package cli

import (
	"flag"
	"fmt"
	"io"
	"sort"

	"git.vakhrushev.me/av/convy/internal/doc"
	"git.vakhrushev.me/av/convy/internal/lang"
	"git.vakhrushev.me/av/convy/internal/suite"
)

// suite list answers two questions. Bare, it says what the suite holds: topics,
// their layers, the prefixes taken. Given an axis, it says what a component
// would take — which is the read-only half of assembly, and the reason to build
// it before anything starts writing copies into other repositories.

func runSuiteList(env Env, args []string) ExitCode {
	fs := flag.NewFlagSet("convy suite list", flag.ContinueOnError)
	fs.SetOutput(env.Err)
	root := fs.String("root", "", "root of the suite; by default it is looked up upwards")
	topic := fs.String("topic", "", "show one topic only")
	langAxis := fs.String("lang", "", "language of the component, to show what it would take")
	stackAxis := fs.String("stack", "", "stack of the component, comma-separated, to show what it would take")
	retired := fs.Bool("retired", false, "show the retired names instead of the live ones")
	if err := fs.Parse(args); err != nil {
		return Usage
	}

	dir, code := suiteRoot(env, *root)
	if code != OK {
		return code
	}
	s, err := suite.Load(dir)
	if err != nil {
		fmt.Fprintln(env.Err, err)
		return Usage
	}

	if *retired {
		listRetired(env.Out, s)
		return OK
	}

	topics := s.Manifest.LiveTopics()
	if *topic != "" {
		if !s.Manifest.TopicLive(*topic) {
			fmt.Fprintf(env.Err, "the suite declares no live topic %q\n", *topic)
			return Usage
		}
		topics = []string{*topic}
	}

	// The path column is sized to the suite rather than guessed: a name that
	// overruns a fixed width breaks every row below it.
	width := 0
	for _, d := range s.Docs {
		width = max(width, len(d.Path))
	}

	selecting := *langAxis != "" || *stackAxis != ""
	component := suite.Component{Lang: split(*langAxis), Stack: split(*stackAxis)}
	for i, name := range topics {
		if i > 0 {
			fmt.Fprintln(env.Out)
		}
		listTopic(env.Out, s, name, component, selecting, width)
	}

	if !selecting {
		fmt.Fprintf(env.Out, "\n%s, %s, language version %d (%s)\n",
			plural(len(topics), "topic"), plural(len(s.Docs), "file"),
			s.Manifest.Language.Version, s.Manifest.Language.Lang)
	}
	return OK
}

func listTopic(w io.Writer, s *suite.Suite, name string, c suite.Component, selecting bool, width int) {
	fmt.Fprintf(w, "%s — %s\n", name, s.Manifest.Topics.Live[name])

	if !selecting {
		for _, d := range s.Layers(name) {
			fmt.Fprintln(w, "  "+layerLine(s, d, width))
		}
		return
	}

	taken, left := s.Assemble(name, c)
	if len(taken) == 0 {
		fmt.Fprintln(w, "  nothing: the topic has no layer this component takes")
	}
	for _, d := range taken {
		fmt.Fprintln(w, "  "+layerLine(s, d, width))
	}
	for _, d := range left {
		fmt.Fprintln(w, "  · "+layerLine(s, d, width)+"  left out")
	}
}

// layerLine describes one layer: its prefix, where it lies, what axis it is on
// and how much of it there is.
func layerLine(s *suite.Suite, d *doc.Document, width int) string {
	rules, retired := 0, 0
	for _, r := range d.Rules {
		rules++
		if _, ok := r.Block(lang.Retired); ok {
			retired++
		}
	}
	count := plural(rules, "rule")
	if retired > 0 {
		count += fmt.Sprintf(", %d retired", retired)
	}
	return fmt.Sprintf("%-6s %-*s %-22s %s", s.Prefix(d), width, d.Path, suite.Axis(d), count)
}

func listRetired(w io.Writer, s *suite.Suite) {
	sections := []struct {
		title   string
		entries map[string]string
	}{
		{"topics", s.Manifest.Topics.Retired},
		{"prefixes", s.Manifest.Prefixes.Retired},
	}
	empty := true
	for _, section := range sections {
		if len(section.entries) == 0 {
			continue
		}
		empty = false
		fmt.Fprintf(w, "%s\n", section.title)
		for _, key := range sortedKeys(section.entries) {
			fmt.Fprintf(w, "  %-16s %s\n", key, section.entries[key])
		}
	}
	if empty {
		fmt.Fprintln(w, "nothing has been retired yet")
		return
	}
	fmt.Fprintln(w, "\nnone of these names is ever handed out again")
}

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