package recipe

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"strings"
	"time"

	"gitea.stevedudenhoeffer.com/steve/go-extractor"
)

// Recipe holds structured recipe data extracted from a web page.
type Recipe struct {
	Name         string
	Description  string
	Author       string
	PrepTime     string
	CookTime     string
	TotalTime    string
	Yield        string // servings
	Ingredients  []string
	Instructions []string
	ImageURL     string
	Rating       float64
	Calories     string
	SourceURL    string
}

// Config holds configuration for the recipe extractor.
type Config struct{}

// DefaultConfig is the default recipe configuration.
var DefaultConfig = Config{}

func (c Config) validate() Config {
	return c
}

// ExtractRecipe extracts structured recipe data from any URL.
// Uses JSON-LD structured data when available, falls back to DOM parsing.
func (c Config) ExtractRecipe(ctx context.Context, b extractor.Browser, url string) (*Recipe, error) {
	c = c.validate()

	slog.Info("fetching recipe", "url", url)
	doc, err := b.Open(ctx, url, extractor.OpenPageOptions{})
	if err != nil {
		return nil, fmt.Errorf("failed to open recipe page: %w", err)
	}
	defer extractor.DeferClose(doc)

	timeout := 10 * time.Second
	if err := doc.WaitForNetworkIdle(&timeout); err != nil {
		slog.Warn("WaitForNetworkIdle failed", "err", err)
	}

	r, err := extractRecipeFromJSONLD(doc)
	if err == nil && r.Name != "" {
		r.SourceURL = url
		return r, nil
	}

	// Fall back to DOM parsing
	r = extractRecipeFromDOM(doc)
	r.SourceURL = url
	return r, nil
}

// ExtractRecipe is a convenience function using DefaultConfig.
func ExtractRecipe(ctx context.Context, b extractor.Browser, url string) (*Recipe, error) {
	return DefaultConfig.ExtractRecipe(ctx, b, url)
}

// jsonLDGraph represents a JSON-LD @graph container.
type jsonLDGraph struct {
	Graph []json.RawMessage `json:"@graph"`
}

// jsonLDRecipe represents the JSON-LD Recipe schema fields we extract.
type jsonLDRecipe struct {
	Type         interface{} `json:"@type"`
	Name         string      `json:"name"`
	Description  string      `json:"description"`
	Author       interface{} `json:"author"`
	PrepTime     string      `json:"prepTime"`
	CookTime     string      `json:"cookTime"`
	TotalTime    string      `json:"totalTime"`
	Yield        interface{} `json:"recipeYield"`
	Ingredients  []string    `json:"recipeIngredient"`
	Instructions interface{} `json:"recipeInstructions"`
	Image        interface{} `json:"image"`
	Nutrition    *struct {
		Calories string `json:"calories"`
	} `json:"nutrition"`
	Rating *struct {
		RatingValue interface{} `json:"ratingValue"`
	} `json:"aggregateRating"`
}

func extractRecipeFromJSONLD(doc extractor.Node) (*Recipe, error) {
	var recipe Recipe

	scripts := doc.Select("script[type='application/ld+json']")
	if len(scripts) == 0 {
		return nil, fmt.Errorf("no JSON-LD scripts found")
	}

	for _, script := range scripts {
		txt, err := script.Text()
		if err != nil {
			continue
		}
		txt = strings.TrimSpace(txt)

		r, err := parseJSONLDRecipe(txt)
		if err == nil && r.Name != "" {
			return r, nil
		}
	}

	return &recipe, fmt.Errorf("no Recipe JSON-LD found")
}

func parseJSONLDRecipe(raw string) (*Recipe, error) {
	// Try direct Recipe object
	var jr jsonLDRecipe
	if err := json.Unmarshal([]byte(raw), &jr); err == nil {
		if isRecipeType(jr.Type) {
			return convertJSONLDRecipe(&jr), nil
		}
	}

	// Try @graph array
	var graph jsonLDGraph
	if err := json.Unmarshal([]byte(raw), &graph); err == nil && len(graph.Graph) > 0 {
		for _, item := range graph.Graph {
			var jr jsonLDRecipe
			if err := json.Unmarshal(item, &jr); err == nil && isRecipeType(jr.Type) {
				return convertJSONLDRecipe(&jr), nil
			}
		}
	}

