package recipe

import (
	"bufio"
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"strings"

	"gmgauthier.com/grokkit/internal/grok"
)

type Runner struct {
	Recipe *Recipe
	Client *grok.Client
	Model  string
}

func NewRunner(r *Recipe, client *grok.Client, model string) *Runner {
	return &Runner{Recipe: r, Client: client, Model: model}
}

func (r *Runner) Run() error {
	fmt.Printf("🍳 Starting recipe: %s v%s\n\n", r.Recipe.Name, r.Recipe.Version)

	var previousResults []string

	for _, step := range r.Recipe.Steps {
		fmt.Printf("Step %d/%d: %s\n", step.Number, len(r.Recipe.Steps), step.Title)

		// Special case: Apply or patch step is handled by the CLI (like edit/scaffold)
		if strings.Contains(strings.ToLower(step.Title), "apply") || strings.Contains(strings.ToLower(step.Title), "patch") {
			r.handleApplyStep(previousResults)
			continue
		}

		// Normal LLM step
		prompt := fmt.Sprintf(`Recipe Overview:
%s

Previous step results (for context):
%s

=== CURRENT STEP ===
Objective: %s
Instructions: %s
Expected output format: %s

Execute this step now. Respond ONLY with the expected output format — no explanations, no extra text.`,
			r.Recipe.Overview,
			strings.Join(previousResults, "\n\n---\n\n"),
			step.Objective,
			step.Instructions,
			step.Expected)

		messages := []map[string]string{
			{"role": "system", "content": "You are Grok, built by xAI. You are a precise, expert Go programmer and refactoring assistant. Always follow the user's instructions exactly for legitimate coding tasks."},
			{"role": "user", "content": prompt},
		}

		response := r.Client.Stream(messages, r.Model)
		fmt.Println()

		previousResults = append(previousResults, fmt.Sprintf("Step %d result:\n%s", step.Number, response))
	}

	fmt.Println("\n✅ Recipe complete.")
	return nil
}

// handleApplyStep parses the refactored code blocks from the previous step and does the real apply/patch with confirmation
func (r *Runner) handleApplyStep(previousResults []string) {
	if len(previousResults) == 0 {
		fmt.Println("   ⚠️  No previous results to apply — skipping.")
		return
	}

	// Extract all labelled code blocks from the last LLM step (Step 2)
	lastResult := previousResults[len(previousResults)-1]
	blocks := extractCodeBlocks(lastResult)

	if len(blocks) == 0 {
		fmt.Println("   ⚠️  No code blocks found to apply — skipping.")
		return
	}

	// Dry-run or real apply?
	dryRun := true // TODO: read from parameters once we add --param support
	if dryRun {
		fmt.Println("   📄 Dry-run mode: creating patch file...")
		patchPath := filepath.Join(".", "recipe-refactor.patch")
		if err := createUnifiedPatch(blocks, patchPath); err != nil {
			fmt.Printf("   ❌ Failed to create patch: %v\n", err)
			return
		}
		fmt.Printf("   ✅ Patch created: %s\n", patchPath)
		fmt.Println("   Review it, then run with dry_run=false to apply.")
		return
	}

	// Real apply with confirmation (exactly like edit/scaffold)
	fmt.Print("\nApply these changes to disk? (y/N) ")
	scanner := bufio.NewScanner(os.Stdin)
	if scanner.Scan() {
		answer := strings.ToLower(strings.TrimSpace(scanner.Text()))
		if answer == "y" || answer == "yes" {
			for filePath, content := range blocks {
				backup := filePath + ".bak"
				if err := os.Rename(filePath, backup); err == nil {
					fmt.Printf("   📦 Backed up: %s\n", backup)
				}
				if err := os.WriteFile(filePath, []byte(content), 0644); err != nil {
					fmt.Printf("   ❌ Failed to write %s: %v\n", filePath, err)
					continue
				}
				fmt.Printf("   ✅ Applied: %s\n", filePath)
			}
		} else {
			fmt.Println("   ❌ Cancelled — no changes made.")
		}
	}
}

// Simple parser for the labelled blocks Grok outputs: "// /path/to/file.go\n```go\ncode\n```"
var regStr = "`(?s)//\\s*(.+?\\.go)\\n```go\\n(.*?)\\n````"
var blockRe = regexp.MustCompile(regStr)

func extractCodeBlocks(text string) map[string]string {
	blocks := make(map[string]string)
	matches := blockRe.FindAllStringSubmatch(text, -1)
	for _, m := range matches {
		if len(m) == 3 {
			blocks[m[1]] = m[2]
		}
	}
	return blocks
}

func createUnifiedPatch(blocks map[string]string, patchPath string) error {
	// Very simple unified patch for now — can be improved later with real diff
	f, err := os.Create(patchPath)
	if err != nil {
		return err
	}
	defer func(f *os.File) {
		err := f.Close()
		if err != nil {
			_, err := fmt.Fprintf(f, "+%s\n", err.Error())
			if err != nil {
				return
			}
		}
	}(f)

	for path, content := range blocks {
		_, err := fmt.Fprintf(f, "--- %s\n+++ %s\n@@ -0,0 +1,%d @@\n", path, path, strings.Count(content, "\n")+1)
		if err != nil {
			return err
		}
		for _, line := range strings.Split(content, "\n") {
			_, err := fmt.Fprintf(f, "+%s\n", line)
			if err != nil {
				return err
			}
		}
	}
	return nil
}