// Package scraper provides document scraping capabilities for various sources.
package scraper

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"strings"
	"time"
)

// SourceType represents the type of documentation source.
type SourceType string

const (
	SourceTypeWeb            SourceType = "url"
	SourceTypeGitHub         SourceType = "github"
	SourceTypeOpenAPI        SourceType = "openapi"
	SourceTypeLocal          SourceType = "local"
	SourceTypeLocalSearch    SourceType = "localsearch"
	SourceTypeGoDocs         SourceType = "godocs"
	SourceTypeRustDocs       SourceType = "rustdocs"
	SourceTypePythonDocs     SourceType = "pythondocs"
	SourceTypeJavaDocs       SourceType = "javadocs"
	SourceTypeSpringDocs     SourceType = "springdocs"
	SourceTypeTSDocs         SourceType = "tsdocs"
	SourceTypeReactDocs      SourceType = "reactdocs"
	SourceTypeVueDocs        SourceType = "vuedocs"
	SourceTypeNuxtDocs       SourceType = "nuxtdocs"
	SourceTypeMCPDocs        SourceType = "mcpdocs"
	SourceTypeDockerDocs     SourceType = "dockerdocs"
	SourceTypeCloudflareDocs SourceType = "cloudflaredocs"
	SourceTypeAstroDocs      SourceType = "astrodocs"
)

// Source represents a documentation source to scrape.
type Source struct {
	Name        string     `yaml:"name"`
	Type        SourceType `yaml:"type"`
	URL         string     `yaml:"url,omitempty"`
	Query       string     `yaml:"query,omitempty"`
	ResultLimit int        `yaml:"result_limit,omitempty"`
	Domains     []string   `yaml:"domains,omitempty"`
	Repo        string     `yaml:"repo,omitempty"`
	Branch      string     `yaml:"branch,omitempty"`
	Path        string     `yaml:"path,omitempty"`
	Include     []string   `yaml:"include,omitempty"`
	Exclude     []string   `yaml:"exclude,omitempty"`
	Schedule    string     `yaml:"schedule,omitempty"`
}

// Document represents a scraped document.
type Document struct {
	ID        string                 `json:"id"`
	Source    string                 `json:"source"`
	Type      string                 `json:"type"`
	Title     string                 `json:"title"`
	Content   string                 `json:"content"`
	URL       string                 `json:"url,omitempty"`
	Metadata  map[string]interface{} `json:"metadata"`
	Hash      string                 `json:"hash"`
	Timestamp time.Time              `json:"timestamp"`
}

// Config holds scraper configuration.
type Config struct {
	UserAgent   string        `yaml:"user_agent"`
	Timeout     time.Duration `yaml:"timeout"`
	RetryCount  int           `yaml:"retry_count"`
	RetryDelay  time.Duration `yaml:"retry_delay"`
	Concurrency int           `yaml:"concurrency"`
	RateLimit   time.Duration `yaml:"rate_limit"`
	MaxDepth    int           `yaml:"max_depth"`
	CacheDir    string        `yaml:"cache_dir"`
}

// Scraper defines the interface for document scrapers.
type Scraper interface {
	// Scrape fetches and parses documents from the source.
	Scrape(ctx context.Context, source *Source) ([]*Document, error)

	// DetectChanges checks if the source has changed since last scrape.
	DetectChanges(ctx context.Context, source *Source, lastHash string) (bool, string, error)
}

// NewScraper creates a new scraper for the given source type using the registry.
func NewScraper(sourceType SourceType, config *Config) Scraper {
	return CreateScraper(sourceType, config)
}

// DetectSourceType determines the source type from a URL or path.
func DetectSourceType(input string) SourceType {
	// Check for GitHub repositories
	if strings.Contains(input, "github.com") {
		return SourceTypeGitHub
	}

	// Check for known documentation hosts
	docsHosts := map[string]SourceType{
		"pkg.go.dev":                SourceTypeGoDocs,
		"docs.rs":                   SourceTypeRustDocs,
		"docs.python.org":           SourceTypePythonDocs,
		"docs.oracle.com":           SourceTypeJavaDocs,
		"docs.spring.io":            SourceTypeSpringDocs,
		"typescriptlang.org":        SourceTypeTSDocs,
		"react.dev":                 SourceTypeReactDocs,
		"vuejs.org":                 SourceTypeVueDocs,
		"nuxt.com":                  SourceTypeNuxtDocs,
		"docs.docker.com":           SourceTypeDockerDocs,
		"developers.cloudflare.com": SourceTypeCloudflareDocs,
		"docs.astro.build":          SourceTypeAstroDocs,
	}

	for host, sourceType := range docsHosts {
		if strings.Contains(input, host) {
			return sourceType
		}
	}

	// MCP servers are hosted under Docker Hub paths.
	if strings.Contains(input, "hub.docker.com/mcp/") {
		return SourceTypeMCPDocs
	}

	// Check for OpenAPI specs
	if strings.HasSuffix(input, ".json") || strings.HasSuffix(input, ".yaml") || strings.HasSuffix(input, ".yml") {
		if strings.Contains(strings.ToLower(input), "openapi") || strings.Contains(strings.ToLower(input), "swagger") {
			return SourceTypeOpenAPI
		}
	}

	// Check for web URLs
	if strings.HasPrefix(input, "http://") || strings.HasPrefix(input, "https://") {
		return SourceTypeWeb
	}

	// Default to local
	return SourceTypeLocal
}

// generateDocID generates a unique ID for a document.
func generateDocID(urlStr string) string {
	hash := sha256.Sum256([]byte(urlStr))
	return hex.EncodeToString(hash[:12])
}