package main

import (
	"bufio"
	"encoding/json"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"strings"

	"golang.org/x/sys/unix"
)

const statuslineWidthOffset = 7

// Input JSON structure from Claude Code
type StatusInput struct {
	Model struct {
		DisplayName string `json:"display_name"`
	} `json:"model"`
	Workspace struct {
		CurrentDir string `json:"current_dir"`
	} `json:"workspace"`
	ContextWindow struct {
		ContextWindowSize int `json:"context_window_size"`
		CurrentUsage      *struct {
			InputTokens          int `json:"input_tokens"`
			CacheCreationTokens  int `json:"cache_creation_input_tokens"`
			CacheReadInputTokens int `json:"cache_read_input_tokens"`
		} `json:"current_usage"`
	} `json:"context_window"`
}

// ANSI color codes
const (
	reset     = "\033[0m"
	bold      = "\033[1m"
	red       = "\033[31m"
	green     = "\033[32m"
	yellow    = "\033[33m"
	magenta   = "\033[35m"
	cyan      = "\033[36m"
	boldGreen = "\033[1;32m"
)

func main() {
	// Read JSON from stdin
	reader := bufio.NewReader(os.Stdin)
	var input strings.Builder
	for {
		line, err := reader.ReadString('\n')
		input.WriteString(line)
		if err != nil {
			break
		}
	}

	var data StatusInput
	if err := json.Unmarshal([]byte(input.String()), &data); err != nil {
		fmt.Fprintf(os.Stderr, "Error parsing JSON: %v\n", err)
		os.Exit(1)
	}

	// Calculate context info
	contextInfo := formatContextInfo(data.ContextWindow.ContextWindowSize, data.ContextWindow.CurrentUsage)

	// Get directory name
	dirName := filepath.Base(data.Workspace.CurrentDir)

	// Check gitea status
	giteaStatus := getGiteaStatus()

	// Get git info
	gitInfo := getGitInfo(data.Workspace.CurrentDir)

	// Build left part
	left := fmt.Sprintf("%s %s%s%s %s➜%s %s%s%s%s",
		giteaStatus,
		magenta, data.Model.DisplayName, reset,
		boldGreen, reset,
		cyan, dirName, reset,
		gitInfo)

	// Build right part
	right := fmt.Sprintf("%s%s%s", yellow, contextInfo, reset)

	// Calculate visible lengths (strip ANSI)
	leftVisible := stripANSI(left)
	rightVisible := stripANSI(right)

	// Get terminal width
	termWidth := getTerminalWidth() - statuslineWidthOffset

	// Calculate padding
	padding := termWidth - len(leftVisible) - len(rightVisible)
	if padding < 1 {
		padding = 1
	}

	// Output with padding
	fmt.Printf("%s%s%s", left, strings.Repeat(" ", padding), right)
}

func formatContextInfo(contextSize int, usage *struct {
	InputTokens          int `json:"input_tokens"`
	CacheCreationTokens  int `json:"cache_creation_input_tokens"`
	CacheReadInputTokens int `json:"cache_read_input_tokens"`
}) string {
	totalK := contextSize / 1000

	if usage == nil {
		return fmt.Sprintf("0/%dk", totalK)
	}

	currentTokens := usage.InputTokens + usage.CacheCreationTokens + usage.CacheReadInputTokens
	currentK := currentTokens / 1000
	return fmt.Sprintf("%dk/%dk", currentK, totalK)
}

func getGiteaStatus() string {
	// Check if gitea process is running using pgrep
	cmd := exec.Command("pgrep", "-x", "gitea")
	if err := cmd.Run(); err == nil {
		return green + "●" + reset
	}
	return red + "●" + reset
}

func getGitInfo(cwd string) string {
	// Change to the directory
	oldDir, _ := os.Getwd()
	if err := os.Chdir(cwd); err != nil {
		return ""
	}
	defer os.Chdir(oldDir)

	// Check if we're in a git repo
	cmd := exec.Command("git", "rev-parse", "--git-dir")
	cmd.Stderr = nil
	if err := cmd.Run(); err != nil {
		return ""
	}

	// Get branch name
	branch := ""
	cmd = exec.Command("git", "symbolic-ref", "--short", "HEAD")
	cmd.Stderr = nil
	if out, err := cmd.Output(); err == nil {
		branch = strings.TrimSpace(string(out))
	} else {
		// Fallback to short SHA
		cmd = exec.Command("git", "rev-parse", "--short", "HEAD")
		cmd.Stderr = nil
		if out, err := cmd.Output(); err == nil {
			branch = strings.TrimSpace(string(out))
		}
	}

	if branch == "" {
		return ""
	}

	// Check if working tree is dirty
	isDirty := false

	// Check unstaged changes
	cmd = exec.Command("git", "diff", "--no-ext-diff", "--quiet", "--exit-code", "--no-optional-locks")
	cmd.Stderr = nil
	if err := cmd.Run(); err != nil {
		isDirty = true
	}

	// Check staged changes
	if !isDirty {
		cmd = exec.Command("git", "diff-index", "--cached", "--quiet", "HEAD", "--no-optional-locks")
		cmd.Stderr = nil
		if err := cmd.Run(); err != nil {
			isDirty = true
		}
	}

	if isDirty {
		return fmt.Sprintf(" git:(%s) ✗", branch)
	}
	return fmt.Sprintf(" git:(%s)", branch)
}

func getTerminalWidth() int {
	ws, err := unix.IoctlGetWinsize(int(os.Stdout.Fd()), unix.TIOCGWINSZ)
	if err != nil {
		return 80
	}
	return int(ws.Col)
}

var ansiRegex = regexp.MustCompile(`\x1b\[[0-9;]*m`)

func stripANSI(s string) string {
	return ansiRegex.ReplaceAllString(s, "")
}