard/readline"
+import (
+	"path/filepath"
+	"strings"
+	"os"
+
+	"github.com/Rosettea/readline"
+	"github.com/yuin/gopher-lua"
+)
 
 type LineReader struct {
 	Prompt string
 }
 
-// other gophers might hate this naming but this is local, shut up
 func NewLineReader(prompt string) *LineReader {
-	readline.Completer = readline.FilenameCompleter
+	readline.Completer = func(query string, ctx string) []string {
+		var completions []string
+		// trim whitespace from ctx
+		ctx = strings.TrimLeft(ctx, " ")
+		fields := strings.Split(ctx, " ")
+
+		if len(fields) == 0 {
+			return nil
+		}
+
+		if len(fields) == 1 {
+			prefixes := []string{"./", "../"}
+			for _, prefix := range prefixes {
+				if strings.HasPrefix(query, prefix) {
+					if matches, err := filepath.Glob(query + "*"); err == nil {
+						for _, match := range matches {
+							if info, err := os.Stat(match); err == nil && info.Mode().Perm() & 0100 == 0 {
+								continue
+							}
+							name := filepath.Base(match)
+							completions = append(completions, name)
+						}
+					}
+					if len(completions) == 1 {
+						// we have add the base dir of query since the completion entries are basename
+						// why? so readline will display just that
+						// and we want to complete the full path when its the only completion entry
+						// query will be incomplete so adding it will be broken
+						// also Dir doesn't have a trailing slash so we need to filepath join
+						// to account to windows
+						// AND ANOTHER THING is it returns . if the arg is ./ and Join will
+						// ignore that so we have to check and just add the prefix instead
+						if prefix != "./" {
+							completions[0] = filepath.Join(filepath.Dir(query), completions[0])
+						} else {
+							completions[0] = prefix + completions[0]
+						}
+					}
+					return completions
+				}
+			}
+
+			for _, dir := range filepath.SplitList(os.Getenv("PATH")) {
+				// print dir to stderr for debugging
+				// search for an executable which matches our query string
+				if matches, err := filepath.Glob(filepath.Join(dir, query + "*")); err == nil {
+					// get basename from matches
+					for _, match := range matches {
+						// check if we have execute permissions for our match
+						if info, err := os.Stat(match); err == nil && info.Mode().Perm() & 0100 == 0 {
+							continue
+						}
+						// get basename from match
+						name := filepath.Base(match)
+						// print name to stderr for debugging
+						// add basename to completions
+						completions = append(completions, name)
+					}
+				}
+			}
+			// add lua registered commands to completions
+			for cmdName := range commands {
+				if strings.HasPrefix(cmdName, query) {
+					completions = append(completions, cmdName)
+				}
+			}
+		} else {
+			if completecb, ok := luaCompletions["command." + fields[0]]; ok {
+				err := l.CallByParam(lua.P{
+					Fn: completecb,
+					NRet: 1,
+					Protect: true,
+				})
+
+				if err != nil {
+					return []string{}
+				}
+
+				luacompleteTable := l.Get(-1)
+				l.Pop(1)
+
+				if cmpTbl, ok := luacompleteTable.(*lua.LTable); ok {
+					cmpTbl.ForEach(func(key lua.LValue, value lua.LValue) {
+						// print key and value to stderr for debugging
+						// if key is a number (index), we just check and complete that
+						if key.Type() == lua.LTNumber {
+							// if we have only 2 fields then this is fine
+							if len(fields) == 2 {
+								if strings.HasPrefix(value.String(), fields[1]) {
+									completions = append(completions, value.String())
+								}
+							}
+						} else if key.Type() == lua.LTString {
+							if len(fields) == 2 {
+								if strings.HasPrefix(key.String(), fields[1]) {
+									completions = append(completions, key.String())
+								}
+							} else {
+								// if we have more than 2 fields, we need to check if the key matches
+								// the current field and if it does, we need to check if the value is a string
+								// or table (nested sub completions)
+								if key.String() == fields[1] {
+									// if value is a table, we need to iterate over it
+									// and add each value to completions
+									valueTbl := value.(*lua.LTable)
+									valueTbl.ForEach(func(key lua.LValue, value lua.LValue) {
+										val := value.String()
+										if val == "<file>" {
+											// complete files
+											completions = append(completions, readline.FilenameCompleter(query, ctx)...)
+										} else {
+											if strings.HasPrefix(val, query) {
+												completions = append(completions, val)
+											}
+										}
+									})
+								}
+							}
+						}
+					})
+				}
+			}
+
+			if len(completions) == 0 {
+				completions = readline.FilenameCompleter(query, ctx)
+			}
+		}
+		return completions
+	}
 	readline.LoadHistory(defaultHistPath)
 
 	return &LineReader{