package main

import (
	"encoding/json"
	"fmt"
	"os"
	"os/exec"
	"strings"
)

const (
	needRequired = "required"
	needAgent    = "agent"
	needOptional = "optional"
)

type check struct {
	Name     string `json:"name"`
	Need     string `json:"need"`
	For      string `json:"for"`
	OK       bool   `json:"ok"`
	Command  string `json:"command"`
	Fix      string `json:"fix"`
	Blocking bool   `json:"blocking"`
}

func checks() []check {
	return []check{
		gitCheck(),
		command("claude", needAgent, "Claude models", "curl -fsSL https://claude.ai/install.sh | bash", "Then run claude once to sign in."),
		command("codex", needAgent, "GPT models", "brew install --cask codex", "Then run codex once to sign in."),
		command("agy", needAgent, "Gemini models", "brew install --cask antigravity-cli", "Then run agy once to sign in."),
		command("npx", needOptional, "reviewers' Playwright browser tools", "brew install node", ""),
		appCheck("Google Chrome", needOptional, "browser tools for agents and reviewers", "brew install --cask google-chrome"),
	}
}

func gitCheck() check {
	c := check{Name: "git", Need: needRequired, For: "worktrees, snapshots and merges", Command: "xcode-select --install"}
	path, err := exec.LookPath("git")
	// /usr/bin/git is a stub that offers to install the Command Line Tools when they're missing.
	c.OK = err == nil && (path != "/usr/bin/git" || exec.Command("xcode-select", "-p").Run() == nil)
	return c
}

func command(name, need, purpose, install, fix string) check {
	_, err := exec.LookPath(name)
	return check{Name: name, Need: need, For: purpose, OK: err == nil, Command: install, Fix: fix}
}

func appCheck(name, need, purpose, install string) check {
	_, err := os.Stat("/Applications/" + name + ".app")
	return check{Name: name, Need: need, For: purpose, OK: err == nil, Command: install}
}

func markBlocking(cs []check) bool {
	agentOK := false
	for _, c := range cs {
		agentOK = agentOK || (c.Need == needAgent && c.OK)
	}
	ready := true
	for i, c := range cs {
		cs[i].Blocking = !c.OK && (c.Need == needRequired || (c.Need == needAgent && !agentOK))
		ready = ready && !cs[i].Blocking
	}
	return ready
}

func checkCmd() {
	cs := checks()
	ready := markBlocking(cs)
	out, err := json.Marshal(struct {
		Ready    bool    `json:"ready"`
		Loopback string  `json:"loopback"`
		Checks   []check `json:"checks"`
	}{ready, loopbackURL, cs})
	if err != nil {
		fatal("encode checks", "err", err)
	}
	fmt.Println(string(out))
}

func requireChecks() {
	cs := checks()
	if markBlocking(cs) {
		return
	}
	fmt.Println("byre can't run on this Mac yet. It needs git and at least one of claude, codex and agy:")
	for _, c := range cs {
		if c.Blocking {
			fmt.Printf("  %s: %s\n", c.Name, strings.TrimSpace(c.Command+" "+c.Fix))
		}
	}
	os.Exit(1)
}