package cli

import (
	"flag"
	"fmt"
	"path/filepath"
	"strings"

	"git.vakhrushev.me/av/convy/internal/manifest"
	"git.vakhrushev.me/av/convy/internal/project"
)

// convy list answers two questions in one view: what this repository takes and
// what the suite has that it does not. The second half is the reason the
// command reaches the suite at all — a listing of the manifest alone is the
// manifest, and reading it needs no tool.

func runList(env Env, args []string) ExitCode {
	fs := flag.NewFlagSet("convy list", flag.ContinueOnError)
	fs.SetOutput(env.Err)
	root := fs.String("root", "", "root of the project; it is looked up upwards by default")
	forComponent := fs.String("for", "", "component to show; every one of them by default")
	if err := fs.Parse(args); err != nil {
		return Usage
	}
	if code := noStrayArgs(env, "convy list", fs.Args()); code != OK {
		return code
	}

	o, code := openProject(env, *root)
	if code != OK {
		return code
	}
	defer o.Close()

	names, code := components(env, o.Manifest, *forComponent)
	if code != OK {
		return code
	}

	fmt.Fprintf(env.Out, "source %s\n", o.Manifest.Source)
	fmt.Fprintf(env.Out, "%s, language version %d (%s)\n",
		plural(len(o.Suite.Manifest.LiveTopics()), "topic"),
		o.Suite.Manifest.Language.Version, o.Suite.Manifest.Language.Lang)

	for _, name := range names {
		c := o.Manifest.Components[name]
		fmt.Fprintf(env.Out, "\n%s — %s%s\n", name, c.Dir, axisOf(c))
		listComponent(env, o, c)
	}
	return OK
}

func listComponent(env Env, o *opened, c manifest.Component) {
	if len(c.Topics) == 0 {
		fmt.Fprintln(env.Out, "  subscribed to nothing yet")
	}
	for _, topic := range c.Topics {
		if !o.Suite.Manifest.TopicLive(topic) {
			fmt.Fprintf(env.Out, "  %-20s the suite declares no such topic any more\n", topic)
			continue
		}
		taken, _ := o.Suite.Assemble(topic, project.Axis(c))
		file := filepath.ToSlash(filepath.Join(c.Dir, topic+".md"))
		mark := " "
		if !exists(filepath.Join(o.Root, filepath.FromSlash(file))) {
			mark = "!"
		}
		fmt.Fprintf(env.Out, "%s %-20s %-16s %s\n", mark, topic, plural(len(taken), "layer"),
			o.Suite.Manifest.Topics.Live[topic])
		if mark == "!" {
			fmt.Fprintf(env.Out, "  %-20s subscribed, and no file: convy pull assembles it\n", "")
		}
	}

	var free []string
	for _, topic := range o.Suite.Manifest.LiveTopics() {
		if !c.Subscribed(topic) {
			free = append(free, topic)
		}
	}
	if len(free) == 0 {
		return
	}
	fmt.Fprintln(env.Out, "\n  not taken:")
	for _, topic := range free {
		taken, _ := o.Suite.Assemble(topic, project.Axis(c))
		if len(taken) == 0 {
			fmt.Fprintf(env.Out, "· %-20s %-16s %s\n", topic, "no layer fits",
				o.Suite.Manifest.Topics.Live[topic])
			continue
		}
		fmt.Fprintf(env.Out, "· %-20s %-16s %s\n", topic, plural(len(taken), "layer"),
			o.Suite.Manifest.Topics.Live[topic])
	}
}

// axisOf describes the axis of a component the way the suite writes it.
func axisOf(c manifest.Component) string {
	var parts []string
	if len(c.Lang) > 0 {
		parts = append(parts, "lang="+strings.Join(c.Lang, ","))
	}
	if len(c.Stack) > 0 {
		parts = append(parts, "stack="+strings.Join(c.Stack, ","))
	}
	if len(parts) == 0 {
		return ""
	}
	return " (" + strings.Join(parts, " ") + ")"
}