package agent

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"strings"

	"github.com/iomodo/staff/llm"
	"github.com/iomodo/staff/tm"
	"golang.org/x/text/cases"
	"golang.org/x/text/language"
)

type Thinker struct {
	roles        []string
	llmProvider  llm.LLMProvider
	model        string // TODO: abstract away in llmProvider
	systemPrompt string // TODO abstract away in llmProvider
	maxTokens    int
	temperature  float64
	logger       *slog.Logger
}

func NewThinker(llmProvider llm.LLMProvider, model string, systemPrompt string, maxTokens int, temperature float64, roles []string, logger *slog.Logger) *Thinker {
	return &Thinker{llmProvider: llmProvider, model: model, maxTokens: maxTokens, temperature: temperature, roles: roles, logger: logger}
}

// shouldGenerateSubtasks determines if a task should be broken down into subtasks using LLM
func (t *Thinker) ShouldGenerateSubtasks(task *tm.Task) bool {
	// Don't generate subtasks for subtasks
	if task.ParentTaskID != "" {
		return false
	}

	// Don't generate if already evaluated
	if task.SubtasksEvaluated {
		return false
	}

	// Ask LLM to decide
	ctx := context.Background()
	decision, err := t.shouldGenerateSubtasks(ctx, task)
	if err != nil {
		t.logger.Warn("Failed to get LLM subtask decision for task",
			slog.String("task_id", task.ID),
			slog.String("error", err.Error()))
		// Fallback to simple heuristics
		return task.Priority == tm.PriorityHigh || len(task.Description) > 200
	}

	task.SubtasksEvaluated = true
	t.logger.Info("LLM subtask decision for task",
		slog.String("task_id", task.ID),
		slog.Bool("needs_subtasks", decision.NeedsSubtasks),
		slog.Int("complexity_score", decision.ComplexityScore),
		slog.String("reasoning", decision.Reasoning))

	return decision.NeedsSubtasks
}

// AnalyzeTaskForSubtasks uses LLM to analyze a task and propose subtasks
func (t *Thinker) GenerateSubtasksForTask(ctx context.Context, task *tm.Task) (*tm.SubtaskAnalysis, error) {
	prompt := buildSubtaskAnalysisPrompt(task)

	req := llm.ChatCompletionRequest{
		Model: t.model,
		Messages: []llm.Message{
			{
				Role:    llm.RoleSystem,
				Content: getSubtaskAnalysisSystemPrompt(t.roles),
			},
			{
				Role:    llm.RoleUser,
				Content: prompt,
			},
		},
		MaxTokens:   &[]int{4000}[0],
		Temperature: &[]float64{0.3}[0],
	}

	resp, err := t.llmProvider.ChatCompletion(ctx, req)
	if err != nil {
		return nil, fmt.Errorf("LLM analysis failed: %w", err)
	}

	if len(resp.Choices) == 0 {
		return nil, fmt.Errorf("no response from LLM")
	}

	// Parse the LLM response
	analysis, err := parseSubtaskAnalysis(resp.Choices[0].Message.Content, task.ID, t.roles, t.logger)
	if err != nil {
		return nil, fmt.Errorf("failed to parse LLM response: %w", err)
	}

	return analysis, nil
}

// generateSolution uses the agent's LLM to generate a solution
func (t *Thinker) GenerateSolution(ctx context.Context, task *tm.Task) (string, error) {
	prompt := buildTaskPrompt(task)

	req := llm.ChatCompletionRequest{
		Model: t.model,
		Messages: []llm.Message{
			{
				Role:    llm.RoleSystem,
				Content: t.systemPrompt,
			},
			{
				Role:    llm.RoleUser,
				Content: prompt,
			},
		},
		MaxTokens:   &t.maxTokens,
		Temperature: &t.temperature,
	}

	resp, err := t.llmProvider.ChatCompletion(ctx, req)
	if err != nil {
		return "", fmt.Errorf("LLM request failed: %w", err)
	}

	if len(resp.Choices) == 0 {
		return "", fmt.Errorf("no response from LLM")
	}

	return resp.Choices[0].Message.Content, nil
}

// ShouldGenerateSubtasks asks LLM whether a task needs subtasks based on existing agents
func (t *Thinker) shouldGenerateSubtasks(ctx context.Context, task *tm.Task) (*tm.SubtaskDecision, error) {
	prompt := buildSubtaskDecisionPrompt(task)

	req := llm.ChatCompletionRequest{
		Model: t.model,
		Messages: []llm.Message{
			{
				Role:    llm.RoleSystem,
				Content: getSubtaskDecisionSystemPrompt(t.roles),
			},
			{
				Role:    llm.RoleUser,
				Content: prompt,
			},
		},
		MaxTokens:   &[]int{1000}[0],
		Temperature: &[]float64{0.3}[0],
	}

