package acr

import (
	"net/url"
	"strconv"

	"gno.land/p/jeronimoalbi/pager"
	"gno.land/p/nt/ufmt"
	"gno.land/r/akkadia/admin"
)

const pageSize = 20

// Render handles RESTful routing and returns Markdown responses
func Render(iUrl string) string {
	u, err := url.Parse(iUrl)
	if err != nil {
		return renderError("Invalid URL")
	}

	query := u.Query()

	switch u.Path {
	case "":
		return renderHome()
	case "top/balance":
		return renderTopByBalance(iUrl)
	case "top/minted":
		return renderTopByMinted(iUrl)
	case "account":
		addr := query.Get("address")
		if addr == "" {
			return renderError("Address required")
		}
		return renderAccount(addr)
	default:
		return renderError("Page not found")
	}
}

// renderHome renders the home page with stats, description, and links
func renderHome() string {
	output := ufmt.Sprintf("# %s (%s)\n\n", token.GetName(), token.GetSymbol())

	output += `## Introduction

**Akkadia Community Rune (ACR)** is the utility token of the Akkadia ecosystem.
Users earn ACR through in-game activities and community participation.

`
	output += "## Token Info\n\n"
	output += ufmt.Sprintf("* **Decimals**: %d\n", token.GetDecimals())
	output += ufmt.Sprintf("* **Total Supply**: %s\n", formatAmount(token.TotalSupply()))
	output += ufmt.Sprintf("* **Known Accounts**: %d\n", token.KnownAccounts())

	output += `
## Quick Links

* [Top Holders by Balance](/r/akkadia/acr:top/balance)
* [Top Holders by Minted](/r/akkadia/acr:top/minted)

## Account Lookup

<gno-form path="account">
  <gno-input name="address" placeholder="Enter wallet address (g1...)" />
</gno-form>
`
	return output
}

// renderTopByBalance renders paginated list of top holders by balance
func renderTopByBalance(iUrl string) string {
	output := "# Top Holders by Balance\n\n"
	output += "[← Home](/r/akkadia/acr:)\n\n"

	totalAccounts := token.KnownAccounts()
	if totalAccounts == 0 {
		output += "*No accounts yet.*\n"
		return output
	}

	pages, err := pager.New(iUrl, totalAccounts, pager.WithPageSize(pageSize))
	if err != nil {
		return renderError("Invalid page")
	}

	// Convert pager offset to 1-indexed page for ListTopUsersByBalance
	page := (pages.Offset() / pages.PageSize()) + 1
	count := pages.PageSize()

	users := ListTopUsersByBalance(page, count)

	if len(users) == 0 {
		output += "*No data available.*\n"
		return output
	}

	output += "| Rank | Address | Balance |\n"
	output += "|------|---------|--------|\n"

	startRank := pages.Offset() + 1
	for i, u := range users {
		addr := u["user"]
		balance, _ := strconv.ParseInt(u["balance"], 10, 64)
		addrLink := ufmt.Sprintf("%s [[View on Explorer](%s/m/explorer/player?address=%s)]", addr, admin.GetExplorerURL(), addr)
		output += ufmt.Sprintf("| %d | %s | %s |\n", startRank+i, addrLink, formatAmount(balance))
	}

	if pages.HasPages() {
		output += "\n" + pager.Picker(pages)
	}

	return output
}

// renderTopByMinted renders paginated list of top holders by minted amount
func renderTopByMinted(iUrl string) string {
	output := "# Top Holders by Minted Amount\n\n"
	output += "[← Home](/r/akkadia/acr:)\n\n"

	totalAccounts := token.KnownAccounts()
	if totalAccounts == 0 {
		output += "*No accounts yet.*\n"
		return output
	}

	pages, err := pager.New(iUrl, totalAccounts, pager.WithPageSize(pageSize))
	if err != nil {
		return renderError("Invalid page")
	}

	// Convert pager offset to 1-indexed page for ListTopUsersByMinting
	page := (pages.Offset() / pages.PageSize()) + 1
	count := pages.PageSize()

	users := ListTopUsersByMinting(page, count)

	if len(users) == 0 {
		output += "*No data available.*\n"
		return output
	}

	output += "| Rank | Address | Total Minted |\n"
	output += "|------|---------|-------------|\n"

	startRank := pages.Offset() + 1
	for i, u := range users {
		addr := u["user"]
		minted, _ := strconv.ParseInt(u["minted"], 10, 64)
		addrLink := ufmt.Sprintf("%s [[View on Explorer](%s/m/explorer/player?address=%s)]", addr, admin.GetExplorerURL(), addr)
		output += ufmt.Sprintf("| %d | %s | %s |\n", startRank+i, addrLink, formatAmount(minted))
	}

	if pages.HasPages() {
		output += "\n" + pager.Picker(pages)
	}

	return output
}

// renderAccount renders a single account's ACR details
func renderAccount(addrStr string) string {
	addr := address(addrStr)
	if !addr.IsValid() {
		return renderError("Invalid address")
	}

	balance := BalanceOf(addr)
	minted := MintedOf(addr)

	output := "# Account Details\n\n"
	output += "[← Home](/r/akkadia/acr:)\n\n"

	output += ufmt.Sprintf("* **Address**: %s [[View on Explorer](%s/m/explorer/player?address=%s)]\n", addrStr, admin.GetExplorerURL(), addrStr)
	output += ufmt.Sprintf("* **Balance**: %s %s\n", formatAmount(balance), token.GetSymbol())
	output += ufmt.Sprintf("* **Total Minted**: %s %s\n", formatAmount(minted), token.GetSymbol())

	return output
}

// renderError renders an error page
func renderError(message string) string {
	output := "# Error\n\n"
	output += ufmt.Sprintf("> %s\n\n", message)
	output += "[← Back to Home](/r/akkadia/acr:)\n"
	return output
}

// formatAmount formats token amount with proper decimal places
func formatAmount(amount int64) string {
	decimals := token.GetDecimals()
	if decimals == 0 {
		return ufmt.Sprintf("%d", amount)
	}

	// Calculate divisor (10^decimals)
	divisor := int64(1)
	for i := 0; i < decimals; i++ {
		divisor *= 10
	}

	intPart := amount / divisor
	fracPart := amount % divisor

	// Format with proper decimal places
	format := ufmt.Sprintf("%%d.%%0%dd", decimals)
	return ufmt.Sprintf(format, intPart, fracPart)
}