package main

import (
	"context"
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strings"
	"time"

	"i3/internal/desktop"
)

type i3 struct {
	d         desktop.Desk
	socket    func() (string, error)
	configDir string
	layouts   string
	watcher   *Watcher
}

func (t *i3) ask(kind uint32, payload string, out any) error {
	sock, err := t.socket()
	if err != nil {
		return err
	}
	return Ask(sock, kind, payload, out)
}

// command runs i3 commands and fails when any of them did.
func (t *i3) command(cmd string) ([]Outcome, error) {
	var out []Outcome
	if err := t.ask(RunCommand, cmd, &out); err != nil {
		return nil, err
	}
	for _, o := range out {
		if !o.Success {
			return out, fmt.Errorf("i3 refused %q: %s", cmd, o.Error)
		}
	}
	return out, nil
}

func (t *i3) tree() (Node, error) {
	var root Node
	err := t.ask(GetTree, "", &root)
	return root, err
}

// check runs `i3 -C` on the configuration on disk. It needs no display.
func (t *i3) check(ctx context.Context) ([]ConfigError, error) {
	res := t.d.Plain(ctx, "i3", "-C", "-c", filepath.Join(t.configDir, "config"))
	if res.Code == 127 {
		return nil, fmt.Errorf("i3 is not installed here")
	}
	problems := append([]ConfigError{}, ParseCheck(res.Stdout+"\n"+res.Stderr)...)
	if !res.OK() && len(problems) == 0 {
		problems = []ConfigError{{Text: strings.TrimSpace(res.Stdout + res.Stderr)}}
	}
	return problems, nil
}

func (t *i3) watcherStatus() any {
	if t.watcher == nil {
		return nil
	}
	return t.watcher.Status()
}

func (t *i3) reload(ctx context.Context, a desktop.Args) (any, error) {
	force, _, err := a.Bool("force")
	if err != nil {
		return nil, err
	}
	problems, err := t.check(ctx)
	if err != nil {
		return nil, err
	}
	if len(problems) > 0 && !force {
		return map[string]any{"reloaded": false, "errors": problems, "why": "the configuration on disk has errors; fix them, or force"}, nil
	}
	out, err := t.command("reload")
	if err != nil {
		return nil, err
	}
	return map[string]any{"reloaded": true, "i3": out, "errors": problems, "watcher": t.watcherStatus()}, nil
}

// WorkspaceInfo is one workspace as GET_WORKSPACES answers it.
type WorkspaceInfo struct {
	Num     int    `json:"num"`
	Name    string `json:"name"`
	Output  string `json:"output"`
	Visible bool   `json:"visible"`
	Focused bool   `json:"focused"`
	Urgent  bool   `json:"urgent"`
}

func (t *i3) workspaces(ctx context.Context, a desktop.Args) (any, error) {
	var ws []WorkspaceInfo
	if err := t.ask(GetWorkspaces, "", &ws); err != nil {
		return nil, err
	}
	return map[string]any{"workspaces": ws}, nil
}

func (t *i3) windows(ctx context.Context, a desktop.Args) (any, error) {
	root, err := t.tree()
	if err != nil {
		return nil, err
	}
	all := Windows(root)
	ws := a.Opt("workspace", "")
	out := []Window{}
	for _, w := range all {
		if ws == "" || w.Workspace == ws {
			out = append(out, w)
		}
	}
	return map[string]any{"windows": out}, nil
}

func (t *i3) focus(ctx context.Context, a desktop.Args) (any, error) {
	crit, err := Criteria(a)
	if err != nil {
		return nil, err
	}
	var cmd string
	switch ws := a.Opt("workspace", ""); {
	case crit != "" && ws != "":
		return nil, fmt.Errorf("a window or a workspace, not both")
	case crit != "":
		cmd = crit + " focus"
	case ws != "":
		cmd = "workspace " + Quote(ws)
	default:
		return nil, fmt.Errorf("name a window (con_id, window, class, instance, title, mark) or a workspace")
	}
	out, err := t.command(cmd)
	if err != nil {
		return nil, err
	}
	return map[string]any{"command": cmd, "i3": out}, nil
}

var direction = regexp.MustCompile(`^(left|right|up|down|current|primary|next|prev)$`)

func target(output string) string {
	if direction.MatchString(output) {
		return output
	}
	return Quote(output)
}

