package computer

import (
	"context"
	"encoding/json"
	"fmt"
	"regexp"
	"strings"

	"github.com/gooseek/backend/internal/llm"
	"github.com/google/uuid"
)

type Planner struct {
	registry *llm.ModelRegistry
}

func NewPlanner(registry *llm.ModelRegistry) *Planner {
	return &Planner{
		registry: registry,
	}
}

func (p *Planner) Plan(ctx context.Context, query string, memory map[string]interface{}) (*TaskPlan, error) {
	client, _, err := p.registry.GetBest(llm.CapReasoning)
	if err != nil {
		client, _, err = p.registry.GetBest(llm.CapCoding)
		if err != nil {
			return nil, fmt.Errorf("no suitable model for planning: %w", err)
		}
	}

	memoryContext := ""
	if len(memory) > 0 {
		memoryJSON, _ := json.Marshal(memory)
		memoryContext = fmt.Sprintf("\n\nUser context and memory:\n%s", string(memoryJSON))
	}

	prompt := fmt.Sprintf(`You are a task planning AI. Analyze this query and create an execution plan.

Query: %s%s

Break this into subtasks. Each subtask should be:
1. Atomic - one clear action
2. Independent where possible (for parallel execution)
3. Have clear dependencies when needed

Available task types:
- research: Search web, gather information
- code: Write/generate code
- analysis: Analyze data, extract insights
- design: Design architecture, create plans
- deploy: Deploy applications, run code
- monitor: Set up monitoring, tracking
- report: Generate reports, summaries
- communicate: Send emails, messages
- transform: Convert data formats
- validate: Check, verify results

For each subtask specify:
- type: one of the task types above
- description: what to do
- dependencies: list of subtask IDs this depends on (empty if none)
- capabilities: required AI capabilities (reasoning, coding, search, creative, fast, long_context, vision, math)

Respond in JSON format:
{
  "summary": "Brief summary of the plan",
  "subtasks": [
    {
      "id": "1",
      "type": "research",
      "description": "Search for...",
      "dependencies": [],
      "capabilities": ["search"]
    },
    {
      "id": "2", 
      "type": "code",
      "description": "Write code to...",
      "dependencies": ["1"],
      "capabilities": ["coding"]
    }
  ],
  "estimatedCost": 0.05,
  "estimatedTimeSeconds": 120
}

Create 3-10 subtasks. Be specific and actionable.`, query, memoryContext)

	messages := []llm.Message{
		{Role: llm.RoleUser, Content: prompt},
	}

	response, err := client.GenerateText(ctx, llm.StreamRequest{
		Messages: messages,
		Options:  llm.StreamOptions{MaxTokens: 4096},
	})
	if err != nil {
		return p.createDefaultPlan(query), nil
	}

	plan, err := p.parsePlanResponse(response)
	if err != nil {
		return p.createDefaultPlan(query), nil
	}

	plan.Query = query
	plan.ExecutionOrder = p.calculateExecutionOrder(plan.SubTasks)

	return plan, nil
}

func (p *Planner) parsePlanResponse(response string) (*TaskPlan, error) {
	jsonRegex := regexp.MustCompile(`\{[\s\S]*\}`)
	jsonMatch := jsonRegex.FindString(response)
	if jsonMatch == "" {
		return nil, fmt.Errorf("no JSON found in response")
	}

	var rawPlan struct {
		Summary              string  `json:"summary"`
		EstimatedCost        float64 `json:"estimatedCost"`
		EstimatedTimeSeconds int     `json:"estimatedTimeSeconds"`
		SubTasks             []struct {
			ID           string   `json:"id"`
			Type         string   `json:"type"`
			Description  string   `json:"description"`
			Dependencies []string `json:"dependencies"`
			Capabilities []string `json:"capabilities"`
		} `json:"subtasks"`
	}

	if err := json.Unmarshal([]byte(jsonMatch), &rawPlan); err != nil {
		return nil, fmt.Errorf("failed to parse plan JSON: %w", err)
	}

	plan := &TaskPlan{
		Summary:       rawPlan.Summary,
		EstimatedCost: rawPlan.EstimatedCost,
		EstimatedTime: rawPlan.EstimatedTimeSeconds,
		SubTasks:      make([]SubTask, len(rawPlan.SubTasks)),
	}

	for i, st := range rawPlan.SubTasks {
		caps := make([]llm.ModelCapability, len(st.Capabilities))
		for j, c := range st.Capabilities {
			caps[j] = llm.ModelCapability(c)
		}

		plan.SubTasks[i] = SubTask{
			ID:           st.ID,
			Type:         TaskType(st.Type),
			Description:  st.Description,
			Dependencies: st.Dependencies,
			RequiredCaps: caps,
			Status:       StatusPending,
			MaxRetries:   3,
		}
	}

	return plan, nil
}

func (p *Planner) calculateExecutionOrder(subTasks []SubTask) [][]string {
	taskMap := make(map[string]*SubTask)
	for i := range subTasks {
		taskMap[subTasks[i].ID] = &subTasks[i]
	}

	inDegree := make(map[string]int)
	for _, st := range subTasks {
		if _, ok := inDegree[st.ID]; !ok {
			inDegree[st.ID] = 0
		}
		for _, dep := range st.Dependencies {
			inDegree[st.ID]++
			if _, ok := inDegree[dep]; !ok {
				inDegree[dep] = 0
			}
		}
	}

	var order [][]string
	completed := make(map[string]bool)

