package imdb

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

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

// Movie holds structured movie/TV information from IMDB.
type Movie struct {
	ID        string   // e.g. "tt1234567"
	Title     string
	Year      int
	Rating    float64 // IMDB score (0-10)
	Votes     int
	Runtime   string
	Genres    []string
	Director  string
	Cast      []string
	Plot      string
	PosterURL string
	BoxOffice string // e.g. "$200,000,000"
}

// SearchResult holds a search result entry from IMDB.
type SearchResult struct {
	ID    string
	Title string
	Year  int
}

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

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

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

// titleURL returns the IMDB URL for a given title ID.
func titleURL(id string) string {
	return fmt.Sprintf("https://www.imdb.com/title/%s/", id)
}

// findURL returns the IMDB search URL for a given query.
func findURL(query string) string {
	return fmt.Sprintf("https://www.imdb.com/find/?q=%s&s=tt&ttype=ft", strings.ReplaceAll(query, " ", "+"))
}

// GetMovie extracts structured movie data from an IMDB title page.
func (c Config) GetMovie(ctx context.Context, b extractor.Browser, id string) (*Movie, error) {
	c = c.validate()

	u := titleURL(id)

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

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

	return extractMovie(doc, id)
}

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

// Search searches IMDB for titles matching the query.
func (c Config) Search(ctx context.Context, b extractor.Browser, query string) ([]SearchResult, error) {
	c = c.validate()

	u := findURL(query)

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

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

	return extractSearchResults(doc)
}

// Search is a convenience function using DefaultConfig.
func Search(ctx context.Context, b extractor.Browser, query string) ([]SearchResult, error) {
	return DefaultConfig.Search(ctx, b, query)
}

// jsonLDMovie represents the JSON-LD Movie schema from IMDB.
type jsonLDMovie struct {
	Type        string      `json:"@type"`
	Name        string      `json:"name"`
	Description string      `json:"description"`
	DatePublished string    `json:"datePublished"`
	Image       interface{} `json:"image"`
	Duration    string      `json:"duration"`
	Genre       interface{} `json:"genre"`
	Director    interface{} `json:"director"`
	Actor       interface{} `json:"actor"`
	Rating      *struct {
		RatingValue interface{} `json:"ratingValue"`
		RatingCount interface{} `json:"ratingCount"`
	} `json:"aggregateRating"`
}

func extractMovie(doc extractor.Node, id string) (*Movie, error) {
	m := &Movie{ID: id}

	// Try JSON-LD first (most reliable on IMDB)
	scripts := doc.Select("script[type='application/ld+json']")
	for _, script := range scripts {
		txt, err := script.Text()
		if err != nil {
			continue
		}

		var jm jsonLDMovie
		if err := json.Unmarshal([]byte(txt), &jm); err != nil {
			continue
		}

		if jm.Type == "Movie" || jm.Type == "TVSeries" || jm.Type == "TVMiniSeries" {
			m.Title = jm.Name
			m.Plot = jm.Description
			m.Runtime = formatDuration(jm.Duration)
			m.PosterURL = extractImage(jm.Image)
			m.Genres = extractGenres(jm.Genre)
			m.Director = extractPerson(jm.Director)
			m.Cast = extractPersonList(jm.Actor)

			if jm.DatePublished != "" {
				m.Year = extractYear(jm.DatePublished)
			}

			if jm.Rating != nil {
				m.Rating = toFloat(jm.Rating.RatingValue)
				m.Votes = toInt(jm.Rating.RatingCount)
			}

			break
		}
	}

	// Box office from DOM (not in JSON-LD)
	_ = doc.ForEach("li[data-testid='title-boxoffice-section'] span", func(n extractor.Node) error {
		txt, _ := n.Text()
		if strings.HasPrefix(txt, "$") {
			m.BoxOffice = txt
		}
		return nil
	})

	// Fallback: title from DOM if JSON-LD didn't work
	if m.Title == "" {
		titles := doc.Select("h1[data-testid='hero__pageTitle'] span")
		if len(titles) == 0 {
			titles = doc.Select("h1")
		}
		if len(titles) > 0 {
			m.Title, _ = titles[0].Text()
			m.Title = strings.TrimSpace(m.Title)
		}
	}

	return m, nil
}

func extractSearchResults(doc extractor.Node) ([]SearchResult, error) {
	var results []SearchResult

	_ = doc.ForEach("li.find-result-item", func(n extractor.Node) error {
		var sr SearchResult

		// Title link contains the ID in href
		links := n.Select("a.ipc-metadata-list-summary-item__t")
		if len(links) > 0 {
			sr.Title, _ = links[0].Text()
			sr.Title = strings.TrimSpace(sr.Title)

			href, _ := links[0].Attr("href")
			sr.ID = extractTitleID(href)
		}

		// Year
		years := n.Select("span.ipc-metadata-list-summary-item__li")
		if len(years) > 0 {
			txt, _ := years[0].Text()
			sr.Year = extractYear(txt)
		}

		if sr.Title != "" {
			results = append(results, sr)
		}
		return nil
	})

	return results, nil
}

// extractTitleID extracts "tt1234567" from an IMDB URL path like "/title/tt1234567/".
func extractTitleID(href string) string {
	parts := strings.Split(href, "/")
	for _, p := range parts {
		if strings.HasPrefix(p, "tt") {
			return p
		}
	}
	return ""
}

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
		}
	}
	return ""
}

func extractGenres(v interface{}) []string {
	switch g := v.(type) {
	case string:
		return []string{g}
	case []interface{}:
		var genres []string
		for _, item := range g {
			if s, ok := item.(string); ok {
				genres = append(genres, s)
			}
		}
		return genres
	}
	return nil
}

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

func extractPersonList(v interface{}) []string {
	switch a := v.(type) {
	case []interface{}:
		var people []string
		for _, item := range a {
			if name := extractPerson(item); name != "" {
				people = append(people, name)
			}
		}
		return people
	case map[string]interface{}:
		if name := extractPerson(a); name != "" {
			return []string{name}
		}
	}
	return nil
}

func extractYear(s string) int {
	// Try to find a 4-digit year in the string
	for i := 0; i <= len(s)-4; i++ {
		if s[i] >= '0' && s[i] <= '9' {
			chunk := s[i : i+4]
			if y, err := strconv.Atoi(chunk); err == nil && y >= 1888 && y <= 2100 {
				return y
			}
		}
	}
	return 0
}

// formatDuration converts ISO 8601 duration (PT2H30M) 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+"h")
				num = ""
			}
		case c == 'M' || c == 'm':
			if num != "" {
				parts = append(parts, num+"m")
				num = ""
			}
		}
	}

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

	return strings.Join(parts, " ")
}

func toFloat(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
}

func toInt(v interface{}) int {
	switch i := v.(type) {
	case float64:
		return int(i)
	case string:
		val, _ := strconv.Atoi(strings.ReplaceAll(i, ",", ""))
		return val
	}
	return 0
}