	// Try array of objects
	var arr []json.RawMessage
	if err := json.Unmarshal([]byte(raw), &arr); err == nil {
		for _, item := range arr {
			var jr jsonLDRecipe
			if err := json.Unmarshal(item, &jr); err == nil && isRecipeType(jr.Type) {
				return convertJSONLDRecipe(&jr), nil
			}
		}
	}

	return nil, fmt.Errorf("no Recipe type in JSON-LD")
}

func isRecipeType(t interface{}) bool {
	switch v := t.(type) {
	case string:
		return v == "Recipe"
	case []interface{}:
		for _, item := range v {
			if s, ok := item.(string); ok && s == "Recipe" {
				return true
			}
		}
	}
	return false
}

func convertJSONLDRecipe(jr *jsonLDRecipe) *Recipe {
	r := &Recipe{
		Name:        jr.Name,
		Description: jr.Description,
		PrepTime:    formatDuration(jr.PrepTime),
		CookTime:    formatDuration(jr.CookTime),
		TotalTime:   formatDuration(jr.TotalTime),
		Ingredients: jr.Ingredients,
	}

	// Author can be string or object
	r.Author = extractAuthor(jr.Author)

	// Yield can be string or array
	r.Yield = extractYield(jr.Yield)

	// Instructions can be string, array of strings, or array of HowToStep objects
	r.Instructions = extractInstructions(jr.Instructions)

	// Image can be string or object or array
	r.ImageURL = extractImage(jr.Image)

	// Nutrition
	if jr.Nutrition != nil {
		r.Calories = jr.Nutrition.Calories
	}

	// Rating
	if jr.Rating != nil {
		r.Rating = extractFloat(jr.Rating.RatingValue)
	}

	return r
}

func extractAuthor(v interface{}) string {
	switch a := v.(type) {
	case string:
		return a
	case map[string]interface{}:
		if name, ok := a["name"].(string); ok {
			return name
		}
	case []interface{}:
		if len(a) > 0 {
			return extractAuthor(a[0])
		}
	}
	return ""
}

func extractYield(v interface{}) string {
	switch y := v.(type) {
	case string:
		return y
	case []interface{}:
		if len(y) > 0 {
			if s, ok := y[0].(string); ok {
				return s
			}
		}
	case float64:
		return fmt.Sprintf("%.0f", y)
	}
	return ""
}

func extractInstructions(v interface{}) []string {
	switch inst := v.(type) {
	case string:
		return []string{inst}
	case []interface{}:
		var steps []string
		for _, item := range inst {
			switch step := item.(type) {
			case string:
				steps = append(steps, step)
			case map[string]interface{}:
				if text, ok := step["text"].(string); ok {
					steps = append(steps, text)
				}
			}
		}
		return steps
	}
	return nil
}

func extractImage(v interface{}) string {
	switch img := v.(type) {
	case string:
		return img
	case map[string]interface{}:
		if url, ok := img["url"].(string); ok {
			return url
		}
	case []interface{}:
		if len(img) > 0 {
			return extractImage(img[0])
		}
	}
	return ""
}

func extractFloat(v interface{}) float64 {
	switch f := v.(type) {
	case float64:
		return f
	case string:
		var val float64
		fmt.Sscanf(f, "%f", &val)
		return val
	}
	return 0
}

// formatDuration converts ISO 8601 duration (PT1H30M) to human-readable form.
func formatDuration(iso string) string {
	if iso == "" {
		return ""
	}

	iso = strings.TrimPrefix(iso, "PT")
	iso = strings.TrimPrefix(iso, "pt")

	if iso == "" {
		return ""
	}

	var parts []string
	var num string

	for _, c := range iso {
		switch {
		case c >= '0' && c <= '9':
			num += string(c)
		case c == 'H' || c == 'h':
			if num != "" {
				parts = append(parts, num+" hr")
				num = ""
			}
		case c == 'M' || c == 'm':
			if num != "" {
				parts = append(parts, num+" min")
				num = ""
			}
		case c == 'S' || c == 's':
			if num != "" {
				parts = append(parts, num+" sec")
				num = ""
			}
		}
	}

	if len(parts) == 0 {
		return iso
	}

	return strings.Join(parts, " ")
}

func extractRecipeFromDOM(doc extractor.Node) *Recipe {
	var r Recipe

	// Name — typically in h1 or h2
	names := doc.Select("h1.recipe-title")
	if len(names) == 0 {
		names = doc.Select("h1")
	}
	if len(names) > 0 {
		r.Name, _ = names[0].Text()
		r.Name = strings.TrimSpace(r.Name)
	}

	// Description
	descs := doc.Select("div.recipe-summary p")
	if len(descs) > 0 {
		r.Description, _ = descs[0].Text()
	}

	// Ingredients
	_ = doc.ForEach("li.ingredient", func(n extractor.Node) error {
		txt, _ := n.Text()
		txt = strings.TrimSpace(txt)
		if txt != "" {
			r.Ingredients = append(r.Ingredients, txt)
		}
		return nil
	})

	// Instructions
	_ = doc.ForEach("li.instruction", func(n extractor.Node) error {
		txt, _ := n.Text()
		txt = strings.TrimSpace(txt)
		if txt != "" {
			r.Instructions = append(r.Instructions, txt)
		}
		return nil
	})

	return &r
}