func (t *i3) move(ctx context.Context, a desktop.Args) (any, error) {
	crit, err := Criteria(a)
	if err != nil {
		return nil, err
	}
	toWS, toOut, wsMove := a.Opt("to_workspace", ""), a.Opt("to_output", ""), a.Opt("workspace_to_output", "")
	var cmd string
	switch {
	case wsMove != "":
		if toOut == "" {
			return nil, fmt.Errorf("workspace_to_output needs to_output")
		}
		cmd = "[workspace=" + Quote("^"+regexp.QuoteMeta(wsMove)+"$") + "] move workspace to output " + target(toOut)
	case toWS != "" && toOut != "":
		return nil, fmt.Errorf("to a workspace or to an output, not both")
	case toWS != "":
		cmd = strings.TrimSpace(crit + " move container to workspace " + Quote(toWS))
	case toOut != "":
		cmd = strings.TrimSpace(crit + " move container to output " + target(toOut))
	default:
		return nil, fmt.Errorf("name to_workspace or to_output")
	}
	out, err := t.command(cmd)
	if err != nil {
		return nil, err
	}
	return map[string]any{"command": cmd, "i3": out}, nil
}

var layoutName = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9._-]{0,63}$`)

func (t *i3) layoutSave(ctx context.Context, a desktop.Args) (any, error) {
	name, err := a.Text("name")
	if err != nil {
		return nil, err
	}
	if !layoutName.MatchString(name) {
		return nil, fmt.Errorf("a layout's name is letters, digits, dot, dash and underscore")
	}
	root, err := t.tree()
	if err != nil {
		return nil, err
	}
	ws, ok := Workspace(root, a.Opt("workspace", ""))
	if !ok {
		return nil, fmt.Errorf("no workspace %q", a.Opt("workspace", "(focused)"))
	}
	top, windows := Layout(ws)
	if windows == 0 {
		return nil, fmt.Errorf("workspace %s holds no windows to save", str(ws.Name))
	}
	if err := os.MkdirAll(t.layouts, 0o755); err != nil {
		return nil, err
	}
	path := filepath.Join(t.layouts, name+".json")
	if err := os.WriteFile(path, []byte(LayoutFile(str(ws.Name), time.Now().Format(time.RFC3339), top)), 0o644); err != nil {
		return nil, err
	}
	return map[string]any{"name": name, "workspace": str(ws.Name), "windows": windows, "path": path}, nil
}

func (t *i3) savedLayouts() []map[string]string {
	files, _ := filepath.Glob(filepath.Join(t.layouts, "*.json"))
	sort.Strings(files)
	out := []map[string]string{}
	for _, f := range files {
		b, _ := os.ReadFile(f)
		out = append(out, map[string]string{"name": strings.TrimSuffix(filepath.Base(f), ".json"), "workspace": SavedWorkspace(string(b)), "path": f})
	}
	return out
}

func (t *i3) layoutRestore(ctx context.Context, a desktop.Args) (any, error) {
	name, err := a.Text("name")
	if err != nil {
		return nil, err
	}
	if name == "list" {
		return map[string]any{"layouts": t.savedLayouts()}, nil
	}
	if !layoutName.MatchString(name) {
		return nil, fmt.Errorf("a layout's name is letters, digits, dot, dash and underscore")
	}
	path := filepath.Join(t.layouts, name+".json")
	b, err := os.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("no saved layout %q (i3_layout_restore with name list shows them)", name)
	}
	ws := a.Opt("workspace", SavedWorkspace(string(b)))
	if ws == "" {
		return nil, fmt.Errorf("name the workspace to lay it on")
	}
	cmd := "workspace " + Quote(ws) + "; append_layout " + Quote(path)
	out, err := t.command(cmd)
	if err != nil {
		return nil, err
	}
	return map[string]any{"layout": name, "workspace": ws, "i3": out,
		"then": "each placeholder swallows the next window of its class as it opens; start the programs (i3_exec) to fill them"}, nil
}

func (t *i3) exec(ctx context.Context, a desktop.Args) (any, error) {
	command, err := a.Text("command")
	if err != nil {
		return nil, err
	}
	cmd := "exec --no-startup-id " + Quote(command)
	if ws := a.Opt("workspace", ""); ws != "" {
		cmd = "workspace " + Quote(ws) + "; " + cmd
	}
	out, err := t.command(cmd)
	if err != nil {
		return nil, err
	}
	return map[string]any{"started": command, "i3": out, "how": "a child of i3, in the session; i3 does not answer whether the program itself started"}, nil
}

