package main

import (
	"fmt"
	"strings"
)

type options struct {
	searchValue  string
	searchSet    bool
	includeDesc  bool
	prettyOutput bool
	temperatureU string
	clearCache   bool
	refresh      bool
	iconTest     bool
	radarMode    bool
	discussion   bool
	wayland      bool
}

func parseArgs(args []string) (options, error) {
	opts := options{temperatureU: "F"}

	nextValue := func(i *int) (string, error) {
		if *i+1 >= len(args) {
			return "", fmt.Errorf("missing value for %s", args[*i])
		}
		*i = *i + 1
		return args[*i], nil
	}

	for i := 0; i < len(args); i++ {
		arg := args[i]
		if !strings.HasPrefix(arg, "-") {
			return opts, fmt.Errorf("unexpected argument: %s", arg)
		}

		if strings.HasPrefix(arg, "--") {
			key, val, hasVal := strings.Cut(strings.TrimPrefix(arg, "--"), "=")
			switch key {
			case "search":
				opts.searchSet = true
				if hasVal {
					opts.searchValue = val
				} else if i+1 < len(args) && !strings.HasPrefix(args[i+1], "-") {
					val, _ = nextValue(&i)
					opts.searchValue = val
				}
			case "desc":
				opts.includeDesc = true
			case "pretty":
				opts.prettyOutput = true
			case "units":
				if hasVal {
					opts.temperatureU = val
				} else {
					val, err := nextValue(&i)
					if err != nil {
						return opts, err
					}
					opts.temperatureU = val
				}
			case "clear-cache":
				opts.clearCache = true
			case "refresh":
				opts.refresh = true
			case "icon-test":
				opts.iconTest = true
			case "radar":
				opts.radarMode = true
			case "discussion":
				opts.discussion = true
			case "wayland":
				opts.wayland = true
			default:
				return opts, fmt.Errorf("unknown flag: --%s", key)
			}
			continue
		}

		switch arg {
		case "-s":
			opts.searchSet = true
			if i+1 < len(args) && !strings.HasPrefix(args[i+1], "-") {
				val, _ := nextValue(&i)
				opts.searchValue = val
			}
		case "-d":
			opts.includeDesc = true
		case "-p":
			opts.prettyOutput = true
		case "-u":
			val, err := nextValue(&i)
			if err != nil {
				return opts, err
			}
			opts.temperatureU = val
		case "-c":
			opts.clearCache = true
		case "-r":
			opts.refresh = true
		case "-i":
			opts.iconTest = true
		case "-R":
			opts.radarMode = true
		case "-D":
			opts.discussion = true
		default:
			return opts, fmt.Errorf("unknown flag: %s", arg)
		}
	}

	opts.temperatureU = strings.ToUpper(strings.TrimSpace(opts.temperatureU))
	if opts.temperatureU == "" {
		opts.temperatureU = "F"
	}
	if opts.temperatureU != "F" && opts.temperatureU != "C" {
		return opts, fmt.Errorf("invalid unit: %s", opts.temperatureU)
	}

	return opts, nil
}