package templates

import (
	"fmt"
	"html/template"
	"log"
	"path/filepath"
	"strings"
	"sync"

	"github.com/juanatsap/cv-site/internal/config"
)

// Manager handles template parsing and rendering
type Manager struct {
	templates *template.Template
	config    *config.TemplateConfig
	mu        sync.RWMutex
}

// IsInitialized returns true if the template manager has been properly initialized
// with a config. Empty Manager structs (e.g., in tests) will return false.
func (m *Manager) IsInitialized() bool {
	return m != nil && m.config != nil
}

// NewManager creates a new template manager
func NewManager(cfg *config.TemplateConfig) (*Manager, error) {
	m := &Manager{
		config: cfg,
	}

	if err := m.loadTemplates(); err != nil {
		return nil, fmt.Errorf("failed to load templates: %w", err)
	}

	return m, nil
}

// loadTemplates parses all templates from the configured directory
func (m *Manager) loadTemplates() error {
	m.mu.Lock()
	defer m.mu.Unlock()
	return m.loadTemplatesLocked()
}

// loadTemplatesLocked parses templates without acquiring lock (caller must hold lock)
func (m *Manager) loadTemplatesLocked() error {
	// Create template with custom functions
	funcMap := template.FuncMap{
		"iterate": func(count int) []int {
			var result []int
			for i := 0; i < count; i++ {
				result = append(result, i)
			}
			return result
		},
		"eq": func(a, b string) bool {
			return a == b
		},
		// safeHTML marks string as safe HTML to prevent escaping
		// SECURITY NOTE: Only use with trusted content from CV YAML files
		// Never use with user-generated content to prevent XSS attacks
		"safeHTML": func(s string) template.HTML {
			return template.HTML(s)
		},
		// replaceDrolosoft links "drolosoft" in the summary text
		"replaceDrolosoft": func(s string) string {
			return strings.Replace(s, "drolosoft", `<a href="https://drolosoft.com" target="_blank" rel="noopener noreferrer">drolosoft</a>`, 1)
		},
		// dict creates a map from key-value pairs for passing to sub-templates
		"dict": func(values ...interface{}) (map[string]interface{}, error) {
			if len(values)%2 != 0 {
				return nil, fmt.Errorf("dict requires even number of arguments")
			}
			dict := make(map[string]interface{}, len(values)/2)
			for i := 0; i < len(values); i += 2 {
				key, ok := values[i].(string)
				if !ok {
					return nil, fmt.Errorf("dict keys must be strings")
				}
				dict[key] = values[i+1]
			}
			return dict, nil
		},
	}

	// Parse main templates
	pattern := filepath.Join(m.config.Dir, "*.html")
	tmpl, err := template.New("").Funcs(funcMap).ParseGlob(pattern)
	if err != nil {
		return fmt.Errorf("error parsing templates from %s: %w", pattern, err)
	}

	// Parse partials recursively from all subdirectories
	partialsPattern := filepath.Join(m.config.PartialsDir, "**", "*.html")
	partialsMatches, _ := filepath.Glob(partialsPattern)

	// Also match direct children
	partialsDirectPattern := filepath.Join(m.config.PartialsDir, "*.html")
	directMatches, _ := filepath.Glob(partialsDirectPattern)

	// Combine all matches
	allPartials := append(partialsMatches, directMatches...)

	if len(allPartials) > 0 {
		tmpl, err = tmpl.ParseFiles(allPartials...)
		if err != nil {
			log.Printf("Warning: error parsing partials: %v", err)
		} else {
			log.Printf("📦 Loaded %d partial templates", len(allPartials))
		}
	}

	m.templates = tmpl
	log.Printf("📋 Templates loaded successfully from %s", m.config.Dir)

	return nil
}

// Reload reloads all templates (useful for hot-reload in development)
func (m *Manager) Reload() error {
	return m.loadTemplates()
}

// Render executes a template with the given data
// Note: This method is thread-safe. Hot reload acquires full lock to prevent race conditions.
func (m *Manager) Render(name string) (*template.Template, error) {
	// Hot reload in development mode
	// Use full lock to prevent race condition between reload and lookup
	if m.config.HotReload {
		m.mu.Lock()
		if err := m.loadTemplatesLocked(); err != nil {
			m.mu.Unlock()
			log.Printf("Warning: template reload failed: %v", err)
			// Fall back to read lock for cached templates
			m.mu.RLock()
			defer m.mu.RUnlock()
			tmpl := m.templates.Lookup(name)
			if tmpl == nil {
				return nil, fmt.Errorf("template %q not found", name)
			}
			return tmpl, nil
		}
		tmpl := m.templates.Lookup(name)
		m.mu.Unlock()
		if tmpl == nil {
			return nil, fmt.Errorf("template %q not found", name)
		}
		return tmpl, nil
	}

	// Production mode: just read
	m.mu.RLock()
	defer m.mu.RUnlock()

	tmpl := m.templates.Lookup(name)
	if tmpl == nil {
		return nil, fmt.Errorf("template %q not found", name)
	}

	return tmpl, nil
}