package recipe

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"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)

		titleLower := strings.ToLower(step.Title)

		switch {
		case strings.Contains(titleLower, "discover") || strings.Contains(titleLower, "find"):
			files := r.discoverFiles()
			result := strings.Join(files, "\n")
			previousResults = append(previousResults, "Discovered files:\n"+result)
			fmt.Println(result)

		case strings.Contains(titleLower, "refactor"):
			r.refactorFiles(previousResults) // <-- new one-file-at-a-time handler
			continue

		case strings.Contains(titleLower, "apply") || strings.Contains(titleLower, "patch"):
			r.handleApplyStep(previousResults)
			continue

		default:
			// fallback for any other 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. Precise expert programmer and refactoring assistant."},
				{"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
}

// discoverFiles — real filesystem scan (we'll generalize with extensions next)
func (r *Runner) discoverFiles() []string {
	var files []string
	root := "internal"

	_ = filepath.WalkDir(root, func(path string, d os.DirEntry, err error) error {
		if err != nil || d.IsDir() || !strings.HasSuffix(path, ".go") {
			return nil
		}
		b, _ := os.ReadFile(path)
		if strings.Contains(string(b), "if err != nil") {
			files = append(files, path)
		}
		return nil
	})

	if len(files) == 0 {
		files = append(files, "No files found matching the criteria.")
	}
	return files
}

// refactorFiles — one file at a time (small JSON, no truncation)
func (r *Runner) refactorFiles(previousResults []string) {
	discoveredLine := previousResults[len(previousResults)-1]
	lines := strings.Split(discoveredLine, "\n")

	for _, line := range lines {
		filePath := strings.TrimSpace(line)
		if filePath == "" || strings.HasPrefix(filePath, "Discovered") || filePath == "No files found matching the criteria." {
			continue
		}

		fmt.Printf("   Refactoring %s...\n", filePath)

		content, err := os.ReadFile(filePath)
		if err != nil {
			fmt.Printf("   ❌ Could not read %s\n", filePath)
			continue
		}

		prompt := fmt.Sprintf(`Refactor the following file to use Result[T] instead of naked errors.
Follow existing style and preserve all comments.
Return ONLY this exact JSON (no extra text, no markdown):

{
  "file": "%s",
  "content": "the complete refactored file here"
}

Original file:
%s`, filePath, string(content))

		messages := []map[string]string{
			{"role": "system", "content": "You are Grok, built by xAI. Precise expert programmer and refactoring assistant."},
			{"role": "user", "content": prompt},
		}

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

		// store the JSON response for the apply step
		previousResults = append(previousResults, response)
	}
}

type FileChange struct {
	File    string `json:"file"`
	Content string `json:"content"`
}

func (r *Runner) handleApplyStep(previousResults []string) {
	if len(previousResults) == 0 {
		fmt.Println("   ⚠️  No previous results to apply — skipping.")
		return
	}

	// collect all JSON objects from the refactor step(s)
	var allChanges []FileChange
	for _, res := range previousResults {
		start := strings.Index(res, "{")
		end := strings.LastIndex(res, "}") + 1
		if start == -1 {
			continue
		}
		jsonStr := res[start:end]

		var ch FileChange
		if err := json.Unmarshal([]byte(jsonStr), &ch); err == nil {
			allChanges = append(allChanges, ch)
		}
	}

	if len(allChanges) == 0 {
		fmt.Println("   ⚠️  No valid file changes found — skipping.")
		return
	}

	fmt.Println("   📄 Dry-run mode: creating patch file...")
	patchPath := filepath.Join(".", "recipe-refactor.patch")
	if err := createUnifiedPatch(allChanges, 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.")
}

func createUnifiedPatch(changes []FileChange, patchPath string) error {
	f, err := os.Create(patchPath)
	if err != nil {
		return err
	}
	defer func(f *os.File) {
		err := f.Close()
		if err != nil {
			return
		}
	}(f)

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