	resp, err := t.llmProvider.ChatCompletion(ctx, req)
	if err != nil {
		return nil, fmt.Errorf("LLM decision failed: %w", err)
	}

	if len(resp.Choices) == 0 {
		return nil, fmt.Errorf("no response from LLM")
	}

	// Parse the LLM response
	decision, err := parseSubtaskDecision(resp.Choices[0].Message.Content)
	if err != nil {
		return nil, fmt.Errorf("failed to parse LLM decision: %w", err)
	}

	return decision, nil
}

func buildSubtaskDecisionPrompt(task *tm.Task) string {
	return fmt.Sprintf(`Please evaluate whether the following task needs to be broken down into subtasks:

**Task Title:** %s

**Description:** %s

**Priority:** %s

**Current Status:** %s

Consider:
- Can this be completed by a single agent with existing capabilities?
- Does it require multiple specialized skills?
- Is the scope too large for one person?
- Are there logical components that could be parallelized?

Provide your decision in the JSON format specified in the system prompt.`,
		task.Title,
		task.Description,
		task.Priority,
		task.Status)
}

func getSubtaskDecisionSystemPrompt(roles []string) string {
	availableRoles := strings.Join(roles, ", ")

	return fmt.Sprintf(`You are an expert project manager and task analyst. Your job is to determine whether a task needs to be broken down into subtasks.

Currently available team roles and their capabilities: %s

When evaluating a task, consider:
1. Task complexity and scope
2. Whether multiple specialized skills are needed
3. If the task can be completed by a single agent with current capabilities
4. Whether new agent roles might be needed for specialized skills

Respond with a JSON object in this exact format:
{
  "needs_subtasks": true/false,
  "reasoning": "Clear explanation of why subtasks are or aren't needed",
  "complexity_score": 5,
  "required_skills": ["skill1", "skill2", "skill3"]
}

Complexity score should be 1-10 where:
- 1-3: Simple tasks that can be handled by one agent
- 4-6: Moderate complexity, might benefit from subtasks
- 7-10: Complex tasks that definitely need breaking down

Required skills should list all technical/domain skills needed to complete the task.`, availableRoles)
}

func parseSubtaskDecision(response string) (*tm.SubtaskDecision, error) {
	// Try to extract JSON from the response
	jsonStart := strings.Index(response, "{")
	jsonEnd := strings.LastIndex(response, "}")

	if jsonStart == -1 || jsonEnd == -1 {
		return nil, fmt.Errorf("no JSON found in LLM response")
	}

	jsonStr := response[jsonStart : jsonEnd+1]

	var decision tm.SubtaskDecision
	if err := json.Unmarshal([]byte(jsonStr), &decision); err != nil {
		return nil, fmt.Errorf("failed to unmarshal JSON: %w", err)
	}

	return &decision, nil
}

func buildSubtaskAnalysisPrompt(task *tm.Task) string {
	return fmt.Sprintf(`Please analyze the following task and break it down into subtasks:

**Task Title:** %s

**Description:** %s

**Priority:** %s

**Current Status:** %s

Please analyze this task and provide a detailed breakdown into subtasks. Consider:
- Technical complexity and requirements
- Logical task dependencies 
- Appropriate skill sets needed for each subtask
- Risk factors and potential blockers
- Estimated effort for each component

Provide the analysis in the JSON format specified in the system prompt.`,
		task.Title,
		task.Description,
		task.Priority,
		task.Status)
}

func getSubtaskAnalysisSystemPrompt(roles []string) string {
	availableRoles := strings.Join(roles, ", ")

	return fmt.Sprintf(`You are an expert project manager and technical architect. Your job is to analyze complex tasks and break them down into well-defined subtasks that can be assigned to specialized team members.

Currently available team roles: %s

When analyzing a task, you should:
1. Understand the task requirements and scope
2. Break it down into logical, manageable subtasks
3. Assign each subtask to the most appropriate team role OR propose creating new agents
4. Estimate effort and identify dependencies
5. Provide a clear execution strategy

If you need specialized skills not covered by existing roles, propose new agent creation.

