// Package handlers holds the HTTP handlers for the OpenYield web UI screens.
//
// Each screen (Reach signup, Stash dashboard, Window authorization, Standing
// progress, Bloom accrual) gets its own handler file. handlers/server.go wires
// routes into the mux from web/server.go. Handlers render html/template
// templates against the mock store (web/store). Lexicon-clean by construction
// (REQ-012 / REQ-045): the lexicon_meta_web firewall scans these files.
package handlers

import (
	"fmt"
	"html/template"
	"net/http"
	"os"
	"path/filepath"

	"github.com/oy/openyield/web/store"
	standingtypes "github.com/oy/openyield/x/standing/types"
	windowtypes "github.com/oy/openyield/x/window/types"
)

// Server bundles the mock store + per-page templates + route registration.
// Each screen handler is a method on Server so it shares the store + tmpl.
//
// Template loading: base.html is parsed once, then each page template is
// parsed in a CLONE of the base set so the per-page "content" block does not
// collide across pages (Go html/template shares the block namespace within
// one set; cloning per page isolates each page's content block). This is the
// standard Go template pattern for layouts + pages.
type Server struct {
	Store *store.Store
	Pages map[string]*template.Template
}

// New constructs a Server with the given store + per-page templates loaded
// from templatesDir (the absolute or relative path to web/templates/).
func New(s *store.Store, templatesDir string) (*Server, error) {
	funcs := template.FuncMap{
		"divGrain": func(grain, unit int64) int64 {
			if unit == 0 {
				return 0
			}
			return grain / unit
		},
		"string": func(v any) string {
			switch t := v.(type) {
			case string:
				return t
			case windowtypes.WindowStatus:
				return string(t)
			case standingtypes.StandingBucket:
				return string(t)
			default:
				return ""
			}
		},
	}
	basePath := filepath.Join(templatesDir, "base.html")
	base, err := template.New("base.html").Funcs(funcs).ParseFiles(basePath)
	if err != nil {
		return nil, fmt.Errorf("parse base: %w", err)
	}
	pages := map[string]*template.Template{}
	pageGlob := filepath.Join(templatesDir, "*.html")
	matches, err := filepath.Glob(pageGlob)
	if err != nil {
		return nil, fmt.Errorf("glob pages: %w", err)
	}
	for _, p := range matches {
		name := filepath.Base(p)
		if name == "base.html" {
			continue
		}
		clone, cerr := base.Clone()
		if cerr != nil {
			return nil, fmt.Errorf("clone for %s: %w", name, cerr)
		}
		pt, perr := clone.ParseFiles(p)
		if perr != nil {
			return nil, fmt.Errorf("parse %s: %w", name, perr)
		}
		pages[name] = pt
	}
	return &Server{Store: s, Pages: pages}, nil
}

// Register wires all screen routes into the given mux (Go 1.22 method
// patterns). Called by web/server.go after constructing the Server.
func (s *Server) Register(mux *http.ServeMux) {
	s.registerReach(mux)
	s.registerStash(mux)
	s.registerWindow(mux)
	s.registerStanding(mux)
	s.registerBloom(mux)
}

// render executes the named page template with the given data, writing HTML
// to w. The page template invokes base.html and overrides the "content" block.
func (s *Server) render(w http.ResponseWriter, name string, data any) {
	tmpl, ok := s.Pages[name]
	if !ok {
		http.Error(w, "template not found: "+name, http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	if err := tmpl.ExecuteTemplate(w, "base.html", data); err != nil {
		http.Error(w, "render error", http.StatusInternalServerError)
	}
}

// RenderHome renders the home page (public so web/server.go can call it for
// the "/" route which lives outside handlers.Register).
func (s *Server) RenderHome(w http.ResponseWriter, data any) {
	s.render(w, "home.html", data)
}

// templatesDir returns the default web/templates directory relative to the
// working directory. Used by web/server.go when constructing via New().
func DefaultTemplatesDir() string {
	dir, _ := os.Getwd()
	if filepath.Base(dir) == "web" || filepath.Base(dir) == "handlers" {
		return filepath.Join(dir, "templates")
	}
	return "web/templates"
}