	for len(completed) < len(subTasks) {
		var wave []string

		for _, st := range subTasks {
			if completed[st.ID] {
				continue
			}

			canExecute := true
			for _, dep := range st.Dependencies {
				if !completed[dep] {
					canExecute = false
					break
				}
			}

			if canExecute {
				wave = append(wave, st.ID)
			}
		}

		if len(wave) == 0 {
			for _, st := range subTasks {
				if !completed[st.ID] {
					wave = append(wave, st.ID)
				}
			}
		}

		for _, id := range wave {
			completed[id] = true
		}

		order = append(order, wave)
	}

	return order
}

func (p *Planner) createDefaultPlan(query string) *TaskPlan {
	queryLower := strings.ToLower(query)

	subTasks := []SubTask{
		{
			ID:           uuid.New().String(),
			Type:         TaskResearch,
			Description:  "Research and gather information about: " + query,
			Dependencies: []string{},
			RequiredCaps: []llm.ModelCapability{llm.CapSearch},
			Status:       StatusPending,
			MaxRetries:   3,
		},
	}

	if strings.Contains(queryLower, "код") || strings.Contains(queryLower, "code") ||
		strings.Contains(queryLower, "приложение") || strings.Contains(queryLower, "app") ||
		strings.Contains(queryLower, "скрипт") || strings.Contains(queryLower, "script") {
		subTasks = append(subTasks, SubTask{
			ID:           uuid.New().String(),
			Type:         TaskDesign,
			Description:  "Design architecture and structure",
			Dependencies: []string{subTasks[0].ID},
			RequiredCaps: []llm.ModelCapability{llm.CapReasoning},
			Status:       StatusPending,
			MaxRetries:   3,
		})
		subTasks = append(subTasks, SubTask{
			ID:           uuid.New().String(),
			Type:         TaskCode,
			Description:  "Generate code implementation",
			Dependencies: []string{subTasks[1].ID},
			RequiredCaps: []llm.ModelCapability{llm.CapCoding},
			Status:       StatusPending,
			MaxRetries:   3,
		})
	}

	if strings.Contains(queryLower, "отчёт") || strings.Contains(queryLower, "report") ||
		strings.Contains(queryLower, "анализ") || strings.Contains(queryLower, "analysis") {
		subTasks = append(subTasks, SubTask{
			ID:           uuid.New().String(),
			Type:         TaskAnalysis,
			Description:  "Analyze gathered information",
			Dependencies: []string{subTasks[0].ID},
			RequiredCaps: []llm.ModelCapability{llm.CapReasoning},
			Status:       StatusPending,
			MaxRetries:   3,
		})
		subTasks = append(subTasks, SubTask{
			ID:           uuid.New().String(),
			Type:         TaskReport,
			Description:  "Generate comprehensive report",
			Dependencies: []string{subTasks[len(subTasks)-1].ID},
			RequiredCaps: []llm.ModelCapability{llm.CapCreative},
			Status:       StatusPending,
			MaxRetries:   3,
		})
	}

	if strings.Contains(queryLower, "email") || strings.Contains(queryLower, "письмо") ||
		strings.Contains(queryLower, "telegram") || strings.Contains(queryLower, "отправ") {
		subTasks = append(subTasks, SubTask{
			ID:           uuid.New().String(),
			Type:         TaskCommunicate,
			Description:  "Send notification/message",
			Dependencies: []string{subTasks[len(subTasks)-1].ID},
			RequiredCaps: []llm.ModelCapability{llm.CapFast},
			Status:       StatusPending,
			MaxRetries:   3,
		})
	}

	plan := &TaskPlan{
		Query:         query,
		Summary:       "Auto-generated plan for: " + query,
		SubTasks:      subTasks,
		EstimatedCost: float64(len(subTasks)) * 0.01,
		EstimatedTime: len(subTasks) * 30,
	}

	plan.ExecutionOrder = p.calculateExecutionOrder(subTasks)

	return plan
}

func (p *Planner) Replan(ctx context.Context, plan *TaskPlan, newContext string) (*TaskPlan, error) {
	completedTasks := make([]SubTask, 0)
	pendingTasks := make([]SubTask, 0)

	for _, st := range plan.SubTasks {
		if st.Status == StatusCompleted {
			completedTasks = append(completedTasks, st)
		} else if st.Status == StatusPending || st.Status == StatusFailed {
			pendingTasks = append(pendingTasks, st)
		}
	}

	completedJSON, _ := json.Marshal(completedTasks)
	pendingJSON, _ := json.Marshal(pendingTasks)

	client, _, err := p.registry.GetBest(llm.CapReasoning)
	if err != nil {
		return plan, nil
	}

	prompt := fmt.Sprintf(`You need to replan a task based on new context.

Original query: %s

Completed subtasks:
%s

Pending subtasks:
%s

New context/feedback:
%s

Adjust the plan. Keep completed tasks, modify or remove pending tasks as needed.
Add new subtasks if the new context requires it.

Respond in the same JSON format as before.`, plan.Query, string(completedJSON), string(pendingJSON), newContext)

	messages := []llm.Message{
		{Role: llm.RoleUser, Content: prompt},
	}

	response, err := client.GenerateText(ctx, llm.StreamRequest{
		Messages: messages,
		Options:  llm.StreamOptions{MaxTokens: 4096},
	})
	if err != nil {
		return plan, nil
	}

	newPlan, err := p.parsePlanResponse(response)
	if err != nil {
		return plan, nil
	}

	newPlan.Query = plan.Query
	newPlan.ExecutionOrder = p.calculateExecutionOrder(newPlan.SubTasks)

	return newPlan, nil
}