Respond with a JSON object in this exact format:
{
  "analysis_summary": "Brief analysis of the task and approach",
  "subtasks": [
    {
      "title": "Subtask title",
      "description": "Detailed description of what needs to be done",
      "priority": "high|medium|low",
      "assigned_to": "role_name",
      "estimated_hours": 8,
      "dependencies": ["subtask_index_1", "subtask_index_2"],
      "required_skills": ["skill1", "skill2"]
    }
  ],
  "agent_creations": [
    {
      "role": "new_role_name",
      "skills": ["specialized_skill1", "specialized_skill2"],
      "description": "Description of what this agent does",
      "justification": "Why this new agent is needed"
    }
  ],
  "recommended_approach": "High-level strategy for executing these subtasks",
  "estimated_total_hours": 40,
  "risk_assessment": "Potential risks and mitigation strategies"
}

For existing roles, use: %s
For new agents, propose appropriate role names and skill sets.
Dependencies should reference subtask indices (e.g., ["0", "1"] means depends on first and second subtasks).`, availableRoles, availableRoles)
}

func parseSubtaskAnalysis(response string, parentTaskID string, agentRoles []string, logger *slog.Logger) (*tm.SubtaskAnalysis, error) {
	// Try to extract JSON from the response (LLM might wrap it in markdown)
	jsonStart := strings.Index(response, "{")
	jsonEnd := strings.LastIndex(response, "}")

	if jsonStart == -1 || jsonEnd == -1 {
		return nil, fmt.Errorf("no JSON found in LLM response")
	}

	jsonStr := response[jsonStart : jsonEnd+1]

	var rawAnalysis struct {
		AnalysisSummary string `json:"analysis_summary"`
		Subtasks        []struct {
			Title          string   `json:"title"`
			Description    string   `json:"description"`
			Priority       string   `json:"priority"`
			AssignedTo     string   `json:"assigned_to"`
			EstimatedHours int      `json:"estimated_hours"`
			Dependencies   []string `json:"dependencies"`
			RequiredSkills []string `json:"required_skills"`
		} `json:"subtasks"`
		AgentCreations      []tm.AgentCreationProposal `json:"agent_creations"`
		RecommendedApproach string                     `json:"recommended_approach"`
		EstimatedTotalHours int                        `json:"estimated_total_hours"`
		RiskAssessment      string                     `json:"risk_assessment"`
	}

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

	// Convert to our types
	analysis := &tm.SubtaskAnalysis{
		ParentTaskID:        parentTaskID,
		AnalysisSummary:     rawAnalysis.AnalysisSummary,
		AgentCreations:      rawAnalysis.AgentCreations,
		RecommendedApproach: rawAnalysis.RecommendedApproach,
		EstimatedTotalHours: rawAnalysis.EstimatedTotalHours,
		RiskAssessment:      rawAnalysis.RiskAssessment,
	}

	// Convert subtasks
	for _, st := range rawAnalysis.Subtasks {
		priority := tm.PriorityMedium // default
		switch strings.ToLower(st.Priority) {
		case "high":
			priority = tm.PriorityHigh
		case "low":
			priority = tm.PriorityLow
		}

		subtask := tm.SubtaskProposal{
			Title:          st.Title,
			Description:    st.Description,
			Priority:       priority,
			AssignedTo:     st.AssignedTo,
			EstimatedHours: st.EstimatedHours,
			Dependencies:   st.Dependencies,
			RequiredSkills: st.RequiredSkills,
		}

		analysis.Subtasks = append(analysis.Subtasks, subtask)
	}

	// Validate agent assignments and handle new agent creation
	if err := validateAndHandleAgentAssignments(analysis, agentRoles, logger); err != nil {
		logger.Warn("Warning during agent assignment handling", slog.String("error", err.Error()))
	}

	return analysis, nil
}

func validateAndHandleAgentAssignments(analysis *tm.SubtaskAnalysis, agentRoles []string, logger *slog.Logger) error {
	// Collect all agent roles that will be available (existing + proposed new ones)
	availableRoles := make(map[string]bool)
	for _, role := range agentRoles {
		availableRoles[role] = true
	}

	// Add proposed new agent roles
	for _, agentCreation := range analysis.AgentCreations {
		availableRoles[agentCreation.Role] = true

		// Create a subtask for agent creation
		agentCreationSubtask := tm.SubtaskProposal{
			Title:          fmt.Sprintf("Create %s Agent", cases.Title(language.English).String(agentCreation.Role)),
			Description:    fmt.Sprintf("Create and configure a new %s agent with skills: %s. %s", agentCreation.Role, strings.Join(agentCreation.Skills, ", "), agentCreation.Justification),
			Priority:       tm.PriorityHigh, // Agent creation is high priority
			AssignedTo:     "ceo",           // CEO creates new agents
			EstimatedHours: 4,               // Estimated time to set up new agent
			Dependencies:   []string{},      // No dependencies for agent creation
			RequiredSkills: []string{"agent_configuration", "system_design"},
		}

		// Insert at the beginning so agent creation happens first
		analysis.Subtasks = append([]tm.SubtaskProposal{agentCreationSubtask}, analysis.Subtasks...)

