package kalshi

import (
	"context"
	"fmt"
	"net/http"
	"strings"
	"time"
)

// Market represents a single prediction market on Kalshi.
type Market struct {
	Ticker       string
	EventTicker  string
	Title        string
	Subtitle     string
	Status       string
	YesBid       float64 // 0-1 (probability)
	YesAsk       float64
	NoBid        float64
	NoAsk        float64
	LastPrice    float64
	Volume       int
	Volume24h    int
	OpenInterest int
	Result       string // "yes", "no", or "" if unresolved
	Rules        string
	CloseTime    time.Time
}

// URL returns the Kalshi web URL for this market.
func (m Market) URL() string {
	if m.Ticker == "" {
		return ""
	}
	return "https://kalshi.com/markets/" + m.Ticker
}

// Event represents a prediction market event on Kalshi, which may contain
// one or more individual markets.
type Event struct {
	EventTicker  string
	SeriesTicker string
	Title        string
	Subtitle     string
	Category     string
	Markets      []Market
}

// URL returns the Kalshi web URL for this event.
func (e Event) URL() string {
	if e.EventTicker == "" {
		return ""
	}
	return "https://kalshi.com/markets/" + e.EventTicker
}

// Config holds configuration for the Kalshi extractor.
type Config struct {
	// BaseURL overrides the API base URL. Leave empty for the default.
	BaseURL string

	// HTTPClient overrides the HTTP client used for API requests. Leave nil for default.
	HTTPClient *http.Client

	// MaxSearchResults limits the number of results returned by Search.
	// Defaults to 20 if zero.
	MaxSearchResults int
}

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

func (c Config) validate() Config {
	if c.MaxSearchResults <= 0 {
		c.MaxSearchResults = 20
	}
	return c
}

// Search finds events matching the given query string by fetching open events
// and filtering by title. Kalshi does not provide a text search API, so this
// performs client-side substring matching.
func (c Config) Search(ctx context.Context, query string) ([]Event, error) {
	c = c.validate()
	return c.searchEvents(ctx, query, c.MaxSearchResults)
}

// GetMarket retrieves a single market by its ticker.
func (c Config) GetMarket(ctx context.Context, ticker string) (*Market, error) {
	c = c.validate()
	return c.getMarketByTicker(ctx, strings.ToUpper(ticker))
}

// GetEvent retrieves an event by its ticker, including all nested markets.
func (c Config) GetEvent(ctx context.Context, eventTicker string) (*Event, error) {
	c = c.validate()
	return c.getEventByTicker(ctx, strings.ToUpper(eventTicker))
}

// GetMarketFromURL extracts the market ticker from a Kalshi URL and retrieves
// the market details.
func (c Config) GetMarketFromURL(ctx context.Context, rawURL string) (*Market, error) {
	c = c.validate()

	ticker, err := parseKalshiURL(rawURL)
	if err != nil {
		return nil, err
	}

	return c.getMarketByTicker(ctx, ticker)
}

// GetEventFromURL extracts the event ticker from a Kalshi URL and retrieves
// the event details.
func (c Config) GetEventFromURL(ctx context.Context, rawURL string) (*Event, error) {
	c = c.validate()

	ticker, err := parseKalshiURL(rawURL)
	if err != nil {
		return nil, err
	}

	// The ticker from the URL could be either a market ticker or event ticker.
	// Try as event first, then fall back to getting the market and looking up its event.
	ev, err := c.getEventByTicker(ctx, ticker)
	if err == nil {
		return ev, nil
	}

	// Try as market ticker - get the market, then get its event
	m, mErr := c.getMarketByTicker(ctx, ticker)
	if mErr != nil {
		return nil, fmt.Errorf("getting event from URL: %w", err)
	}

	return c.getEventByTicker(ctx, m.EventTicker)
}

// Convenience functions using DefaultConfig.

func Search(ctx context.Context, query string) ([]Event, error) {
	return DefaultConfig.Search(ctx, query)
}

func GetMarket(ctx context.Context, ticker string) (*Market, error) {
	return DefaultConfig.GetMarket(ctx, ticker)
}

func GetEvent(ctx context.Context, eventTicker string) (*Event, error) {
	return DefaultConfig.GetEvent(ctx, eventTicker)
}

func GetMarketFromURL(ctx context.Context, rawURL string) (*Market, error) {
	return DefaultConfig.GetMarketFromURL(ctx, rawURL)
}

func GetEventFromURL(ctx context.Context, rawURL string) (*Event, error) {
	return DefaultConfig.GetEventFromURL(ctx, rawURL)
}