// Package zsh installs zsh, oh-my-zsh, and configured plugins.
package zsh

import (
	"context"
	"fmt"
	"os"
	"path/filepath"

	"github.com/MDietermann/ArduinoArchSetup/internal/config"
	"github.com/MDietermann/ArduinoArchSetup/internal/module"
	"github.com/MDietermann/ArduinoArchSetup/internal/platform"
)

type Module struct {
	cfg config.ZshConfig
	pm  platform.PackageManager
	git platform.GitClient
}

func New(cfg config.ZshConfig, pm platform.PackageManager, git platform.GitClient) Module {
	return Module{cfg: cfg, pm: pm, git: git}
}

type state struct {
	ZshInstalled   bool
	OMZInstalled   bool
	MissingPlugins []config.ZshPlugin
}

func omzHome() (string, error) {
	h, err := os.UserHomeDir()
	if err != nil {
		return "", err
	}
	return filepath.Join(h, ".oh-my-zsh"), nil
}

func (Module) Meta() module.Meta {
	return module.Meta{ID: "zsh", Name: "Zsh + oh-my-zsh", Description: "Install zsh, oh-my-zsh, and plugins."}
}

func (m Module) Detect(ctx context.Context) (module.State, error) {
	var s state
	ok, err := m.pm.IsInstalled(ctx, "zsh")
	if err != nil {
		return nil, err
	}
	s.ZshInstalled = ok
	omz, err := omzHome()
	if err != nil {
		return nil, err
	}
	if _, err := os.Stat(omz); err == nil {
		s.OMZInstalled = true
	}
	for _, p := range m.cfg.Plugins {
		path := filepath.Join(omz, "custom", "plugins", p.Name, ".git")
		if _, err := os.Stat(path); err != nil {
			s.MissingPlugins = append(s.MissingPlugins, p)
		}
	}
	return s, nil
}

func (m Module) Plan(ctx context.Context, cur module.State) (module.Plan, error) {
	s, _ := cur.(state)
	var actions []module.Action
	if !s.ZshInstalled {
		actions = append(actions, module.Action{
			Description: "pacman install zsh",
			Kind:        module.ActionPackageInstall,
			Exec:        func(ctx context.Context) error { return m.pm.Install(ctx, []string{"zsh"}) },
		})
	}
	if !s.OMZInstalled {
		actions = append(actions, module.Action{
			Description: "clone oh-my-zsh from " + m.cfg.OhMyZshRepo,
			Kind:        module.ActionGitClone,
			Exec: func(ctx context.Context) error {
				omz, err := omzHome()
				if err != nil {
					return err
				}
				return m.git.EnsureRepo(ctx, m.cfg.OhMyZshRepo, omz)
			},
		})
	}
	for _, p := range s.MissingPlugins {
		p := p // capture
		actions = append(actions, module.Action{
			Description: "clone plugin " + p.Name,
			Kind:        module.ActionGitClone,
			Exec: func(ctx context.Context) error {
				omz, err := omzHome()
				if err != nil {
					return err
				}
				return m.git.EnsureRepo(ctx, p.Repo, filepath.Join(omz, "custom", "plugins", p.Name))
			},
		})
	}
	return module.Plan{Actions: actions}, nil
}

func (m Module) Apply(ctx context.Context, p module.Plan, r module.Reporter) error {
	for i, a := range p.Actions {
		r.Progress(m.Meta().ID, i+1, len(p.Actions), a.Description)
		if err := a.Exec(ctx); err != nil {
			return err
		}
	}
	return nil
}

func (m Module) Verify(ctx context.Context) error {
	st, err := m.Detect(ctx)
	if err != nil {
		return err
	}
	s := st.(state)
	if !s.ZshInstalled {
		return fmt.Errorf("zsh not installed")
	}
	if !s.OMZInstalled {
		return fmt.Errorf("oh-my-zsh not installed")
	}
	if len(s.MissingPlugins) > 0 {
		return fmt.Errorf("plugins missing: %v", s.MissingPlugins)
	}
	return nil
}