		// Update dependencies to account for the new subtask at index 0
		for i := 1; i < len(analysis.Subtasks); i++ {
			for j, dep := range analysis.Subtasks[i].Dependencies {
				// Convert dependency index and increment by 1
				if depIndex := parseDependencyIndex(dep); depIndex >= 0 {
					analysis.Subtasks[i].Dependencies[j] = fmt.Sprintf("%d", depIndex+1)
				}
			}
		}
	}

	// Now validate all assignments against available roles
	defaultRole := "ceo" // fallback role
	if len(agentRoles) > 0 {
		defaultRole = agentRoles[0]
	}

	for i := range analysis.Subtasks {
		if !availableRoles[analysis.Subtasks[i].AssignedTo] {
			logger.Warn("Unknown agent role for subtask, using default",
				slog.String("unknown_role", analysis.Subtasks[i].AssignedTo),
				slog.String("subtask_title", analysis.Subtasks[i].Title),
				slog.String("assigned_role", defaultRole))
			analysis.Subtasks[i].AssignedTo = defaultRole
		}
	}

	return nil
}

func parseDependencyIndex(dep string) int {
	var idx int
	if _, err := fmt.Sscanf(dep, "%d", &idx); err == nil {
		return idx
	}
	return -1 // Invalid dependency format
}

func generateSubtaskPRContent(analysis *tm.SubtaskAnalysis) string {
	var content strings.Builder

	content.WriteString(fmt.Sprintf("# Subtasks Created for Task %s\n\n", analysis.ParentTaskID))
	content.WriteString(fmt.Sprintf("This PR creates **%d individual task files** in `/operations/tasks/` ready for agent assignment.\n\n", len(analysis.Subtasks)))
	content.WriteString(fmt.Sprintf("✅ **Parent task `%s` has been marked as completed** - the complex task has been successfully broken down into actionable subtasks.\n\n", analysis.ParentTaskID))
	content.WriteString(fmt.Sprintf("## Analysis Summary\n%s\n\n", analysis.AnalysisSummary))
	content.WriteString(fmt.Sprintf("## Recommended Approach\n%s\n\n", analysis.RecommendedApproach))
	content.WriteString(fmt.Sprintf("**Estimated Total Hours:** %d\n\n", analysis.EstimatedTotalHours))

	// List the created task files
	content.WriteString("## Created Task Files\n\n")
	for i, subtask := range analysis.Subtasks {
		taskID := fmt.Sprintf("%s-subtask-%d", analysis.ParentTaskID, i+1)
		content.WriteString(fmt.Sprintf("### %d. `%s.md`\n", i+1, taskID))
		content.WriteString(fmt.Sprintf("- **Title:** %s\n", subtask.Title))
		content.WriteString(fmt.Sprintf("- **Assigned to:** %s\n", subtask.AssignedTo))
		content.WriteString(fmt.Sprintf("- **Priority:** %s\n", subtask.Priority))
		content.WriteString(fmt.Sprintf("- **Estimated Hours:** %d\n", subtask.EstimatedHours))
		content.WriteString(fmt.Sprintf("- **Description:** %s\n\n", subtask.Description))
	}

	if analysis.RiskAssessment != "" {
		content.WriteString(fmt.Sprintf("## Risk Assessment\n%s\n\n", analysis.RiskAssessment))
	}

	content.WriteString("## Proposed Subtasks\n\n")

	for i, subtask := range analysis.Subtasks {
		content.WriteString(fmt.Sprintf("### %d. %s\n", i+1, subtask.Title))
		content.WriteString(fmt.Sprintf("- **Assigned to:** %s\n", subtask.AssignedTo))
		content.WriteString(fmt.Sprintf("- **Priority:** %s\n", subtask.Priority))
		content.WriteString(fmt.Sprintf("- **Estimated Hours:** %d\n", subtask.EstimatedHours))

		if len(subtask.Dependencies) > 0 {
			deps := strings.Join(subtask.Dependencies, ", ")
			content.WriteString(fmt.Sprintf("- **Dependencies:** %s\n", deps))
		}

		content.WriteString(fmt.Sprintf("- **Description:** %s\n\n", subtask.Description))
	}

	content.WriteString("---\n")
	content.WriteString("*Generated by Staff AI Agent System*\n\n")
	content.WriteString("**Instructions:**\n")
	content.WriteString("- Review the proposed subtasks\n")
	content.WriteString("- Approve or request changes\n")
	content.WriteString("- When merged, the subtasks will be automatically created and assigned\n")

	return content.String()
}

// buildTaskPrompt creates a detailed prompt for the LLM
func buildTaskPrompt(task *tm.Task) string {
	return fmt.Sprintf(`Task: %s

Priority: %s
Description: %s

Please provide a complete solution for this task. Include:
1. Detailed implementation plan
2. Code changes needed (if applicable)
3. Files to be created or modified
4. Testing considerations
5. Any dependencies or prerequisites

Your response should be comprehensive and actionable.`,
		task.Title,
		task.Priority,
		task.Description)
}