package stacks

import (
	"os"
	"path/filepath"
	"strings"

	"gopkg.in/yaml.v3"
)

// Metadata holds app information parsed from .felhom.yml.
type Metadata struct {
	DisplayName string          `yaml:"display_name" json:"display_name"`
	Description string          `yaml:"description" json:"description"`
	Category    string          `yaml:"category" json:"category"`
	Subdomain   string          `yaml:"subdomain" json:"subdomain"`
	Slug        string          `yaml:"slug" json:"slug"`
	Resources   ResourceHints   `yaml:"resources" json:"resources"`
	DeployFields []DeployField  `yaml:"deploy_fields" json:"deploy_fields"`
}

// ResourceHints describe what the app needs.
type ResourceHints struct {
	RAM           string `yaml:"ram" json:"ram"`
	PiCompatible  bool   `yaml:"pi_compatible" json:"pi_compatible"`
	NeedsHDD      bool   `yaml:"needs_hdd" json:"needs_hdd"`
}

// DeployField defines one configuration field shown during first deployment.
type DeployField struct {
	EnvVar           string          `yaml:"env_var" json:"env_var"`
	Label            string          `yaml:"label" json:"label"`
	Type             string          `yaml:"type" json:"type"`               // domain, secret, password, path, text, select, boolean
	Generate         string          `yaml:"generate" json:"generate"`       // e.g., "password:24", "hex:32", "static:admin"
	Default          string          `yaml:"default" json:"default"`
	Required         bool            `yaml:"required" json:"required"`
	Placeholder      string          `yaml:"placeholder" json:"placeholder"`
	Description      string          `yaml:"description" json:"description"`
	LockedAfterDeploy bool           `yaml:"locked_after_deploy" json:"locked_after_deploy"`
	Options          []SelectOption  `yaml:"options" json:"options,omitempty"`
}

// SelectOption is a choice for "select" type fields.
type SelectOption struct {
	Value string `yaml:"value" json:"value"`
	Label string `yaml:"label" json:"label"`
}

// LoadMetadata reads .felhom.yml from a stack directory.
// Returns default metadata if the file doesn't exist.
func LoadMetadata(stackDir string) Metadata {
	meta := Metadata{}

	path := filepath.Join(stackDir, ".felhom.yml")
	data, err := os.ReadFile(path)
	if err != nil {
		// No metadata file — build defaults from directory name
		dirName := filepath.Base(stackDir)
		meta.DisplayName = toTitleCase(strings.ReplaceAll(dirName, "-", " "))
		meta.Slug = dirName
		meta.Category = "tools"
		return meta
	}

	if err := yaml.Unmarshal(data, &meta); err != nil {
		// Parse error — still return defaults
		dirName := filepath.Base(stackDir)
		meta.DisplayName = toTitleCase(strings.ReplaceAll(dirName, "-", " "))
		meta.Slug = dirName
		return meta
	}

	// Fill in defaults for missing fields
	dirName := filepath.Base(stackDir)
	if meta.Slug == "" {
		meta.Slug = dirName
	}
	if meta.DisplayName == "" {
		meta.DisplayName = toTitleCase(strings.ReplaceAll(dirName, "-", " "))
	}
	if meta.Category == "" {
		meta.Category = "tools"
	}

	// DOMAIN field is always auto-filled — mark it implicitly required
	for i := range meta.DeployFields {
		if meta.DeployFields[i].Type == "domain" {
			meta.DeployFields[i].Required = true
			meta.DeployFields[i].LockedAfterDeploy = true
		}
		// secret fields are always locked after deploy
		if meta.DeployFields[i].Type == "secret" {
			meta.DeployFields[i].LockedAfterDeploy = true
		}
	}

	return meta
}

// HasDeployFields returns true if the app has any user-facing deploy fields
// (i.e., fields beyond auto-filled domain and auto-generated secrets).
func (m *Metadata) HasDeployFields() bool {
	for _, f := range m.DeployFields {
		if f.Type != "domain" && f.Type != "secret" {
			return true
		}
	}
	return false
}

// UserFacingFields returns only fields the user needs to interact with.
// Excludes auto-filled (domain) and fully hidden (secret) fields.
func (m *Metadata) UserFacingFields() []DeployField {
	var fields []DeployField
	for _, f := range m.DeployFields {
		if f.Type != "domain" && f.Type != "secret" {
			fields = append(fields, f)
		}
	}
	return fields
}

// AutoGeneratedFields returns fields that are generated without user input.
func (m *Metadata) AutoGeneratedFields() []DeployField {
	var fields []DeployField
	for _, f := range m.DeployFields {
		if f.Type == "secret" || f.Type == "domain" {
			fields = append(fields, f)
		}
	}
	return fields
}