// Package cli 实现 errcode 命令：list / show / search / validate / export / serve。
package cli

import (
	"encoding/json"
	"flag"
	"fmt"
	"io"
	"os"
	"strings"

	"error-code-system/errcode"
	"error-code-system/server"
)

// Main 执行命令行并返回进程退出码。
func Main(args []string) int {
	return Run(args, os.Stdout, os.Stderr)
}

// Run 执行命令。stdout 写结果，stderr 写用法与错误。
func Run(args []string, stdout, stderr io.Writer) int {
	if len(args) == 0 {
		fmt.Fprintln(stderr, usage)
		return 2
	}
	switch args[0] {
	case "list":
		return cmdList(args[1:], stdout, stderr)
	case "show":
		return cmdShow(args[1:], stdout, stderr)
	case "search":
		return cmdSearch(args[1:], stdout, stderr)
	case "validate":
		return cmdValidate(args[1:], stdout, stderr)
	case "export":
		return cmdExport(args[1:], stdout, stderr)
	case "serve":
		return cmdServe(args[1:], stderr)
	case "-h", "--help", "help":
		fmt.Fprintln(stdout, usage)
		return 0
	default:
		fmt.Fprintf(stderr, "未知命令 %q\n%s\n", args[0], usage)
		return 2
	}
}

const usage = `用法:
  errcode list [--domain 域] [--json]
  errcode show <码或别名>
  errcode search <关键词>
  errcode validate <码或别名>
  errcode export [--domain 域]
  errcode serve [--addr :8091]`

func registry() *errcode.Registry { return errcode.Default }

func cmdList(args []string, stdout, stderr io.Writer) int {
	fs := flag.NewFlagSet("list", flag.ContinueOnError)
	fs.SetOutput(stderr)
	domain := fs.String("domain", "", "只列出该域")
	asJSON := fs.Bool("json", false, "以 JSON 输出")
	if err := fs.Parse(args); err != nil {
		return 2
	}
	defs := registry().List(*domain)
	if *asJSON {
		enc := json.NewEncoder(stdout)
		enc.SetEscapeHTML(false)
		enc.SetIndent("", "  ")
		if err := enc.Encode(defs); err != nil {
			fmt.Fprintln(stderr, err)
			return 1
		}
		return 0
	}
	for _, def := range defs {
		fmt.Fprintf(stdout, "%s\t%d\t%s\t%s\n", def.Code, def.HTTP, def.Retry, def.Summary)
	}
	return 0
}

func cmdShow(args []string, stdout, stderr io.Writer) int {
	if len(args) != 1 {
		fmt.Fprintln(stderr, "用法: errcode show <码或别名>")
		return 2
	}
	def, ok := registry().Lookup(args[0])
	if !ok {
		fmt.Fprintf(stderr, "未登记: %s（回落 %s）\n", args[0], errcode.SysUnknownCode)
		return 1
	}
	enc := json.NewEncoder(stdout)
	enc.SetEscapeHTML(false)
	enc.SetIndent("", "  ")
	if err := enc.Encode(def); err != nil {
		fmt.Fprintln(stderr, err)
		return 1
	}
	return 0
}

func cmdSearch(args []string, stdout, stderr io.Writer) int {
	if len(args) < 1 {
		fmt.Fprintln(stderr, "用法: errcode search <关键词>")
		return 2
	}
	q := strings.Join(args, " ")
	for _, def := range registry().Search(q) {
		fmt.Fprintf(stdout, "%s\t%s\n", def.Code, def.Summary)
	}
	return 0
}

func cmdValidate(args []string, stdout, stderr io.Writer) int {
	if len(args) != 1 {
		fmt.Fprintln(stderr, "用法: errcode validate <码或别名>")
		return 2
	}
	def, ok := registry().Lookup(args[0])
	resolved := def
	if !ok {
		resolved = registry().Resolve(args[0])
	}
	fmt.Fprintf(stdout, "input=%s known=%t resolved=%s\n", args[0], ok, resolved.Code)
	if !ok {
		return 1
	}
	return 0
}

func cmdExport(args []string, stdout, stderr io.Writer) int {
	fs := flag.NewFlagSet("export", flag.ContinueOnError)
	fs.SetOutput(stderr)
	domain := fs.String("domain", "", "只导出该域")
	if err := fs.Parse(args); err != nil {
		return 2
	}
	var data []byte
	var err error
	if *domain == "" {
		data, err = registry().ExportJSON()
	} else {
		encBuf := &strings.Builder{}
		enc := json.NewEncoder(encBuf)
		enc.SetEscapeHTML(false)
		enc.SetIndent("", "  ")
		err = enc.Encode(registry().List(*domain))
		data = []byte(encBuf.String())
	}
	if err != nil {
		fmt.Fprintln(stderr, err)
		return 1
	}
	if _, err := stdout.Write(data); err != nil {
		fmt.Fprintln(stderr, err)
		return 1
	}
	return 0
}

func cmdServe(args []string, stderr io.Writer) int {
	fs := flag.NewFlagSet("serve", flag.ContinueOnError)
	fs.SetOutput(stderr)
	addr := fs.String("addr", server.DefaultAddr, "监听地址")
	if err := fs.Parse(args); err != nil {
		return 2
	}
	fmt.Fprintf(stderr, "errcode serve %s\n", *addr)
	if err := server.New(registry()).ListenAndServe(*addr); err != nil {
		fmt.Fprintln(stderr, err)
		return 1
	}
	return 0
}