func (t *i3) kill(ctx context.Context, a desktop.Args) (any, error) {
	crit, err := Criteria(a)
	if err != nil {
		return nil, err
	}
	focused, _, err := a.Bool("focused")
	if err != nil {
		return nil, err
	}
	if crit == "" && !focused {
		return nil, fmt.Errorf("name the windows to close, or focused: true")
	}
	force, _, _ := a.Bool("force")
	cmd := strings.TrimSpace(crit + " kill")
	if force {
		cmd += " client"
	}
	before, _ := t.tree()
	out, err := t.command(cmd)
	if err != nil {
		return nil, err
	}
	return map[string]any{"command": cmd, "i3": out, "windows_before": len(Windows(before))}, nil
}

type configReply struct {
	Config   string `json:"config"`
	Included []struct {
		Path     string `json:"path"`
		Raw      string `json:"raw_contents"`
		Replaced string `json:"variable_replaced_contents"`
	} `json:"included_configs"`
}

// loaded is each file the running i3 loaded, with the text it read.
func (t *i3) loaded() (map[string]string, error) {
	var c configReply
	if err := t.ask(GetConfig, "", &c); err != nil {
		return nil, err
	}
	out := map[string]string{}
	for _, inc := range c.Included {
		out[inc.Path] = inc.Raw
	}
	if len(out) == 0 {
		out[filepath.Join(t.configDir, "config")] = c.Config
	}
	return out, nil
}

func (t *i3) bindings(ctx context.Context, a desktop.Args) (any, error) {
	var c configReply
	if err := t.ask(GetConfig, "", &c); err != nil {
		return nil, err
	}
	var all []Binding
	if len(c.Included) == 0 {
		all = Bindings("(main)", c.Config)
	}
	for _, inc := range c.Included {
		all = append(all, Bindings(inc.Path, inc.Replaced)...)
	}
	match := strings.ToLower(a.Opt("match", ""))
	out := []Binding{}
	for _, b := range all {
		if match == "" || strings.Contains(strings.ToLower(b.Keys+" "+b.Command), match) {
			out = append(out, b)
		}
	}
	return map[string]any{"bindings": out, "from": "the configuration i3 loaded at its last start or reload"}, nil
}

func (t *i3) configCheck(ctx context.Context, a desktop.Args) (any, error) {
	problems, err := t.check(ctx)
	if err != nil {
		return nil, err
	}
	answer := map[string]any{"valid": len(problems) == 0, "errors": problems, "config": filepath.Join(t.configDir, "config"),
		"on_disk": sortedKeys(Watched(t.configDir)), "watcher": t.watcherStatus()}
	var v struct {
		Loaded   string   `json:"loaded_config_file_name"`
		Included []string `json:"included_config_file_names"`
		Human    string   `json:"human_readable"`
	}
	if err := t.ask(GetVersion, "", &v); err == nil {
		answer["running"] = map[string]any{"version": v.Human, "loaded": append([]string{v.Loaded}, v.Included...)}
	}
	return answer, nil
}

func sortedKeys(m map[string]string) []string {
	out := make([]string, 0, len(m))
	for k := range m {
		out = append(out, k)
	}
	sort.Strings(out)
	return out
}

func (t *i3) marks(ctx context.Context, a desktop.Args) (any, error) {
	root, err := t.tree()
	if err != nil {
		return nil, err
	}
	type marked struct {
		Mark   string `json:"mark"`
		Window Window `json:"window"`
	}
	out := []marked{}
	for _, w := range Windows(root) {
		for _, m := range w.Marks {
			out = append(out, marked{m, w})
		}
	}
	return map[string]any{"marks": out}, nil
}

func (t *i3) scratchpad(ctx context.Context, a desktop.Args) (any, error) {
	action, err := a.OneOf("action", "list", "list", "show", "move")
	if err != nil {
		return nil, err
	}
	crit, err := Criteria(a)
	if err != nil {
		return nil, err
	}
	switch action {
	case "list":
		root, err := t.tree()
		if err != nil {
			return nil, err
		}
		out := []Window{}
		for _, w := range Windows(root) {
			if w.Scratchpad {
				out = append(out, w)
			}
		}
		return map[string]any{"scratchpad": out}, nil
	case "show":
		cmd := strings.TrimSpace(crit + " scratchpad show")
		out, err := t.command(cmd)
		if err != nil {
			return nil, err
		}
		return map[string]any{"command": cmd, "i3": out}, nil
	default:
		cmd := strings.TrimSpace(crit + " move scratchpad")
		out, err := t.command(cmd)
		if err != nil {
			return nil, err
		}
		return map[string]any{"command": cmd, "i3": out}, nil
	}
}