package cmd

import (
	"github.com/Masterminds/cookoo"
	"github.com/kylelemons/go-gypsy/yaml"
	"fmt"
)

// ParseYaml parses the glide.yaml format and returns a Configuration object.
//
// Params:
// 	- filename (string): YAML filename as a string
//
// Context:
// 	- yaml.File: This puts the parsed YAML file into the context.
//
// Returns:
// 	- *Config: The configuration.
func ParseYaml(c cookoo.Context, p *cookoo.Params) (interface{}, cookoo.Interrupt) {
	fname := p.Get("filename", "glide.yaml").(string)
	conf := new(Config)
	f, err := yaml.ReadFile(fname)
	if err != nil {
		return nil, err
	}

	c.Put("yaml.File", f)

	// Convenience:
	top, ok := f.Root.(yaml.Map)
	if !ok {
		return nil, fmt.Errorf("Expected YAML root to be map, got %t", f.Root)
	}

	vals := map[string]yaml.Node(top)
	if name, ok := vals["package"]; ok {
		//c.Put("cfg.package", name.(yaml.Scalar).String())
		conf.Name = name.(yaml.Scalar).String()
	} else {
		Warn("The 'package' directive is required in Glide YAML.\n")
	}

	// Allow the user to override the behavior of `glide in`.
	if incmd, ok := vals["incmd"]; ok {
		conf.InCommand = incmd.(yaml.Scalar).String()
	}

	conf.Imports = make([]*Dependency, 0, 1)
	if imp, ok := vals["import"]; ok {
		imports, ok := imp.(yaml.List)

		if ok {
			for _, v := range imports {
				pkg := v.(yaml.Map)
				dep := Dependency {
					Name: valOrEmpty("package", pkg),
					Reference: valOrEmpty("ref", pkg),
					VcsType: getVcsType(pkg),
					Repository: valOrEmpty("repo", pkg),
					Subpackages: subpkg("subpackages", pkg),
				}
				conf.Imports = append(conf.Imports, &dep)
			}
		}
	}

	return conf, nil
}

// WriteYaml writes a yaml.Node to the console as a string.
//
// Params:
// 	- yaml.Node: A yaml.Node to render.
func WriteYaml(c cookoo.Context, p *cookoo.Params) (interface{}, cookoo.Interrupt) {
	top := p.Get("yaml.Node", yaml.Scalar("nothing to print")).(yaml.Node)

	fmt.Print(yaml.Render(top))

	return true, nil
}

// Convert a Config object and a yaml.File to a single yaml.File.
func MergeToYaml(c cookoo.Context, p *cookoo.Params) (interface{}, cookoo.Interrupt) {
	root := c.Get("yaml.File", nil).(*yaml.File).Root
	cfg := p.Get("conf", nil).(*Config)

	rootMap, ok := root.(yaml.Map)
	if !ok {
		return nil, fmt.Errorf("Expected root node to be a map.")
	}

	rootMap["package"] = yaml.Scalar(cfg.Name)
	if cfg.InCommand != "" {
		rootMap["incmd"] = yaml.Scalar(cfg.InCommand)
	}

	// Imports
	imports := make([]yaml.Node, len(cfg.Imports))
	for i, imp := range cfg.Imports {

		if imp.VcsType == NoVCS {
			imp.VcsType, _ = GuessVCS(imp)
		}

		impmap := make(map[string]yaml.Node)
		impmap["package"] = yaml.Scalar(imp.Name)
		if imp.VcsType != NoVCS {
			impmap["vcs"] = yaml.Scalar(vcsString(imp.VcsType))
		}
		if imp.Reference != "" {
			impmap["ref"] = yaml.Scalar(imp.Reference)
		}
		if imp.Repository != "" {
			impmap["repo"] = yaml.Scalar(imp.Repository)
		}

		if len(imp.Subpackages) > 0 {
			subs := make([]yaml.Node, len(imp.Subpackages))
			for ii, sub := range imp.Subpackages {
				subs[ii] = yaml.Scalar(sub)
			}
			impmap["subpackages"] = yaml.List(subs)
		}

		imports[i] = yaml.Map(impmap)
	}

	rootMap["import"] = yaml.List(imports)


	return root, nil
}

// AddDependencies adds a list of *Dependency objects to the given *Config.
//
// This is used to merge in packages from other sources or config files.
func AddDependencies(c cookoo.Context, p *cookoo.Params) (interface{}, cookoo.Interrupt) {
	deps := p.Get("dependencies", []*Dependency{}).([]*Dependency)
	config := p.Get("conf", nil).(*Config)

	// Make a set of existing package names for quick comparison.
	pkgSet := make(map[string]bool, len(config.Imports))
	for _, p := range config.Imports {
		pkgSet[p.Name] = true
	}

	// If a dep is not already present, add it.
	for _, dep := range deps {
		if _, ok := pkgSet[dep.Name]; ok {
			Warn("Package %s is already in glide.yaml. Skipping.\n", dep.Name)
			continue
		}
		config.Imports = append(config.Imports, dep)
	}

	return true, nil
}

func vcsString(vtype uint) string {
	switch vtype {
	case Git:
		return "git"
	case Hg:
		return "hg"
	case Bzr:
		return "bzr"
	case Svn:
		return "svn"
	default:
		return ""
	}
}

func valOrEmpty(key string, store map[string]yaml.Node) string {
	val, ok := store[key]
	if !ok {
		return ""
	}
	return val.(yaml.Scalar).String()
}

func subpkg(key string, store map[string]yaml.Node) []string {
	val, ok := store[key]

	subpackages := []string{}
	if !ok {
		return subpackages
	}

	pkgs, ok := val.(yaml.List)

	if !ok {

		// Special case: Allow 'subpackages: justOne'
		if one, ok := val.(yaml.Scalar); ok {
			return []string{ one.String() }
		}

		Warn("Expected list of subpackages.\n")
		return subpackages
	}


	for _, pkg := range pkgs {
		subpackages = append(subpackages, pkg.(yaml.Scalar).String())
	}
	return subpackages
}

func getVcsType(store map[string]yaml.Node) uint {

	val, ok := store["vcs"]
	if !ok {
		return NoVCS
	}

	name := val.(yaml.Scalar).String()

	switch name {
	case "git":
		return Git
	case "hg", "mercurial":
		return Hg
	case "bzr", "bazaar":
		return Bzr
	case "svn", "subversion":
		return Svn
	default:
		return NoVCS
	}
}

// Config is the top-level configuration object.
type Config struct {
	Name string
	Imports []*Dependency
	DevImports []*Dependency
	// InCommand is the default shell command run to start a 'glide in'
	// session.
	InCommand string
}

// Dependency describes a package that the present package depends upon.
type Dependency struct {
	Name, Reference, Repository string
	VcsType uint
	Subpackages []string
}